stilbenes and 3-3--4-5--tetrahydroxystilbene

The skin is the largest organ of the human body and has several functions such as barrier against external agents, the maintenance of temperature and homeostatic functions. Skin ageing is a natural process that can be influenced by environmental factors, intrinsic skin factors and lifestyle. UV light plays an important role in skin ageing and can cause spots, requiring the use of depigmenting agents. Nowadays, there is a great demand for ingredients that prevent skin ageing, with natural agents occupying a promising position. Among the natural agents, polyphenols, such as resveratrol and piceatannol, found in grapes, passion fruits and other fruits, have a huge relevance. Great benefits of piceatannol have been reported, so thus, this work focuses specifically on a review of the literature regarding the application of this polyphenol in skin care products. This polyphenol can be used in a wound-healing, or as anti-ageing, antioxidant, anti-acne and skin whitening, among other effects.

Topics: Antioxidants; Humans; Resveratrol; Skin; Stilbenes

Cardiovascular disease is a global health problem. According to the World Health Organization, ischemic heart disease was the leading cause of death globally in 2019, followed by stroke. The French paradox, which has been known since the early 1990s, describes the lower incidence of ischemic heart disease in French people despite the consumption of a diet rich in saturated fatty acids. This phenomenon has been attributed to the high intake of red wine, which is rich in polyphenols, namely, resveratrol and piceatannol. It is becoming clear that scirpusin B, a dimer of piceatannol, has anti-atherosclerotic properties such as vasodilation, antioxidant effects, and suppression of postprandial hyperglycemia; nonetheless, the effects of scirpusin B on the cardiovascular system have not been fully elucidated. This review aimed to describe the cardiovascular effects of piceatannol and scirpusin B on aortic and coronary artery dilation and cardiac function and to outline the cardiovascular effects of prostacyclin and nitric oxide, as these substances are involved in the vasodilatory effects exerted by these polyphenols.

Topics: Benzofurans; Cardiovascular System; Fruit; Humans; Passiflora; Polyphenols; Seeds; Stilbenes

The World Health Organization (WHO) has documented that cancer is the second foremost reason for death worldwide. Various factors are responsible for cancer, for instance, exposure to different physical, chemical and biological carcinogens, infections, hereditary, poor dietary habits and lifestyle etc. Cancer is a preventable disease if detected at an early stage; however, most of the cases of cancer are diagnosed at an incurable advanced or metastatic stage. According to WHO about 70 % of deaths due to cancer occur in countries with low- or middle-income. The major problems associated with the conventional therapies are cancer recurrence, development of chemoresistance, affordability, late-stage diagnosis, adverse side effects and inaccessible treatment. Thus, there is an urgent need to find alternative treatment modalities, which have easy accessibility and are affordable with minimum side effects. In this article, we reviewed the natural stilbene known as "Piceatannol" for its anticancer properties. Numerous preclinical studies have reported the potential of Piceatannol to prevent or impede the growth of various cancers originating from different organs such as brain, breast, cervical, colon, liver, lung, prostate, skin, etc. The current review primarily emphasises on the insights of Piceatannol source, chemistry, and the molecular mechanisms involved in the regression of the tumor. This review supports Piceatannol as a potential anticancer and chemopreventive agent and suggests that it can be effectively employed as a capable anti-cancer drug.

Topics: Antineoplastic Agents, Phytogenic; Humans; Molecular Structure; Molecular Targeted Therapy; Neoplasms; Protein Kinase Inhibitors; Protein-Tyrosine Kinases; Stilbenes

Topics: Animals; Benzoquinones; Biological Products; Biomimetics; Caffeic Acids; Curcumin; Cytokines; Exosomes; Humans; Inflammation; Inflammatory Bowel Diseases; Insecta; Macromolecular Substances; Nanomedicine; Oxidative Stress; Phenylethyl Alcohol; Phytochemicals; Plant Extracts; Polysaccharides; Quercetin; Resveratrol; Stilbenes; Transcription Factors; Translational Research, Biomedical; Vasoactive Intestinal Peptide; Zingiber officinale

With the recent technological advancements, a new golden era of natural products drug discovery has dawned. Increasingly it is being realized that structural modularity of many pharmacologically active products derived natural sources allows a building-block approach which can be exploited for analysis of regulation of deregulated oncogenic protein networks in different cancers. Piceatannol has been shown to effectively modulate JAK/STAT, Wnt/β-catenin, mTOR pathway in different cancers. In addition, certain hints have emerged which shed light on the regulation of microRNAs by piceatannol in some cancers. Regulation of deregulated oncogenic pathways by Piceatannol is gradually capturing attention and might be helpful in the multi-targeting of deregulated oncogenic networks in cancers.

Topics: Animals; beta Catenin; Humans; Janus Kinases; Medical Oncology; Neoplasms; Signal Transduction; STAT Transcription Factors; Stilbenes; Wnt Proteins

Stilbenoids are a group of naturally occurring phenolic compounds found in various plant species. They share a common backbone structure known as stilbene. However, differences in the nature and position of substituents have made it possible to produce many derivatives. Piceatannol [PT], a hydroxylated derivative from resveratrol, exerts various biological activities ranging from cancer prevention, cardio- protection, neuro-protection, anti-diabetic, depigmentation and so on. Although positive results were obtained in most cell culture and animal studies, the relevant cellular and molecular mechanisms of cytokines and signaling pathway about their biological effects still unclear. Thus, in the current review, we focus on the latest findings of PT on cellular biology in order to better understand the underlying therapeutic mechanisms of PT among various diseases.

Topics: Animals; Cardiovascular Diseases; Cell Cycle; Fabaceae; Humans; Neoplasms; Neuroprotection; Phytotherapy; Protein Kinase Inhibitors; Resveratrol; Signal Transduction; Stilbenes

Topics: Animals; Antineoplastic Agents; B7-H1 Antigen; Humans; Neoplasms; Resveratrol; Stilbenes

Resveratrol (3,5,4'-trihydroxystilbene) and piceatannol (3,5,3',4'-tetrahydroxystilbene) are well-known natural products that are produced by plants. They are important ingredients in pharmaceutical industries and nutritional supplements. They display a wide spectrum of biological activity. Thus, the needs for these compounds are increasing. The natural products have been found in diverse plants, mostly such as grapes, passion fruit, white tea, berries, and many more. The extraction of these products from plants is quite impractical because of the low production in plants, downstream processing difficulties, chemical hazards, and environmental issues. Thus, alternative production in microbial hosts has been devised with combinatorial biosynthetic systems, including metabolic engineering, synthetic biology, and optimization in production process. Since the biosynthesis is not native in microbial hosts such as Escherichia coli, Saccharomyces cerevisiae, and Corynebacterium glutamicum, genetic engineering and manipulation have made it possible. In this review, the discussion will mainly focus on recent progress in production of resveratrol and piceatannol, including the various strategies used for their production.

Topics: Biosynthetic Pathways; Corynebacterium glutamicum; Escherichia coli; Metabolic Engineering; Microorganisms, Genetically-Modified; Resveratrol; Saccharomyces cerevisiae; Stilbenes; Synthetic Biology

Stilbenoids are a group of naturally occurring phenolic compounds found in various plant species. They share a common backbone structure known as stilbene, but differ in the nature and position of substituents. Stilbenoids are classified as phytoalexins, which are antimicrobial compounds produced de novo in plants to protect against fungal infection and toxins. In this review, the biological effects of stilbenoids such as resveratrol, pterostilbene, gnetol and piceatannol are discussed. Stilbenoids exert various biological activities ranging from cardioprotection, neuroprotection, anti-diabetic properties, depigmentation, anti-inflammation, cancer prevention and treatment. The results presented cover a myriad of models, from cell culture to animal studies as well as clinical human trials. Although positive results were obtained in most cell culture and animal studies, further human studies are needed to substantiate beneficial effects of stilbenoids. Resveratrol remains the most widely studied stilbenoid. However, there is limited information regarding the potential of less common stilbenoids. Therefore, further research is warranted to evaluate the salutary effects of various stilbenoids.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Antineoplastic Agents, Phytogenic; Cardiotonic Agents; Cell Line, Tumor; Humans; Hypoglycemic Agents; Models, Animal; Neuroprotective Agents; Resveratrol; Stilbenes

A number of independent studies have shown the contribution of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in the pathogenesis of several neurodegenerative disorders. Indeed, GAPDH aggregates have been found in many post-mortem samples of brains of patients diagnosed with Alzheimer's and Parkinson disease. Currently, it is accepted that GAPDH-mediated cell death pathways in the neurodegenerative processes are associated with apoptosis caused by GAPDH nuclear translocation and excessive aggregation under oxidative stress conditions. Also the role of GAPDH in neurodegenerative diseases is linked to it directly binding to specific amyloidogenic proteins and petides such as β-amyloid precursor protein, β-amyloid peptide and tau protein in Alzheimer's disease, huntingtin in Huntington's disease and α-synuclein in Parkinson disease. One of the latest studies indicated that GAPDH aggregates significantly accelerate amyloidogenesis of the β-amyloid peptide, which implies that aggregates of GAPDH may act as a specific aggregation "seed" in vitro. Previous detailed studies revealed that the active-site cysteine (Cys152) of GAPDH plays an essential role in the oxidative stress-induced aggregation of GAPDH associated with cell death. Furthermore, oxidative modification of this cysteine residue initiates the translocation of the enzyme to the nucleus, subsequently leading to apoptosis. The crystallographic structure of GAPDH shows that the Cys152 residue is located close to the surface of the molecule in a hydrophilic environment, which means that it can react with low molecular weight compounds such as hydroxynonenal or piceatannol. Therefore, it is highly possible that GAPDH may serve as a target for small molecule compounds with the potential to slow down or prevent the progression of neurodegenerative disorders. Recently appearing new evidence has highlighted the significance of low molecular weight compounds in counteracting the oxidation of GAPDH and consequently its aggregation and other unfavourable pathological processes. Hence, this review aims to present all recent findings concerning molecules that are able to interact with GAPDH and counteract its aggregation and translocation to the nucleus.

Topics: Active Transport, Cell Nucleus; Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Apoptosis; Glyceraldehyde-3-Phosphate Dehydrogenases; Humans; Neurodegenerative Diseases; Oxidative Stress; Protein Aggregation, Pathological; Protein Structure, Secondary; Protein Structure, Tertiary; Stilbenes; tau Proteins

Metabolic disease comprises a set of risk factors highly associated with obesity and insulin resistance and is a consequence of central adiposity, hyperglycemia, and dyslipidemia. Furthermore, obesity increases the risk of the development of metabolic disease due to ectopic fat deposition, low-grade inflammation, and systemic energy disorders caused by dysregulated adipose tissue function. Piceatannol is a naturally occurring polyphenolic stilbene found in various fruits and vegetables and has been reported to exhibit anticancer and anti-inflammatory properties. In addition, recently reported beneficial effects of piceatannol on hypercholesterolemia, atherosclerosis, and angiogenesis underscore its therapeutic potential in cardiovascular disease. However, investigation of its role in metabolic disease is still in its infancy. This review intensively summarizes in vitro and in vivo studies supporting the potential therapeutic effects of piceatannol in metabolic disease, including inhibition of adipogenesis and lipid metabolism in adipocytes, and regulation of hyperlipidemia, hyperglycemia, insulin resistance, and fatty acid-induced inflammation and oxidative stress.

Topics: Animals; Humans; Metabolic Diseases; Plant Extracts; Stilbenes

Cancer is a diverse class of diseases characterized by uncontrolled cell growth that constitutes the greatest cause of mortality and morbidity worldwide. Despite steady progress, the treatment modalities of cancer are still insufficient. Several new concepts have emerged for therapeutic intervention in malignant diseases with the goal of identifying specific targets and overcoming resistance against current cytotoxic therapies. Many studies have reported the remarkable and significant properties of dietary plant polyphenols such as curcumin, resveratrol, flavopiridol, indirubin, magnolol, piceatannol, parthenolide, epigallocatechin gallate, and cucurbitacin as anticancer agents known for their pleiotropic effects on cancer, immune cells, and inflammation. Piceatannol, an analogue and metabolite of resveratrol, is a natural stilbene commonly found in grape skins and wine. Compared to resveratrol, this molecule exhibits superior bioactivities as an inhibitor of COX-1/2 and the CSN-associated kinase. Piceatannol is thought to be a potent natural compound with many therapeutic effects, such as the prevention of hypercholesterolemia, arrhythmia, atherosclerosis, angiogenesis, and cardiovascular diseases. It also demonstrates vasorelaxation, antioxidant, and anticancer activities. This comprehensive review summarizes the current data regarding the mechanisms of action of piceatannol, its chemopreventive properties, and its possible therapeutic potential against various types of human cancer.

Topics: Animals; Antineoplastic Agents, Phytogenic; Cell Line, Tumor; Humans; Neoplasms; Resveratrol; Stilbenes

The incidence of cardiovascular diseases (CVDs) is high in both developed and developing countries. It has a high global rate of mortality and causes heavy social burden. Drugs are available for managing or treating CVDs and its complications. Consumption of dietary supplements or functional foods for reducing the risk of CVDs has also gained wide recognition by the general public. Piceatannol, an analog and metabolite of resveratrol, is a natural stilbene commonly found in the skin of grapes and wine. Piceatannol is believed to be a potent compound with certain cardiovascular therapeutic effects, such as the prevention of hypercholesterolemia, arrhythmia, atherosclerosis, and angiogenesis. It also has vasorelaxation and antioxidant activities. A comprehensive review of piceatannol concludes that piceatannol has the potential to be developed into health products for the cardiovascular system to help modern society reduce the high CVD incidence. However, further investigations are warranted in order to increase the bioavailability and understand the biological mechanisms and safety of using piceatannol.

Topics: Animals; Cardiovascular Diseases; Humans; Stilbenes

Dietary stilbenes comprise a class of natural compounds that display significant biological activities of medicinal interest. Among them, their antioxidant, anti-aging and anti-angiogenesic properties are well established and subjects of numerous research endeavors. This mini-review aspires to account and present the literature reports published on research concerning various natural and synthetic stilbenes, such as trans-resveratrol. Special focus was given to most recent research findings, while the mechanisms underlying their anti-aging and anti-angiogenic effects as well as the respective signaling pathways involved were also presented and discussed.

Topics: Aging; Angiogenesis Inhibitors; Animals; Antineoplastic Agents, Phytogenic; Benzofurans; Dibenzocycloheptenes; Dietary Supplements; Humans; Plants; Resorcinols; Resveratrol; Rodentia; Stilbenes

Resveratrol is considered to have a number of beneficial effects. Recently, our group modified the molecule and synthesized a number of compounds with different biochemical effects. Polymethoxy and polyhydroxy derivatives of resveratrol were shown to inhibit tumor cell growth in various cell lines and inflammation pathways (cyclooxygenases activity), in part more effectively than resveratrol itself. One lead compound (hexahydroxystilbene, M8) turned out to be the most effective inhibitor of tumor cell growth and of cyclooxygenase 2 activity. M8 was then studied in two different human melanoma mouse models. This novel resveratrol analog was able to inhibit melanoma tumors in a primary tumor model alone and in combination with dacarbacine, an anticancer compound that is used for melanoma treatment. We also tested the development of lymph node metastasis in a second melanoma model and again M8 successfully inhibited the tumor as well as the size and weight of lymph node metastasis. Hydroxylated resveratrol analogs therefore represent a novel class of anticancer compounds and promising candidates for in vivo studies.

Topics: Animals; Antineoplastic Agents, Phytogenic; Chemoprevention; Humans; Neoplasms; Resveratrol; Stilbenes; Structure-Activity Relationship

Oral squamous cell carcinoma ranks among the top ten most common cancers worldwide. Despite the success in diagnosis and therapy during the past 30 years, oral squamous cell carcinoma still belongs to the tumor types with a very unfavorable prognosis. In an effort to identify genomic alterations with prognostic relevance, we applied the comparative genomic hybridization technique on oral squamous cell carcinoma. The tumors exhibited from five up to 47 DNA copy number alterations, indicating a considerable degree of genomic imbalance. Out of 35 tumors, 19 showed a gain of chromosome band 7p12. Genomic imbalances were investigated by hierarchical cluster analysis and clustered image mapping to investigate whether genomic profiles correlate with clinical data. Results of the present investigation show that profiling of genomic imbalances in general, and especially of the epidermal growth factor receptor (EGFR) on 7p12, may be suitable as prognostic factors. In order to identify small-molecule inhibitors for EGFR, we established a database of 531 natural compounds derived from medicinal plants used in traditional Chinese medicine. Candidate compounds were identified by correlation analysis using the Kendall tau-test of IC50 values of tumor cell lines and microarray-based EGFR mRNA expression. Further validation was performed by molecular docking studies using the AutoDock program with the crystal structure of EGFR tyrosine kinase domain as docking template. We estimate these results will be a further step toward the ultimate goal of individualized, patient-adapted tumor treatment based on tumor molecular profiling.

Topics: Age Factors; Alcohol Drinking; Antineoplastic Agents; Aporphines; Azo Compounds; Berberine; Carcinoma, Squamous Cell; Chromosome Aberrations; Crystallography, X-Ray; Databases, Factual; DNA, Neoplasm; Drug Screening Assays, Antitumor; Drugs, Chinese Herbal; ErbB Receptors; Erlotinib Hydrochloride; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Genes, erbB-1; Humans; Mouth Neoplasms; Neoplasm Proteins; Nucleic Acid Hybridization; Polymorphism, Single Nucleotide; Prognosis; Protein Kinase Inhibitors; Quinazolines; Risk Factors; Smoking; Stilbenes; Structure-Activity Relationship

Stilbenes are small molecular weight (approximately 200-300 g/mol), naturally occurring compounds and are found in a wide range of plant sources, aromatherapy products, and dietary supplements. These molecules are synthesized via the phenylpropanoid pathway and share some structural similarities to estrogen. Upon environmental threat, the plant host activates the phenylpropanoid pathway and stilbene structures are produced and subsequently secreted. Stilbenes act as natural protective agents to defend the plant against viral and microbial attack, excessive ultraviolet exposure, and disease. One stilbene, resveratrol, has been extensively studied and has been shown to possess potent anti-cancer, antiinflammatory and anti-oxidant activities. Found primarily in the skins of grapes, resveratrol is synthesized by Vitis vinifera grapevines in response to fungal infection or other environmental stressors. Considerable research showing resveratrol to be an attractive candidate in combating a wide variety of cancers and diseases has fueled interest in determining the disease-fighting capabilities of other structurally similar stilbene compounds. The purpose of this review is to describe four such structurally similar stilbene compounds, piceatannol, pinosylvin, rhapontigenin, and pterostilbene and detail some current pharmaceutical research and highlight their potential clinical applications.

Topics: Humans; Resveratrol; Stilbenes

Stilbenes are natural compounds occurring in a number of plant families, including Vitaceae and (within this family) Vitis vinifera L., which is the most important species grown worldwide for grape and wine production. Stilbenes (resveratrol and viniferins) are present in grapevine as constitutive compounds of the woody organs (roots, canes, stems) and as induced substances (in leaves and fruit) acting as phytoalexins in the mechanisms of grape resistance against certain pathogens. Resveratrol (3, 5, 4'-trihydroxystilbene) was also detected in wine and it was thought to be the active principle of red wines that were shown to reduce heart diseases. This paper reviews data, obtained by the Viticulture Institute of the Catholic University at Piacenza and taken from the literature, on some aspects of stilbene physiology in grapevine and on their relation to resveratrol wine levels. Constitutive stilbene contents of woody organs are reported, as well as the possible role of cluster stems as a source of resveratrol for wine. The accumulation of stilbenes in grape berries infected by grey mould (Botrytis cinerea Pers.) has been investigated and the effects of environmental factors on resveratrol grape and wine levels will be discussed. An unidentified new hydroxystilbene was detected in wine.

Topics: Anti-Infective Agents; Chromatography, High Pressure Liquid; Phytoalexins; Plant Extracts; Platelet Aggregation Inhibitors; Rosales; Sesquiterpenes; Stilbenes; Terpenes; Wine

Piceatannol has been reported to have a wide variety of effects on the skin, including promoting collagen production, inhibiting melanin synthesis, inducing the antioxidant glutathione, and eliminating reactive oxygen species. In this study, a randomized, placebo-controlled, double-blind trial was conducted to clinically evaluate the effects of piceatannol-rich passion fruit seed extract on the skin of healthy Japanese women (age, 35-54 y). Thirty-two women with dry skin received either passion fruit seed extract (5 mg piceatannol) or a placebo (dextrin) for 8 wk. Skin hydration and other parameters on the face were assessed at 0, 4, and 8 wk by using specialized equipment. Furthermore, questionnaire interviews were conducted regarding the physical condition of subjects at 0, 4, and 8 wk. The results showed that consumption of passion fruit seed extract led to significant increases in the moisture content of human skin after 4 and 8 wk compared with that before the trial. The amount of transepidermal water loss decreased over time, although the differences were not significant. Moreover, a stratified analysis of subjects with moisture values of ≤200 μS revealed increased moisture content in the passion fruit seed extract group as compared with the placebo group. Furthermore, the results of questionnaires showed significant reductions in "perspiration" and "fatigue" in the passion fruit seed extract group as compared with the placebo group. These results indicate that oral intake of passion fruit seed extract that is rich in piceatannol could improve the moisture of dry skin and reduce fatigue.

Topics: Adult; Antioxidants; Double-Blind Method; Feces; Female; Humans; Middle Aged; Passiflora; Plant Extracts; Seeds; Skin; Stilbenes; Surveys and Questionnaires

Animal studies have shown the beneficial effects of piceatannol on metabolic health; however, there is a lack of human studies designed to examine these effects. The objective of this study was to investigate the effects of piceatannol on metabolic health in humans. This randomized, placebo-controlled study was conducted on 39 subjects, including 10 overweight men and 9 overweight women (BMI ≥ 25), as well as 10 non-overweight men and 10 non-overweight women (BMI < 25). Subjects received piceatannol (20 mg/day) or placebo capsules for eight weeks in a random order. The primary outcome was the effect of piceatannol on glucose-metabolism, including insulin sensitivity. The secondary outcomes were the effects on other parameters, including blood pressure (BP), heart rate (HR), endothelial function, lipids, inflammation, oxidative stress, mood status, and Sirt1 and phospho-AMP-activated kinase (p-AMPK) expression in isolated peripheral blood mononuclear cells (PBMNCs). Supplementation with piceatannol in overweight men reduced serum insulin levels, HOMA-IR, BP and HR. Other groups, including non-overweight men, as well as overweight and non-overweight women, showed no beneficial effects on insulin sensitivity, BP and HR. Furthermore, piceatannol is not associated with other data, including body weight (BW), body composition, endothelial function, lipids, inflammation, oxidative stress, mood status, and Sirt1/p-AMPK expression in PBMNCs. In conclusion, supplementation with piceatannol can improve metabolic health, including insulin sensitivity, BP and HR, in overweight men.

Topics: Administration, Oral; Adult; Aged; Biomarkers; Blood Pressure; Capsules; Double-Blind Method; Energy Metabolism; Female; Health Status; Heart Rate; Humans; Insulin Resistance; Japan; Male; Middle Aged; Overweight; Passiflora; Phytotherapy; Plants, Medicinal; Seeds; Stilbenes; Time Factors; Treatment Outcome; Young Adult

Stilbenoids are anti-inflammatory and antioxidant compounds, with resveratrol being the most investigated molecule in this class. However, the actions of most other stilbenoids are much less studied. This study compares five monomeric (resveratrol, piceatannol, pterostilbene, pinostilbene, and trimethoxy-resveratrol) and two dimeric (dehydro-δ-viniferin and

Topics: Animals; Antioxidants; Bone Marrow; Cytokines; Dendritic Cells; Escherichia coli; Interleukin-10; Interleukin-12; Lipopolysaccharides; Mice; Reactive Oxygen Species; Resveratrol; Stilbenes; Tumor Necrosis Factor-alpha

Rheum lhasaense A. J. Li et P. K. Hsiao, a stout herb plant from the Polygonaceae, is a typical Tibetan folk herb with heat-clearing and detoxifying effects, but does not have the typical laxative effect compared with other rhubarb plants. Nevertheless, its chemical composition and pharmacological activities still lack in-depth research. The present study endeavored to analyze the possible phytochemical constituents in R. lhasaense and explore the main compound piceatannol-3'-O-β-D-glucopyranoside (PG) effect on cognitive impairment and its underlying mechanism. The chemical profile of R. lhasaense discovered 46 compounds, including 27 stilbenoids and 13 gallotannins using UPLC-Q-TOF-MS/MS. The UPLC determined the contents of 6 main stilbenoids, among which the content of PG was the highest, up to 61.06 mg/g. Moreover, behavioral tests showed that PG (40 mg/kg and 160 mg/kg) administration markedly ameliorated memory impairments of scopolamine-induced mice. Biochemical parameters showed that PG treatment alleviated the levels of Ach, AchE, and inflammatory factors while elevating the levels of antioxidants in mice. In addition, network pharmacology was performed to reveal PG exert an mild cognitive impairment effect by participating in neurodegenerative disease pathways, proliferation and apoptosis-, and inflammation-related pathways. Eventually, the results of molecular docking and the qRT-PCR revealed that PG down-regulated the mRNA expressions of MMP3, MMP9 and BACE1 in cognitive impairment mice brain tissue. In conclusion, our results demonstrated that PG mitigated scopolamine-induced cognitive dysfunction in mice by targeting the BACE1-MMP3/9 pathway, and PG might be a promising mild AD drug candidate.

Topics: Amyloid Precursor Protein Secretases; Animals; Aspartic Acid Endopeptidases; Matrix Metalloproteinase 3; Mice; Molecular Docking Simulation; Neurodegenerative Diseases; Rheum; Scopolamine Derivatives; Stilbenes; Tandem Mass Spectrometry

This paper discusses the possibility of using plant polyphenols as viral fusion inhibitors with a lipid-mediated mechanism of action. The studied agents are promising candidates for the role of antiviral compounds due to their high lipophilicity, low toxicity, bioavailability, and relative cheapness. Fluorimetry of calcein release at the calcium-mediated fusion of liposomes, composed of a ternary mixture of dioleoyl phosphatidylcholine, dioleoyl phosphatidylglycerol, and cholesterol, in the presence of 4'-hydroxychalcone, cardamonin, isoliquiritigenin, phloretin, resveratrol, piceatannol, daidzein, biochanin A, genistein, genistin, liquiritigenin, naringenin, catechin, taxifolin, and honokiol, was performed. It was found that piceatannol significantly inhibited the calcium-induced fusion of negatively charged vesicles, while taxifolin and catechin showed medium and low antifusogenic activity, respectively. As a rule, polyphenols containing at least two OH-groups in both phenolic rings were able to inhibit the calcium-mediated fusion of liposomes. In addition, there was a correlation between the ability of the tested compounds to inhibit vesicle fusions and to perturb lipid packing. We suggest that the antifusogenic action of polyphenols was determined by the depth of immersion and the orientation of the molecules in the membrane.

Topics: Calcium; Catechin; Flavonoids; Hydroxylation; Lipids; Liposomes; Membrane Fusion; Polyphenols; Stilbenes

Subarachnoid hemorrhage (SAH) accounts for 5% of all stroke cases and is responsible for significant permanent brain and neurological damage within the first few days. Loss of smell is one of those neurological disorders following olfactory bulb injury after SAH. Olfaction plays a critical role in several aspects of life. The primary underlying mechanism of olfactory bulb (OB) injury and loss of smell after SAH remains unknown. Piceatannol (PIC), a natural stilbene, possesses anti-inflammatory and anti-apoptotic effects against various diseases. In this study, we aimed to investigate the potential therapeutic effects of PIC on OB injury following SAH at molecular mechanism based on SIRT1, inflammatory (TNF-α, IL1-β, NF-κB, IL-6, TLR4), and apoptosis (p53, Bax, Bcl-2, caspase-3)-related gene expression markers and histopathology level; 27 male Wistar Albino rats were used in a pre-chiasmatic subarachnoid hemorrhage model. Animals were divided into groups (n = 9): SHAM, SAH, and PIC. Garcia's neurological examination, brain water content, RT-PCR, histopathology, and TUNEL analyses were performed in all experimental groups with OB samples. Our results indicated that PIC administration significantly suppressed inflammatory molecules (TNF-α, IL-6, IL1-β, TLR4, NF-κB, SIRT1) and apoptotic molecules (caspase-3, p53, Bax). We also evaluated edema levels and cell damage in OB injury after SAH. Ameliorative effects of PIC are also observed at the histopathology level. Garcia's neurological score test performed a neurological assessment. This study is the first to demonstrate the neuroprotective effects of PIC on OB injury after SAH. It suggests that PIC would be a potential therapeutic agent for alleviating OB injury after SAH.

Topics: Animals; Anosmia; bcl-2-Associated X Protein; Caspase 3; Interleukin-6; Male; Neuroprotective Agents; NF-kappa B; Olfactory Bulb; Rats; Signal Transduction; Sirtuin 1; Stilbenes; Subarachnoid Hemorrhage; Toll-Like Receptor 4; Tumor Necrosis Factor-alpha; Tumor Suppressor Protein p53

The stilbene-rich acetone fraction in high yield (6.6 %, PEAS) of Passiflora edulis Sims was prepared and evaluated for neuroprotective activity in murine Alzheimer's disease model induced by aluminum chloride and D-galactose. The phytochemical and HPLC-DAD-MS analysis of the polyphenolic stilbene-rich acetone fraction showed that it contained different stilbenes including trans-piceatannol, scirpusins A-B and cassigarol E. The total phenolic content (TPC) of PEAS was 413.87±1.71 mg GAE eqv/g. The neuroprotective activity of PEAS is typically presented in the Morris water maze-reference Spatial Memory test, where the Alzheimer's mice treated at 100 mg/kg (Alz-ED1) and 200 mg/kg (Alz-ED2) spent less than 47 % and 66 % of the time, respectively, than the Alzheimer's model mice (Alz). Two simple stilbenes, trans-piceatannol and trans-resveratrol, showed selectively inhibitory activity in silico against acetylcholinesterase (AChE). Two stilbene dimers, cassigarol E and scirpusin A, exhibited low nanomolar inhibitory potential against AChE and butyrylcholinesterase (BChE), significantly lower than those of the positive control, donepezil and tacrine. These findings suggest that the stilbenes from P. edulis seeds, particularly the stilbene dimers, warrant further investigation as potential neuroprotective candidates in the prevention of cognitive deficits associated with Alzheimer's disease.

Topics: Acetone; Acetylcholinesterase; Alzheimer Disease; Animals; Butyrylcholinesterase; Cholinesterase Inhibitors; Mice; Passiflora; Plant Extracts; Seeds; Stilbenes

Evidence shows that the dietary intake of polycyclic aromatic hydrocarbons (PAHs) from food processing induces the cellular DNA damage response and leads to the development of colorectal cancer (CRC). Therefore, protecting from cellular DNA damage might be an effective strategy in preventing CRC. Benzo[

Topics: Antioxidants; Benzo(a)pyrene; DNA Damage; Epithelial Cells; Glutathione; Humans; NF-E2-Related Factor 2; Reactive Oxygen Species; Stilbenes

Given the magnitude of influenza pandemics as a threat to the global population, it is crucial to have as many prevention and treatment options as possible. Piceatannol (PIC) is a tetrahydroxylated stilbenoid (trans-3,4,3',5'-tetrahydroxystilbene), also known as 3'- hydroxy resveratrol, which has demonstrated many different biological activities such as anti-inflammatory and antiviral activities.. In this study, the anti-influenza A virus (IAV) activities and mechanisms of PIC in vitro and in vivo were investigated in order to provide reference for the development of novel plant-derived anti-IAV drugs.. The viral plaque assay, RT-PCR and western blot assay were used to evaluate the anti-IAV effects of PIC in vitro. The anti-IAV mechanism of PIC was determined by HA syncytium assay, DARTS assay and Surface Plasmon Resonance assay. The mouse pneumonia model combined with HE staining were used to study the anti-IAV effects of PIC in vivo.. PIC shows inhibition on the multiplication of both H1N1 and H3N2 viruses, and blocks the infection of H5N1 pseudovirus with low toxicity. PIC may directly act on the envelope of IAV to induce the rupture and inactivation of IAV particles. PIC can also block membrane fusion via binding to HA2 rather than HA1 and cleavage site of HA0. PIC may interact with the two residues (HA2-T68 and HA2-I75) of HA2 to block the conformational change of HA so as to inhibit membrane fusion. Importantly, oral therapy of PIC also markedly improved survival and reduced viral titers in IAV-infected mice.. PIC possesses significant anti-IAV effects both in vitro and in vivo and may block IAV infection mainly through interaction with HA to block membrane fusion. Thus, PIC has the potential to be developed into a new broad-spectrum anti-influenza drug for the prevention and treatment of influenza.

Topics: Animals; Disease Models, Animal; Hemagglutinins; Humans; Influenza A virus; Influenza A Virus, H1N1 Subtype; Influenza A Virus, H3N2 Subtype; Influenza A Virus, H5N1 Subtype; Influenza, Human; Mice; Stilbenes

Dysfunction of the blood-brain barrier (BBB) is involved in the pathogenesis of many cerebral diseases. Oxidative stress and inflammation are contributing factors for BBB injury. Piceatannol, a natural ingredient found in various plants, such as grapes, white tea, and passion fruit, plays an important role in antioxidant and anti-inflammatory responses. In this study, we examined the protective effects of piceatannol on lipopolysaccharide (LPS) insult in mouse brain endothelial cell line (bEnd.3) cells and the underlying mechanisms. The results showed that piceatannol mitigated the upregulated expression of adhesion molecules (ICAM-1 and VCAM-1) and iNOS in LPS-treated bEnd.3 cells. Moreover, piceatannol prevented the generation of reactive oxygen species in bEnd.3 cells stimulated with LPS. Mechanism investigations suggested that piceatannol inhibited NF-κB and MAPK activation. Taken together, these observations suggest that piceatannol reduces inflammation and oxidative stress through inactivating the NF-κB and MAPK signaling pathways on cerebral endothelial cells in vitro.

Topics: Antioxidants; Brain; Cell Adhesion Molecules; Cell Line; Endothelial Cells; Gene Expression Regulation; Inflammation; Lipopolysaccharides; MAP Kinase Signaling System; Molecular Structure; NF-kappa B; Oxidative Stress; Protective Agents; Stilbenes

Rheumatoid arthritis (RA) is a chronic inflammatory disease that mainly targets the synovial membrane, thus causing stiffness, deformity and dysfunction of joints. To date, no effective anti‑inflammatory treatments are available for RA. Piceatannol (PIC) is a natural derivative of resveratrol, which has been reported to attenuate the inflammatory response. To evaluate the effect of PIC on RA and to determine the underlying molecular target of PIC, both

Topics: Animals; Apoptosis; Arthritis, Rheumatoid; Cell Proliferation; Cells, Cultured; Fibroblasts; Humans; Inflammation; MAP Kinase Signaling System; NF-kappa B; Rats; Stilbenes; Synoviocytes

Overly elevated circulating non-esterified fatty acids (NEFAs) is an emerging health concern of obesity-associated energy disorders. However, methods to reduce circulating NEFAs remain elusive. The present study determined the effect of piceatannol, a naturally occurring stilbene, on adipocyte lipolysis and its underlying mechanism. Differentiated 3T3-L1 adipocytes, brown adipocytes and isolated white adipose tissue were treated with various concentrations of piceatannol for 1.5-h both in the basal and stimulated lipolysis conditions. Piceatannol significantly inhibited NEFAs and glycerol release with a concomitant reduction of ATGL, CGI-58 and PLIN1 expression in adipocytes. Using a series of inhibitor assays, piceatannol-induced degradation of these proteins was found to be mediated by upregulation of the autophagy-lysosome pathway. Moreover, we demonstrated that piceatannol is capable of stimulating autophagy in vitro. Importantly, piceatannol administration tended to lower fasting-induced serum glycerol levels in healthy mice. Furthermore, piceatannol administration lowered lipolysis, central adiposity and hyperinsulinemia in diet-induced obese mice. Our study provides profound evidence of a novel inhibitory role of piceatannol in lipolysis through autophagy-lysosome-dependent degradation of the key lipolytic proteins in adipocytes. This study offers a mechanistic foundation for investigating the potential of piceatannol-containing foods in reducing lipolysis and its associated metabolic disorders.

Topics: 3T3-L1 Cells; Adipocytes; Animals; Autophagy; Fatty Acids, Nonesterified; Glycerol; Lipolysis; Lysosomes; Mice; Stilbenes

Endometrial hyperplasia (EH) is the most common risk factor for endometrial malignancy in females. The pathogenesis of EH has been directly linked to uterine inflammation, which can result in abnormal cell division and decreased apoptosis. Piceatannol (PIC), a natural polyphenolic stilbene, is known to exert anti-inflammatory, antioxidant and anti-proliferative activities. The aim of the present study was to examine the potential preventive role of PIC in estradiol benzoate (EB)-induced EH in rats. A self-nanoemulsifying drug delivery system (SNEDDS) was prepared to improve the solubility of the PIC. Therefore, thirty female Wistar rats were divided into five groups: (1) control, (2) PIC SNEDDS (10 mg/kg), (3) EB (0.6 mg/kg), (4) EB + PIC SNEDDS (5 mg/kg) and (5) EB + PIC SNEDDS (10 mg/kg). The administration of PIC SNEDDS prevented EB-induced increases in uterine weights and histopathological changes. Additionally, it displayed pro-apoptotic and antioxidant activity in the endometrium. Immunohistochemical staining of uterine sections co-treated with PIC SNEDDS showed significantly decreased expression of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and nuclear transcription factor-kappa B (NF-κB). This anti-inflammatory effect was further confirmed by a significant increase in Nrf2 and heme oxygenase-1 (HO-1) expression. These results indicate that SNEDDS nanoformulation of PIC possesses protective effects against experimentally induced EH.

Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Endometrial Hyperplasia; Estradiol; Female; Heme Oxygenase-1; Humans; NF-E2-Related Factor 2; NF-kappa B; Oxidative Stress; Rats; Rats, Wistar; Stilbenes

M2 phenotype tumor-associated macrophages (M2-TAMs) play a key role in distant metastasis and poor clinical outcomes. Herein, a specific molecular mechanism that contributes to malignant progression is illuminated and investigates whether piceatannol (PIC) can target the crosstalk between M2-TAMs and cancer cells for potential colorectal cancer (CRC) therapy.. To mimic the tumor microenvironment (TME), direct and indirect coculture systems in vitro and in vivo mouse xenograft models are established. The results demonstrate that post-treatment with PIC in TME more effectively prevented the aggressive features and stemness of SW480 cells by restricting the polarization of M2-like macrophages and blocking the transforming growth factor β1 (TGF-β1) positive feedback autocrine/paracrine loop that exists between M2-like polarized macrophages and cancer cells. Furthermore, xenograft assays also observe significant repression in tumor growth and lung metastases with the administration of PIC. The key mechanism underlying the antimetastasis effects of PIC may include its directly inhibitory activity against TGF-β receptor type-1 (TGF-βR1) in the M2-like TAMs-created TME.. These novel findings demonstrate that PIC is a potent TGF-β1/TGF-βR1 pathway inhibitor and TME modulator for preventing tumor progression and metastasis in CRC by reeducating TAMs.

Topics: Animals; Cell Line, Tumor; Colonic Neoplasms; Feedback; Humans; Mice; Signal Transduction; Stilbenes; Transforming Growth Factor beta1; Tumor Microenvironment; Tumor-Associated Macrophages

Cancer-associated cachexia (CAC) is the nutrition-independent loss of lean muscle and adipose tissues, and results in reduced chemotherapy effectiveness and increased mortality. Preventing adipose loss is considered a key target in the early stages of cachexia. Lipolysis is considered the central driver of adipose loss in CAC. We recently found that piceatannol, but not its analogue resveratrol, exhibits an inhibitory effect on lipolysis. The objective of this study was to investigate the role of piceatannol in cancer-associated lipolysis and cachexia-induced weight loss. Cancer cell-induced lipolysis in adipocytes was stimulated using cancer-conditioned media (CCM) or co-culture with human pancreatic cancer cells and the cachexia-associated cytokines TNF-α and interleukin-6 in 3T3-L1 adipocytes. C26 colon carcinoma-bearing mice were modeled using CAC

Topics: Adipose Tissue; Animals; Cachexia; Colonic Neoplasms; Culture Media, Conditioned; Cytokines; Lipolysis; Mice; Neoplasms; Polyphenols; Stilbenes; Weight Loss

Epilepsy is a common neurological disorder which affects 50 million people worldwide. Patients with epilepsy may present cognitive deficits and psychological impairment. Currently, 30% of patients fail to respond to any available antiseizure drug, and a significant number of patients do not well tolerate the offered treatments. Then, it is necessary to find out alternatives for controlling epileptic seizures. Studies have shown that despite its neuroprotective effects, resveratrol shows poor anticonvulsant properties. Resveratrol analog, piceatannol, possesses higher biological activity than resveratrol and could be an alternative to control seizure. Thus, the present study investigated the effects of resveratrol and piceatannol in pentylenetetrazole-induced seizures in adult zebrafish (Danio rerio). Only the experimental positive control (diazepam) showed anticonvulsant effect in this study. In addition, no behavioral changes were observed 24 h after seizure occurrence. Finally, the expression of genes related to neuronal activity (c-fos), neurogenesis (p70S6Ka and p70S6Kb), inflammatory response (interleukin 1β), and cell apoptosis (caspase-3) did not change by pentylenetetrazole-induced seizures. Therefore, we failed to observe any anticonvulsant and neuroprotective potential of resveratrol and piceatannol in adult zebrafish. However, resveratrol and piceatannol benefits in epilepsy are not discharged, and more studies are necessary.

Topics: Animals; Anticonvulsants; Caspase 3; Diazepam; Epilepsy; Interleukin-1beta; Neuroprotective Agents; Pentylenetetrazole; Resveratrol; Seizures; Stilbenes; Zebrafish

Myricetin (a flavonol) and piceatannol (a stilbenoid) are naturally occurring phenolic compounds in red wine with cardio-protective and anti-carcinogenic effects, but their potential reproductive effects have not been investigated. Thus, the present study was designed to determine if myricetin and piceatannol can directly affect ovarian function using bovine granulosa cells (GC) and theca cells (TC) as in vitro model systems to evaluate effects on cell proliferation and steroid production. In Experiment 1 and 2, myricetin and piceatannol at 30 μM blocked insulin-like growth factor 1 (IGF1)-induced progesterone production by GC without affecting GC numbers. In contrast, myricetin stimulated IGF1-induced estradiol production, whereas piceatannol at 30 μM inhibited IGF1-induced estradiol production by 90% in GC. In Experiment 3 and 4, TC androstenedione and progesterone production and TC proliferation was inhibited by myricetin and piceatannol at 30 μM. In Experiment 5, piceatannol (30 μM) reduced the Fusarium mycotoxin, beauvericin (6 μM)-induced inhibition on progesterone production and cell proliferation. Myricetin (30 μM) reduced the inhibitory effect of beauvericin on estradiol but not progesterone production or cell proliferation. In conclusion, the red wine phenols, myricetin and piceatannol, directly affected GC and TC steroidogenesis, and were able to reduce some of the inhibitory effects of beauvericin on GC function.

Topics: Animals; Cattle; Cell Proliferation; Cells, Cultured; Estradiol; Female; Flavonoids; Granulosa Cells; Phenols; Progesterone; Steroids; Stilbenes; Theca Cells; Vitis

This study aimed to investigate the protective effects of piceatannol (PIC) on selenite-induced cataracts in Sprague-Dawley rats and explore its therapeutic effects as an antioxidant.. This study determined that compared with the model group, the degree of lens opacity was significantly reduced in PIC-treated groups. The histopathological damage of the lenses in the PIC-treated groups improved compared to the model group. There were fewer signs of lesions, such as vacuoles and atrophy. The biochemical results indicated that malondialdehyde (MDA) content of the PIC-treated groups were downregulated and the antioxidant enzyme activities (GSH and catalase) and antioxidant status (SOD) were upregulated compared with the model group.. Pretreatment with piceatannol may achieve a protective effect on cataract development through upregulating antioxidant enzyme activity.

Topics: Animals; Antioxidants; Cataract; Female; Glutathione; Hydrogen Peroxide; Lens, Crystalline; Malondialdehyde; Oxidative Stress; Rats; Rats, Sprague-Dawley; Sodium Selenite; Stilbenes

Pulmonary fibrosis (PF) is characterized by oxidative injury and excessive collagen synthesis in lung fibroblasts, causing impaired pulmonary function and chronic lung injury. Piceatannol, a dietary polyphenol, possesses vital pharmacological effects in metabolic disorders, cancers, cardiovascular disease and infectious disease; however, its role in PF is still not completely elucidated. Mice (8 to 10 weeks old) were administered bleomycin (BLM) intratracheally (2 U/kg) to establish an in vivo PF model. Murine primary lung fibroblasts were isolated and stimulated with TGF-β (10 ng/mL) for 48 h to induce its activation. Meanwhile, mice or primary lung fibroblasts were treated with different doses of piceatannol to observe its protective roles. Pulmonary function and arterial blood gas were detected to assess pulmonary physiological status. Collagen deposition and the mRNA levels of profibrotic genes were determined by H&E staining and RT-PCR. Meanwhile, the protein and mRNA markers, as well as end-product of oxidative stress were detected in vivo and in vitro. The results showed that pulmonary function was significantly impaired in BLM-induced mice, accompanied by elevated oxidative stress and excessive collagen synthesis. Piceatannol significantly improved pulmonary function and decreased oxidative injury as well as collagen synthesis in mice with PF. Mechanically, piceatannol treatment significantly inhibited the activation of JAK2/STAT3 signaling pathway in BLM-induced mice and TGF-β-induced lung fibroblasts. Additional findings also demonstrated that coumermycin A1 (C-A1), an agonist of JAK2, could abolish the effects of piceatannol on TGF-β-induced lung fibroblasts and reactivated the phosphorylation STAT3. Taken together, our study demonstrated that piceatannol could protect against oxidative injury and collagen synthesis during PF in a JAK2/STAT3 signaling pathway-dependent manner.

Topics: Animals; Bleomycin; Collagen; Fibroblasts; Janus Kinase 2; Lung; Mice; Mice, Inbred C57BL; Oxidative Stress; Pulmonary Fibrosis; RNA, Messenger; Signal Transduction; Stilbenes; Transforming Growth Factor beta

Topics: Adenosine Triphosphate; Animals; Antineoplastic Agents; Autophagy; Calreticulin; Cell Line, Tumor; Mice; Oxaliplatin; Stilbenes

Topics: Australia; Cyperaceae; Neoprene; Quinone Reductases; Resveratrol; Stilbenes

Piceatannol is a naturally occurring plant-derived phenolic compound (stilbenoid), an analogue of resveratrol. It has been shown that, piceatannol has biological activity properties such as antiproliferative, antioxidative, anti-inflammatory and proapoptotic, in various human cancer studies in vitro and in vivo.. In this study, it was aimed to investigate whether piceatannol induces apoptosis through anticancer activity methods (cell viability, colony formation, annexin-V/7-AAD, ROS (Reactive oxygen species), MMP (Mitochondrial membrane potential), wound healing, invasion assay, RT-qPCR (Real-Time Quantitative Polymerase Chain Reaction), western blotting in PANC-1 and MIA PaCa-2 pancreatic cancer (PC) cell lines.. According to our results, piceatannol decreased cell viability in a dose and time-dependent manner [the half-maximal inhibitory concentration (IC. Our results show that piceatannol has an anti-cancerogenic effect on PANC-1 and MIA PaCa-2 cells, and exerts this effect by suppressing proliferation and inducing apoptosis. Therefore, piceatannol could be considered to be a potential chemotherapeutic agent candidate for the treatment and prevention of PC.

Topics: Apoptosis; Caspases; Cell Line, Tumor; Cell Survival; Humans; Mitochondria; Pancreatic Neoplasms; Reactive Oxygen Species; Stilbenes; Up-Regulation

Topics: Mitochondria; Proto-Oncogene Proteins c-bcl-2; Reactive Oxygen Species; Signal Transduction; Sirtuin 3; Stilbenes

Defense compounds generally inhibit microbial colonization of plants. In this study, we examined the presence of endophytes in Passiflora edulis seeds that accumulate resveratrol and piceatannol at extremely high levels as defense compounds. Interestingly, although no microbial colonies appeared on an agar growth medium from the cut or homogenized seeds, colonies were generated from cut seedlings derived from the seeds. A total of 19 bacterial strains were isolated, of which 15 were classified as Gram-positive. As we hypothesized that extremely high levels of piceatannol in the seeds would inhibit the growth of endophytes cultured directly from the seeds, we examined the antimicrobial activity of this compound against the isolated bacteria. Piceatannol exerted bacteriostatic rather than bactericidal effects on most of the bacteria tested. These results suggest that the bacteria remain static in the seeds due to the presence of piceatannol and are transmitted to the seedlings during the germination process, enabling colonies to be established from the seedlings on the agar medium. We also investigated the biocatalytic activity of the isolated bacteria toward resveratrol and piceatannol. One bacterium, Brevibacterium sp. PE28-2, converted resveratrol and piceatannol to their respective derivatives. This strain is the first endophyte shown to exhibit such activity.

Topics: Bacteria; Disease Resistance; Endophytes; Microbial Sensitivity Tests; Passiflora; Resveratrol; Seeds; Stilbenes

Radiotherapy is among the most important methods for breast cancer treatment. However, this method's effectiveness is limited by radioresistance. The aim of this study was to investigate whether the stilbene derivatives piceid, resveratrol, and piceatannol have a radiosensitising effect on breast cancer cells (MCF-7). The conducted research enabled us to determine which of the tested compounds has the greatest potential in sensitising cells to ionising radiation (IR). Among the stilbene derivatives, resveratrol significantly increased the effect of IR. Resveratrol and IR used in combination had a higher cytotoxic effect on MCF-7 cells than using piceatannol, piceid, or radiation alone. This was due to a significant decrease in the activity of antioxidant enzymes, which resulted in the accumulation of formed reactive oxygen species (ROS). The effect of resveratrol and IR enhanced the expression of apoptotic genes, such as

Topics: Breast Neoplasms; Female; Glucosides; Humans; MCF-7 Cells; Radiation Tolerance; Radiation, Ionizing; Resveratrol; Stilbenes

Acute myeloid leukemia is characterized by uncontrolled clonal proliferation of abnormal myeloid progenitor cells. Despite recent advances in the treatment of this disease, the prognosis and overall long-term survival for patients remain poor, which drives the search for new chemotherapeutics and treatment strategies. Piceatannol, a polyphenolic compound present in grapes and wine, appears to be a promising chemotherapeutic agent in the treatment of leukemia. The aim of the present study was to examine whether piceatannol induces autophagy and/or apoptosis in HL-60 human acute myeloid leukemia cells and whether HL-60 cells are able to acquire resistance to piceatannol toxicity. We found that piceatannol at the IC

Topics: Antineoplastic Agents; Apoptosis; ATP Binding Cassette Transporter, Subfamily B, Member 1; Autophagy; Caspase 3; Cell Cycle; Cell Survival; DNA Fragmentation; Drug Resistance, Multiple; HL-60 Cells; Humans; Inhibitory Concentration 50; Leukemia, Myeloid, Acute; Membrane Potential, Mitochondrial; Molecular Structure; Reactive Oxygen Species; Resveratrol; Signal Transduction; Stilbenes

Several investigations on senescence and its causative role in aging have underscored the importance of developing senotherapeutics, a field focused on killing senescent cells and/or preventing their accumulation within tissues. Using polyphenols in counteracting senescence may facilitate the development of senotherapeutics given their presence in the human diet, their confirmed tolerability and absence of severe side effects, and their role in preventing senescence and inducing the death of senescent cells. Against that background, we evaluated the effect of piceatannol, a natural polyphenol, on the senescence of mesenchymal stromal cells (MSCs), which play a key role in the body's homeostasis. Among our results, piceatannol reduced the number of senescent cells both after genotoxic stress that induced acute senescence and in senescent replicative cultures. Such senotherapeutics activity, moreover, promoted the recovery of cell proliferation and the stemness properties of MSCs. Altogether, our findings demonstrate piceatannol's effectiveness in counteracting senescence by targeting its associated pathways and detecting and affecting P53-dependent and P53-independent senescence. Our study thus suggests that, given piceatannol's various mechanisms to accomplish its pleiotropic activities, it may be able to counteract any senescent phenotypes.

Topics: Aging; Cell Proliferation; Cellular Senescence; DNA Damage; Humans; Mesenchymal Stem Cells; Senotherapeutics; Stilbenes

Topics: Antioxidants; Apoptosis; Cell Differentiation; Cell Line; Heme Oxygenase-1; Humans; Mitochondria; Myoblasts; Oxidative Stress; Reactive Oxygen Species; Resveratrol; Sirtuin 1; Stilbenes; Up-Regulation

Senna siamea has been used as an antidiabetic drug since antiquity. With regard to traditional Thai medicine, the use of S. siamea was described for diabetes therapy. To understand the molecular mechanism regarding insulin resistance. Pure compounds were isolated from wood extract. We studied their biological activities on insulin-resistance using an in vivo zebrafish model. We also performed an in silico study; molecular docking, and in vitro study by taking advantage of the enzyme inhibitory activities of α-glucosidase, PTP1B, and DPP-IV. Based on the preliminary investigation that ethyl acetate and ethanol extracts have potent effects against insulin resistance on zebrafish larvae, five compounds were isolated from two fractions following: resveratrol, piceatannol, dihydropiceatannol, chrysophanol, and emodin. All of the isolated compounds had anti-insulin resistance effects on zebrafish larvae. Resveratrol, piceatannol, and dihydropiceatannol also demonstrated inhibitory effects against α-glucosidase. Chrysophanol and emodin inhibited PTP1B activity, while resveratrol showed a DPP-IV inhibition effect via the molecular docking. The results of enzyme assay were similar. In conclusions, S. siamea components demonstrated effects against insulin resistance. The chemical structure displayed identical biological activity to that of the compounds. Therefore, S. siamea wood extract and their components are potential therapeutic options in the treatment of diabetes.

Topics: alpha-Glucosidases; Animals; Anthraquinones; Diabetes Mellitus; Dipeptidyl Peptidase 4; Emodin; Hypoglycemic Agents; Insulin Resistance; Molecular Docking Simulation; Molecular Structure; Plant Extracts; Protein Tyrosine Phosphatase, Non-Receptor Type 1; Resveratrol; Senna Plant; Stilbenes; Structure-Activity Relationship; Thailand; Wood; Zebrafish

Inflammatory bowel disease (IBD) has emerged a global disease and the ascending incidence and prevalence is accompanied by elevated morbidity, mortality, and substantial healthcare system costs. However, the current typical one-size-fits-all therapeutic approach is suboptimal for a substantial proportion of patients due to the variability in the course of IBD and a considerable number of patients do not have positive response to the clinically approved drugs, so there is still a great, unmet demand for novel alternative therapeutic approaches. Spleen tyrosine kinase (Syk), a cytoplasmic nonreceptor protein tyrosine kinase, plays crucial roles in signal transduction and there are emerging data implicating that Syk participates in pathogenesis of several gut disorders, such as IBD. In this study, we observed the Syk expression in IBD patients and explored the effects of therapeutic Syk inhibition using small-molecule Syk inhibitor piceatannol in bone marrow-derived macrophages (BMDMs). In addition, due to the poor bioavailability and pharmacokinetics of small-molecule tyrosine kinase inhibitors and superiority of targeting nanoparticles-based drug delivery system, we herein prepared piceatannol-encapsulated poly(lactic-co-glycolic acid) nanoparticles that conjugated with chemokine C-C motif ligand 4 (P-NPs-C) and studied its therapeutic effects in vitro in BMDMs and in vivo in experimental colitis model. Our results indicated that in addition to alleviating colitis, oral administration of P-NPs-C promoted the restoration of intestinal barrier function and improved intestinal microflora dysbiosis, which represents a promising treatment for IBD.

Topics: Animals; Caco-2 Cells; Chemokine CCL4; Disease Models, Animal; Humans; Inflammatory Bowel Diseases; Intestinal Mucosa; Ligands; Male; Mice; Mice, Inbred C57BL; Nanoparticle Drug Delivery System; Stilbenes; Syk Kinase; THP-1 Cells

Synthetic arylamines and dietary phytophenolics could inhibit ferroptosis, a recently discovered regulated cell death process. However, no study indicates whether their inhibitory mechanisms are inherently different. Herein, the ferroptosis-inhibitory mechanisms of selected ferrostatin-1 (Fer-1) and two dietary stilbenes (piceatannol and astringin) were compared. Cellular assays suggested that the ferroptosis-inhibitory and electron-transfer potential levels decreased as follows: Fer-1 >> piceatannol > astringin; however, the hydrogen-donating potential had an order different from that observed by the antioxidant experiments and quantum chemistry calculations. Quantum calculations suggested that Fer-1 has a much lower ionization potential than the two stilbenes, and the aromatic N-atoms were surrounded by the largest electron clouds. By comparison, the C4'O-H groups in the two stilbenes exhibited the lowest bond disassociation enthalpies. Finally, the three were found to produce corresponding dimer peaks through ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry analysis. In conclusion, Fer-1 mainly depends on the electron transfer of aromatic N-atoms to construct a redox recycle. However, piceatannol and astringin preferentially donate hydrogen atoms at the 4'-OH position to mediate the conventional antioxidant mechanism that inhibits ferroptosis, and to ultimately form dimers. These results suggest that dietary phytophenols may be safer ferroptosis inhibitors for balancing normal and ferroptotic cells than arylamines with high electron-transfer potential.

Topics: Animals; Antioxidants; Cyclic N-Oxides; Cyclohexylamines; Diet; Ferroptosis; Glucosides; Imidazoles; Inhibitory Concentration 50; Male; Mesenchymal Stem Cells; Models, Molecular; Phenylenediamines; Piperazines; Rats, Sprague-Dawley; Static Electricity; Stilbenes

Piceatannol (PCT), a natural polyphenolic stilbene, has pleiotropic pharmacological potentials. It possesses cytotoxic activities toward variant cancerous cells. Zein nanospheres (ZN NSs) have been introduced as ideal nanostructures due to their natural origin, safety, histocompatibility. and convenient method of formulation. The purpose of this study was to explore the impact of PCT-ZN NSs formula on pharmacotherapy potential of PCT against human breast cancer MCF-7 cells. PCT-ZN NSs were formulated and characterized selectively to particle size, zeta potential, encapsulation efficiency and diffusion of PCT. The selected formula has a particle size of 84.4 ± 2.3 nm, zeta potential value of 33.8 ± 1.2 mV and encapsulation efficiency of 89.5 ± 4.1%. PCT-ZN NSs displayed significantly lower IC

Topics: Antioxidants; Apoptosis; Breast Neoplasms; Cell Proliferation; Female; Humans; MCF-7 Cells; Nanostructures; Oxidative Stress; Stilbenes; Zein

Piceatannol is a natural plant-derived compound with protective effects against cardiovascular diseases. However, its effect on cerebral ischaemia-reperfusion injury (CIRI) induced by oxidative stress remains unclear. This study aimed to investigate piceatannol's antioxidation in CIRI. An in vitro oxygen-glucose deprivation followed by reoxygenation model was used and cell viability was measured. A middle cerebral artery occlusion followed by reperfusion model was used in vivo. Neurological function, encephalisation quotient, oedema, and volume of the cerebral infarction were then evaluated. The effects of piceatannol on histopathological findings, as well as the ultrastructure of the cortex, were analysed. The activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and lactate dehydrogenase (LDH) and the malondialdehyde (MDA) content was measured both in vitro and in vivo. Finally, the expression of nuclear factor erythroid-2-related factor 2 (Nrf2), hemeoxygenase-1 (HO-1), and nicotinamide adenine dinucleotide phosphate quinone oxidoreductase 1 (NQO1) in cerebral tissue was detected using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blotting. Our results demonstrated that cell viability in the piceatannol groups was increased. The SOD, GSH-Px activities were increased as LDH activity and MDA content decreased in the piceatannol groups both in vitro and in vivo, reflecting a decrease in oxidative stress. The neurological severity score and infarction volume in the piceatannol groups at doses of 10 and 20 mg/kg were lower than those of the model group. Furthermore, the damage seen on histopathological examination was partially attenuated by piceatannol. RT-qPCR and western blot analysis indicated that the expression of Nrf2, HO-1, and NQO1 were significantly increased by piceatannol. The results of the study demonstrate that piceatannol exerts a protective effect against CIRI.

Topics: Animals; Brain; Cell Hypoxia; Cell Survival; Glucose; Heme Oxygenase-1; Infarction, Middle Cerebral Artery; Male; Membrane Proteins; Mice, Inbred ICR; Neuroprotective Agents; NF-E2-Related Factor 2; Oxidative Stress; Oxygen; Reperfusion Injury; Signal Transduction; Stilbenes

Failure of conventional clinical therapies such as tumor resection and chemotherapy are mainly due to the ineffective control of tumor metastasis. Metastasis consists of three steps: (i) tumor cells extravasate from the primary sites into the circulation system via epithelial-mesenchymal transition (EMT), (ii) the circulating tumor cells (CTCs) form "micro-thrombi" with platelets to evade the immune surveillance in circulation, and (iii) the CTCs colonize in the pre-metastatic niche. Here, we design a systemic metastasis-targeted nanotherapeutic (H@CaPP) composed of an anti-inflammatory agent, piceatannol, and an anti-thrombotic agent, low molecular weight heparin, to hinder the multiple steps of tumor metastasis. H@CaPP is found efficiently impeded EMT, inhibited the formation of "micro-thrombi", and prevented the development of pre-metastatic niche. When combined with surgical resection or chemotherapy, H@CaPP efficiently inhibits tumor metastasis and prolonged overall survival of tumor-bearing mice. Collectively, we provide a simple and effective systemic metastasis-targeted nanotherapeutic for combating tumor metastasis.

Topics: Animals; Anti-Inflammatory Agents; Anticoagulants; Antineoplastic Combined Chemotherapy Protocols; Cell Line, Tumor; Chemotherapy, Adjuvant; Disease Models, Animal; Drug Carriers; Epithelial-Mesenchymal Transition; Female; Heparin, Low-Molecular-Weight; Human Umbilical Vein Endothelial Cells; Humans; Male; Mammary Glands, Animal; Mammary Neoplasms, Experimental; Mice; Nanoparticles; Neoplasm Metastasis; Neoplastic Cells, Circulating; Paclitaxel; Proof of Concept Study; Rats; Stilbenes; Theranostic Nanomedicine

Topics: Cassia; Catechin; HIV Envelope Protein gp120; HIV Infections; HIV-1; Humans; Oleanolic Acid; Palmitic Acid; Plant Extracts; Plant Roots; Quercetin; Stilbenes; Virus Internalization

Sepsis-induced myocardial dysfunction (SIMD) represents one of the serious complications secondary to sepsis, which is a leading cause of the high mortality rate among septic cases. Subsequent cardiomyocyte apoptosis, together with the uncontrolled inflammatory response, has been suggested to be closely related to SIMD. Piceatannol (PIC) is verified with potent anti-apoptotic and anti-inflammatory effects, but its function and molecular mechanism in SIMD remain unknown so far. This study aimed to explore the potential role and mechanism of action of PIC in resisting SIMD. The interaction of PIC with JAK2 proteins was evaluated by molecular docking, molecular dynamics (MD) simulation and surface plasmon resonance imaging (SPRi). The cecal ligation and puncture-induced septicemia mice and the LPS-stimulated H9C2 cardiomyocytes were prepared as the models in vivo and in vitro, separately. Molecular docking showed that JAK2-PIC complex had the -8.279 kcal/mol binding energy. MD simulations showed that JAK2-PIC binding was stable. SPRi analysis also showed that PIC has a strong binding affinity to JAK2. PIC treatment significantly ameliorated the cardiac function, attenuated the sepsis-induced myocardial loss, and suppressed the myocardial inflammatory responses both in vivo and in vitro. Further detection revealed that PIC inhibited the activation of the JAK2/STAT3 signaling, which was tightly associated with apoptosis and inflammation. Importantly, pre-incubation with a JAK2 inhibitor (AG490) partially blocked the cardioprotective effects of PIC. Collectively, the findings demonstrated that PIC restored the impaired cardiac function by attenuating the sepsis-induced apoptosis and inflammation via suppressing the JAK2/STAT3 pathway both in septic mice and H9C2 cardiomyocytes.

Topics: Animals; Apoptosis; Cardiomyopathies; Cardiotonic Agents; Cell Line; Disease Models, Animal; Inflammation; Janus Kinase 2; Male; Mice, Inbred C57BL; Molecular Docking Simulation; Molecular Dynamics Simulation; Myocytes, Cardiac; Rats; Sepsis; Signal Transduction; STAT3 Transcription Factor; Stilbenes; Tyrphostins

The co-encapsulation of multiple bioactive components in a carrier may produce synergistic effects and improve health benefits. In this study, the interactions of β-lactoglobulin (β-LG) with epigallocatechin-3-gallate (EGCG) and/or piceatannol (PIC)/oxyresveratrol (OXY) were investigated by multispectroscopic techniques, isothermal titration calorimetry, and molecular docking. The static quenching mechanism of β-LG by EGCG, PIC and OXY was confirmed by fluorescence spectroscopy and UV-vis absorption difference spectroscopy. The binding sites of these three polyphenols in β-LG were identified by site marking fluorescence experiments and molecular docking. The thermodynamic parameters of the β-LG + EGCG/PIC/OXY binary complex and β-LG + EGCG + PIC/OXY ternary complex were obtained from fluorescence data and used to analyze the main driving force for complex formation. The exothermic binding process was further confirmed by isothermal titration calorimetry. The α-helical content, particle size and morphology of free and ligand-bound β-LG were determined by circular dichroism spectroscopy, dynamic light scattering and transmission electron microscopy, respectively. The effect of EGCG, PIC and OXY on the conformation of β-LG was studied by Fourier transform infrared spectroscopy. In addition, the maximum synergistic antioxidant activity between EGCG and PIC/OXY was obtained by response surface analysis. The effects of β-LG in the binary and ternary systems on the antioxidant activity, stability, solubility and cytotoxicity of the polyphenols were also studied. Finally, the different cytotoxicities of the complexes and nanoparticles of the binary and ternary systems were compared. The results of this study are expected to provide a theoretical basis for the development of β-LG-based carriers co-encapsulating a variety of bioactive components.

Topics: Antioxidants; Catechin; In Vitro Techniques; Lactoglobulins; Molecular Docking Simulation; Plant Extracts; Protein Binding; Spectrometry, Fluorescence; Stilbenes

Peripheral neurotoxicity is a dose-limiting and a potentially lifelong persistent toxicity of cisplatin. This study investigated the possible protective effect of piceatannol (PIC) in a model of cisplatin-induced peripheral neuropathy in rats. PIC (10 mg/kg, i.p.) was given for 7 days, starting 2 days before cisplatin single injection (7 mg/kg, i.p.). Behavioural, biochemical and histological examinations were conducted. Cisplatin administration resulted in thermal hypoalgesia evidenced by increased paw and tail withdrawal latency times in the hotplate and tail flick tests, respectively, and reduced the abdominal constrictions in response to the acetic acid injection. Moreover, cisplatin treatment decreased rat locomotor activity and grip strength. These behavioural alterations were reversed by PIC coadministration. In addition, PIC decreased cisplatin-induced elevation in serum neurotensin and platinum accumulation in sciatic nerve. Also, PIC reversed, to a large extent, cisplatin-induced microscopical alterations in nerve axons and restored normal myelin thickness. Therefore, PIC may protect against cisplatin-induced peripheral neuropathy.

Topics: Animals; Antineoplastic Agents; Behavior, Animal; Cisplatin; Hand Strength; Locomotion; Male; Peripheral Nervous System Diseases; Rats; Rats, Wistar; Sciatic Nerve; Stilbenes

To study the antitumor effect of piceatannol (PIC) on malignant melanoma. B16F10 cells were cultured. The cell viability of B16F10 decreased with increasing PIC concentration. The results of the Transwell assay showed that invasion ability decreased with increasing PIC concentration, and healing time was prolonged at increased PIC concentration in the wound healing assay. Western blot results showed that PIC mainly inhibited the phosphorylation of Syk and inhibited the expression of MMP-2, MMP-9, and VEGF. RNA interference pointed out that blocking the expression of Syk can reveal the same inhibition effect on B16F10 cells as PIC.. PIC might block the progression of malignant melanoma by inhibiting spleen tyrosine kinase.

Topics: Animals; Cell Line, Tumor; Cell Movement; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Melanoma; Mice; Neoplasm Invasiveness; Stilbenes; Syk Kinase; Vascular Endothelial Growth Factor A

The Cutibacterium acnes (also called Propionibacterium acnes, P. acnes)-induced proliferation and migration of keratinocytes contribute to acne vulgaris (AV), which is a common inflammatory skin disease that causes physical and psychological impairments. Piceatannol (3, 5, 3', 4'-tetrahydroxy-trans-stilbene, PCT) is naturally present in many human diets and plays antioxidant and anti-inflammatory roles that inhibit cell proliferation and migration. We aimed to analyse the functions and underlying mechanisms of PCT in P. acnes-stimulated keratinocytes. First, PCT showed no toxicity against the normal human keratinocyte cell line HaCaT but inhibited P. acnes-induced HaCaT cell proliferation. Next, PCT promoted the nuclear translocation and target gene transcription of the antioxidant transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2), thereafter decreasing intracellular reactive oxygen species (ROS) levels. In addition, PCT inhibited the nuclear translocation of p65 [a subunit of nuclear factor kappa B (NF-κB)] and the secretion of pro-inflammatory cytokines, including interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α) and interleukin-8 (IL-8). Finally, a transfection assay showed that PCT inhibited P. acnes-induced HaCaT cell proliferation and migration by activating the antioxidant Nrf2 pathway and inhibiting the inflammatory NF-κB pathway. Our data suggested that PCT alleviated P. acnes-induced HaCaT cell proliferation and migration through its antioxidant and anti-inflammatory roles, suggesting the potential of PCT to treat AV.

Topics: Acne Vulgaris; Anti-Inflammatory Agents; Antioxidants; Cell Line; Cell Movement; Cell Proliferation; Host-Pathogen Interactions; Humans; Inflammation Mediators; Keratinocytes; NF-E2-Related Factor 2; Oxidative Stress; Propionibacterium acnes; Signal Transduction; Skin; Stilbenes; Transcription Factor RelA

Piceatannol (PIC) displays a wide spectrum of biological activities, such as antioxidation, antibacterial activity and anti-inflammation, but the biochemical and molecular mechanism is not fully understood. In this study, the interaction of PIC with bovine serum albumin (BSA) was studied by fluorescence spectroscopy, ultraviolet-visible absorption spectroscopy, circular dichroism spectroscopy and molecular simulation. The effects of PIC on BSA non-enzymatic glycosylation, fibrillation, thermal stability, and structure information were also studied. The results showed that the formation of PIC-BSA complex by mainly hydrogen-bonding forces resulted in the conformational changes of protein. PIC inhibited the formation of β-sheets structures of BSA. BSA still maintained the esterase-like good activity in the presence of PIC. In addition, PIC significantly reduced the degree of BSA glycosylation. These results provided a basis for the molecular interaction between PIC and protein, and suggested the potential effect of PIC in preventing the progression of diabetes mellitus.

Topics: Amyloid; Animals; Cattle; Circular Dichroism; Density Functional Theory; Esterases; Glycation End Products, Advanced; Glycosylation; Models, Molecular; Protein Binding; Protein Structure, Secondary; Serum Albumin, Bovine; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Stilbenes

Hepatitis B virus (HBV) polymerase is the only virus-encoded enzyme essential for producing the HBV genome and is regarded as an attractive drug target. However, the difficulty of synthesizing and purifying recombinant HBV polymerase protein has hampered the development of new drugs targeting this enzyme, especially compounds unrelated to the nucleoside structure. We recently have developed a technique for the synthesis and purification of recombinant HBV polymerase containing the reverse transcriptase (RT) domain that carried DNA elongation activity in vitro.. We used the overproduced protein to establish an in vitro high-throughput screening system to identify compounds that inhibit the elongation activity of HBV polymerase.. We report the development of a screening system that is useful for identifying non-nucleos(t)ide RT inhibitors.

Topics: Antiviral Agents; DNA, Viral; Drug Evaluation, Preclinical; Drug Resistance, Viral; Guanine; Hep G2 Cells; Hepatitis B virus; Humans; In Vitro Techniques; Inhibitory Concentration 50; Lamivudine; Protein Biosynthesis; Recombinant Proteins; Reverse Transcriptase Inhibitors; RNA-Directed DNA Polymerase; Stilbenes; Virus Replication

To evaluate the health-promoting potentials of piceatannol (PIC), a dietary resveratrol derivative, its biotransformation is examined.. The biotransformation is tested in human/rat hepatic microsomes and cytosols; its pharmacokinetic profiles are assessed in rats. Although limited phase I metabolism exists in microsomes, PIC is rapidly converted to two pharmacologically active metabolites, namely rhapontigenin (RHA) and isorhapontigenin (ISO) in cytosols. Such biotransformation is completely blocked by entacapone, a well-known catechol-O-methyltransferase (COMT) inhibitor, demonstrating that the O-methylation is mediated by COMT. Moreover, PIC is identified as a substrate inhibitor of COMT, suggesting its potential benefits in Alzheimer's disease. Due to extensive phase II metabolism including glucuronidation, sulfation, and O-methylation, PIC displays rapid clearance and at least 4.02% ± 0.61% and 17.70% ± 0.91% of PIC is converted to RHA and ISO, respectively, in rats after intravenous administration. Similarly, PIC serves as an effective precursor of ISO upon oral administration.. Since PIC and its metabolites possess pleiotropic health-promoting activities, it has emerged as a promising nutraceutical candidate for further development. This study also reinforces the importance of in vivo testing in nutritional researches as the active metabolite(s) may be absent from the in vitro system.

Topics: Administration, Oral; Animals; Biotransformation; Catechol O-Methyltransferase; Catechol O-Methyltransferase Inhibitors; Catechols; Cytosol; Humans; Injections, Intravenous; Male; Methylation; Microsomes, Liver; Nitriles; Rats, Sprague-Dawley; Stilbenes

Phenylpropanoid (PPPN) compounds are widely used in agriculture, medical, food, and cosmetic industries because of their multiple bioactivities.

Topics: Alternaria; Biosynthetic Pathways; Coumaric Acids; Endophytes; Fungal Proteins; Metabolomics; Phenols; Quercetin; Secondary Metabolism; Stilbenes; Vitis

Natural UV photoprotection plays a vital role in physiological protection. It has been reported that UVC radiation can make resveratrol (RSV) and piceatannol (PIC) accumulate in grape skin. In this work, we demonstrated that RSV and PIC could significantly absorb UVA and UVB, and confirmed their satisfactory photostability. Furthermore, we clarified the UV photoprotection mechanism of typical stilbenoids of RSV and PIC for the first time by using combined femtosecond transient absorption (FTA) spectroscopy and time-dependent density functional theory (TD-DFT) calculations. RSV and PIC can be photoexcited to the excited state after UVA and UVB absorption. Subsequently, the photoisomerized RSV and PIC quickly relax to the ground state via nonadiabatic transition from the S

Topics: Density Functional Theory; Fruit; Molecular Structure; Photochemical Processes; Protective Agents; Resveratrol; Stereoisomerism; Stilbenes; Ultraviolet Rays; Vitis

The impact of maternal nutrition on neurodevelopment and neonatal neuroprotection is a research topic with increasing interest. Maternal diet can also have deleterious effects on fetal brain development. Fetal exposure to alcohol is responsible for poor neonatal global development, and may increase brain vulnerability to hypoxic-ischemic encephalopathy, one of the major causes of acute mortality and chronic neurological disability in newborns. Despite frequent prevention campaigns, about 10% of women in the general population drinks alcohol during pregnancy and breastfeeding. This study was inspired by this alarming fact. Its aim was to evaluate the beneficial effects of maternal supplementation with two polyphenols during pregnancy and breastfeeding, on hypoxic-ischemic neonate rat brain damages, sensorimotor and cognitive impairments, in a context of moderate maternal alcoholism. Both stilbenoid polyphenols, trans-resveratrol (RSV - 0.15 mg/kg/day), and its hydroxylated analog, trans-piceatannol (PIC - 0.15 mg/kg/day), were administered in the drinking water, containing or not alcohol (0.5 g/kg/day). In a 7-day post-natal rat model of hypoxia-ischemia (HI), our data showed that moderate maternal alcoholism does not increase brain lesion volumes measured by MRI but leads to higher motor impairments. RSV supplementation could not reverse the deleterious effects of HI coupled with maternal alcoholism. However, PIC supplementation led to a recovery of all sensorimotor and cognitive functions. This neuroprotection was obtained with a dose of PIC corresponding to the consumption of a single passion fruit per day for a pregnant woman.

Topics: Alcohol Drinking; Alcoholism; Animals; Animals, Newborn; Brain; Brain Injuries; Cognitive Dysfunction; Female; Hypoxia; Hypoxia-Ischemia, Brain; Ischemia; Male; Maternal Nutritional Physiological Phenomena; Maternal-Fetal Exchange; Neuroprotection; Neuroprotective Agents; Polyphenols; Pregnancy; Prenatal Exposure Delayed Effects; Rats; Rats, Wistar; Resveratrol; Stilbenes

Piceatannol is a natural polyphenol compound found in passion fruit and blueberry with several biological activities. However, it is unclear whether piceatannol affects the activity of human UDP-glucuronosyltransferases (UGTs) enzymes. The present study aims to assess the potential inhibitory effect of piceatannol against UGTs enzymes, as well as to evaluate its potential food-drug interactions risk via UGTs inhibition. We systematically evaluated the inhibitory effects of piceatannol on UGTs using high-performance liquid chromatography by measuring the formation rates for 4-methylumbelliferoneglucuronide and imipramine N-glucuronide. The results indicated that piceatannol displayed broad-spectrum inhibition against human UGTs. Kinetic analysis showed that inhibition of piceatannol on UGT1A6 and UGT1A7 followed noncompetitive inhibition mechanism, while the inhibition on UGT1A8 and UGT1A9 obeyed competitive and mixed inhibition mechanism, respectively. The quantitative prediction of risks showed that the coadministration of piceatannol with drugs primarily cleared by UGT1A6, UGT1A7, UGT1A8, and UGT1A9 may result in potential food-drug interaction. In conclusion, additional caution should be taken when piceatannol and food containing piceatannol are co-administered with drugs metabolized by UGTs.

Topics: Food-Drug Interactions; Glucuronides; Glucuronosyltransferase; Humans; Recombinant Proteins; Stilbenes

This study aimed to determine the anxiolytic effect of a putative glyoxalase 1 inhibitor, piceatannol, as well as its antitumor activities on the stress-induced tumor growth of Lewis lung carcinoma.. The anxiolytic activities of piceatannol (1-30 mg/kg) were assessed using the elevated plus maze (EPM) test. We also evaluated the pharmacological modulation of stress-induced tumor growth; the mice were treated with piceatannol (3 and 30 mg/kg) from the 10. At the low dose (3 mg/kg), piceatannol significantly increased the time spent in the open arms of the EPM test when compared with the vehicle. At higher doses (30 mg/kg), it significantly suppressed the stress-induced enhancement of tumor growth.. A low dose of piceatannol exerts an anxiolytic effect, and high doses have an antitumor effect.

Topics: Animals; Anti-Anxiety Agents; Antineoplastic Agents; Lactoylglutathione Lyase; Male; Mice; Protein-Tyrosine Kinases; Stilbenes

Resveratrol (RES) is a natural polyphenol with potential as an adjunctive therapeutic modality for periodontitis. However, its inferior pharmacokinetics and toxicity concerns about its commonly used solvent dimethyl sulfoxide (DMSO) hinder translation to clinical applicability. Our study aimed to investigate the comparative antimicrobial properties of RES and its analogues (pterostilbene [PTS], oxyresveratrol [OXY] and piceatannol [PIC]), utilizing 2-hydroxypropyl-β-cyclodextrin (HPβCD) as a solubiliser, which has a well-documented safety profile and FDA approval. These properties were investigated against Fusobacterium nucleatum, a key periodontal pathogen. PTS demonstrated the most potent antibacterial effects in HPβCD, with MIC > 60-fold lower than that of RES, OXY and PIC. In addition, PTS inhibited F. nucleatum biofilm formation. PTS exerted antimicrobial effects by eliciting leakage of cellular contents, leading to loss of bacterial cell viability. PTS also conferred immunomodulatory effects on F. nucleatum-challenged macrophages via upregulation of antioxidant pathways and inhibition of NF-κB activation. Given the superior antimicrobial potency of PTS against F. nucleatum compared to RES and other analogues, and coupled with its immunomodulatory properties, PTS complexed with HPβCD holds promise as a candidate nutraceutical for the adjunctive treatment of periodontitis.

Topics: 2-Hydroxypropyl-beta-cyclodextrin; Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents; Antioxidants; Cell Line; Cell Survival; Cyclodextrins; Fusobacterium nucleatum; Immunologic Factors; Macrophages; Mice; Microbial Viability; NF-kappa B; Periodontitis; Polyphenols; RAW 264.7 Cells; Resveratrol; Signal Transduction; Stilbenes; Up-Regulation

Human cytomegalovirus (hCMV) is a ubiquitous herpesvirus, which results in the establishment of a latent infection that persists throughout the life of the host and can be reactivated when the immunity is low. Currently, there is no vaccine for hCMV infection, and the licensed antiviral drugs mainly target the viral enzymes and have obvious adverse reactions. Thus, it is important to search for compounds with anti-hCMV properties. The present study aimed to investigate the suppressive effects of piceatannol on hCMV Towne strain infection and the putative underlying mechanisms using human diploid fibroblast WI-38 cells. Piceatannol supplementation prevented the lytic changes induced by hCMV infection in WI-38 cells. Furthermore, piceatannol suppressed the expression of hCMV immediate-early (IE) and early (E) proteins as well as the replication of hCMV DNA in a dose-dependent manner. Moreover, hCMV-induced cellular senescence was suppressed by piceatannol, as shown by a decline in the senescence-associated β-galactosidase (SA-β-Gal) activity and decreased production of intracellular reactive oxygen species (ROS). p16

Topics: Antiviral Agents; beta-Galactosidase; Cell Line; Cellular Senescence; Cyclin-Dependent Kinase Inhibitor p16; Cytomegalovirus; Cytomegalovirus Infections; Drug Repositioning; Humans; Immediate-Early Proteins; Reactive Oxygen Species; Stilbenes; Virus Replication

This study was aimed to investigate the effect of piceatannol (PIC) on the proliferation and apoptosis of bladder cancer cell line EJ, and the underlying mechanism.   Bladder cancer cell line EJ was incubated with different concentrations of PIC, and CCK-8 method was used to determine the effect of the treatment on cell proliferation. The effect of PIC on cell cycle, apoptosis and the expressions of related signal pathway proteins were determined using Western blotting. Flow cytometry showed that PIC inhibited the proliferation of EJ cells in a concentration- and time-dependent fashion. Moreover, EJ cells were significantly blocked in G0/G1 phase, when compared with the blank control group (p < 0.05). In addition, PIC enhanced apoptosis of EJ cells in a concentration-dependent manner (p < 0.05). Results from western blotting showed that, compared with the control group, PIC upregulated the protein expression of PTEN, but downregulated Akt protein phosphorylation, relative to control cells. PIC significantly inhibits the proliferation of EJ cells and enhances their apoptosis through a mechanism related to the activation of PTEN/Akt signaling pathway.

Topics: Apoptosis; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cell Survival; Humans; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Signal Transduction; Stilbenes; Urinary Bladder Neoplasms

Topics: Amino Acid Chloromethyl Ketones; Animals; Bone Marrow Cells; Caspase 1; Cell-Derived Microparticles; Dendritic Cells; Echinococcus granulosus; Female; Gene Expression Regulation; Host-Parasite Interactions; Indazoles; Inflammasomes; Interleukin-12; Interleukin-1beta; Lipopolysaccharides; Macrophages; Mice; Mice, Inbred C57BL; NLR Family, Pyrin Domain-Containing 3 Protein; Phagocytosis; Phosphatidylinositol 3-Kinase; Proto-Oncogene Proteins c-akt; Signal Transduction; Stilbenes; Sulfonamides; Wortmannin

In addition to antigen presentation to CD4

Topics: Animals; Antigen Presentation; Bone Marrow Cells; Calcium; Cells, Cultured; Clathrin; Cross-Linking Reagents; Dendritic Cells; Endocytosis; Estrenes; Histocompatibility Antigens Class II; Male; Mice; Phorbol Esters; Protein Kinase C; Pyrrolidinones; Signal Transduction; Specific Pathogen-Free Organisms; Staurosporine; Stilbenes; Syk Kinase; Type C Phospholipases

Piceatannol is also named as

Topics: Angiogenesis Inhibitors; Animals; Cell Proliferation; Human Umbilical Vein Endothelial Cells; Humans; Neovascularization, Physiologic; Phosphorylation; Protein Binding; Receptors, Vascular Endothelial Growth Factor; Signal Transduction; Stilbenes; Vascular Endothelial Growth Factor A; Zebrafish

As a major bioactive compound from grapes, piceatannol (PIC) has been reported to exert anti-atherosclerotic activity in various studies. Nevertheless, the mechanism underlying the effect of piceatannol against atherosclerosis (AS) is elusive. Our study identified miR-200a/Nrf2/GSDMD signaling pathway as critical mediators in the effect of piceatannol on macrophages. In the present study, we confirmed that treatment of piceatannol repressed the oxLDL-induced lipid storage in macrophages. Compared with control group, piceatannol inhibited TG storage and the activity of caspase1. It is noting that in response to oxLDL challenge, piceatannol abated the pyroptosis in RAW264.7 cells, with a decreased expression of caspase1, gasdermin D (GSDMD), IL-18, IL-1β and NLRP3. Moreover, we investigated the role of microRNA (miR)-200a/Nrf2 signaling pathway in the effect of piceatannol. The results declared that after transfection of si-miR-200a or si-Nrf2 plasmids, the effects of piceatannol on macrophages were converted, including lipid storage and pyroptosis. Importantly, si-miR-200a plasmid reduced the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), indicating that miR-200a acted as an enhancer of Nrf2 in macrophages. Collectively, our findings demonstrate that piceatannol exerts anti-atherosclerotic activity on RAW264.7 cells by regulating miR-200a/Nrf2/GSDMD signaling. The present study is the first time to identify miR-200a as a candidate target in AS and declared an association between miR-200a and pyroptosis, which provides a novel therapy for the treatment of AS.

Topics: Animals; Atherosclerosis; Caspase 1; Drug Evaluation, Preclinical; Gene Knockdown Techniques; Humans; Intracellular Signaling Peptides and Proteins; Lipoproteins, LDL; Mice; MicroRNAs; NF-E2-Related Factor 2; Phosphate-Binding Proteins; Pyroptosis; RAW 264.7 Cells; RNA, Small Interfering; Signal Transduction; Stilbenes

Piceatannol (Pice), a natural analog of resveratrol, has been identified as an anticancer agent in various cancers by modulating the expression of microRNAs (miRNAs/miRs). However, the molecular mechanisms underlying the anticancer effects of Pice in osteosarcoma (OS) cells remain unclear. Thus, we hypothesized that Pice exerts anticancer effects on OS cells via the regulation of miRNA expression. Herein, we performed a MTT assay and flow cytometric analysis to determine cell viability and apoptosis in OS cells treated with Pice, respectively. Our results showed that Pice inhibits proliferation in a dose‑dependent manner induces the apoptosis of OS cells. More importantly, miRNA microarray analysis identified that Pice alters miRNA expression profiles in human OS cells after treatment with Pice, and miR‑21 was the most significantly downregulated. In addition, the therapeutic effects of Pice on OS cells were weakened by restoration of miR‑21. In addition, we further verified that phosphatase and tensin homolog (PTEN), a tumor suppressor gene, is the functional target of miR‑21 and Pice blocks the PTEN/AKT signaling pathway through inhibiting miR‑21 expression in OS cells. Our findings suggested that Pice may exert anticancer effects on OS cells via mediating the miR‑21/PTEN/AKT signaling pathway and could be considered to be a potential anticancer agent for treating OS.

Topics: Brain Neoplasms; Cell Line, Tumor; Cell Proliferation; Cell Survival; Dose-Response Relationship, Drug; Gene Expression Regulation, Neoplastic; Humans; MicroRNAs; Osteosarcoma; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Signal Transduction; Stilbenes

The purpose of this study was to investigate the role of piceatannol (PT) in statin (rosuvastatin and simvastatin) resistance and tolerance and its association with PCSK9 expression via its p300 inhibitory (p300i) activity. An in vitro study was performed using HepG2 cells that were exposed to statins (rosuvastatin or simvastatin) with or without PT in delipidated serum (DLPS) medium. In the statin exposed conditions, PCSK9 expression was reduced following PT treatment when compared to HepG2 cells w/o PT treatment. Furthermore, no significant difference was observed in the expression of the transcription factors SREBP2 and HNF1α, which regulate PCSK9 expression. This resulted in low density lipoprotein receptor (LDLR) stabilization and reduced cellular cholesterol levels. This indicates that PT epigenetically controls statin-induced PCSK9 expression. Interestingly, PT attenuated p300 histone acetyltransferase (HAT) activity. Moreover, simulation of PT-p300 binding suggested that PT inhibits p300 as PT could be docked in the p300 HAT domain. Furthermore, inhibition of p300 HAT activity using C-646, a selective p300 inhibitor, or through an siRNA system effectively reduced PCSK9 induction upon statin exposure in HepG2 cells. The chromatin immunoprecipitation (ChIP) assays revealed that PT blocked the recruitment of p300 to the PCSK9 promoter region. In summary, PT attenuated statin-induced PCSK9 expression by inhibiting p300 HAT activity. Finally, co-administration of simvastatin and PT for 10 weeks further reduced plasma low-density lipoprotein-cholesterol (LDL-C) levels and stabilized the hepatic LDLR protein level compared with those resulting from single treatment of simvastatin in a high-fat diet-induced hypercholesterolemia mouse model. Our findings indicate that PT is a new nutraceutical candidate to reduce the statin resistance and tolerance that occurs in patients with hypercholesterolemia.

Topics: Animals; Cholesterol, LDL; Disease Models, Animal; Down-Regulation; Drug Resistance; Hep G2 Cells; Hepatocytes; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypercholesterolemia; Male; Mice, Inbred C57BL; p300-CBP Transcription Factors; Proprotein Convertase 9; Protein Stability; Receptors, LDL; Rosuvastatin Calcium; Simvastatin; Stilbenes

Reperfusion is a critical therapeutic intervention used following acute ischemic stroke; however, it may cause cerebral ischemia/reperfusion injury (CIRI) and aggravate brain damage. Piceatannol (Pic), a hydroxylated analog of resveratrol, has been reported to exhibit anti‑inflammatory effects. However, the detailed molecular mechanisms and its effects on CIRI have not been sufficiently assessed, and, to the best of our knowledge, current methods of prevention of CIRI are limited. The aim of the present study was to investigate the effects of Pic on improving neurological function in a mouse model of CIRI. For the animal experiments, 8‑week‑old C57BL/6 mice were raised and randomly grouped, and an in vivo model of CIRI was established. Mice were administered a low (10 mg/kg/day) or high‑dose (20 mg/kg/d) of Pic 1 h after CIRI orally and once daily for the next 6 days. Neurological dysfunction was assessed using a modified neurological severity score and a rotarod test 1 week after CIRI establishment, and the cognitive status of the mice was assessed using a Morris water maze. Hematoxylin and eosin staining was used to evaluate the histopathological changes. The expression levels of sirtuin 1 (Sirt1), FoxO1, cleaved caspase‑3 (CC‑3), Bax and Bcl‑2 were measured using western blotting. Intracellular reactive oxygen species (ROS) generation, antioxidant enzymes [superoxide dismutase, glutathione (GSH) peroxidase and catalase] and non‑enzymatic antioxidants (GSH) were also detected using spectrophotometry. After inhibition of the Sirt1/FoxO1 pathway, a TUNEL assay was used for the detection of apoptotic cells in vitro and in vivo. The co‑localization of neuron‑specific nuclear protein and CC‑3 was assessing using immunofluorescent staining. Pic improved neurological functions and ameliorated hippocampal neuronal pathology following CIRI. In addition, the expression levels of CC‑3 and Bax and intracellular ROS levels were increased, while levels of antioxidant and non‑enzymatic enzymes were decreased in the mouse model of CIRI. Low and high doses of Pic significantly decreased ROS production and the expression levels of apoptosis‑related proteins, but increased antioxidant enzyme levels. However, a high‑dose of Pic did not result in increased levels of non‑enzymatic enzymes. Furthermore, low and high doses of Pic treatment significantly activated the Sirt1/FoxO1 pathway. Following inhibition of the Sirt1/FoxO1 pathway, the percentage of TUNEL‑positive cells an

Topics: Animals; Antioxidants; Apoptosis; Brain Ischemia; Caspase 3; Forkhead Box Protein O1; Infarction, Middle Cerebral Artery; Male; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Oxidative Stress; Proto-Oncogene Proteins c-bcl-2; Reactive Oxygen Species; Reperfusion Injury; Resveratrol; Signal Transduction; Sirtuin 1; Stilbenes; Stroke

The study on inhibitory effects of resveratrol glucosides (REs) on advanced glycation endproducts (AGEs) formation is still unmet. Herein, for the first time, the antiglycation activities of five REs in the fetal bovine serum proteins (FBS)/fructose system were evaluated, and its structure-activity relationship and antiglycation mechanism were further explored. These REs showed remarkable inhibition toward AGEs formation. Among them, Piceatannol-3'-O-glucoside (PG) exhibited highest antiglycation activity as reflected in approximately 80% inhibition of fluorescent AGEs at the concentration of 1.0 mM. The structure-activity relationship analysis indicated that glucoside attached to the B ring of resveratrol displays a superior antiglycation activity. Moreover, the results of antiglycation mechanism showed that the antiglycation activity of REs was proportional to their antioxidant capacity and methylglyoxal (MGO) trapping capacity. Therefore, the REs are promising candidates worthy of further exploration for preventing AGEs accumulation in vivo, thereby treating AGEs-associated diseases.

Topics: Antioxidants; Glucosides; Glycation End Products, Advanced; Plant Extracts; Pyruvaldehyde; Resveratrol; Stilbenes; Structure-Activity Relationship

The properties of the mitochondrial F

Topics: Adenosine Triphosphate; Animals; Calcium; Catalysis; Cell Death; Hydrolysis; Inhibitory Concentration 50; Kinetics; Magnesium; Membrane Potential, Mitochondrial; Mitochondria, Heart; Permeability; Protein Domains; Proton-Translocating ATPases; Quercetin; Resveratrol; Stilbenes; Succinic Acid; Swine

Cadmium (Cd) is considered a heavy metal and potential pollutant to the environment.. The purpose of this study was to evaluate the protective potential of piceatannol (PT; 10 mg/kg body weight/day) against cadmium (Cd; 5 mg/kg body weight/day)-induced testicular dysfunction in Wistar rats.. Rats were randomly divided into four groups: control, PT, Cd, and Cd + PT.. Treatment with Cd resulted in a significant decrease in body, testicular, and epididymal weights, sperm quantity and quality, steroidogenic marker-enzyme activities, mRNA- and protein-expression levels of SF1, StAR, and P450 side chain-cleaving enzyme, and serum male sex hormonal levels when compared to controls. Testicular malondialdehyde levels were significantly increased, with a significant reduction in enzymatic and nonenzymatic antioxidants in Cd-treated rats compared to control rats. Testicular histomorphometric results supported the biochemical and molecular alterations observed in the study. In addition, significant downregulation in mRNA- and protein-expression levels of cytosolic Nrf2, HO1, γGCS, GPx, and NQO1, as well as significant upregulation in mRNA- and protein-expression levels of Nrf2 and Keap1 in testicular tissue, were noticed in rats administered Cd. PT treatment inCd-treated rats caused marked alleviation in body and organ weights, sperm analysis, steroidogenesis, serum hormonal levels, histomorphometric changes, and oxidative and antioxidative status in testes when compared to Cd alone-treated rats. Further, treatment of rats with PTl showed a marked improvement in mRNA- and protein-expression levels of Nrf2 and its regulated genes and proteins.. The present study provides compelling evidence that PT treatment results in significant protection against Cd-induced testicular dysfunctions, such as spermatogenesis, steroidogenesis, and oxidative stress in rats, possibly through modification of the Nrf2-Keap1 signalling pathway.

Topics: Administration, Intravenous; Administration, Oral; Animals; Cadmium; Male; NF-E2-Related Factor 2; Oxidative Stress; Rats; Rats, Wistar; Signal Transduction; Spermatogenesis; Steroids; Stilbenes; Testis

Natural polyphenols showing a variety of beneficial effects will interact with multiple proteases after administration. The interactions of oxyresveratrol and piceatannol with trypsin and lysozyme were investigated using fluorescence spectroscopy, UV-vis absorption spectroscopy, circular dichroism spectroscopy, differential scanning calorimetry and molecular docking. Fluorescence quenching results and UV-vis absorption difference spectra revealed that the quenching process was a static mode initiated by ground-state complex formation. The different binding ability of oxyresveratrol and piceatannol with trypsin and lysozyme was discussed based on their different molecular structures. Moreover, the major driving force for the binding process was elucidated as hydrogen bonding and van der Waals forces by the negative enthalpy and entropy changes. Synchronous fluorescence, three-dimensional fluorescence and circular dichroism spectral analysis suggested that the binding of oxyresveratrol and piceatannol to trypsin and lysozyme induced some microenvironmental and conformational changes of the two enzymes. The thermal stability of the enzymes in the presence of polyphenols was studied based on the change in melting temperature by differential scanning calorimetry. The above experimental results were validated by the protein-ligand docking studies which showed the location of the two ligands in the enzymes and the surrounding amino acid residues. Furthermore, enzyme activity assays indicated that the enzymatic activity of trypsin and lysozyme was inhibited by oxyresveratrol and piceatannol. The effect of trypsin and lysozyme on the antioxidant activity and stability of oxyresveratrol and piceatannol was also investigated. In conclusion, the comparative study on the interaction of oxyresveratrol and piceatannol with trypsin and lysozyme showed that the positions of hydroxyl groups of the polyphenols had an important influence on their interaction with enzymes and their antioxidant activity and stability as well as the enzyme activities. The obtained results are expected to provide a theoretical basis for the application of polyphenols in functional foods and pharmaceuticals.

Topics: Binding Sites; Circular Dichroism; Enzyme Stability; Hydrogen Bonding; Molecular Docking Simulation; Muramidase; Plant Extracts; Protein Binding; Stilbenes; Trypsin

The natural polyphenol resveratrol and its analogue piceatannol have various beneficial effects including antiarrhythmic properties. The aim of the present study was to examine potential electrophysiologic effects in an experimental whole-heart model of atrial fibrillation (AF). Simultaneous infusion of resveratrol (50 μmol/L) or piceatannol (10 μmol/L) in rabbit hearts resulted in an increase in atrial refractory period. Both agents induced a significant slowing of atrial conduction and of intrinsic heart rate. In both groups, a trend toward a reduction in AF and a regularization of AF was observed.

Topics: Animals; Atrial Fibrillation; Atrial Function; Dose-Response Relationship, Drug; Electrophysiological Phenomena; Heart Atria; Rabbits; Resveratrol; Stilbenes

The individual and combined interactions of bisphenol F and piceatannol with pepsin were investigated using spectroscopic methods (fluorescence, UV-vis absorption, and circular dichroism spectroscopy), combined with isothermal titration calorimetry and molecular docking. Thermodynamic data showed that hydrogen bonds and van der Waals forces might play a major role for the binding process. Site marking experiments and molecular docking confirmed the binding sites of these two ligands on pepsin. The discrepancy in the binding constant between the binary and ternary systems indicated the competitive binding of piceatannol and bisphenol F to pepsin. Circular dichroism spectra studies suggested that the binding of the two ligands led to a loosening of pepsin backbone. Enzyme activity assays indicated that the inhibition of pepsin activity by piceatannol and bisphenol F was competitive. These results will be helpful to understand the mechanism of piceatannol and bisphenol F affecting the activity of digestive proteases in the sight of the food security.

Topics: Benzhydryl Compounds; Binding Sites; Calorimetry; Molecular Docking Simulation; Pepsin A; Phenols; Spectrum Analysis; Stilbenes

Hypoxia inducible factor and nuclear factor-kappa beta pathways have been proposed as therapeutic targets for several inflammatory diseases. Caffeic acid phenethyl ester (CAPE) and piceatannol (PIC) are natural anti-inflammatory compounds; however, poor bioavailability and limited understanding of biomolecular mechanistic limits its clinical use. The aims of this study are to enhance bioavailability and investigate their impact on nuclear p65 and HIF-1α for the first time in experimental colitis.Dextran sulphate sodium was used to induce colitis in mice and effect of either free CAPE/PIC or CAPE/PIC loaded albumin nanoparticles treatment was observed on disease development and levels of cellular p65 and HIF-1α.Our results indicate that albumin nano-encapsulation of CAPE/PIC not only enhances its anti-inflammatory potential but also potentiates its ability to effectively modulate inflammation related biomolecular pathways. Hence, combining nanotechnology with natural compounds could result in development of new therapeutic options for IBD.

Topics: Albumins; Animals; Biological Availability; Caffeic Acids; Colitis; Dextran Sulfate; Disease Models, Animal; Drug Combinations; Drug Compounding; Drug Synergism; Gene Expression Regulation; Hypoxia-Inducible Factor 1, alpha Subunit; Mice; Nanoparticles; Particle Size; Phenylethyl Alcohol; Signal Transduction; Stilbenes; Transcription Factor RelA

Piceatannol (3,3',4,5'-trans-trihydroxystilbene) is a natural polyphenols compound that occurs hydroxylated analogue of resveratrol showing widely biological activities. Previous studies have demonstrated its functions on anti-cancer, neuroprotection and cardioprotection. However, few studies have clarified the benefits of piceatannol on cardiomyocytes except its anti-oxidative effect based on the original property of polyphenols. Here we apply H9c2 cardiomyocytes to study the cardioprotective mechanisms of piceatannol in vitro. We firstly verify its anti-peroxidation effect by using H

Topics: Animals; Cell Line; Cell Survival; Dose-Response Relationship, Drug; Myocytes, Cardiac; Nitric Oxide Synthase Type III; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Rats; Signal Transduction; Stilbenes

Several components isolated from rhubarb, the root of Rheum undulatum L., including emodin, rhein, rhaponticin, and piceatannol, have been reported to induce cell death and inhibit metastasis in various types of cancer. Recently, piceatannol-3-O-β-D-glucopyranoside (PG) isolated from rhubarb was demonstrated to improve vascular dysfunction by inhibiting arginase activity.. In this study, we examined the anti-cancer activities of PG, including effects on the proliferation, metastasis, and angiogenesis of endothelial and malignant cancer cells.. We found that PG did not affect the proliferation of human fibrosarcoma (HT1080) and human umbilical vein endothelial cells (HUVECs) at treatments up to 100  μM. However, PG efficiently suppressed the metastatic ability of HT1080 cells, as determined by scratch wound migration, transwell migration/invasion assay, and three-dimensional (3D) spheroid invasion assay. PG significantly suppressed the phorbol 12-myristate 13-acetate (PMA)-induced increase of matrix metalloproteinase (MMP)-9 expression as well as gelatinolytic MMP-9 activity, which are essential for cancer metastasis. In addition, PG treatment reduced the production of proangiogenic factors in HT1080 cells under normoxic and hypoxic conditions and suppressed hypoxia-induced activation of the hypoxia-inducible factor (HIF)-1α pathway. We also found that HUVEC angiogenic activity, including migration and tubular structure formation, were significantly reduced by PG treatment. Moreover, in an in ovo chick chorioallantoic membrane assay, spontaneous and vascular endothelial growth factor (VEGF)-induced vessel formation were significantly inhibited by PG treatment.. These results collectively indicate that PG has potent anti-metastatic and anti-angiogenic activities with no cytotoxicity. Thus, PG may be useful to limit the hyperplasia of malignant tumors and the spread of cancer to distant secondary organs.

Topics: Adult; Angiogenesis Inhibitors; Animals; Cell Line, Tumor; Cell Movement; Chick Embryo; Chorioallantoic Membrane; Fibrosarcoma; Glucosides; Human Umbilical Vein Endothelial Cells; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Matrix Metalloproteinase 9; Neovascularization, Pathologic; Stilbenes; Tetradecanoylphorbol Acetate; Vascular Endothelial Growth Factor A

For the first time, we developed an electrochemical sensor for piceatannol based on a new type of nanocomposite: graphene oxide nano sheets decorated with core-shell NiO@polypyrrole nanoparticles (NiO@Ppy/GO) mixed with nafion and casted on the surface of glassy carbon electrode. The nanocomposite was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction and Fourier transform infrared spectroscopy (FT-IR) techniques. The square wave voltammetry as a sensitive technique and cyclic voltammetry were selected for the quantification of piceatannol in 0.1 M phosphate buffer solution (pH 7.0). Several parameters were evaluated such as pH value, scan rate and supporting electrolyte type for the determination of piceatannol. In addition, selectivity and repeatability measurements were also evaluated. Under the optimized conditions, linear range and limit of detection were obtained 0.01-10.0 µM and 0.003 µM, respectively. Relative standard deviation for 3.0 µM and 6.5 µM were calculated 3.25% and 1.83%, respectively. The proposed sensor was applied successfully for the quantification analysis of piceatannol in grape skin essential oil and urine sample with satisfactory results.

Topics: Electrochemical Techniques; Electrodes; Fluorocarbon Polymers; Fruit; Graphite; Humans; Nanocomposites; Nanoparticles; Nickel; Oils, Volatile; Oxides; Polymers; Pyrroles; Stilbenes; Vitis

Liver fibrosis and fibrosis-associated hepatocarcinogenesis are driven by chronic inflammation and are leading causes of morbidity and death worldwide. SYK signaling regulates critical processes in innate and adaptive immunity, as well as parenchymal cells. We discovered high SYK expression in the parenchymal hepatocyte, hepatic stellate cell (HSC), and the inflammatory compartments in the fibrotic liver. We postulated that targeting SYK would mitigate hepatic fibrosis and oncogenic progression. We found that inhibition of SYK with the selective small molecule inhibitors Piceatannol and PRT062607 markedly protected against toxin-induced hepatic fibrosis, associated hepatocellular injury and intra-hepatic inflammation, and hepatocarcinogenesis. SYK inhibition resulted in increased intra-tumoral expression of the p16 and p53 but decreased expression of Bcl-xL and SMAD4. Further, hepatic expression of genes regulating angiogenesis, apoptosis, cell cycle regulation, and cellular senescence were affected by targeting SYK. We found that SYK inhibition mitigated both HSC trans-differentiation and acquisition of an inflammatory phenotype in T cells, B cells, and myeloid cells. However, in vivo experiments employing selective targeted deletion of SYK indicated that only SYK deletion in the myeloid compartment was sufficient to confer protection against fibrogenic progression. Targeting SYK promoted myeloid cell differentiation into hepato-protective TNFα

Topics: Animals; Carcinogenesis; Carcinoma, Hepatocellular; Cell Transdifferentiation; Cyclohexylamines; Female; Fibrosis; Hepatic Stellate Cells; Humans; Interleukin-8; Lectins, C-Type; Liver; Liver Cirrhosis; Liver Neoplasms; Male; Mannose Receptor; Mannose-Binding Lectins; Mice; Mice, Inbred C57BL; Myeloid Cells; Neoplasms, Experimental; Oxidative Phosphorylation; Phenotype; Pyrimidines; Receptors, Cell Surface; Signal Transduction; Stilbenes; Syk Kinase; Transcriptome

Stilbenoids represent a large group of bioactive compounds, which occur in food and medicinal plants. Twenty-five stilbenoids were screened in vitro for their ability to inhibit COX-1, COX-2 and 5-LOX. Piceatannol and pinostilbene showed activity comparable to the zileuton and ibuprofen, respectively. The anti-inflammatory potential of stilbenoids was further evaluated using THP-1 human monocytic leukemia cell line. Tests of the cytotoxicity on the THP-1 and HCT116 cell lines showed very low toxic effects. The tested stilbenoids were evaluated for their ability to attenuate the LPS-stimulated activation of NF-κB/AP-1. Most of the tested substances reduced the activity of NF-κB/AP-1 and later attenuated the expression of TNF-α. The effects of selected stilbenoids were further investigated on inflammatory signaling pathways. Non-prenylated stilbenoids regulated attenuation of NF-ĸB/AP-1 activity upstream by inhibiting the phosphorylation of MAPKs. A docking study used to in silico analyze the tested compounds confirmed their interaction with NF-ĸB, COX-2 and 5-LOX.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Cyclooxygenase 2 Inhibitors; Drug Evaluation, Preclinical; HCT116 Cells; Humans; Lipopolysaccharides; Lipoxygenase Inhibitors; Macrophages; Molecular Docking Simulation; NF-kappa B; Prenylation; Signal Transduction; Stilbenes; Transcription Factor AP-1; Tumor Necrosis Factor-alpha

The currently accepted paradigm is that fruits and vegetables should be consumed fresh and that their quality deteriorates during storage; however, there are indications that some metabolic properties can, in fact, be improved. We examined the effects of low temperature and high-CO

Topics: Acetates; Anaerobiosis; Benzofurans; Carbon Dioxide; Cold Temperature; Food Storage; Metabolomics; Pyruvic Acid; Signal Transduction; Stilbenes; Transcription Factors; Transcriptome; Up-Regulation; Vitis

Liver plays a pivotal role in host defense mechanisms related to endotoxemia. However, liver dysfunction often occurs in early sepsis. This study investigated the hepatoprotective potential of natural stilbenoid piceatannol (PIC) in lipopolysaccharide (LPS)-induced endotoxemic mice. Swiss Albino mice were divided into four groups: Control (C), LPS administrated (LPS), PIC administrated (PIC), and LPS administrated/PIC preadministrated (LPS+PIC) animals. PIC was administrated intraperitoneally (i.p.) at the dose of 4 mg/kg/day during 7 days. Endotoxemia was induced with a single i.p. administration of LPS at the dose of 4 mg/kg. Superoxide dismutase (SOD), catalase (CAT) and lipid peroxidation (LP) levels, light microscopic pathology, and genotoxicity were investigated. Proliferating cell nuclear antigen and SQSTM1/p62 immunofluorescence were measured. PIC preadministration restored SOD activity, reduced LP and genotoxicity. However, moderate level of oxidative stress (OS) had been progressed in PIC preadministrated animals depending upon prolonged autophagic response and selective degradation of CAT. Positive OS stimulated liver regeneration by upregulating oval cells' and downregulating hepatocytes' proliferation and resulted in the maintanence of hepatic tissue integrity in PIC preadministrated animals. These results suggested that PIC may be a useful hepatoprotective agent in LPS-induced endotoxemia as a modulator of OS and genotoxicity, as an inducer of autophagy, and as a promoter of liver regeneration.

Topics: Animals; Catalase; Endotoxemia; Humans; Liver; Male; Mice; Oxidative Stress; Regeneration; Stilbenes; Superoxide Dismutase

Stilbenoids are dietary phenolics with notable biological effects on humans. Epidemiological, clinical, and nutritional studies from recent years have confirmed the significant biological effects of stilbenoids, such as oxidative stress protection and the prevention of degenerative diseases, including cancer, cardiovascular diseases, and neurodegenerative diseases. Stilbenoids are intensively metabolically transformed by colon microbiota, and their corresponding metabolites might show different or stronger biological activity than their parent molecules. The aim of the present study was to determine the metabolism of six stilbenoids (resveratrol, oxyresveratrol, piceatannol, thunalbene, batatasin III, and pinostilbene), mediated by colon microbiota. Stilbenoids were fermented in an in vitro faecal fermentation system using fresh faeces from five different donors as an inoculum. The samples of metabolized stilbenoids were collected at 0, 2, 4, 8, 24, and 48 h. Significant differences in the microbial transformation among stilbene derivatives were observed by liquid chromatography mass spectrometry (LC/MS). Four stilbenoids (resveratrol, oxyresveratrol, piceatannol and thunalbene) were metabolically transformed by double bond reduction, dihydroxylation, and demethylation, while batatasin III and pinostilbene were stable under conditions simulating the colon environment. Strong inter-individual differences in speed, intensity, and pathways of metabolism were observed among the faecal samples obtained from the donors.

Topics: Chromatography, Liquid; Colon; Feces; Fermentation; Humans; Mass Spectrometry; Microbiota; Phenols; Resveratrol; Stilbenes; Tandem Mass Spectrometry

Piceatannol, a polyphenolic compound present in grapes and wine, has been reported to exhibit anticancer properties. Recently, it has been demonstrated to exert antiproliferative and proapoptotic effects in various human cancer types. The aim of our study was to investigate whether piceatannol induces autophagy and apoptosis in MOLT-4 human leukemia cells. Our results revealed that piceatannol activated autophagy in MOLT-4 cells, as evidenced by the detection of an increased level of LC3-II protein and a concomitant decrease in p62/SQSTM1 protein level. Moreover, piceatannol induced apoptosis in MOLT-4 cells which was accompanied by phosphatidylserine externalization, caspase-3 activation, disruption of mitochondrial membrane potential, internucleosomal DNA fragmentation, PARP1 cleavage, chromatin condensation, and fragmentation of cell nuclei. However, the toxic effects exerted by piceatannol in MOLT4 cells diminished after longer periods of exposure to the compound. Our findings imply that MOLT-4 cells may acquire resistance to piceatannol toxicity, which may result from the induction of efflux transporters such as P-glycoprotein. The present study provides new data showing that the use of piceatannol as a potential chemotherapeutic agent in the treatment of leukemia may be associated with the risk of multidrug resistance.

Topics: Antineoplastic Agents; Apoptosis; ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP Binding Cassette Transporter, Subfamily G, Member 2; Autophagy; Cell Line, Tumor; Drug Resistance, Neoplasm; Humans; Leukemia; Multidrug Resistance-Associated Proteins; Neoplasm Proteins; Stilbenes

Hypoxia-ischemia (HI) remains a major cause of perinatal mortality and chronic disability in newborns worldwide (1-6 for 1000 births) with a high risk of future motor, behavioral and neurological deficits. Keeping newborns under moderate hypothermia is the unique therapeutic approach but is not sufficiently successful as nearly 50% of infants do not respond to it. In a 7-day post-natal rat model of HI, we used pregnant and breastfeeding female nutritional supplementation with piceatannol (PIC), a polyphenol naturally found in berries, grapes and passion fruit, as a neuroprotective strategy. Maternal supplementation led to neuroprotection against neonate brain damage and reversed their sensorimotor deficits as well as cognitive impairments. Neuroprotection of per os maternal supplementation with PIC is a preventive strategy to counteract brain damage in pups induced by HI. This nutritional approach could easily be adopted as a preventive strategy in humans.

Topics: Animals; Animals, Newborn; Behavior, Animal; Brain; Brain Injuries; Cognitive Dysfunction; Dietary Supplements; Disease Models, Animal; Female; Hypoxia; Hypoxia-Ischemia, Brain; Ischemia; Maternal Nutritional Physiological Phenomena; Neurons; Neuroprotection; Neuroprotective Agents; Pregnancy; Rats; Stilbenes

Recent investigations have revealed that, in addition to monolignols, some phenolic compounds derived from the flavonoid and hydroxystilbene biosynthetic pathways can also function as true lignin monomers in some plants. In this study, we found that the hydroxystilbene glucosides isorhapontin (isorhapontigenin-

Topics: Glucosides; Lignin; Magnetic Resonance Spectroscopy; Models, Chemical; Molecular Structure; Norway; Picea; Plant Bark; Resveratrol; Stilbenes

Recent experimental work has revealed that the hydroxystilbene piceatannol can function as a monomeric unit in the lignification of palm fruit endocarp tissues. Results indicated that piceatannol homo-couples and cross-couples with monolignols through radical reactions and is integrally incorporated into the lignin polymer. The current work reports on the thermodynamics of the proposed reactions using density functional theory calculations. The results indicated that, in general, the energetics of both homo-coupling and cross-coupling are not dissimilar from those of the monolignol coupling, demonstrating the compatibility of piceatannol with the lignification process. Moreover, the DFT methods appear to predict the correct courses of post-coupling rearomatization reactions.

Topics: Density Functional Theory; Free Radicals; Lignin; Molecular Structure; Stilbenes; Thermodynamics

Piceatannol is a valuable natural polyphenol with therapeutic potential in cardiovascular and metabolic disease treatment. In this study, we screened for microorganisms capable of producing piceatannol from resveratrol via regioselective hydroxylation. In the first screening, we isolated microorganisms utilizing resveratrol, phenol, or 4-hydroxyphenylacetic acid as a carbon source for growth. In the second screening, we assayed the isolated microorganisms for hydroxylation of resveratrol. Using this screening procedure, a variety of resveratrol-converting microorganisms were obtained. One Gram-negative bacterium, Ensifer sp. KSH1, and one Gram-positive bacterium, Arthrobacter sp. KSH3, utilized 4-hydroxyphenylacetic acid as a carbon source for growth and efficiently hydroxylated resveratrol to piceatannol without producing any detectable by-products. The hydroxylation activity of strains KSH1 and KSH3 was strongly induced by cultivation with 4-hydroxyphenylacetic acid as a carbon source during stationary growth phase. Using the 4-hydroxyphenylacetic acid-induced cells as a biocatalyst under optimal conditions, production of piceatannol by strains KSH1 and KSH3 reached 3.6 mM (0.88 g/L) and 2.6 mM (0.64 g/L), respectively. We also cloned genes homologous to the monooxygenase gene hpaBC from strains KSH1 and KSH3. Introduction of either hpaBC homolog into Escherichia coli endowed the host with resveratrol-hydroxylating activity.

Topics: Arthrobacter; Bacterial Proteins; Biocatalysis; Carbon; Gram-Negative Bacteria; Gram-Positive Bacteria; Hydroxylation; Resveratrol; Stilbenes

The objective of this work is to investigate the inhibition effects on AGEs formation and the ability of scavenging toxic carbonyls of three stilbenes, resveratrol, oxyresveratrol, and piceatannol. The results showed that the three stilbenes had the activity to inhibit the AGEs formation in BSA-acrolein and BSA-methylglyoxal models, especially piceatannol which showed the strongest inhibition effects on the formation of AGEs with the half maximal inhibitory concentrations (IC

Topics: Acrolein; Glycation End Products, Advanced; Hydrogen-Ion Concentration; Plant Extracts; Pyruvaldehyde; Resveratrol; Serum Albumin, Bovine; Stilbenes; Temperature

This study investigates the molecular mechanisms of the nephroprotective effect of piceatannol (PIC) against cisplatin-induced nephrotoxicity in rats. PIC (10 mg/kg i.p.) was given for 7 days, starting 2 days before cisplatin single injection (7 mg/kg i.p.). Serum creatinine, blood urea nitrogen (BUN), kidney injury molecule 1, and neutrophil gelatinase-associated lipocalin were used as nephrotoxicity markers. Oxidative stress, inflammatory, and apoptotic markers were determined. In addition, the role of PIC in Nrf2 activation and its subsequent induction of antioxidant enzymes, as well as its potential cross talk with nuclear factor kappa-B, were addressed. PIC reversed cisplatin-induced elevation of nephrotoxicity markers and restored the normal kidney ultrastructure. PIC attenuated cisplatin-induced reduction in Nrf2 expression and the relative mRNA level of antioxidant enzymes: hemeoxygenase-1, cysteine ligase catalytic, and modifier subunits, as well as superoxide dismutase and glutathione-S-transferase activities. Cisplatin pro-inflammatory response was reduced by PIC treatment as evidenced by the suppression of nuclear factor kappa-B activation and the subsequent decreased tissue levels of interleukin-1β, tumor necrosis factor-α, cyclooxygenase-2, and inducible nitric oxide synthase. PIC suppressed cisplatin-induced apoptosis by decreasing p53 and cytochrome C expression and caspase-3 activity. Therefore, PIC may protect against cisplatin-induced nephrotoxicity by modulating Nrf2/HO-1 signaling and hindering the inflammatory and apoptotic pathways.

Topics: Animals; Antineoplastic Agents; Apoptosis; Biomarkers; Cisplatin; Cytokines; Heme Oxygenase (Decyclizing); Kidney; Kidney Diseases; Male; NF-E2-Related Factor 2; NF-kappa B; Oxidative Stress; Protective Agents; Rats, Wistar; Signal Transduction; Stilbenes

Neutrophils are implicated in numerous inflammatory diseases, and especially in acute ischemic stroke (AIS). The unchecked migration of neutrophils into cerebral ischemic regions, and their subsequent release of reactive oxygen species, are considered the primary causes of reperfusion injury following AIS. Reducing the infiltration of inflammatory neutrophils may therefore be a useful therapy for AIS. Here, inspired by the specific cell-cell recognition that occurs between platelets and inflammatory neutrophils, we describe platelet-mimetic nanoparticles (PTNPs) that can be used to directly recognize, intervene, and monitor inflammatory neutrophils in the AIS treatment and therapeutic evaluation. We demonstrate that PTNPs, coloaded with piceatannol, a selective spleen tyrosine kinase inhibitor, and superparamagnetic iron oxide (SPIO), a T2 contrast agent, can successfully recognize adherent neutrophils via platelet membrane coating. The loaded piceatannol could then be delivered to adherent neutrophils and detach them into circulation, thus decreasing neutrophil infiltration and reducing infarct size. Moreover, when coupled with magnetic resonance imaging, internalized SPIO could be used to monitor the inflammatory neutrophils, associated with therapeutic effects, in real time. This approach is an innovative method for both the treatment and therapeutic evaluation of AIS, and provides new insights into how to treat and monitor neutrophil-associated diseases.

Topics: Animals; Biomimetic Materials; Blood Platelets; Brain; Brain Ischemia; Cell Tracking; Contrast Media; Magnetite Nanoparticles; Mice; Neutrophils; RAW 264.7 Cells; Stilbenes; Stroke

Piceatannol (PIC) is a natural hydroxylated analog of resveratrol (RSV) and considered as a potential metabolic regulator. The purpose of this study was to compare the effects of PIC and RSV on parameters affecting inflammation, oxidative stress, and sirtuins (Sirt). Male C57BL/6J mice, 20 weeks old, were assigned to the following groups; (1) lean control, (2) high-fat diet control (HF), (3) HF_PIC, and (4) HF_RSV. Oral administration of PIC and RSV (10 mg/kg/day) for 4 weeks improved glucose control as shown by decreasing levels of area under the curve (AUC) during the oral glucose tolerance test compared with HF group. PIC improved glycemic control by increasing hepatic levels of insulin receptor and AMP-activated protein kinase. PIC increased the levels of Sirt1, Sirt3, and Sirt6 and also increased two downstream targets of Sirt, peroxisome proliferator-activated receptor gamma coactivator 1-alpha and forkhead box O1, in the liver. The inflammatory markers, interleukin (IL)-1 and IL-6, in the liver were downregulated by RSV treatment. Exposure to PIC and RSV significantly lowered hepatic levels of tumor necrosis factor-alpha. However, PIC and RSV treatments showed minimal effects on hepatic markers of oxidative stress. The levels of antioxidant enzyme, NAD(P)H:quinone oxidoreductase 1 (NQO1), were only increased in livers of RSV-treated mice compared with HF control mice. In conclusion, PIC was superior to an equal concentration of RSV in the regulation of Sirt and its downstream targets as well as insulin signaling-related parameters, while RSV potentially suppressed levels of proinflammatory markers and increased NQO1 protein levels.

Topics: Animals; Diet, High-Fat; Humans; Liver; Liver Diseases; Male; Mice; Mice, Inbred C57BL; NAD(P)H Dehydrogenase (Quinone); Oxidative Stress; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Resveratrol; Sirtuins; Stilbenes; Tumor Necrosis Factor-alpha

Topics: Antioxidants; Apoptosis; Apoptosis Regulatory Proteins; Cell Line; Cytoprotection; Epithelial Cells; Heme Oxygenase-1; Humans; Hydrogen Peroxide; NF-E2-Related Factor 2; Oxidative Stress; Phosphatidylinositol 3-Kinase; Proto-Oncogene Proteins c-akt; Retinal Pigment Epithelium; Signal Transduction; Stilbenes

Diabetic cardiomyopathy (DCM) is one of the leading causes of morbidity and mortality in diabetic patients. Piceatannol (PIC) has protective effects against cardiovascular disease; however, it remains unknown whether it also protects against DCM. A Cell Counting Kit-8 (CCK-8) assay was used to evaluate the effects of PIC on the viability of high glucose (HG)-induced H9C2 cells. Protein expression and mRNA levels were detected by western blotting and real-time polymerase chain reaction (RT-PCR), respectively. In vivo, physical and biochemical analyses, together with transthoracic echocardiography and hemodynamic measurements, were used to detect the effects of PIC treatment on cardiac function in DCM rats. Reactive oxygen species production was determined using an ELISA kit, and inflammatory cytokines were detected by RT-PCR. Pathological changes were assessed by hematoxylin-eosin staining, immunohistochemical staining, and TUNEL staining. According to the results, PIC treatment improved cell viability and inhibited cell apoptosis in HG-induced H9C2 cardiac myoblasts. In addition, PIC not only attenuated the over-production of interleukin-6 (IL-6) (P < 0.05) and tumor necrosis factor alpha (TNF-α) (P < 0.05), but also improved the expression of nuclear factor E2-related factor 2 (Nrf2) (P < 0.05) and heme oxygenase-1 (HO-1) (P < 0.01). Importantly, knockdown of Nrf2 suppressed PIC-mediated activation of the Nrf2/HO-1 pathway and abolished its anti-inflammatory effects. In vivo, oral administration of PIC suppressed STZ-induced inflammation, oxidative stress hypertrophy, fibrosis(myocardial collagen volume fraction in 5 mg/kg and 10 mg/kg PIC group was decreased 25.83% and 55.61% compared with the DM group), and apoptosis(Caspase-3 level in 5 mg/kg and 10 mg/kg PIC group was decreased 13.21% and 33.91% compared with the DM group), thereby relieving cardiac dysfunction and improving both fibrosis and pathological changes in cardiac tissues of diabetic rats. These findings define for the first time that the effects of PIC against DCM can be attributed to its role in inflammation and oxidative stress inhibition.

Topics: Animals; Cell Line; Diabetic Cardiomyopathies; Heme Oxygenase-1; Humans; Inflammation; NF-E2-Related Factor 2; NF-kappa B; Oxidative Stress; Rats; Signal Transduction; Stilbenes

As a traditional natural medicine for treating many kinds of diseases,

Topics: Allopurinol; Biphenyl Compounds; Enzyme Inhibitors; Free Radical Scavengers; Gnetum; High-Throughput Screening Assays; Kinetics; Least-Squares Analysis; Picrates; Plant Extracts; Resveratrol; Stilbenes; Ultrafiltration; Xanthine Oxidase

Stilbenes with well-known antioxidant and antiradical properties are beneficial in different pathologies including cardiovascular diseases. The present research was performed to investigate the potential protective effect of resveratrol (1) and piceatannol (2), against hypoxia-induced oxidative stress in the H9c2 cardiomyoblast cell line, and the underlying mechanisms. Compounds 1 and 2 significantly inhibited the release of peroxynitrite and thiobarbituric acid levels at na no- or submicromolar concentrations, and this effect was more evident in piceatannol-treated cells, that significantly increased MnSOD protein level in a concentration dependent manner. Furthermore, since piceatannol, which is far less abundant in natural sources, displayed a higher bioactivity than the parent compound, we hereby report on a very fast synthesis and detailed structure-based design of a focused stilbene library. Finally, taking into account that hypoxia-induced ROS accumulation also increases expression and activity of 5-lipoxygenase (5-LOX) with production of leukotrienes, we have disclosed structural key factors crucial for 5-LOX activity. Among the synthesized analogues ( 3-7), compound 7 was the most effective in improving cardiomyocytes viability and in 5-LOX inhibition. In conclusion, modeling and experimental studies provided the basis for further optimization of stilbene analogues as multi-target inhibitors of the inflammatory and oxidative pathway.

Topics: Animals; Arachidonate 5-Lipoxygenase; Cell Proliferation; Cells, Cultured; Dose-Response Relationship, Drug; Hypoxia; Lipoxygenase Inhibitors; Molecular Structure; Myocytes, Cardiac; Protective Agents; Rats; Stilbenes; Structure-Activity Relationship

Mastocytoma are frequently diagnosed cutaneous neoplasms in dogs. In non-resectable mastocytoma patients, novel targeted drugs are often applied. The transcription factor STAT5 has been implicated in the survival of human neoplastic mast cells (MC). Our study evaluated the JAK2/STAT5 pathway as a novel target in canine mastocytoma.. We employed inhibitors of JAK2 (R763, TG101348, AZD1480, ruxolitinib) and STAT5 (pimozide, piceatannol) and evaluated their effects on 2 mastocytoma cell lines, C2 and NI-1.. Activated JAK2 and STAT5 were detected in both cell lines. The drugs applied were found to inhibit proliferation and survival in these cells with the following rank-order of potency: R763 > TG101348 > AZD1480 > pimozide > ruxolitinib > piceatannol. Moreover, synergistic anti-neoplastic effects were obtained by combining pimozide with KIT-targeting drugs (toceranib, masitinib, nilotinib, midostaurin) in NI-1 cells.. The JAK2/STAT5 pathway is a novel potential target of therapy in canine mastocytoma.

Topics: Animals; Apoptosis; Cell Line, Tumor; Cell Proliferation; Dog Diseases; Dogs; Flow Cytometry; Janus Kinase 2; Mastocytoma; Nitriles; Norbornanes; Pimozide; Pyrazoles; Pyrimidines; Pyrrolidines; Signal Transduction; STAT5 Transcription Factor; Stilbenes; Sulfonamides

Aging is a complex process that is accompanied by neurological damage. Chronic injection of d-galactose (d-gal) can accelerate the aging process similar to natural aging and is commonly used to build an aging model to investigate aging. In the present study, the effects of piceatannol on d-gal-induced aging in mice were evaluated. Piceatannol treatment showed an observable anti-aging effect. Results obtained in vivo showed that piceatannol retained spontaneous motor activity and enhanced spatial learning and memory abilities in mice in which aging was induced by d-gal. Morphometric analysis displayed that piceatannol prevented d-gal-induced neuronal loss, increased the number of Nissl bodies, and promoted cell proliferation in the hippocampus and cortex. Piceatannol also significantly decreased the level of MDA and elevated SOD and CAT activity in the hippocampal and cortical tissues. Furthermore, western blotting results revealed that piceatannol treatment noticeably reversed the suppression of Nrf2 nuclear translocation and increased the expressions of HO-1 and NOQ1 in mice with aging induced by d-gal. Furthermore, piceatannol activated the Nrf2 pathway in natural aging mice, whereas treatment with the Nrf2 inhibitor brusatol reversed the increased expressions of Nrf2, HO-1, and NOQ1. In conclusion, treatment with piceatannol ameliorates behavioral disorder and brain injury in an aging mouse model; this suggests that piceatannol is a promising pharmaceutical candidate for the treatment of age-associated diseases.

Topics: Aging; Animals; Disease Models, Animal; Hippocampus; Humans; Male; Maze Learning; Memory; Mice; Nervous System Diseases; Neuroprotective Agents; NF-E2-Related Factor 2; Oxidative Stress; Stilbenes

The lignins from different anatomical parts of macaúba (Acrocomia aculeata) palm fruit, namely stalks, epicarp, and endocarp, were studied. The lignin from stalks was enriched in S-lignin units (S/G 1.2) and β-ether linkages (84% of the total) and was partially acylated at the γ-OH of the lignin side-chains (26% lignin acylation), predominantly with p-hydroxybenzoates and acetates. The epicarp lignin was highly enriched in G-lignin units (S/G 0.2) and consequently depleted in β-ethers (65%) and enriched in condensed structures such as phenylcoumarans (24%) and dibenzodioxocins (3%). The endocarp lignin was strikingly different from the rest and presented large amounts of piceatannol units incorporated into the polymer. This resulted in a lignin polymer depleted in β-ethers but enriched in condensed structures and linked piceatannol moieties. The incorporation of piceatannol into the lignin polymer seems to have a role in seed protection.

Topics: Acylation; Arecaceae; Cell Wall; Chromatography, Gel; Gas Chromatography-Mass Spectrometry; Lignin; Magnetic Resonance Spectroscopy; Molecular Weight; Polysaccharides; Stilbenes

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is one of the key redox-sensitive proteins whose activity is largely affected by oxidative modifications at its highly reactive cysteine residue in the enzyme's active site (Cys149). Prolonged exposure to oxidative stress may cause, inter alia, the formation of intermolecular disulfide bonds leading to accumulation of GAPDH aggregates and ultimately to cell death. Recently these anomalies have been linked with the pathogenesis of Alzheimer's disease. Novel evidences indicate that low molecular compounds may be effective inhibitors potentially preventing the GAPDH translocation to the nucleus, and inhibiting or slowing down its aggregation and oligomerization. Therefore, we decided to establish the ability of naturally occurring compound, piceatannol, to interact with GAPDH and to reveal its effect on functional properties and selected parameters of the dehydrogenase structure. The obtained data revealed that piceatannol binds to GAPDH. The ITC analysis indicated that one molecule of the tetrameric enzyme may bind up to 8 molecules of polyphenol (7.3 ± 0.9). Potential binding sites of piceatannol to the GAPDH molecule were analyzed using the Ligand Fit algorithm. Conducted analysis detected 11 ligand binding positions. We indicated that piceatannol decreases GAPDH activity. Detailed analysis allowed us to presume that this effect is due to piceatannol ability to assemble a covalent binding with nucleophilic cysteine residue (Cys149) which is directly involved in the catalytic reaction. Consequently, our studies strongly indicate that piceatannol would be an exceptional inhibitor thanks to its ability to break the aforementioned pathologic disulfide linkage, and therefore to inhibit GAPDH aggregation. We demonstrated that by binding with GAPDH piceatannol blocks cysteine residue and counteracts its oxidative modifications, that induce oligomerization and GAPDH aggregation.

Topics: Calorimetry; Catalytic Domain; Circular Dichroism; Glyceraldehyde-3-Phosphate Dehydrogenases; Hydrogen Peroxide; Ligands; Microscopy, Electron, Transmission; Models, Molecular; Protein Binding; Protein Structure, Secondary; Stilbenes

The aim of the study was to synthesize nanoparticles (NPs) with chitosan (CS), and poly (lactic acid) (PLA) as a carrier for the drug piceatannol (PIC). The synthesized nanoparticles form the composite of polymeric-drug nanoparticles (CS/PLA-PIC NPs) by dropping method. The preliminary and stability studies were determined for the polymers drug-loading capacity and encapsulation efficiencies. The in vitro drug release study showed that NPs provided a continuous release of the entrapped PIC. The NPs found to be a good scavenger for DPPH, SOD and NO radicals. MTT and LDH assays revealed higher cytotoxic efficacy of CS/PLA-PIC NPs in HepG2, A549 and MCF7 cells compared to CS-PLA NPs and PIC. Dual staining results showed the early/late-stages of apoptotic and necrotic cells. Furthermore, cells treated with CS/PLA-PIC NPs showed fragmenting DNA and also demonstrated for apoptotic cells percentage by flow cytometry. These results suggested that upon CS/PLA-PIC NPs exposure leads to decrease in cancer cell viability due to apoptosis.

Topics: Apoptosis; Biphenyl Compounds; Breast Neoplasms; Cell Line, Tumor; Chitosan; DNA Fragmentation; Drug Carriers; Drug Liberation; Humans; Liver; Lung Neoplasms; MCF-7 Cells; Nanoparticles; Nitric Oxide; Picrates; Polyesters; Stilbenes; Superoxide Dismutase

Congenital diaphragmatic hernia (CDH) is a life-threatening developmental anomaly, intrinsically combining severe pulmonary hypoplasia and hypertension. During development, signal transducers and activators of transcription (STAT) are utilized to elicit cell growth, differentiation, and survival.. We used the nitrofen-induced CDH rat model. At selected gestational time points, lungs were divided into two experimental groups, i.e., control or CDH. We performed immunohistochemistry and western blotting analysis to investigate the developmental expression profile of the complete family of STATs (STAT1-6), plus specific STATs activation (p-STAT3, p-STAT6) and regulation by SOCS (SOCS3) in normal lungs against those of diseased lungs. The normal fetal lung explants were treated with piceatannol (STAT3 inhibitor) in vitro followed by morphometrical analysis.. Molecular profiling of STATs during the lung development revealed distinct early and late expression signatures. Experimental CDH altered the STATs expression, activation, and regulation in the fetal lungs. In particular, STAT3 and STAT6 were persistently over-expressed and early over-activated. Piceatannol treatment dose-dependently stimulated the fetal lung growth.. These findings suggest that STATs play an important role during normal fetal lung development and CDH pathogenesis. Moreover, functionally targeting STAT signaling modulates fetal lung growth, which highlights that STAT3 and STAT6 signaling might be promising therapeutic targets in reducing or preventing pulmonary hypoplasia in CDH.

Topics: Animals; Female; Fetal Development; Gene Expression; Hernias, Diaphragmatic, Congenital; Immunohistochemistry; Lung; Phenyl Ethers; Rats; Rats, Sprague-Dawley; STAT Transcription Factors; STAT3 Transcription Factor; STAT6 Transcription Factor; Stilbenes; Suppressor of Cytokine Signaling 3 Protein

Topics: Apigenin; Bacterial Proteins; Cytochrome P-450 Enzyme System; Doxorubicin; Ferredoxins; Flavanones; Flavones; Hydroxylation; Mixed Function Oxygenases; Models, Molecular; Molecular Docking Simulation; Oxidation-Reduction; Protein Conformation; Resveratrol; Stilbenes; Streptomyces; Substrate Specificity

Piceatannol is a rare, costly plant-based stilbene derivative and exhibits various health-enhancing properties. Recently, we demonstrated that piceatannol could be produced from resveratrol through site-selective hydroxylation using Escherichia coli cells expressing the monooxygenase HpaBC. However, piceatannol production ceased at approximately 25 mM, even when sufficient levels of the substrate resveratrol remained in the reaction mixture. In this study, we found that high concentrations (>20-25 mM) of piceatannol significantly inhibited the HpaBC-catalyzed reaction. Cyclodextrins (CDs) reportedly encapsulate various hydrophobic compounds. We found that the addition of β-CD or γ-CD to the reaction mixture reduced the inhibition caused by the product piceatannol. The effects of β-CD on piceatannol production were more pronounced than those of γ-CD at high concentrations of the substrate resveratrol and CDs. The production of piceatannol reached 49 mM (12 g L

Topics: Bacterial Proteins; Biocatalysis; Cyclodextrins; Escherichia coli; Mixed Function Oxygenases; Pseudomonas aeruginosa; Resveratrol; Stilbenes

Methylglyoxal (MG) is a reactive α-oxoaldehyde that increases under diabetic conditions and subsequently contributes to the complications associated with this disease. Piceatannol is a naturally occurring analogue of resveratrol that possesses multiple biological functions. The present study investigated the effects of piceatannol on MG-induced cytotoxicity in MC3T3-E1 osteoblastic cells. Piceatannol significantly restored MG-induced reductions in cell viability and reduced lactate dehydrogenase release in MG-treated MC3T3-E1 osteoblastic cells, which suggests that it suppressed MG-induced cytotoxicity. Piceatannol also increased glyoxalase I activity and glutathione levels in MG-treated cells, which indicates that it enhanced the glyoxalase system and thus cellular protection. The present study also showed that piceatannol inhibited the generation of inflammatory cytokines and reactive oxygen species and ameliorated mitochondrial dysfunction induced by MG. Furthermore, piceatannol treatment significantly reduced the levels of endoplasmic reticulum stress and autophagy induced by MG. Therefore, piceatannol could be a potent option for the development of antiglycating agents for the treatment of diabetic osteopathy.

Topics: Animals; Autophagy; Cell Line; Cell Survival; Endoplasmic Reticulum Stress; Enzyme Activation; Glutathione; L-Lactate Dehydrogenase; Lactoylglutathione Lyase; Mice; Osteoblasts; Protective Agents; Pyruvaldehyde; Reactive Oxygen Species; Stilbenes

Piceatannol, a grape-derived polyphenol, has been linked to proarrhythmic properties by aggravating inhomogeneous conduction delay in the ischemia-reperfusion (IR) zone to enhance arrhythmogenic alternans in heart failure (HF) rabbits. The underlying molecular mechanisms of piceatannol-induced conduction disturbance were unclear in this model.. HF was induced by 4 weeks' rapid ventricular pacing. IR injury was induced in vivo using a protocol of left coronary artery ligation and release. Left ventricular cardiomyocytes were isolated enzymatically for whole-cell patch-clamp studies. Piceatannol (10 μM) was administrated to test its inhibitory effect on sodium current (I. Peak I. Downregulation of NaV 1.5 protein expression and reduced peak I

Topics: Animals; Blotting, Western; Down-Regulation; Heart Failure; Myocytes, Cardiac; NAV1.5 Voltage-Gated Sodium Channel; Patch-Clamp Techniques; Rabbits; Reperfusion Injury; Stilbenes

Phenolic compounds are among the most investigated herbal remedies, as is especially the case for resveratrol. Many reports have shown its anti-aging properties and the ability to reduce obesity and diabetes induced by high-fat diet in mice. However, such beneficial effects hardly translate from animal models to humans. The scientific community has therefore tested whether other plant phenolic compounds may surpass the effects of resveratrol. In this regard, it has been reported that piceatannol reproduces in rodents the anti-obesity actions of its parent polyphenol. However, the capacity of piceatannol to inhibit adipocyte differentiation in humans has not been characterized so far. Here, we investigated whether piceatannol was antiadipogenic and antilipogenic in human preadipocytes. Human mesenchymal stem cells (hMSC), isolated from adipose tissues of lean and obese individuals, were differentiated into mature adipocytes with or without piceatannol, and their functions were explored. Fifty μM of piceatannol deeply limited synthesis/accumulation of lipids in both murine and hMSC-derived adipocytes. Interestingly, this phenomenon occurred irrespective of being added at the earlier or later stages of adipocyte differentiation. Moreover, piceatannol lowered glucose transport into adipocytes and decreased the expression of key elements of the lipogenic pathway (PPARγ, FAS, and GLUT4). Thus, the confirmation of the antiadipogenic properties of piceatanol in vitro warrants the realization of clinical studies for the application of this compound in the treatment of the metabolic complications associated with obesity.

Topics: 3T3-L1 Cells; Adipocytes; Adipogenesis; Adipose Tissue; Adult; Animals; Antioxidants; Biological Transport; Cells, Cultured; Dietary Supplements; fas Receptor; Glucose; Glucose Transporter Type 4; Humans; Lipogenesis; Mesenchymal Stem Cells; Mice; PPAR gamma; Stilbenes

The flavin-dependent monooxygenase Sam5 was previously reported to be a bifunctional hydroxylase with a coumarte 3-hydroxylase and a resveratrol 3'-hydroxylase activity. In this article, we showed the Sam5 enzyme has 3'-hydroxylation activities for methylated resveratrol (pinostilbene and pterostilbene), hydroxylated resveratrol (oxyresveratrol) and glycosylated resveratrol (piceid) as substrates. However, the use of piceid, a glycone type stilbene, as a substrate for bioconversion experiments with the Sam5 enzyme expressed in,

Topics: Dinitrocresols; Escherichia coli; Flavins; Glucosides; Hydroxylation; Mixed Function Oxygenases; Plant Extracts; Resveratrol; Stilbenes

Programmed cell death ligand 1 (PD‑L1) expressed in cancer cells interacting with its receptor programmed cell death 1 (PD‑1) expressed in immune cells represents a regulatory axis linked to the suppression and evasion of host immune functions. The blockade of PD‑1/PD‑L1 interaction using monoclonal antibodies has emerged as an effective therapy for several solid tumors; however, durable response has been observed in a subset of patients with PD‑L1-positive tumors. Thus, the understanding of the mechanisms responsible for the expression of PD‑L1 in tumor cells may help to improve the response to PD‑L1 blockade therapies. In this study, we investigated whether resveratrol, a grape-derived stilbenoid with immunoregulatory activity, modulates the expression of PD‑L1 in breast and colorectal cancer cells. The surface expression of PD‑L1 was determined by flow cytometry in cancer cells treated with resveratrol and/or piceatannol. Each stilbenoid alone induced PD‑L1 and when used in combination, elicited a synergistic upregulation of PD‑L1 in some cell lines. The induction of PD‑L1 by the combined use of stilbenoids was most pronounced in the Cal51 triple-negative breast cancer (TNBC) and SW620 colon cancer cells. The observed induction of PD‑L1 was transcriptionally mediated by nuclear factor (NF)-κB, as shown by NF‑κB reporter assays, the nuclear accumulation of the p65 subunit of NF‑κB, inhibition by the IKK inhibitor, BMS‑345541, and histone the modification inhibitors, resminostat, entinostat or anacardic acid. Combined treatment with resveratrol and piceatannol also decreased tumor cell survival as indicated by the upregulation of the DNA damaging marker, γH2AX, the cleavage of caspase 3, the downregulation of the survival markers, p38-MAPK/c‑Myc, and G1-to-S cell cycle arrest.

Topics: Antineoplastic Combined Chemotherapy Protocols; B7-H1 Antigen; Cell Line, Tumor; Cell Survival; Colonic Neoplasms; E1A-Associated p300 Protein; Female; G1 Phase Cell Cycle Checkpoints; Histone Deacetylases; Humans; NF-kappa B; Programmed Cell Death 1 Receptor; Resveratrol; Signal Transduction; Stilbenes; Treatment Outcome; Triple Negative Breast Neoplasms; Up-Regulation

Piceatannol, a natural derivative of resveratrol, has been shown to exert similar anti-oxidant and anti-inflammatory effects as resveratrol. However, it remains unknown whether piceatannol has hepatoprotective effect against acute liver injury. In this study, we investigated the in vivo effect of piceatannol on D-GalN/LPS-induced fulminant hepatic failure (FHF), and its in vitro effect on ER stress-inducing drug thapsigargin (TG)-induced proinflammatory cytokines production and ROS release. Our results indicated that piceatannol markedly decreased the mortality rate, reduced the serum levels of alanine transaminase and aspartic aminotransferase, ameliorated the liver damage induced by D-GalN/LPS in mice. In addition, piceatannol reduced the expression of proinflammatory cytokines, including TNF-α, IL-1β and IL-6, the expression of ER stress markers CHOP and phosphorylated-IRE1α, and the generation of oxidative stress in D-GalN/LPS-treated mouse liver. In vitro results were consistent with in vivo observations, demonstrating that piceatannol suppressed the secretion of proinflammatory cytokines, inflammasome activation and the production of ROS induced by TG with or without LPS priming in J774A.1 macrophages. Our study proposes piceatannol as a promising medication for preventing acute liver failure and the mechanisms may be related to its inhibitory effects on ER stress, inflammation and oxidative stress.

Topics: Animals; Anti-Inflammatory Agents; Cells, Cultured; Cytokines; Endoplasmic Reticulum Stress; Female; Galactosamine; Lipopolysaccharides; Liver; Liver Failure, Acute; Mice; Mice, Inbred C57BL; Oxidative Stress; Reactive Oxygen Species; Stilbenes

Piceatannol, a naturally occurring stilbene derivative mainly found in grapes, possesses apoptotic activity in various cancer cell lines, in addition to potent antioxidant activity. In the current study, we showed that piceatannol exhibits potent cytotoxic effects in all tested leukemia cell lines (THP-1, HL-60, U937, and K562). These effects were accompanied by induction of DNA damage, an increase in the proportion of cells in the sub-G

Topics: Acetylcysteine; Antineoplastic Agents, Phytogenic; Apoptosis; Cell Line, Tumor; Down-Regulation; Humans; Leukemia; Stilbenes; X-Linked Inhibitor of Apoptosis Protein

Resveratrol and its ortho-hydroxylated derivative piceatannol were biosynthesized by modular pathway engineering in Escherichia coli. The biosynthetic pathway was divided into three different modules. Module I includes polyketide biosynthetic genes; module II genes include acetyl-CoA and malonyl-CoA pool-enhancing genes from three different organisms; and module III genes are regiospecific 3'-hydroxylating enzymes. E. coli BL21(DE3) with module I produced 8.6 mg/L of resveratrol from exogenously fed 1 mM p-coumaric acid after 72 h. Combination of module I and acetyl-CoA supplementing module IIb genes from N. farcinica IFM10152 produced 2.5-fold higher (60 mg/L) titer of resveratrol than the module IIa genes from E. coli. The exogenous supplementation of sodium acetate further enhanced production to 64 mg/L. Furthermore, module I with module IIc harboring matBC from S. coelicolor A3(2) produced 73 mg/L of resveratrol, which was elevated to 151 mg/L upon supplementing disodium malonate exogenously. This increment is 17.5-fold higher than module I harboring E. coli BL21(DE3). The combination of module I and two different module II genes yielded 137 mg/L resveratrol when supplemented with both sodium acetate and disodium malonate. The high resveratrol-producing combination module was further modified with incorporation of hpaBC for the ortho-hydroxylation of resveratrol to produce piceatannol. The engineered strain harboring modules I, IIc and III produced 124 mg/L of piceatannol, the highest titer after 72 h in disodium malonate-supplemented strain, which is 2-fold higher than in non-supplemented strain. The remaining resveratrol was about 30 mg/L. Furthermore, caffeic acid (85.5 mg/L) was also produced in the same strain. Resveratrol and piceatannol were biosynthesized along with caffeic acid by three different modules overexpressing acetate and malonate assimilation pathway genes from three different sources. The production titer of both resveratrol and piceatannol could be achieved higher upon blocking acetyl-CoA and malonyl-CoA utilizing pathway genes in host strain.

Topics: Acetyl Coenzyme A; Biosynthetic Pathways; Escherichia coli; Escherichia coli Proteins; Malonyl Coenzyme A; Metabolic Engineering; Resveratrol; Stilbenes

Topics: Amyloid beta-Peptides; Animals; Antioxidants; Cell Survival; Cerebral Cortex; Gene Expression Regulation; Models, Molecular; Molecular Docking Simulation; Neurons; Neuroprotective Agents; Phosphatidylinositol 3-Kinases; Phosphorylation; Proto-Oncogene Proteins c-akt; Rats; Resveratrol; Signal Transduction; Stilbenes

The naturally occurring stilbenes piceatannol and its derivatives are excellent antioxidants. In this work, the antioxidative activities of piceatannol and different piceatannol derivatives have been investigated using the density functional theory (DFT) method based on three widely accepted radical scavenging mechanisms, namely, the hydrogen atom transfer (HAT), single electron transfer followed by proton transfer (SET-PT) and sequential proton loss electron transfer (SPLET). The gas and four solvent phases, namely, bond dissociation enthalpy (BDE), ionization potential (IP), proton dissociation enthalpy (PDE), proton affinity (PA) and electron transfer enthalpy (ETE), related to these mechanisms were calculated to elucidate the antioxidative capacities of the investigated compounds. This work focuses specifically on the thermodynamically preferred mechanism, antioxidative site and antioxidative activity order of the investigated stilbenes. The substituted effects of the methyl group and prenyl group on the chemical properties of the remaining OH and CH groups are also analysed. This work confirms the vital role of the OH and CH groups on free radical scavenging of piceatannol and its derivatives.

Topics: Antioxidants; Electron Transport; Molecular Structure; Protons; Quantum Theory; Stilbenes; Thermodynamics

It is currently possible to transfer a biosynthetic pathway from a plant to another organism. This system has been exploited to transfer the metabolic richness of certain plant species to other plants or even to more simple metabolic organisms such as yeast or bacteria for the production of high added value plant compounds. Another application is to bioconvert substrates into scarcer or biologically more interesting compounds, such as piceatannol and pterostilbene. These two resveratrol-derived stilbenes, which have very promising pharmacological activities, are found in plants only in small amounts. By transferring the human cytochrome P450 hydroxylase 1B1 (HsCYP1B1) gene to tobacco hairy roots and cell cultures, we developed a system able to bioconvert exogenous t-resveratrol into piceatannol in quantities near to mg L

Topics: Biosynthetic Pathways; Cell Culture Techniques; Cytochrome P-450 CYP1B1; Gene Expression Regulation, Plant; Genetic Engineering; Humans; Methyltransferases; Mixed Function Oxygenases; Nicotiana; Plant Proteins; Plant Roots; Plants, Genetically Modified; Resveratrol; Stilbenes; Vitis

Extracellular vesicles (EVs) are nanoscale membrane-formed compartments naturally secreted from cells, which are intercellular mediators regulating physiology and pathogenesis, therefore they could be a novel therapeutic carrier for targeted delivery. However, the translation of EVs is hindered by the heterogeneous composition, low yield, inefficient drug loading and unlikely scalability. Here we report a strategy to generate EVs using nitrogen cavitation (NC-EVs) that instantly disrupts neutrophils to form nanosized membrane vesicles. NC-EVs are similar to naturally secreted EVs (NS-EVs), but contain less subcellular organelles and nuclear acids. The production of NC-EVs was increased by 16 folds and is easy to scale up for clinical use compared to NS-EVs. To examine the usefulness of NC-EVs as a drug delivery platform, piceatannol (an anti-inflammation drug) was remotely loaded in NC-EVs via the pH gradient. We found that piceatannol-loaded NC-EVs dramatically alleviated acute lung inflammation/injury and sepsis induced by lipopolysaccharide (LPS). Our studies reveal that nitrogen cavitation is a novel approach to efficiently generate EVs from any cell type and could be exploited for personalized nanomedicine.

Topics: Animals; Cell-Derived Microparticles; Cells, Cultured; Extracellular Vesicles; HL-60 Cells; Humans; Inflammation; Lipopolysaccharides; Mice; Neutrophils; Sepsis; Stilbenes

Excess fat accumulation and abnormal metabolism are involved in numerous diseases and thus the research on identification of compounds that can regulate energy homeostasis could significantly facilitate the current effort to prevent and/or treat metabolic disorders. Piceatannol, one of the natural stilbenes, was previously found to decrease lipid accumulation of 3T3-L1 adipocytes. However, its role in fat metabolism in vivo is not known. Thus, Caenorhabditis elegans as an animal model was used in the current study to determine the effect of piceatannol on fat accumulation and its underlying mechanisms. The results showed that 50 and 100 μM piceatannol significantly reduced fat accumulation of wild-type worms grown in normal and high-glucose conditions without altering the growth rate, worm length, pumping rate, or moving speed. The current study further indicated that piceatannol decreased the expression of sbp-1 (encodes an ortholog of mammalian sterol regulatory element-binding protein) and its target gene fasn-1 (encodes an ortholog of fatty acid synthase) as well as increased the expression of hosl-1 (encodes an ortholog of hormone-sensitive lipase) in glucose-treated worms. These data suggested that piceatannol reduced fat accumulation in C. elegans by suppression of genes involved in lipid synthesis and possibly through stimulation of lipolysis. Given that piceatannol exerts similar effects in both C. elegans and 3T3-L1 cells, our finding could provide a mechanistic insight into the role of piceatannol in lipid metabolism in mammals.

Topics: 3T3-L1 Cells; Adipocytes; Animals; Caenorhabditis elegans; Fats; Glucose; Mice; Models, Animal; Stilbenes

Piceatannol, a bioactive component in grape and blueberry, was examined for its potential in decreasing the inflammatory activities in adipocytes using a cocultured adipocyte and macrophage system, and suppressing tumor necrosis factor-α (TNF-α)-mediated inflammation and the related insulin resistance using a 3T3-L1 adipocyte model. Piceatannol at 10 μM significantly reduced the release of inflammatory cytokines of TNF-α and monocyte chemoattractant protein-1 (MCP-1) by 19 and 31% in the cocultured system, respectively. Pretreatment with piceatannol also inhibited TNF-α-induced expression of interleukin-6 (IL-6) and MCP-1 at both mRNA and protein levels in the 3T3-L1 adipocytes. Piceatannol also partially improved the malfunction of insulin-stimulated glucose uptake, which was reduced by TNF-α in 3T3-L1 adipocytes. Furthermore, the inhibitions were mediated by significant blocking of IκBα phosphorylation and nuclear factor-κB (NF-κB) activation through suppressing nuclear translocation of NF-κB p65 along with c-Jun N-terminal kinase (JNK)-mitogen activated protein kinase (MAPK) activation. In addition, the Akt-dependent forkhead box O1 (FoxO1) signaling pathway was involved in the restoration of insulin-stimulated glucose uptake through suppressing the down-regulation of phosphorylation of Akt and FoxO1 expressions. These results suggested the potential of piceatannol in improving chronic inflammatory condition and insulin sensitivity in obese adipose tissues.

Topics: 3T3-L1 Cells; Adipocytes; Animals; Chemokine CCL2; Forkhead Box Protein O1; Humans; Inflammation; Insulin; Insulin Resistance; Interleukin-6; Mice; Phosphorylation; Plant Extracts; Stilbenes; Tumor Necrosis Factor-alpha

Lignin, the plant cell wall polymer that binds fibers together but makes processing difficult, is traditionally formed from three monomers, the so-called monolignols (

Topics: Arecaceae; Dimerization; Fruit; Lignin; Magnetic Resonance Spectroscopy; Polymers; Stilbenes

The polyphenol resveratrol and its metabolite piceatannol have beneficial health effects including antiarrhythmic properties in ischemia/reperfusion. The objective of this study was to determine potential antiarrhythmic effects in acquired long-QT-syndrome (LQTS).. 26 rabbit hearts were isolated and Langendorff-perfused. The I. Resveratrol showed beneficial antiarrhythmic properties in acquired LQTS. Underlying mechanism is a substantial decrease dispersion of repolarization leading to a suppression of triggered activity.

Topics: Animals; Anti-Arrhythmia Agents; Female; Heart; Isolated Heart Preparation; Long QT Syndrome; Rabbits; Resveratrol; Stilbenes; Treatment Outcome

Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is the master regulator of the antioxidant response, and its function is tightly regulated at the transcriptional, translational, and post-translational levels. It is well-known that Nrf2 is regulated at the protein level by proteasomal degradation via Kelch-like ECH-associated protein 1 (Keap1), but how Nrf2 is regulated at the translational level is less clear. Here, we show that pharmacological stimulation increases Nrf2 levels by overcoming basal translational repression. We developed a novel reporter assay that enabled identification of natural compounds that induce Nrf2 translation by a mechanism independent of Keap1-mediated degradation. Apigenin, resveratrol, and piceatannol all induced Nrf2 translation. More importantly, the pharmacologically induced Nrf2 overcomes Keap1 regulation, translocates to the nucleus, and activates the antioxidant response. We conclude that translational regulation controls physiological levels of Nrf2, and this can be modulated by apigenin, resveratrol, and piceatannol. Also, targeting this mechanism with novel compounds could provide new insights into prevention and treatment of multiple diseases in which oxidative stress plays a significant role.

Topics: Active Transport, Cell Nucleus; Antioxidant Response Elements; Antioxidants; Apigenin; Cell Nucleus; CRISPR-Cas Systems; Gene Expression Regulation; Genes, Reporter; HEK293 Cells; Hep G2 Cells; Humans; Kelch-Like ECH-Associated Protein 1; Luciferases; Mutation; NF-E2-Related Factor 2; Peptide Fragments; Proteasome Endopeptidase Complex; Proteolysis; Recombinant Fusion Proteins; Resveratrol; Small Molecule Libraries; Stilbenes

Polyphenols have received a significant amount of attention in disease prevention because of their unique chemical and biological properties. However, the underlying molecular mechanism for their beneficial effects remains unclear. We have now identified a polyphenol as a source of innate epitopes detected in natural IgM and established a unique gain-of-function mechanism in the formation of innate epitopes by polyphenol via the polymerization of proteins. Upon incubation with bovine serum albumin (BSA) under physiological conditions, several polyphenols converted the protein into the innate epitopes recognized by the IgM Abs. Interestingly, piceatannol, a naturally occurring hydroxylated analogue of a red wine polyphenol, resveratrol, mediated the modification of BSA, whose polymerized form was specifically recognized by the IgMs. The piceatannol-mediated polymerization of the protein was associated with the formation of a lysine-derived cross-link, dehydrolysinonorleucine. In addition, an oxidatively deaminated product, α-aminoadipic semialdehyde, was detected as a potential precursor for the cross-link in the piceatannol-treated BSA, suggesting that the polymerization of the protein might be mediated by the oxidation of a lysine residue by piceatannol followed by a Schiff base reaction with the ε-amino group of an unoxidized lysine residue. The results of this study established a novel mechanism for the formation of innate epitopes by small dietary molecules and support the notion that many of the beneficial effects of polyphenols could be attributed, at least in part, to their lysyl oxidase-like activity. They also suggest that resveratrol may have beneficial effects on human health because of its conversion to piceatannol.

Topics: Aging; Animals; Epitopes; Female; Immunoglobulin M; Mice; Mice, Inbred Strains; Molecular Structure; Polyphenols; Resveratrol; Serum Albumin, Bovine; Stilbenes

Prostate cancer growth and progression are mainly dependent on androgens and many current prostate cancer treatment options target the synthesis or function of androgens. We have previously reported that resveratrol and synthetic analogs of resveratrol with a higher bioavailability inhibit the synthesis of androgens in human adrenocortical H295R cells. Now we have studied the antiandrogenic properties of resveratrol, piceatannol and analogs in two different prostate cell lines; LNCaP and RWPE. LNCaP carry a T877A mutation in the androgen receptor while RWPE has a wild-type androgen receptor. We found that resveratrol, piceatannol and all studied analogs were able to inhibit a dihydrotestosterone-induced activation of the androgen receptor, showing that they act as antiandrogens. In LNCaP cells, all studied compounds were able to statistically significantly decrease the androgenic signaling in concentrations ≥1μM and the synthetic analogs trimethylresveratrol (RSVTM) and tetramethylpiceatannol (PICTM) were the most potent compounds. RWPE cells were not as responsive to the studied compounds as the LNCaP cells. A statistically significant decrease in the androgenic signaling was observed at concentrations ≤5μM for most compounds and RSVTM was found to be the most potent compound. Further, we studied the effects of resveratrol, piceatannol and analogs on the levels of prostate-specific antigen (PSA) in LNCaP cells and found that all studied compounds decreased the level of PSA and that the synthetic analogs diacetylresveratrol (RSVDA), triacetylresveratrol (RSVTA) and RSVTM were the most potent compounds, decreasing the PSA level by approx. 50% at concentrations ≥10μM. In a cell-free receptor binding assay we were unable to show binding of resveratrol or analogs to the ligand binding domain of the androgen receptor, indicating that the observed effects are mediated via other mechanisms than direct ligand competition. We conclude that the resveratrol, piceatannol and analogs are highly interesting for chemoprevention of prostate cancer, since they have a high potency both as inhibitors of androgen synthesis and androgen receptor activation.

Topics: Androgen Receptor Antagonists; Cell Line, Tumor; Cell Survival; Humans; Kallikreins; Prostate-Specific Antigen; Receptors, Androgen; Resveratrol; Stilbenes

Topics: Animals; Chondrocytes; Cyclooxygenase 2; Drugs, Chinese Herbal; Euphorbia; Heme Oxygenase-1; Humans; Interleukin-1beta; Male; Mice; Mice, Inbred C57BL; NF-E2-Related Factor 2; NF-kappa B; Nitric Oxide; Osteoarthritis; Stilbenes

Melanoma took top position among the lethal cancers and, despite there have been some great attempts made to increase the natural life of patients with metastatic disease, long-lasting and complete remissions are few. Piceatannol, owns the similar function as resveratrol, has been defined as an anti-cancer agent playing important role in inhibition of proliferation, migration and metastasis in various cancer. Thus, we aim to investigate the anti-cancer effect and mechanisms of piceatannol in melanoma cells.. Melanoma cell lines WM266-4 and A2058 were treated either with or without piceatannol. Cell viability and cell apoptosis were assessed by using MTT and Annexin V/PI assay, respectively. Cells were transfected with specific miRNA using Lipfectamine 2000. miRNA bingding ability to 3'-UTR region within specific gene was assed by firefly luciferase analysis. Gene and protein expression was eveluated by qRT-PCR and western blot analysis, respectively.. Our study showed that piceatannol inhibited WM266-4 and A2058 cells growth and induced apoptosis. Totally, 16 differentially expressed miRNAs were screened out including 8 up-regulated and 8 down-regulated miRNAs. Expression level of miR-181a is significantly higher in piceatannol-treated cells than normal control and is lower in melanoma cancer tissues than its adjacent normal tissues. Bcl-2 is a target gene of miR-181a. Moreover, silencing of miR-181a reverses the decrease of cell viability induced by piceatannol in WM266-4 and A2058 cells. Taken together, present study uncovered the ability of piceatannol to repress melanoma cell growth and clarified the contribution of miR-181a in the anticancer role of piceatannol.. The present study proposes that piceatannol can be taken into account to be a hopeful anticancer agent for melanoma.

Topics: Anticarcinogenic Agents; Apoptosis; Cell Line, Tumor; Cell Survival; Gene Expression Regulation, Neoplastic; Humans; Melanoma; MicroRNAs; Stilbenes; Up-Regulation

Schistosomiasis is one of the most common parasitic diseases affecting millions of humans and animals worldwide. Understanding the signal transduction pathways and the molecular basis of reproductive regulation in schistosomes is critically important for developing new strategies for preventing and treating these infections. Syk kinases regulate the proliferation, differentiation, morphogenesis, and survival of various types of cells and have been identified in invertebrates. Tyrosine kinase 4 (TK4), a member of the Syk kinase family, plays a pivotal role in gametogenesis in S. mansoni, affecting the development of the testis and ovaries in this parasite. The role of TK4, however, in the reproduction of S. japonicum is poorly understood.. Here, the complete coding sequence of TK4 gene in S. japonicum (SjTK4) was cloned and characterized. The expression of SjTK4 was analyzed at different life-cycle stages and in various tissues of S. japonicum by qPCR. Piceatannol, a Syk kinase inhibitor, was applied to S. japonicum in vitro. The piceatannol-induced morphological changes of the parasites were observed using confocal laser scanning microscopy and the alterations in important egg-shell synthesis-related genes were examined using qPCR analyses.. SjTK4 mRNA was differentially expressed throughout the life-cycle of S. japonicum. SjTK4 mRNA was highly expressed in the ovary and testis of S. japonicum, with the level of gene expression significantly higher in males than in females. The expression levels of some important egg-shell synthesis related genes were higher in the piceatannol-treated groups than in the vehicle-treated control group and the number of eggs and germ cells also decreased in a concentration-dependent manner. Importantly, large pore-like structures can be found in the testis and ovaries of males and females after treating with piceatannol.. The results suggest that SjTK4 may play an important role in regulating gametogenesis of S. japonicum. The findings may help better understand the fundamental biology of S. japonicum. Moreover, the effect of S. japonicum treatment by piceatannol provides us with a new idea that inhibition of SjTK4 signaling pathway can effectively retard the development of the testis and ovaries.

Topics: Animals; Coinfection; Female; Humans; Male; Mice; Protein-Tyrosine Kinases; Reproduction; Schistosoma japonicum; Schistosomiasis japonica; Stilbenes

The DNAX adaptor protein 12 (DAP12) is a transmembrane adaptor molecule that signals through the activation of Syk (Spleen Tyrosine Kinase) in myeloid cells. The purpose of this study is to investigate the role of DAP12 and Syk pathways in inflammatory bowel diseases (IBDs).. DAP12 deficient and DAP12 transgenic, overexpressing an increased amount of DAP12, mice and Syk deficient mice in the C57/BL6 background were used for these studies. Colitis was induced by administering mice with dextran sulfate sodium (DSS), in drinking water, or 2,4,6-trinitrobenzene sulfonic acid (TNBS), by intrarectal enema.. Abundant expression of DAP12 and Syk was detected in colon samples obtained from Crohn's disease patients with expression restricted to immune cells infiltrating the colonic wall. In rodents development of DSS colitis as measured by assessing severity of wasting diseases, global colitis score,and macroscopic and histology scores was robustly attenuated in DAP12-/- and Syk-/- mice. In contrast, DAP12 overexpression resulted in a striking exacerbation of colon damage caused by DSS. Induction of colon expression of proinflammatory cytokines and chemokines in response to DSS administration was attenuated in DAP12-/- and Syk-/- mice, whereas opposite results were observed in DAP12 transgenic mice. Treating wild-type mice with a DAP-12 inhibitor or a Syk inhibitor caused a robust attenuation of colitis induced by DSS and TNBS.. DAP12 and Syk are essential mediators in inflammation-driven immune dysfunction in murine colitides. Because DAP12 and Syk expression is upregulated in patients with active disease, present findings suggest a beneficial role for DAP12 and Syk inhibitors in IBD.

Topics: Adaptor Proteins, Signal Transducing; Adult; Animals; Antipruritics; Colitis; Cytokines; Disease Models, Animal; Female; Humans; Inflammation; Inflammatory Bowel Diseases; Intestinal Diseases; Ketotifen; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Transgenic; Stilbenes; Syk Kinase

The present study investigated the pharmacological effects of three stilbenoids, resveratrol (RES), pterostilbene (PTR) and piceatannol (PIC), in transformed and normal macrophages. Our first aim was to comparatively assess the cytotoxicity of RES, PTR and PIC in unstimulated transformed mouse macrophages (RAW 264.7 cells) and primary peritoneal macrophages (PMs) harvested from both wild type and Nrf2 (nuclear factor erythroid 2-related factor 2)-deficient female mice. Our second aim was to investigate whether the inhibitory effect of RES, PTR and PIC on nitric oxide (NO) release from stimulated PMs depends on the status of the transcription factor Nrf2. The rationale for investigating Nrf2 status was based upon recent reports showing that certain compounds (sulforaphane and linalool) suppress LPS-induced inflammation in an Nrf2-dependent manner. Cell viability studies confirmed our prior work in unstimulated RAW 264.7 cells, with cytotoxic potency decreasing in the order of PTR > PIC > RES. Unstimulated PMs, regardless of Nrf2 status, were less sensitive to stilbenes, requiring at least a threefold higher stilbene concentration to inhibit cell viability, with cytotoxic potency again decreasing in the order of PTR > PIC > RES. In studies focused on our second aim, IC

Topics: Animals; Cell Line, Transformed; Cell Survival; Dose-Response Relationship, Drug; Female; Lipopolysaccharides; Macrophages, Peritoneal; Mice; Mice, Inbred C57BL; Mice, Knockout; NF-E2-Related Factor 2; Nitric Oxide; Primary Cell Culture; Resveratrol; Stilbenes

Diabetic nephropathy is one of the major microvascular complications of diabetes mellitus which ultimately gives rise to cardiovascular diseases. Prolonged hyperglycaemia and chronic renal inflammation are the two key players in the development and progression of diabetic nephropathy. Nuclear factor kB (NF-kB)-mediated inflammatory cascade is a strong contributor to the renovascular inflammation in diabetic nephropathy. Here, we studied the effects of piceatannol, a potent NF-kB inhibitor, on various oxidative stress markers and NF-kB dependent diabetic renoinflammatory cascades in rat induced by alloxan (ALX). Experimental diabetes was induced in male Wistar rats by a single intraperitoneal dose, 150 mg/kg body-weight (b.w.) of ALX. Diabetic rats were treated with Piceatannol (PCTNL) at a dose of 30 and 50 mg/kg b.w. After 14 days of oral treatment, PCTNL significantly restored blood sugar level, glomerular filtration rate, serum markers and plasma lipids. PCTNL administration also reversed the declined activity of cellular antioxidant machineries namely superoxide dismutase and glutathione and the elevated levels of malondialdehyde and nitric oxide. Moreover, piceatannol-treated groups showed marked inhibition of renal pro-inflammatory cytokines and NF-kB p65/p50 binding to DNA. Renal histopathological investigations also supported its ameliorative effects against diabetic kidney damage. Importantly, effects were more prominent at a dose of 50 mg/kg, and in terms of body-weight gain, PCTNL failed to effect significantly. However, overall findings clearly demonstrated that PCTNL provides remarkable renoprotection in diabetes by abrogating oxidative stress and NF-kB activation - and might be helpful in early stage of diabetic nephropathy.

Topics: Alloxan; Animals; Antioxidants; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Dose-Response Relationship, Drug; Glomerular Filtration Rate; Glutathione; Inflammation; Kidney; Male; Malondialdehyde; NF-kappa B; Oxidative Stress; Rats; Rats, Wistar; Stilbenes; Superoxide Dismutase

Propolis samples from Kangaroo Island, South Australia, were investigated for chemical constituents using high-field nuclear magnetic resonance spectral profiling. A type of propolis was found containing a high proportion of prenylated hydroxystilbenes. Subsequently, the botanical origin of this type of propolis was identified using a beehive propolis depletion method and analysis of flora. Ligurian honey bees, Apis mellifera ligustica Spinola, were found to produce propolis from resin exuded by the Australian native sedge plant Lepidosperma sp. Montebello (Cyperaceae). The plants, commonly known as sword sedge, were found to have resin that matched with the propolis samples identified as the most abundant propolis type on the island containing C- and O-prenylated tetrahydroxystilbenes (pTHOS) in addition to a small amount of prenylated p-coumarate. The isolation of five pTHOS not previously characterized are reported: (E)-4-(3-methyl-2-buten-1-yl)-3,4',5-trihydroxy-3'-methoxystilbene, (E)-2,4-bis(3-methyl-2-buten-1-yl)-3,3',4',5-tetrahydroxystilbene, (E)-2-(3-methyl-2-buten-1-yl)-3-(3-methyl-2-butenyloxy)-3',4',5-trihydroxystilbene, (E)-2,6-bis(3-methyl-2-buten-1-yl)-3,3',5,5'-tetrahydroxystilbene and (E)-2,6-bis(3-methyl-2-buten-1-yl)-3,4',5-trihydroxy-3'-methoxystilbene. A National Cancer Institute 60 human cell line anticancer screen of three of these compounds showed growth inhibitory activity. The large Australasian genus Lepidosperma is identified as a valuable resource for the isolation of substances with medicinal potential.

Topics: Animals; Antineoplastic Agents; Australia; Bees; Coumarins; Cyperaceae; Macropodidae; Prenylation; Propolis; Stilbenes

A growing body of evidence implicates endoplasmic reticulum (ER)-induced cellular dysfunction and apoptosis as important factors to a variety of diseases. In endothelial cells (ECs), the sulfur-containing amino acid homocysteine (Hcy) causes EC apoptosis and reactive oxygen species (ROS) generation through induction of ER stress. Here, we have investigated whether piceatannol (Pic), a resveratrol analog, could protect ECs against Hcy-induced apoptosis, oxidative stress and ER stress, with specific emphasis on heme oxygenase-1 (HO-1). In human ECs, we determined the effects of Hcy and Pic on annexin V positivity, glucose-regulated protein 78 kDa (GRP78) and C/EBP homologous protein (CHOP) expression, X-box binding protein 1 (Xbp-1) mRNA slicing, and ROS-sensitive dihydroethidium (DHE) oxidation. Hcy increased annexin V-positive cells, DHE oxidation, GRP78 and CHOP expression and Xbp-1 mRNA splicing, indicating that Hcy induces apoptosis, oxidative stress and ER stress. Pretreatment of ECs with Pic significantly inhibited Hcy-induced apoptosis, ROS generation and ER stress. Pic also increased HO-1 expression via activation of nuclear factor-E2-related factor 2 (Nrf2). Interestingly, the inhibitory effects of Pic on Hcy-induced apoptosis, ROS generation and ER stress were abolished by down-regulation of HO-1 expression, while mimicked by treatment of ECs with the HO-1 inducer hemin. Overall, these results suggest that Pic may protect ECs against Hcy-induced apoptosis, oxidative stress and ER stress via Nrf2-dependent HO-1 expression.

Topics: Apoptosis; Cells, Cultured; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Endothelial Cells; Heme Oxygenase-1; Homocysteine; Humans; NF-E2-Related Factor 2; Oxidative Stress; Reactive Oxygen Species; Stilbenes

Piceatannol is a natural stilbene with many beneficial effects, such as antioxidative, anti-inflammatory, antiatherogenic activities; however, its role on aging is not known. In this study, we used Caenorhabditis elegans as an animal model to study the effect of piceatannol on its lifespan and investigated the underlying mechanisms. The results showed that 50 and 100 µM piceatannol significantly extended the lifespan of C. elegans without altering the growth rate, worm size and progeny production. Piceatannol delayed the age-related decline of pumping rate and locomotive activity, and protected the worms from heat and oxidative stress. This study further indicated that lifespan extension and enhanced stress resistance induced by piceatannol requires DAF-16. Since DAF-16 is conserved from nematodes to mammals, our study may have important implications in utilizing piceatannol to promote healthy aging and combat age-related disease in humans. © 2016 BioFactors, 43(3):379-387, 2017.

Topics: Adaptation, Physiological; Animals; Antioxidants; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Forkhead Transcription Factors; Gene Expression Profiling; Gene Expression Regulation; Hot Temperature; Humans; Locomotion; Longevity; Oxidative Stress; Reactive Oxygen Species; Signal Transduction; Stilbenes; Stress, Physiological

Human glyoxalase I (GLO I), a rate-limiting enzyme for detoxification of methylglyoxal (MG), a by-product of glycolysis, is known to be a potential therapeutic target for cancer. Here, we searched new scaffolds from natural compounds for designing novel GLO I inhibitors and found trans-stilbene scaffold. We examined the inhibitory abilities to human GLO I of commercially available trans-stilbene compounds. Among them, piceatannol was found to have the most potent inhibitory activity against human GLO I. Piceatannol could inhibit the proliferation of human lung cancer NCI-H522 cells, which are dependent on GLO I for survival, in a dose- and time-dependent manner. In addition, piceatannol more significantly inhibited the proliferation of NCI-H522 cells than that of NCI-H460 cells, which are less dependent on GLO I. Importantly, overexpression of GLO I in NCI-H522 cells resulted in less sensitive to the antiproliferative activity of piceatannol. Taken together, this is the first report demonstrating that piceatannol inhibits GLO I activity and the GLO I-dependent proliferation of cancer cells. Furthermore, we determined a pharmacophore for novel inhibitors of human GLO I by computational simulation analyses of the binding mode of piceatannol to the enzyme hot spot in the active site. We suggest that piceatannol is a possible lead compound for the development of novel GLO I inhibitory anticancer drugs.

Topics: Cell Line, Tumor; Cell Proliferation; Enzyme Inhibitors; Humans; Lactoylglutathione Lyase; Lung Neoplasms; Stilbenes

Piceatannol (3,3',4,5'-tetrahydroxy-trans-stilbene, 2), an oxygenated analog of resveratrol (1), was synthesized. It is one of the naturally occurring polyphenolic stilbenoids contained in red wine, and possesses many kinds of beneficial effects such as anticancer activity. The trans-stilbene skeleton of 2 was constructed by Pd-catalyzed Suzuki-Miyaura cross coupling reaction of triflate 8 with (E)-alkenylboronoate 13. The key intermediate 13 was prepared diastereoselectively by acid-catalyzed hydroboration of pinacolborane 12 to alkyne 11.

Topics: Molecular Structure; Resveratrol; Stilbenes

HpaBC monooxygenase was previously reported to hydroxylate resveratrol to piceatannol. In this article, we report a novel catalytic activity of HpaBC for the synthesis of a pentahydroxylated stilbene. When Escherichia coli cells expressing HpaBC were incubated with resveratrol, the resulting piceatannol was further converted to a new product. This product was identified by mass spectrometry and NMR spectroscopy as a 5-hydroxylated piceatannol, 3,4,5,3',5'-pentahydroxy-trans-stilbene (PHS), which is a reportedly valuable biologically active stilbene derivative. We attempted to produce PHS from piceatannol on a flask scale. After examining the effects of detergents and buffers on PHS production, E. coli cells expressing HpaBC efficiently hydroxylated piceatannol to PHS in a reaction mixture containing 1.5% (v/v) Tween 80 and 100 mM 3-morpholinopropanesulfonic acid-NaOH buffer at pH 7.5. Under the optimized conditions, the whole cells regioselectively hydroxylated piceatannol, and the production of PHS reached 6.9 mM (1.8 g L(-1)) in 48 h.

Topics: Bacterial Proteins; Biocatalysis; Culture Media; Escherichia coli; Gene Expression; Hydrogen-Ion Concentration; Mixed Function Oxygenases; Morpholines; Polysorbates; Resveratrol; Sodium Hydroxide; Stilbenes

Obesity-associated nephropathy is considered to be a leading cause of end-stage renal disease. Resveratrol supplementation represents a promising therapy to attenuate kidney injury, but the poor solubility and limited bioavailability of this polyphenol limits its use in dietary intervention. Piceatannol, a resveratrol analogue, has been suggested as a better option. In this study, we aimed to provide evidence of a preventive action of piceatannol in very early stages of obesity-associated nephropathy. Thirty obese Zucker rats were divided into three experimental groups: one control and two groups orally treated for 6 weeks with 15 and 45 mg piceatannol/kg body weight/day. Enzyme-linked immunosorbent assays (ELISA) were used to determine renal and urinary kidney injury molecule-1 (Kim-1), renal fibrosis markers (transforming growth factor β1 and fibronectin) and renal sirtuin-1 protein. Oxidative stress was assessed in the kidney by measuring lipid peroxidation and nitrosative stress (thiobarbituric acid reactive substrates and 3-nitrotyrosine levels, respectively) together with the activity of the antioxidant enzyme superoxide dismutase. Renal fatty acids profile analysis was performed by thin-layer and gas chromatography. Piceatannol-treated rats displayed lower levels of urinary and renal Kim-1. Renal fibrosis biomarkers and lipid peroxidation exhibited a tendency to decrease in the piceatannol-treated groups. Piceatannol treatment did not modify superoxide dismutase activity or sirtuin-1 protein levels, while it seemed to increase the levels of polyunsaturated and omega-6 polyunsaturated fatty acids in the kidneys. Our findings suggest a mild renoprotective effect of piceatannol in obese Zucker rats and the need of intervention at early stages of renal damage.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Antioxidants; Biomarkers; Cell Adhesion Molecules; Dietary Supplements; Fibrosis; Kidney; Lipid Peroxidation; Male; Obesity; Organ Size; Oxidative Stress; Random Allocation; Rats, Zucker; Renal Insufficiency; Severity of Illness Index; Stilbenes; Thiobarbituric Acid Reactive Substances; Tyrosine

Neuron apoptosis induced by β-amyloid (Aβ) is an important precipitating factor in the pathogenesis of Alzheimer's disease (AD). In the present study, the effects of piceatannol (PT) and pterostilbene (PS) against Aβ-induced apoptosis in PC12 cells were evaluated. PT and PS both showed observable anti-apoptosis activity. Increased cell viability, decreased apoptosis rate and declining intracellular ROS were observed after PT and PS treatment. For the signaling pathway, PT significantly promoted phosphorylation of Akt and Bad, further suppressed Bcl-2/Bax expression and inhibited cleavage of caspase-9, caspase-3 and PARP. PS promoted phosphorylation of Akt without affecting the other factors. The experimental results, for the first time, unambiguously suggested that PT showed a comprehensive protective effect against Aβ-induced apoptosis in PC12 cells via a novel PI3K/Akt/Bad signaling pathway and downstream mitochondria-mediated and caspase-dependent signaling pathway. Unlike PT, PS inhibited apoptosis against Aβ through a different PI3K/Akt signaling pathway in which the downstream targets need to be further investigated. The results also provide the basis for dietary intervention involved in the prevention and adjunctive therapy of AD.

Topics: Amyloid beta-Peptides; Animals; Apoptosis; bcl-2-Associated X Protein; bcl-Associated Death Protein; Caspase 3; Caspase 9; Cell Survival; Mitochondria; Neurons; Neuroprotective Agents; PC12 Cells; Phosphatidylinositol 3-Kinases; Phosphorylation; Proto-Oncogene Proteins c-akt; Rats; Reactive Oxygen Species; Signal Transduction; Stilbenes

Piceatannol is a phytochemical in the seeds of passion fruit that has a hypoglycemic effect when orally administered. To elucidate the contribution of intact and metabolites of piceatannol after gastro-intestinal absorption to hypoglycemic effect, we examined the influence of piceatannol and isorhapontigenin on blood glucose concentrations during fasting and glucose tolerance tests by administering them intravascularly to freely moving healthy rats. We found that intravascularly administered piceatannol reduced the blood glucose concentrations during both fasting and glucose tolerance tests, but isorhapontigenin did not during either of them. Furthermore, we found that piceatannol increased the insulinogenic index during glucose tolerance tests and that piceatannol had no influence on insulin sensitivity by performing hyperinsulinemic euglycemic clamping tests. These results suggest that piceatannol orally intaken may enhance glucose tolerance by the effect of intact piceatannol through enhanced early-phase secretion of insulin. Therefore, oral intake of piceatannol might contribute to proper control of postprandial glycemic excursions in healthy subjects.

Topics: Administration, Oral; Animals; Blood Glucose; Dose-Response Relationship, Drug; Fasting; Glucose Tolerance Test; Hypoglycemic Agents; Injections, Intra-Arterial; Injections, Intravenous; Insulin Resistance; Male; Rats; Rats, Sprague-Dawley; Stilbenes; Treatment Outcome

Resveratrol is beneficial in obese and diabetic rodents. However, its low bioavailability raises questions about its therapeutic relevance for treating or preventing obesity complications. In this context, many related natural polyphenols are being tested for their putative antidiabetic and anti-obesity effects. This prompted us to study the influence of piceatannol, a polyhydroxylated stilbene, on the prevention of obesity complications in Zucker obese rats. A 6-week supplementation was followed by the determination of various markers in plasma, liver, adipose tissue and heart, together with a large-scale analysis of gut microbiota composition. When given in doses of 15 or 45 mg/kg body weight/day, piceatannol did not reduce either hyperphagia or fat accumulation. It did not modify the profusion of the most abundant phyla in gut, though slight changes were observed in the abundance of several Lactobacillus, Clostridium, and Bacteroides species belonging to Firmicutes and Bacteroidetes. This was accompanied by a tendency to reduce plasma lipopolysaccharides by 30 %, and by a decrease of circulating non-esterified fatty acids, LDL-cholesterol, and lactate. While piceatannol tended to improve lipid handling, it did not mitigate hyperinsulinemia and cardiac hypertrophy. However, it increased cardiac expression of ephrin-B1, a membrane protein that contributes to maintaining cardiomyocyte architecture. Lastly, ascorbyl radical plasma levels and hydrogen peroxide release by adipose tissue were similar in control and treated groups. Thus, piceatannol did not exhibit strong slimming capacities but did limit several obesity complications.

Topics: 3T3-L1 Cells; Adipose Tissue, White; Adiposity; Animals; Anti-Inflammatory Agents, Non-Steroidal; Antioxidants; Biomarkers; Dietary Supplements; Dysbiosis; Heart Diseases; Hydrogen Peroxide; Hyperlipidemias; Liver; Male; Mice; Myocardium; Obesity; Random Allocation; Rats, Zucker; Stilbenes

Grapevine stilbenes, particularly trans-resveratrol, have a demonstrated pharmacological activity. Other natural stilbenes derived from resveratrol such as pterostilbene or piceatannol, display higher oral bioavailability and bioactivity than the parent compound, but are far less abundant in natural sources. Thus, to efficiently obtain these bioactive resveratrol derivatives, there is a need to develop new bioproduction systems. Grapevine cell cultures are able to produce large amounts of easily recoverable extracellular resveratrol when elicited with methylated cyclodextrins and methyl jasmonate. We devised this system as an interesting starting point of a metabolic engineering-based strategy to produce resveratrol derivatives using resveratrol-converting enzymes. Constitutive expression of either Vitis vinifera resveratrol O-methyltransferase (VvROMT) or human cytochrome P450 hydroxylase 1B1 (HsCYP1B1) led to pterostilbene or piceatannol, respectively, after the engineered cell cultures were treated with the aforementioned elicitors. Functionality of both gene products was first assessed in planta by Nicotiana benthamiana agroinfiltration assays, in which tobacco cells transiently expressed stilbene synthase and VvROMT or HsCYP1B1. Grapevine cell cultures transformed with VvROMT produced pterostilbene, which was detected in both intra- and extracellular compartments, at a level of micrograms per litre. Grapevine cell cultures transformed with HsCYP1B1 produced about 20 mg/L culture of piceatannol, displaying a sevenfold increase in relation to wild-type cultures, and reaching an extracellular distribution of up to 45% of total production. The results obtained demonstrate the feasibility of this novel system for the bioproduction of natural and more bioactive resveratrol derivatives and suggest new ways for the improvement of production yields.

Topics: Cell Culture Techniques; Gene Expression Regulation, Plant; Metabolic Engineering; Plants, Genetically Modified; Resveratrol; Stilbenes; Vitis

The androgen receptor (AR) is a therapeutic target for the treatment of prostate cancer. Androgen receptor reactivation during the androgen-independent stage of prostate cancer is mediated by numerous mechanisms including expression of AR mutants and splice variants that become non-responsive to conventional anti-androgenic agents. Resveratrol and its natural analogs exhibit varying degrees of anti-androgenic effects on tumor growth suppression in prostate cancer. However, the structural basis for the observed differential activity remains unknown. Here, anti-androgenic activities of resveratrol and its natural analogs, namely, pterostilbene, piceatannol and trimethoxy-resveratrol were studied in LNCaP cells expressing T877A mutant AR and atomistic simulations were employed to establish the structure activity relationship. Interestingly, essential hydrogen bonding contacts and the binding energies of resveratrol analogs with AR ligand binding domain (LBD), emerge as key differentiating factors for varying anti-androgenic action. Among all the analogs, pterostilbene exhibited strongest anti-androgenic activity and its binding energy and hydrogen bonding interactions pattern closely resembled pure anti-androgen, flutamide. Principal component analysis of our simulation studies revealed that androgenic compounds bind more strongly to AR LBD compared to anti-androgenic compounds and provide conformational stabilization of the receptor in essential subspace. The present study provides critical insight into the structure-activity relationship of the anti-androgenic action of resveratrol analogs, which can be translated further to design novel highly potent anti-androgenic stilbenes.

Topics: Androgen Antagonists; Cell Line, Tumor; Computer Simulation; Flutamide; Humans; Hydrogen Bonding; Male; Molecular Conformation; Molecular Dynamics Simulation; Mutant Proteins; Prostatic Neoplasms; Protein Binding; Receptors, Androgen; Resveratrol; Stilbenes; Thermodynamics

Piceatannol is polyphenolic antioxidant found in passion fruit (Passiflora edulis) seeds. The aim of this study was to improve the absorption of piceatannol using α-cyclodextrin (αCD). The solubility of piceatannol in neutral and acidic solutions increased in an αCD concentration-dependent manner. The maximum plasma concentration of intact piceatannol and the time-to-maximum plasma concentration of O-methylated piceatannol metabolites increased in rats administered αCD-piceatannol inclusion complexes (PICs). Administering the αCD inclusion complexes significantly increased the area under the concentration-time curve of total stilbene derivatives (0-3 h) in terms of the total amount of intact piceatannol, O-methylated piceatannol, conjugated piceatannol, and isorhapontigenin. Gastrointestinal ligation experiments demonstrated that substantially higher levels of piceatannol metabolites were present in the lower intestine (the ileum) at 1 h postintragastric αCD-PICs administration as compared to those observed following piceatannol administration only. These results suggested that αCD enhanced piceatannol movement and absorption in the small intestine.

Topics: alpha-Cyclodextrins; Animals; Male; Passiflora; Plant Extracts; Rats; Rats, Sprague-Dawley; Seeds; Solubility; Stilbenes

In this work, an in-depth study of the interaction between piceatannol (a type of stilbene with high biological activity) and different natural and modified cyclodextrins (CDs) is made, using steady state fluorescence. This bioactive molecule forms a 1 : 1 complex with all the natural (α-CD, β-CD and γ-CD) and modified (HP-β-CD, HE-β-CD and M-β-CD) CDs tested. Among natural CDs, the interaction of piceatannol with β-CD was the most efficient. However, the modified CDs showed higher encapsulation constants (KF) than β-CD, except M-β-CD; the highest KF being found for HP-β-CD (14 048 ± 702 M(-1)). The encapsulation of piceatannol in the internal cavity of CDs showed a strong dependence on pH and temperature. The interaction between HP-β-CD and piceatannol was less effective in the pH region where the stilbene begins to suffer the deprotonation of its hydroxyl group. Moreover, the values of KF decreased as the system temperature increased. To obtain information on the mechanism involved in the piceatannol affinity for CD, the thermodynamic parameters of the complexation (ΔH°, ΔS° and ΔG°) were studied, the results showed a negative entropy (-3.7 ± 0.2 J mol(-1) K(-1)), enthalpy (-24.6 ± 1.2 kJ mol(-1)) and Gibbs free energy change at 25 °C (-23.5 ± 1.2 J mol(-1)). Finally, molecular docking calculations provided further insights into how the different interactions influence the complexation constant. A high degree of correlation was observed between the computed scores and experimental values.

Topics: Chemical Phenomena; Computational Biology; Cyclodextrins; Entropy; Hydrogen-Ion Concentration; Molecular Docking Simulation; Resveratrol; Stilbenes; Temperature; Thermodynamics

Piceatannol is a polyphenolic analog of resveratrol that selectively inhibits the non-receptor tyrosine kinase-Syk. This study investigates the potential ability of piceatannol to attenuate liver fibrosis and protect hepatocytes from injury. Thioacetamide was injected in adult male mice (100 mg/kg, i.p., 3 times/week) for 8 weeks. Piceatannol (1 or 5 mg/kg per day) was administered by oral gavage during the last 4 weeks. Liver function biomarkers, tissue malondialdehyde (MDA), cytokeratin-18 (CK18), hepatocyte growth factor (HGF), and interleukin-10 (IL-10) were measured. Necroinflammation, fibrosis, expression of transforming growth factor (TGF)-β1, and α-smooth muscle actin (SMA) were scored by histopathological examination and immunohistochemistry. Obtained results showed ability of piceatannol (1 mg/kg) to restore liver function and reduce inflammation. It significantly (p < 0.001) reduced MDA, CK18, TGF-β1, and α-SMA expression, and increased HGF and IL-10. It can be concluded that piceatannol at low dose can inhibit TGF-β1 induced hepatocytes apoptosis and exerts an anti-inflammatory effect attenuating fibrosis progression.

Topics: Animals; Gene Expression Regulation; Hepatocyte Growth Factor; Hepatocytes; Interleukin-10; Liver Cirrhosis; Male; Mice; Protective Agents; Stilbenes; Thioacetamide

Piceatannol, an analog and metabolite of resveratrol, is effective against various disorders including malignancy. It is in part effective by triggering suicidal death or apoptosis of tumor cells. Cellular mechanisms mediating the proapoptotic effect of Piceatannol include mitochondrial depolarization and cytochrome c release. Erythrocytes lack mitochondria but may nevertheless enter suicidal death or eryptosis, which is characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Cellular mechanisms involved in the triggering of eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i), oxidative stress and ceramide formation. The present study explored, whether Piceatannol induces eryptosis and, if so, to shed some light on the cellular mechanisms involved.. Phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, reactive oxygen species (ROS) formation from 2',7'-dichlorodihydrofluorescein (DCF) diacetate-dependent fluorescence, and ceramide abundance utilizing specific antibodies. Hemoglobin concentration in the supernatant was taken as measure of hemolysis.. A 48 hours exposure of human erythrocytes to Piceatannol (10 - 20 µM) significantly increased the percentage of annexin-V-binding cells, significantly decreased forward scatter, significantly increased DCFDA-fluorescence, significantly increased ceramide abundance, but did not significantly increase Fluo3-fluorescence. Removal of extracellular Ca2+ slightly blunted but did not abolish the effect of Piceatannol on annexin-V-binding and forward scatter. Piceatannol (20 µM) significantly augmented the increase of annexin-V-binding, but significantly blunted the decrease of forward scatter following treatment with the Ca2+ ionophore ionomycin.. Piceatannol triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect at least in part downstream of Ca2+ and involving oxidative stress and ceramide formation.

Topics: Anti-Infective Agents; Anti-Inflammatory Agents; Calcium; Ceramides; Eryptosis; Erythrocyte Membrane; Erythrocytes; Humans; Oxidative Stress; Phosphatidylserines; Reactive Oxygen Species; Stilbenes

The aggregation of α-synuclein is one on the key pathogenic events in Parkinson's disease. In the present study, we investigated the inhibitory capacities of stilbenes against α-synuclein aggregation and toxicity. Thioflavin T fluorescence, transmission electronic microscopy, and SDS-PAGE analysis were performed to investigate the inhibitory effects of three stilbenes against α-synuclein aggregation: piceatannol, ampelopsin A, and isohopeaphenol. Lipid vesicle permeabilization assays were performed to screen stilbenes for protection against membrane damage induced by aggregated α-synuclein. The viability of PC12 cells was examined using an MTT assay to assess the preventive effects of stilbenes against α-synuclein-induced toxicity. Piceatannol inhibited the formation of α synuclein fibrils and was able to destabilize preformed filaments. It seems to induce the formation of small soluble complexes protecting membranes against α-synuclein-induced damage. Finally, piceatannol protected cells against α-synuclein-induced toxicity. The oligomers tested (ampelopsin A and hopeaphenol) were less active.

Topics: alpha-Synuclein; Animals; Benzothiazoles; Cell Survival; Electrophoresis, Polyacrylamide Gel; Flavonoids; Microscopy, Electron, Transmission; Parkinson Disease; PC12 Cells; Phenols; Rats; Stilbenes; Thiazoles; Wine

Prenylated stilbenoids synthesized in some legumes exhibit plant pathogen defense properties and pharmacological activities with potential benefits to human health. Despite their importance, the biosynthetic pathways of these compounds remain to be elucidated. Peanut (Arachis hypogaea) hairy root cultures produce a diverse array of prenylated stilbenoids upon treatment with elicitors. Using metabolic inhibitors of the plastidic and cytosolic isoprenoid biosynthetic pathways, we demonstrated that the prenyl moiety on the prenylated stilbenoids derives from a plastidic pathway. We further characterized, to our knowledge for the first time, a membrane-bound stilbenoid-specific prenyltransferase activity from the microsomal fraction of peanut hairy roots. This microsomal fraction-derived resveratrol 4-dimethylallyl transferase utilizes 3,3-dimethylallyl pyrophosphate as a prenyl donor and prenylates resveratrol to form arachidin-2. It also prenylates pinosylvin to chiricanine A and piceatannol to arachidin-5, a prenylated stilbenoid identified, to our knowledge, for the first time in this study. This prenyltransferase exhibits strict substrate specificity for stilbenoids and does not prenylate flavanone, flavone, or isoflavone backbones, even though it shares several common features with flavonoid-specific prenyltransferases.

Topics: Arachis; Dimethylallyltranstransferase; Hemiterpenes; Organophosphorus Compounds; Plant Proteins; Plant Roots; Plastids; Prenylation; Resveratrol; Seeds; Stilbenes; Substrate Specificity; Terpenes

Piceatannol is a hydroxylated derivative of resveratrol. While both dietary polyphenols coexist in edible plants and fruits, and share equivalent concentrations in several wines, the influence of piceatannol on adiposity has been less studied than that of resveratrol. Though resveratrol is now recognized to limit fat deposition in various obesity models, the benefit of its dietary supplementation remains under debate regarding human obesity treatment or prevention. The research for more potent resveratrol analogs is therefore still undergoing. This prompted us to compare various effects of piceatannol and resveratrol directly on human adipose tissue (hAT). Hydrogen peroxide release was measured by Amplex Red-based fluorescence in subcutaneous hAT samples from obese patients. Interactions of stilbenes with human amine oxidases and quinone reductase were assessed by radiometric methods, computational docking and electron paramagnetic resonance. Influences on lipogenic and lipolytic activities were compared in mouse adipocytes. Resveratrol and piceatannol inhibited monoamine oxidase (MAO) with respective IC50 of 18.5 and 133.7 μM, but not semicarbazide-sensitive amine oxidase (SSAO) in hAT. For both stilbenes, the docking scores were better for MAO than for SSAO. Piceatannol and resveratrol similarly hampered hydrogen peroxide detection in assays with and without hAT, while they shared pro-oxidant activities when incubated with purified quinone reductase. They exhibited similar dose-dependent inhibition of adipocyte lipogenic activity. Only piceatannol inhibited basal and stimulated lipolysis when incubated at a dose ≥100 μM. Thus, piceatannol exerted on fat cells dose-dependent effects similar to those of resveratrol, except for a stronger antilipolytic action. In this regard, piceatannol should be useful in limiting the lipotoxicity related to obesity when ingested or administered alone - or might hamper the fat mobilization induced by resveratrol when simultaneously administered with it.

Topics: Adipocytes; Adult; Animals; Benzylamines; Biocatalysis; Catalase; Electron Spin Resonance Spectroscopy; Female; Humans; Hydrogen Peroxide; Lipogenesis; Lipolysis; Mice, Inbred C57BL; Molecular Docking Simulation; Monoamine Oxidase; Oxidants; Resveratrol; Stilbenes; Subcutaneous Fat; Tyramine

Stilbenes are valuable phenolic compounds that are synthesized in plants via the phenylpropanoid pathway where stilbene synthase (STS) directly catalyzes resveratrol or pinosylvin formation. Currently, there is a lack of information about the stilbene biosynthetic pathway in spruce (Picea). Resveratrol and piceatannol derivatives have been detected in the spruce bark, needles, and roots. We analyzed seasonal variation in stilbene spectrum and content in the needles of different ages of one tree of spruce Picea jezoensis. HPLC analysis revealed the presence of nine stilbenes: t- and cis-astringin, t- and cis-piceid, t- and cis-isorhapontin, and t-piceatannol were present in amounts of 0.01-6.07 mg/g of dry weight (DW), while t-isorhapontigenin and t-resveratrol were present in traces (0.001-0.312 μg/g DW). T-astringin prevailed over other stilbenoid compounds (66-86% of all stilbenes). The highest total stilbene content was detected in one-year-old needles collected in the autumn and spring (5.4-7.77 mg/g DW). We previously cloned and sequenced full-length cDNAs of the four STS transcripts (PjSTS1a, PjSTS1b, PjSTS2, and PjSTS3) of P. jezoensis. This study presents a detailed analysis of seasonal variations in PjSTS1a, 1b, 2, and 3 transcript levels in the needles of P. jezoensis of different ages using qRT-PCR. PjSTS1a and PjSTS1b transcription was higher in the needles collected in the autumn, spring, or summer than in the winter. PjSTS2 was actively transcribed in the needles of all ages collected in the winter, spring, and summer. PjSTS3 expression did not significantly change during the year and did not depend on the age of the needles. Therefore, the data show that high levels of the stilbene glucosides and PjSTS expression are present in the needles of P. jezoensis.

Topics: Acyltransferases; Glucosides; Phenols; Picea; Plant Bark; Plant Roots; Resveratrol; Stilbenes

Resveratrol and its derivate piceatannol are known to induce cancer cell-specific cell death. While multiple mechanisms of actions have been described including the inhibition of ATP synthase, changes in mitochondrial membrane potential and ROS levels, the exact mechanisms of cancer specificity of these polyphenols remain unclear. This paper is designed to reveal the molecular basis of the cancer-specific initiation of cell death by resveratrol and piceatannol.. The two cancer cell lines EA.hy926 and HeLa, and somatic short-term cultured HUVEC were used. Cell viability and caspase 3/7 activity were tested. Mitochondrial, cytosolic and endoplasmic reticulum Ca2+ as well as cytosolic and mitochondrial ATP levels were measured using single cell fluorescence microscopy and respective genetically-encoded sensors. Mitochondria-ER junctions were analyzed applying super-resolution SIM and ImageJ-based image analysis.. Resveratrol and piceatannol selectively trigger death in cancer but not somatic cells. Hence, these polyphenols strongly enhanced mitochondrial Ca2+ uptake in cancer exclusively. Resveratrol and piceatannol predominantly affect mitochondrial but not cytosolic ATP content that yields in a reduced SERCA activity. Decreased SERCA activity and the strongly enriched tethering of the ER and mitochondria in cancer cells result in an enhanced MCU/Letm1-dependent mitochondrial Ca2+ uptake upon intracellular Ca2+ release exclusively in cancer cells. Accordingly, resveratrol/piceatannol-induced cancer cell death could be prevented by siRNA-mediated knock-down of MCU and Letm1.. Because their greatly enriched ER-mitochondria tethering, cancer cells are highly susceptible for resveratrol/piceatannol-induced reduction of SERCA activity to yield mitochondrial Ca2+ overload and subsequent cancer cell death.

Topics: Adenosine Triphosphate; Antineoplastic Agents, Phytogenic; Apoptosis; Calcium; Calcium Channels; Calcium-Binding Proteins; Caspase 3; Caspase 7; Cell Line, Tumor; Cell Survival; Endoplasmic Reticulum; HeLa Cells; Human Umbilical Vein Endothelial Cells; Humans; Ion Transport; Membrane Proteins; Mitochondria; Organ Specificity; Resveratrol; RNA, Small Interfering; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Stilbenes

Among the many stilbenoids found in a variety of berries, resveratrol and pterostilbene are of particular interest given their potential for use in cancer therapeutics and prevention. We purified four stilbenoids from R. undulatum and found that pterostilbene inhibits cancer cell proliferation more efficiently than rhapontigenin, piceatannol and resveratrol. To investigate the underlying mechanism of this superior action of pterostilbene on cancer cells, we utilized a reverse-phase protein array followed by bioinformatic analysis and found that the ATM/CHK pathway is modified by pterostilbene in a lung cancer cell line. Given that ATM/CHK signaling requires p53 for its biological effects, we hypothesized that p53 is required for the anticancer effect of pterostilbene. To test this hypothesis, we used two molecularly defined precancerous human bronchial epithelial cell lines, HBECR and HBECR/p53i, with normal p53 and suppressed p53 expression, respectively, to represent premalignant states of squamous lung carcinogenesis. Pterostilbene inhibited the cell cycle more efficiently in HBECR cells compared to HBECR/p53i cells, suggesting that the presence of p53 is required for the action of pterostilbene. Pterostilbene also activated ATM and CHK1/2, which are upstream of p53, in both cell lines, though pterostilbene-induced senescence was dependent on the presence of p53. Finally, pterostilbene more effectively inhibited p53-dependent cell proliferation compared to the other three stilbenoids. These results strongly support the potential chemopreventive effect of pterostilbene on p53-positive cells during early carcinogenesis.

Topics: Antineoplastic Agents, Phytogenic; Ataxia Telangiectasia Mutated Proteins; Carcinoma, Non-Small-Cell Lung; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Checkpoint Kinase 1; Checkpoint Kinase 2; Humans; Lung Neoplasms; Proteome; Respiratory Mucosa; Resveratrol; Rheum; Signal Transduction; Stilbenes; Tumor Suppressor Protein p53

Piceatannol (3,3',4',5-trans-tetrahydroxystilbene) is a polyphenolic compound abundant in the seeds of passion fruit (Passiflora edulis). Piceatannol is an analogue of resveratrol (3,4',5-trans-trihydroxystilbene) and shares the structural motif and biological activities such as activation of SIRT1. Several studies have shown that piceatannol is more potent than resveratrol. In this study, we examined the effects of piceatannol on neural stem cell differentiation into astrocytes compared with those of resveratrol. At a concentration of 2.5 μM, piceatannol promoted astrocyte differentiation, while resveratrol had no effect at this concentration. Furthermore, we found that oral administration of piceatannol increased the number of astrocytes in the brains of adult mice, while resveratrol administration showed no effects. These results suggest that piceatannol has a superior effect to resveratrol in promoting astrocyte differentiation.

Topics: Animals; Astrocytes; Cell Differentiation; Gene Expression Regulation; Hippocampus; Male; Mice; Molecular Structure; Neural Stem Cells; Resveratrol; Stilbenes

The effects of chronic administration of piceatannol-enriched (9.5% w/w) passion fruit seed extract (PFSE) on the cardiovascular damage induced in a high-fat (HF) diet-fed model of Fischer 344 rats were evaluated. Rats were fed the control, HF, or HF diets containing PFSE (0.5% w/w) for 16 weeks, and the effects of the various diets on the tissue weight, serum lipid profile, hepatic fibrosis, hepatic ductular reaction, cardiac function and aortic ring reactivity were examined. HF diet-fed rats developed signs of cardiovascular disease with abnormal serum profiles compared to control diet-fed rats. PFSE supplementation improved the liver hypertrophy and hepatic histology of the HF diet-fed rats. In addition, the triglyceride and cholesterol levels, platelet aggregation, cardiac function, and acetylcholine-mediated relaxation of the aortic ring were improved. These results suggest that the chronic intake of PFSE containing piceatannol prevents HF diet-induced cardiovascular disease in rats.

Topics: Animals; Aorta; Cardiovascular Diseases; Diet, High-Fat; Dietary Supplements; Heart Ventricles; Hypolipidemic Agents; Lipotropic Agents; Liver; Male; Non-alcoholic Fatty Liver Disease; Organ Size; Passiflora; Plant Extracts; Platelet Aggregation Inhibitors; Random Allocation; Rats, Inbred F344; Seeds; Stilbenes; Vascular Resistance

Obesity is a global health concern. Piceatannol (Pic), an analog of resveratrol (Res), has many reported biological activities. In this study, we investigated the anti-obesity effect of Pic in a high-fat diet (HFD)-induced obese animal model. The results showed that Pic significantly reduced mouse body weight in a dose-dependent manner without affecting food intake. Serum total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL) levels, and blood glucose (GLU) were significantly lowered in Pic-treated groups. Pic significantly decreased the weight of liver, spleen, perigonadal and retroperitoneal fat compared with the HFD group. Pic significantly reduced the adipocyte cell size of perigonadal fat and decreased the weight of liver. Pic-treated mice showed higher phosphorylated adenosine 5'-monophosphate-activated protein kinase (pAMPK) and phosphorylated acetyl-CoA carboxylase (pACC) protein levels and decreased protein levels of CCAAT/enhancer-binding protein C/EBPα, peroxisome proliferator-activated receptor PPARγ and fatty acid synthase (FAS), resulting in decreased lipid accumulation in adipocytes and the liver. Pic altered the composition of the gut microbiota by increasing Firmicutes and

Topics: Adipogenesis; Animals; Anti-Obesity Agents; Body Weight; Cholesterol; Diet, High-Fat; Disease Models, Animal; Dose-Response Relationship, Drug; Eating; Gastrointestinal Microbiome; Gene Expression Regulation; Lipoproteins, HDL; Lipoproteins, LDL; Mice; Mice, Inbred C57BL; Obesity; Organ Size; Stilbenes

Piceatannol, a resveratrol metabolite, is a phenolic compound found in red wine and grapes. We investigated the effect of piceatannol on renal fibrosis and histone deacetylase (HDAC) expression in a mouse model of unilateral ureteral obstruction (UUO). Fibrosis was established by UUO and piceatannol was intraperitoneally injected for 2 weeks. Piceatannol suppressed extracellular matrix (ECM) protein deposition including collagen type I and fibronectin as well as connective tissue growth factor (CTGF) and α-smooth muscle actin (α-SMA) in UUO kidneys. However, the expressions of epithelial-mesenchymal transition (EMT) marker genes, such as N-cadherin and E-cadherin, were not changed in the kidneys after UUO. Masson's trichrome staining and fluorescence immunostaining showed that piceatannol administration attenuated collagen deposition in UUO kidneys. HDAC1, HDAC4, HDAC5, HDAC6, and HDAC10 protein expression was upregulated in UUO kidneys, whereas that of HDAC8 was downregulated. Piceatannol treatment significantly reduced HDAC4 and HDAC5 protein expression. Further, piceatannol attenuated phosphorylation of p38 mitogen-activated protein kinase (p38-MAPK) in UUO kidneys, but not that of transforming growth factor beta1-Smad2/3. These results suggest that class I HDACs and class IIa/b HDACs are involved in renal fibrosis development. Piceatannol may be a beneficial therapeutic agent for treating renal fibrosis via reduction of HDAC4 and HDAC5 protein expression or suppression of the p38-MAPK signaling pathway.

Topics: Animals; Biomarkers; Down-Regulation; Epithelial-Mesenchymal Transition; Extracellular Matrix Proteins; Fibrosis; Gene Expression Regulation, Enzymologic; Histone Deacetylases; Kidney; Male; MAP Kinase Signaling System; Mice; Mice, Inbred C57BL; p38 Mitogen-Activated Protein Kinases; Stilbenes; Ureteral Obstruction

Resveratrol and related oligostilbenes are defense molecules produced by grapevine in response to stresses including various elicitors or signal molecules. Together with their prominent role in planta, these compounds have been the center of much attention in recent decades due to their pharmacological properties. The cost-effective production of resveratrol derivatives such as viniferins or more structurally complex stilbene oligomers remains a challenging task. In this study, the chemical diversity of stilbenes produced by Vitis vinifera Pinot Noir hairy roots was investigated after elicitation for 4 days with a mixture of methyl jasmonate (100 μM) and cyclodextrins (50 mM). Two crude extracts obtained from the culture medium and from the hairy roots were fractionated by centrifugal partition chromatography. The fractions were chemically investigated by two complementary identification approaches involving a

Topics: Benzofurans; Chromatography, Liquid; Cyclopentanes; Flavanones; Flavonoids; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Oxylipins; Phenols; Plant Roots; Polycyclic Compounds; Resveratrol; Stilbenes; Vitis

The aim was to analyse the efficacy of piceatannol (PIC) loaded chitosan (CS)/poly(lactic acid)(PLA) nanoparticles (CS/PLA-PIC NPs) in zebra fish embryos exposed to aflatoxin B1 (AFB1). FTIR confirmed the chemical interaction between the polymers and drug. SEM showed the size of CS/PLA-PIC NPs approximately 87 to 200nm, compared to CS-PLA NPs of 150nm size. The size was further affirmed as 127nm (CS-PLA NPs) and 147nm (CS/PLA-PIC NPs) by zetasizer depiction. CS/PLA-PIC NPs have not illustrated toxicity at high concentrations when tested in zebrafish embryos. AFB1 wielded their toxic effects on the survival, spontaneous movement, hatching and heart rate and development of embryos were observed in both time and dose-dependent manner at 4μM. Our results suggested that the addition of CS/PLA-PIC NPs increases the survival, heart rate and hatching in time dependent manner at the dosage of 20μg/ml. These hopeful results may prompt the advancement of drug encapsulated polymeric nanoparticles which may have the potential role in improving the AFB1 induced toxicity in humans as well.

Topics: Aflatoxin B1; Animals; Chitosan; Drug Carriers; Embryonic Development; Heart Rate; Lactic Acid; Nanoparticles; Particle Size; Polyesters; Polymers; Stilbenes; Zebrafish

Piceatannol, a metabolite of resveratrol found in red wine and grapes, displays a wide spectrum of biological activity. Although the anti-oxidant, anti-inflammatory, and anti-tumorigenesis activity of piceatannol has been extensively studied, its role in the adaptive immune response has received less attention. Here we investigated the role of piceatannol, a well-known Syk inhibitor, in T cell activation, proliferation, and differentiation using isolated murine splenic T cells from C57BL/6 mice. Piceatannol treatment inhibited surface expression of CD4 and CD8 T cell activation markers CD25 and CD69, reduced production of cytokines IFNγ, IL-2, and IL-17, and suppressed proliferation of activated T cells. Moreover, piceatannol treatment significantly inhibited differentiation of CD4(+)CD25(-)CD62L(+) naïve CD4 T cells into Th1, Th2, and Th17 cells, presumably due to inhibition of TcR signaling through p-Erk, p-Akt, and p-p38. Piceatannol appears to be a useful nutritional or pharmacological biomolecule that regulates effector T cell functions such as cytokine production, differentiation, and proliferation.

Topics: Animals; Antigens, CD; Antigens, Differentiation, T-Lymphocyte; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Cell Differentiation; Cytokines; Female; Interleukin-2 Receptor alpha Subunit; Lectins, C-Type; Mice, Inbred C57BL; Mitogen-Activated Protein Kinases; Phosphorylation; Protein Kinase Inhibitors; Receptors, Antigen, T-Cell; Spleen; Stilbenes

Growing evidence suggests that the elevation of free fatty acids, including palmitic acid (PA), are associated with inflammation and oxidative stress, which may be involved in endothelial dysfunction, characterized by the reduced bioavailability of nitric oxide (NO) synthesized from endothelial NO synthase (eNOS). Heme oxygenase-1 (HO-1) is important in the preservation of NO bioavailability. Piceatannol (Pic), with similar chemical structure to resveratrol, is suggested to possess similar protective effects as resveratrol. In the present study, human umbilical vein endothelial cells (HUVECs), stimulated with PA, were used to examine the endothelial protective effects of Pic. Pic increased the expression of HO-1 via nuclear factor erythroid-2-related factor-2 activation in the HUVECs, and decreased the PA-induced secretions of interleukin-6 and tumor necrosis factor-α, and the formation of reactive oxygen species ROS via inhibition of NF-κB activation. Notably, following inhibition of HO-1 activity by tin protoporphryin-IX, Pic did not prevent cytokine secretion, ROS formation, and NF-κB activation in the PA-stimulated HUVECs. PA attenuated insulin-mediated insulin receptor substrate-1 (IRS-1) tyrosine phosphorylation, leading to decreased glucose uptake, and phosphorylation of eNOS, leading to a reduction in the production of NO. Pic effectively mitigated the inhibitory effects of PA on the insulin-mediated phosphorylation of IRS-1 and eNOS, which was not observed following inhibition of HO‑1 activity. The results of the present study suggested that Pic may have the potential to prevent PA-induced impairment of insulin signaling and eNOS function, by inducing the expression of the anti-inflammatory and antioxidant, HO-1.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Antioxidants; Gene Expression Regulation; Heme Oxygenase-1; Human Umbilical Vein Endothelial Cells; Humans; Insulin; Insulin Receptor Substrate Proteins; Interleukin-6; Metalloporphyrins; NF-E2-Related Factor 2; NF-kappa B; Nitric Oxide; Nitric Oxide Synthase Type III; Oxidants; Oxidative Stress; Palmitic Acid; Protoporphyrins; Reactive Oxygen Species; Resveratrol; Signal Transduction; Stilbenes

We previously found that passion fruit (Passiflora edulis) seeds contained a high amount of piceatannol (3,5,3',4'-trans-tetrahydroxystilbene), a natural analog of resveratrol (3,5,4'-trans-trihydroxystilbene). Resveratrol has been proposed as a potential anti-metabolic disorder compound, by its activation of sirtuin and AMP-activated protein kinase. Many reports show that resveratrol ameliorates diet-induced obesity and insulin resistance. However, it is not known whether piceatannol also affects diet-induced obesity. We explored the effect of piceatannol on high fat diet-fed mice. The results showed that piceatannol did not affect high fat diet-induced body weight gain or visceral fat gain in mice. However, piceatannol did reduce fasting blood glucose levels. Furthermore, to explore the potential of passion fruit seed extract containing piceatannol as a functional food, passion fruit seed extract was administered in a genetic diabetic mouse model (db/db mice). Single administration of passion fruit seed extract, as well as piceatannol reduced the blood glucose levels of these db/db mice. These results suggest that piceatannol and passion fruit seed extract may have potential application in the prevention of diabetes.

Topics: Animals; Blood Glucose; Body Weight; Diabetes Mellitus, Experimental; Diet, High-Fat; Eating; Hypoglycemic Agents; Leptin; Male; Mice, Inbred C57BL; Passiflora; Plant Extracts; Seeds; Stilbenes

Peanut (Arachis hypogaea) produces stilbenoids upon exposure to abiotic and biotic stresses. Among these compounds, the prenylated stilbenoids arachidin-1 and arachidin-3 have shown diverse biological activities with potential applications in human health. These compounds exhibit higher or novel biological activities in vitro when compared to their nonprenylated analogues piceatannol and resveratrol, respectively. However, assessment of these bioactivities in vivo has been challenging because of their limited availability. In this study, hairy root cultures of peanut were induced to produce stilbenoids upon treatment with elicitors. Co-treatment with 100 μM methyl jasmonate (MeJA) and 9 g/L methyl-β-cyclodextrin (CD) led to sustained high levels of resveratrol, piceatannol, arachidin-1, and arachidin-3 in the culture medium when compared to other elicitor treatments. The average yields of arachidin-1 and arachidin-3 were 56 and 148 mg/L, respectively, after co-treatment with MeJA and CD. Furthermore, MeJA and CD had a synergistic effect on resveratrol synthase gene expression, which could explain the higher yield of resveratrol when compared to treatment with either MeJA or CD alone. Peanut hairy root cultures were shown to be a controlled and sustainable axenic system for the production of the diverse types of biologically active stilbenoids.

Topics: Acetates; Arachis; beta-Cyclodextrins; Cell Culture Techniques; Culture Media; Cyclopentanes; Gene Expression Regulation, Plant; Hemiterpenes; Oxylipins; Plant Growth Regulators; Plant Proteins; Plant Roots; Resveratrol; Stilbenes

Stilbenes, as important secondary metabolites of grapevine, represent central phytoalexins and therefore constitute an important element of basal immunity. In this study, potential genetic variation in Vitis vinifera ssp. sylvestris, the ancestor of cultivated grapevine, was sought with respect to their output of stilbenes and potential use for resistance breeding. Considerable variation in stilbene inducibility was identified in V. vinifera ssp. sylvestris. Genotypic differences in abundance and profiles of stilbenes that are induced in response to a UV-C pulse are shown. Two clusters of stilbene 'chemovars' emerged: one cluster showed quick and strong accumulation of stilbenes, almost exclusively in the form of non-glycosylated resveratrol and viniferin, while the second cluster accumulated fewer stilbenes and relatively high proportions of piceatannol and the glycosylated piceid. For all 86 genotypes, a time dependence of the stilbene pattern was observed: piceid, resveratrol, and piceatannol accumulated earlier, whereas the viniferins were found later. It was further observed that the genotypic differences in stilbene accumulation were preceded by differential accumulation of the transcripts for chalcone synthase (CHS) and stilbene-related genes: phenylalanine ammonium lyase (PAL), stilbene synthase (StSy), and resveratrol synthase (RS). A screen of the population with respect to susceptibility to downy mildew of grapevine (Plasmopara viticola) revealed considerable variability. The subpopulation of genotypes with high stilbene inducibility was significantly less susceptible as compared with low-stilbene genotypes, and for representative genotypes it could be shown that the inducibility of stilbene synthase by UV correlated with the inducibility by the pathogen.

Topics: Acyltransferases; Gene Expression Regulation, Plant; Genetic Variation; Genotype; Glucosides; Oomycetes; Phytoalexins; Plant Diseases; Plant Immunity; Plant Leaves; Plant Stomata; Resveratrol; Sesquiterpenes; Stilbenes; Ultraviolet Rays; Vitis

Recombinant tyrosinase from Streptomyces avermitilis MA4680, MelC2 (gi:499291317), was heterologously expressed in Escherichia coli BL21 (DE3). The expression level of active MelC2 was increased by the codon-optimized MelC1 caddie protein (KP198295.1). By performing saturation mutagenesis of the Y91 residue of MelC1, it was found that aromatic residues such as Y, F, and W at the 91st position help produce a correctly folded conformation of MelC2. The recombinant MelC2 was utilized as a biocatalyst to convert trans-resveratrol into piceatannol. In order to improve the product yield through suppression of the formation of melanin, a by-product, an increase in the ratio of monooxygenation (k 1) to dioxygenation (k 2) of MelC2 is desirable. This was achieved by a combination of protein engineering and regeneration of NADH with glucose dehydrogenase (GDH). Saturation mutagenesis was performed at 15 residues within 8-Å radius from copper ions of MelC2. A total of 2760 mutants were examined (99.7 % probability for NNK codon) and I41Y, a mutant, was screened. The ratio of k 1 to k 2 of the mutant increased sevenfold on tyrosine and fivefold on resveratrol, when compared to wild-type MelC2. As a result, the overall product yield from 500 μM resveratrol in 50-mL reaction was 15.4 % (77.4 μM piceatannol), 1.7 times higher than wild type. When I41Y was incorporated with the NADH regeneration system, the total product yield was 58.0 %, an eightfold increase (290.2 μM of piceatannol).

Topics: Bacterial Proteins; Escherichia coli; Gene Expression; Hydroxylation; Monophenol Monooxygenase; Resveratrol; Stilbenes; Streptomyces

A systematic study of the antioxidation mechanisms behind hydroxyl (•OH) and hydroperoxyl (•OOH) radical scavenging activity of piceatannol (PIC) and isorhapontigenin (ISO) was carried out using density functional theory (DFT) method. Two reaction mechanisms, abstraction (ABS) and radical adduct formation (RAF), were discussed. A total of 24 reaction pathways of scavenging •OH and •OOH with PIC and ISO were investigated in the gas phase and solution. The thermodynamic and kinetic properties of all pathways were calculated. Based on these results, we evaluated the antioxidant activity of every active site of PIC and ISO and compared the abilities of PIC and ISO to scavenge radicals. According to our results, PIC and ISO may act as effective •OH and •OOH scavengers in organism. A4-hydroxyl group is a very important active site for PIC and ISO to scavenge radicals. The introducing of -OH or -OCH3 group to the ortho-position of A4-hydroxyl group would increase its antioxidant activity. Meanwhile, the conformational effect was researched, the results suggest that the presence and pattern of intramolecular hydrogen bond (IHB) are considerable in determining the antioxidant activity of PIC and ISO.

Topics: Antioxidants; Gases; Hydrogen Bonding; Hydrogen Peroxide; Hydroxyl Radical; Models, Molecular; Molecular Conformation; Oxidation-Reduction; Quantum Theory; Stilbenes; Thermodynamics; Water

A number of naturally occurring agents are hypothesized to protect against ultraviolet (UV)‑induced skin damage. The present study screened >50 plant extracts for inhibitors of UVB‑induced cytotoxicity, using cultured normal human epidermal keratinocytes (NHEK), and identified that the fruit of rose myrtle (Rhodomyrtus tomentosa) was the most marked inhibitor of cell death. The protective effect of rose myrtle extract and the two key components, piceatannol and piceatannol‑4'‑O‑β‑D‑glucopyranoside, on UVB‑induced damage and inflammation in cultured NHEK was investigated. The 80% ethanol extract from rose myrtle fruit with piceatannol exhibited protection of UVB‑induced cytotoxicity in NHEK; however, piceatannol‑4'‑O‑β‑D‑glucopyranoside exhibited no protection, as determined by a 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazolium bromide assay. This extract and piceatannol reduced the production of UVB‑induced cyclobutane pyrimidine dimers and enhanced the cellular enzyme activity of the DNA polymerases in UVB‑irradiated NHEK, suggesting that UVB‑stimulated DNA damage was repaired by the polymerases. In addition, the secretion of prostaglandin E2, which is an inflammatory mediator, was decreased. These results indicated that rose myrtle fruit extract and its key constituent, piceatannol, are potential photoprotective candidates for UV‑induced skin damage.

Topics: Apoptosis; Cell Survival; Cells, Cultured; Dinoprostone; DNA Damage; DNA-Directed DNA Polymerase; Enzyme Activation; Fruit; Humans; Keratinocytes; Plant Extracts; Rosa; Stilbenes; Ultraviolet Rays

To enhance their water solubility and pharmacological activities, the stilbenes resveratrol, pterostilbene, and piceatannol were glycosylated to their monoglucosides (β-glucosides) and diglycosides (β-maltosides) by cultured cells and cyclodextrin glucanotransferase (CGTase). Cultured cells of Phytolacca americana and glucosyltransferase (PaGT) were capable of glucosylation of resveratrol to its 3- and 4'-β-glucosides. Pterostilbene was slightly transformed into its 4'-β-glucoside by P. americana cells. Piceatannol was readily converted into piceatannol 4'-β-glucoside, with the highest yield among the three substrates. The 3- and 4'-β-glucosides of resveratrol were subjected to further glycosylation by CGTase to give 3- and 4'-β-maltoside derivatives. The inhibitory action of resveratrol and pterostilbene toward histamine release induced with compound 48/80 from rat peritoneal mast cells was improved by β-glucosylation and/or β-maltosylation (i.e., the inhibitory activity for histamine release of the 3- and 4'-β-glucosides of resveratrol, the 3- and 4'-β-maltosides of resveratrol, and the 4'-β-glucoside of pterostilbene was higher than that of the corresponding aglycones, resveratrol and pterostilbene, respectively). In addition, the phosphodiesterase (PDE) inhibitory activity of resveratrol and pterostilbene was enhanced by β-glucosylation and/or β-maltosylation (i.e., the PDE inhibitory activities of the 3- and 4'-β-glucosides of resveratrol, the 4'-β-maltoside of resveratrol, and the 4'-β-glucoside of pterostilbene were higher than those of the corresponding aglycones, resveratrol and pterostilbene, respectively).

Topics: Animals; Anti-Allergic Agents; Cells, Cultured; Drug Evaluation, Preclinical; Free Radical Scavengers; Glycosides; Glycosylation; Inhibitory Concentration 50; Phosphodiesterase Inhibitors; Phytolacca americana; Plant Extracts; Rats; Resveratrol; Solubility; Stilbenes

Piceatannol (PCT), an anti-colitic natural product, undergoes extensive Phase II hepatic metabolism, resulting in very low bioavailability. We investigated whether colon-targeted delivery of PCT could enhance anti-colitic effects and how therapeutic enhancement occurred at the molecular level. Molecular effects of PCT were examined in human colon carcinoma cells and inflamed colons. The anti-colitic effects of PCT in a colon-targeted capsule (colon-targeted PCT) were compared with PCT in a gelatin capsule (conventional PCT) in a trinitrobenzene sulfonic acid-induced rat colitis model. Colon-targeted PCT elicited greatly enhanced recovery of the colonic inflammation. In HCT116 cells, PCT inhibited nuclear factor kappaB while activating anti-colitic transcription factors, nuclear factor-erythroid 2 (NF-E2) p45-related factor 2, and hypoxia-inducible factor-1. Colon-targeted PCT, but not conventional PCT, modulated production of the target gene products of the transcription factors in the inflamed colonic tissues. Rectal administration of PCT, which simulates the therapeutic action of colon-targeted PCT, also ameliorated rat colitis and reproduced the molecular effects in the inflamed colonic tissues. Colon-targeted delivery increased therapeutic efficacy of PCT against colitis, likely resulting from multitargeted effects exerted by colon-targeted PCT. The drug delivery technique may be useful for therapeutic optimization of anti-colitic lead compounds including natural products.

Topics: Administration, Oral; Administration, Rectal; Animals; Anti-Inflammatory Agents; Biomarkers; Capsules; Chemistry, Pharmaceutical; Colitis; Colon; Disease Models, Animal; Gastrointestinal Agents; Gelatin; Gene Expression Regulation; HCT116 Cells; Humans; Inflammation Mediators; Male; Mice; Rats, Sprague-Dawley; RAW 264.7 Cells; Signal Transduction; Stilbenes; Technology, Pharmaceutical; Transfection; Trinitrobenzenesulfonic Acid

Piceatannol, a polyphenol which exhibits anticancer activities, is found in grapes, red wine and berries. It has been shown to inhibit several transcription factor pathways. The present study was conducted to determine whether oral administration of piceatannol inhibits mammary tumor progression. 4T1 mammary carcinoma cells were injected into the mammary fat pad of syngeneic female BALB/c mice. Starting 1 day later, piceatannol (10- or 20-mg/kg body weight/day) was administered by oral gavage for 30 days. Piceatannol treatment reduced tumor growth. In tumor tissues, piceatannol treatment reduced the expression of transcription factors P-NFκB p65, P-STAT3 and HIF-1α and multiple proteins involved in regulation of cell cycle progression (Ki67, cyclin D1, cyclin A, CDK2, CDK4), angiogenesis (VEGF-A, VEGFR-2, VE-cadherin, CD31) and lymphangiogenesis (VEGF-C, LYVE-1), as well as macrophage infiltration. Piceatannol significantly increased apoptotic cells and expression of both Bax and cleaved caspase-3 but reduced Bcl-2 expression in tumor tissues. In addition, piceatannol reduced the number and volume of pulmonary tumor nodules and expression of MMP-9 in both lung and tumor. It also reduced tissue levels of cytokines/chemokines, including M-CSF and MCP-1. In vitro results revealed that piceatannol inhibited migration of 4T1 cells and monocytes, as well as secretion of MCP-1 and M-CSF by 4T1 cells. 4T1 cell-conditioned medium stimulated monocyte migration, which was suppressed by a CCR2 antibody. These results indicate that alteration in tumor microenvironment (macrophages, transcription factors, etc.) is an important mechanism by which piceatannol inhibits tumor proliferation, angiogenesis and lymphangiogenesis, leading to suppression of mammary tumor growth and metastasis.

Topics: Administration, Oral; Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Cell Line, Tumor; Drug Screening Assays, Antitumor; Female; Lung Neoplasms; Macrophages; Mammary Neoplasms, Experimental; Mice, Inbred BALB C; Neovascularization, Pathologic; Phosphorylation; STAT3 Transcription Factor; Stilbenes; Transcription Factor RelA

Endothelial dysfunction associated with many cardiovascular diseases is largely due to reduced nitric oxide (NO) derived from endothelial NO synthase (eNOS). Piceatannol (trans-3,4,3',5'-tetrahydroxystilbene; Pic) is reported to have cardiovascular therapeutic effects. However, the cellular and molecular mechanisms underlying the cardioprotective effects of Pic are still unclear. Here, we investigated whether Pic could influence endothelial NO release in human umbilical vein endothelial cells (HUVECs).. In HUVECs exposed to Pic, NO production and phosphorylation of eNOS and protein kinase B (Akt) were determined by using a commercially available NO assay kit and Western blot analysis, respectively.. Pic stimulated dose- and time-dependent NO production via eNOS phosphorylation. Pic also stimulated dose-dependent phosphorylation of Akt. Interestingly, NO production and eNOS phosphorylation in response to Pic were significantly abolished by the phosphoinositide 3-kinase (PI3K)/Akt inhibitor LY294002.. Pic is capable of inducing eNOS phosphorylation and the subsequent NO release, presumably, by activating PI3K/Akt pathway. The potential efficacy of Pic, a natural hydroxylated analog and a metabolite of resveratrol, may aid in the prevention of cardiovascular diseases characterized by endothelial dysfunction.

Topics: Cells, Cultured; Endothelial Cells; Humans; Nitric Oxide; Nitric Oxide Synthase Type III; Phosphatidylinositol 3-Kinases; Phosphorylation; Stilbenes

Stilbenoids, known an important phytoalexins in plants, were renowned for their beneficial effects on cardiovascular, neurological and hepatic systems. In the present study, quorum sensing inhibition activity of ten stilbenoids were tested using Chromobacterium violaceum CV026 as the bio-indicator strain and the structure-activity relationship was also investigated. Among them, resveratrol (1), piceatannol (2) and oxyresveratrol (3) showed potential anti-QS activities. At the sub-MIC concentrations, 1-3 demonstrated a statistically significant reduction of violacein in C. violaceum CV026 in a concentration dependent manner. Furthermore, the effects of 1-3 on QS regulated virulence factors in Pseudomonas aeruginosa PAO1 were also evaluated. Our results showed that the stilbenoids 1-3 can markedly decreased the production of pyocyanin and swarming motility of P. aeruginosa PAO1. Further transcriptome analyses showed that 1-3 suppressed the expression of QS-induced genes: lasR, lasI, rhlR and rhlI.

Topics: Anti-Bacterial Agents; Cell Movement; Chromobacterium; Genes, Bacterial; Plant Extracts; Pseudomonas aeruginosa; Pyocyanine; Quorum Sensing; Stilbenes; Structure-Activity Relationship

Mulberry (genus Morus) is a significant source of polyphenols, which can promote positive effects on human health. China has various mulberry cultivars, however, many Chinese mulberry cultivars have been only minimally studied. To solve this lack of research, 8 mulberry cultivars (Da10, Tang10, Yueshen74, Yuefenshen, Longsang, Ningxia1hao, Taiwanguosang, and Baiyuwang) from 4 regions of China were assessed to determine their polyphenol profiles using HPLC-MS/MS and then tested for their antioxidant and anti-α-glucosidase activities in vitro. A total of 18 nonanthocyanins and 4 anthocyanins were quantified in mulberry cultivars; among these polyphenols, chlorogenic acid, quercetin 3-O-rutinoside, and cyanidin 3-O-glucoside were confirmed as the major phenolic acid, flavonol derivative, and anthocyanin, respectively. Two types of stilbene compounds, piceid, and piceatannol, were detected for the 1st time in all mulberry cultivars. Moreover, the methanolic extracts of different mulberry cultivars showed disparate antioxidant and α-glucosidase inhibitory activities, and this discrepancy was mainly attributed to varying the anthocyanin content. Based on our results, Taiwanguosang is proposed to be a good candidate suitable for further process due to its high level of anthocyanins.. The polyphenols of mulberry cultivars are vital for human health and are relevant to the further development of mulberry-based products. China has a wide range of mulberry cultivar resources, and many of these cultivars have not yet been studied. Our research concentrated on the polyphenol profiles, antioxidant, and α-glucosidase inhibitory activities of various mulberry cultivars from different regions of China to provide basic information for mulberry cultivar selection and mulberry-based food production.

Topics: alpha-Glucosidases; Anthocyanins; Antioxidants; China; Chlorogenic Acid; Flavonols; Fruit; Glucosides; Humans; Morus; Oxidation-Reduction; Plant Extracts; Polyphenols; Quercetin; Rutin; Species Specificity; Stilbenes; Tandem Mass Spectrometry

Environmental conditions or chemical agents can interfere with the function of the endoplasmic reticulum, and the resulting endoplasmic reticulum (ER) stress can be toxic to the cell if it is not relieved. The classical compensatory response to ER stress is the unfolded protein response (UPR) that reduces protein load in the ER. However, autophagy may also compensate by removing large insoluble protein aggregates. Agents that stress the ER can have anti-cancer activity, and novel applications of ER stress inducing agents are being investigated. Plant stilbenes are a class of stress responsive molecules that includes resveratrol, which are being investigated as potential therapeutics in humans for conditions such as aging or cancer.. We performed a screen of 1726 small, drug like molecules to identify those that could activate an ER-stress responsive luciferase gene. After secondary screening, we determined that the plant stilbenes pterostilbene and piceatannol were the most potent inducers of ER stress from this group. ER stress can be particularly toxic to cells with high ER load, so we examined their effect on cells expressing the Wnt family of secreted glycoprotein growth factors. Molecular analysis determined that these ER stress-inducing stilbenes could block Wnt processing and also induce autophagy in acute lymphoblastic leukemia cells expressing Wnt16. Combining pterostilbene (to induce ER stress) with chloroquine (to inhibit autophagy) lead to significant cellular toxicity in cells from aggressive acute lymphoblastic leukemia.. Plant stilbenes are potent inducers of ER stress. However, their toxicity is more pronounced in cancer cells expressing Wnt growth factors. The toxicity of stilbenes in these ALL cells can be potentiated by the addition of autophagy inhibitors, suggesting a possible therapeutic application.

Topics: Antimalarials; Antineoplastic Agents; Antioxidants; Autophagy; Blotting, Western; Cell Proliferation; Chloroquine; Drug Synergism; Drug Therapy, Combination; Endoplasmic Reticulum Stress; Fibrosarcoma; High-Throughput Screening Assays; Humans; Plants; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Resveratrol; Small Molecule Libraries; Stilbenes; Tumor Cells, Cultured

A set of 66 stilbenoid compounds is classified into a system of periodic properties by using a procedure based on artificial intelligence, information entropy theory. Eight characteristics in hierarchical order are used to classify structurally the stilbenoids. The former five features mark the group or column while the latter three are used to indicate the row or period in the table of periodic classification. Those stilbenoids in the same group are suggested to present similar properties. Furthermore, compounds also in the same period will show maximum resemblance. In this report, the stilbenoids in the table are related to experimental data of bioactivity and antioxidant properties available in the technical literature. It should be noted that stilbenoids with glycoxyl groups esterified with benzoic acid derivatives, in the group g11000 in the extreme right of the periodic table, show the greatest antioxidant activity as confirmed by experiments in the bibliography. Moreover, the second group from the right (g10111) contains E-piceatannol, which antioxidant activity is recognized in the literature. The experiments confirm our results of the periodic classification.

Topics: Antioxidants; Artificial Intelligence; Entropy; Stilbenes

Piceatannol, a hydroxystilbene natural product, has been reported to exert antiarrhythmic action via INa inhibition and slow INa inactivation in ischemia-reperfused (IR) rat hearts. The present study aimed to clarify the proarrhythmic property of piceatannol during regional IR injury in failing rabbit hearts.. Heart failure (HF) was induced by rapid right ventricular pacing for 4 weeks. The IR model was created by coronary artery ligation for 30 min, followed by reperfusion for 15 min in vivo. Simultaneous voltage and intracellular Ca(2+) (Cai) optical mapping was then performed in isolated Langendorff-perfused hearts (n=11 in each HF and control group). Action potential duration (APD) restitution, arrhythmogenic alternans and VF inducibility were evaluated by a dynamic pacing protocol. Conduction velocity was measured along lines across the IR and non-IR zones during pacing. Piceatannol (10 μM) was administered after baseline studies.. In the HF group, piceatannol decreased conduction velocity, induced rate-dependent regional inhomogeneity of conduction delay and wavelength shortening, slowed Cai decay, and facilitated arrhythmogenic alternans instead of APD prolongation to increase VF inducibility. In the control group, the proarrhythmic effects of piceatannol on APD restitution, arrhythmogenic alternans and conduction delay were offset by its antiarrhythmic effects (APD and wavelength prolongation), resulting in a neutral effect on VF inducibility.. Piceatannol (10 μM) is proarrhythmic in failing rabbit hearts with regional IR injury. The increased VF inducibility by piceatannol in HF suggests that its undesirable effects are more pronounced than its benefits in failing hearts.

Topics: Animals; Calcium; Disease Models, Animal; Electrophysiologic Techniques, Cardiac; Heart Block; Heart Conduction System; Heart Failure; Myocardial Reperfusion Injury; Perfusion; Protein-Tyrosine Kinases; Rabbits; Stilbenes; Ventricular Fibrillation

Aberrant activation of Wnt/β-catenin signaling promotes development and progression of various malignant neoplasms. Recent studies observed that the Wnt pathway is constitutively active in myeloma cells and promotes an exaggerated proliferation. Thus, the Wnt signaling pathway might be an attractive therapeutic target for multiple myeloma. In this study, we identified piceatannol as an inhibitor of the Wnt/β-catenin pathway and as a potent inducer of apoptosis in myeloma cells. Interestingly, healthy cells remained mainly unaffected. These results reveal a significant selective induction of apoptosis by piceatannol and suggest a significant in vivo effect against multiple myeloma.

Topics: Animals; Apoptosis; beta Catenin; Cell Line; Cell Line, Tumor; Cell Proliferation; Cell Survival; Fibroblasts; Humans; Immunotherapy; Inhibitory Concentration 50; Mice; Multiple Myeloma; Propidium; Stilbenes; Treatment Outcome; Wnt Proteins; Wnt Signaling Pathway

Stilbene-enriched wine is considered to be an interesting new food product with added value due to its potential health-promoting properties. Stilbene concentration in grape is highly variable and rather scarce. However, it can be increased by stress treatments. For this reason, numerous pre- and postharvest grape treatments, and some combinations of them, have been tested to maximize stilbene content in grapes. In the present manuscript, Syrah grapes were treated with (i) methyl jasmonate (MEJA), (ii) ultraviolet light (UVC), and (iii) methyl jasmonate and ultraviolet light (MEJA-UVC) and compared with untreated grapes. Afterward, winemaking was developed. Wine achieved by combination of both treatments (MEJA-UVC) contained significantly higher stilbene concentration (trans-resveratrol and piceatannol) than its respective control (2.5-fold). Wine quality was improved in color-related parameters (color intensity, L*, a*, b*, ΔE*, anthocyanins, and tannin). Moreover, MEJA-UVC wines obtained the highest score in sensorial analysis. To the best of our knowledge, this is the first time that pre- and postharvest treatments are combined to increase stilbenes in wine.. The effect of treatment combination (methyl jasmonate and UVC light) on grape and wine was evaluated. Our results highlight the positive effect of the treatments in stilbene content, color parameters, and sensorial analysis. Moreover, added-value by-products were achieved.

Topics: Acetates; Anthocyanins; Color; Cyclopentanes; Fruit; Humans; Odorants; Oxylipins; Plant Growth Regulators; Resveratrol; Stilbenes; Tannins; Taste; Ultraviolet Rays; Vitis; Wine

Inflammatory diseases such as acute lung injury and ischaemic tissue injury are caused by the adhesion of a type of white blood cell--polymorphonuclear neutrophils--to the lining of the circulatory system or vascular endothelium and unchecked neutrophil transmigration. Nanoparticle-mediated targeting of activated neutrophils on vascular endothelial cells at the site of injury may be a useful means of directly inactivating neutrophil transmigration and hence mitigating vascular inflammation. Here, we report a method employing drug-loaded albumin nanoparticles, which efficiently deliver drugs into neutrophils adherent to the surface of the inflamed endothelium. Using intravital microscopy of tumour necrosis factor-α-challenged mouse cremaster post-capillary venules, we demonstrate that fluorescently tagged albumin nanoparticles are largely internalized by neutrophils adherent to the activated endothelium via cell surface Fcɣ receptors. Administration of albumin nanoparticles loaded with the spleen tyrosine kinase inhibitor, piceatannol, which blocks 'outside-in' β2 integrin signalling in leukocytes, detached the adherent neutrophils and elicited their release into the circulation. Thus, internalization of drug-loaded albumin nanoparticles into neutrophils inactivates the pro-inflammatory function of activated neutrophils, thereby offering a promising approach for treating inflammatory diseases resulting from inappropriate neutrophil sequestration and activation.

Topics: Animals; Cattle; Cell Adhesion; Drug Carriers; Endothelium, Vascular; Inflammation; Mice; Nanoparticles; Neutrophils; Protein-Tyrosine Kinases; Receptors, IgG; Serum Albumin, Bovine; Stilbenes

Resveratrol (RSV) and resveratrol analogs have a potential use in prostate cancer chemoprevention due to effects on for example, cell growth, apoptosis, angiogenesis, and metastasis. However, inhibition of CYP17A1, a key enzyme in the androgen biosynthesis and a target for prostate cancer therapy, has not been explored as a possible mechanism behind the effects on prostate cancer.. Human adrenocortical carcinoma cells, H295R, were treated with RSV, piceatannol (PIC), 3,5,4'-triacetylresveratrol (RSVTA), 3,5-diacetylresveratrol (RSVDA), and 3,5,4'-trimethylresveratrol (RSVTM) for 24 hr at concentrations of 1, 5, 10, 25, and 50 µM. Steroid secretion, enzyme activities, and gene expression of key steps in steroidogenesis were investigated.. Secretion of dihydroepiandrosterone (DHEA), testosterone, and cortisol were drastically decreased by all test compounds at concentrations that did not affect cell viability. Progesterone and aldosterone secretion were increased. This steroid secretion pattern can be explained by the demonstrated inhibition of CYP17A1 enzyme activity. The most efficient CYP17A1 inhibitors were the synthetic analogs RSVTA, RSVDA, and RSVTM. Inhibition by RSVTM was more selective on the 17,20-lyase activity than hydroxylase activity of CYP17A1. Treatment of cells with all compounds, except RSVTM, caused increased estradiol levels, which could be explained by the demonstrated inhibition of estrogen sulfate conjugation, catalyzed by SULT1E1.. Our results on CYP17A1 inhibition of RSV and RSV analogs suggest a novel mechanism for chemoprevention of prostate cancer by resveratrol and the analogs. Especially RSVTM, which has a preferential inhibition on the 17,20-lyase activity of CYP17A1, may be a promising candidate for prostate cancer chemoprevention.

Topics: Cell Line, Tumor; Cell Survival; Enzyme Inhibitors; Humans; Male; Resveratrol; Steroid 17-alpha-Hydroxylase; Stilbenes

Piceatannol (trans-3,3',4,5'-tetrahydroxystilbene), a natural analogue of resveratrol, has multiple biological functions. Nevertheless, piceatannol's biological fate is yet to be determined. In this study, we evaluated the absorption and metabolism of piceatannol in rats. Furthermore, the area under the plasma concentration curves (AUC) and metabolic pathway of piceatannol were compared with those of resveratrol. We determined the plasma concentrations of piceatannol, resveratrol, and their respective metabolites following their intragastric administration. Resveratrol metabolites were only conjugates, whereas piceatannol metabolites were piceatannol conjugates, O-methyl piceatannol, and its conjugates. The AUC for piceatannol, resveratrol, and their metabolites increased in a dose-dependent manner (90-360 μmol/kg). The AUC for total piceatannol was less than that for total resveratrol, whereas the AUC for piceatannol (8.6 μmol·h/L) after piceatannol and resveratrol coadministration was 2.1 times greater than that for resveratrol (4.1 μmol·h/L). The greater AUC for piceatannol was a result of its higher metabolic stability.

Topics: Absorption; Animals; Male; Molecular Structure; Rats; Rats, Sprague-Dawley; Stilbenes

Topics: Animals; Drug Carriers; Endothelium, Vascular; Inflammation; Nanoparticles; Neutrophils; Serum Albumin, Bovine; Stilbenes

Piceatannol is found in grapes, passion fruit, and Japanese knotweed. Piceatannol pretreatment suppresses cardiac hypertrophy induced by isoproterenol as assessed by heart weight/body weight ratio, cross-sectional area, and expression of hypertrophic markers. The anti-hypertrophic effect of piceatannol in rat neonatal cardiomyocytes is the same as that in vivo. Piceatannol inhibits lentiviral-GATA6-induced cardiomyocyte hypertrophy. Furthermore, piceatannol reduces the interaction between GATA4 and GATA6 as well as the DNA-binding activity of endogenous GATA6 in the ANP promoter. Our results suggest that piceatannol may be a novel therapeutic agent for the prevention of cardiac hypertrophy.

Topics: Animals; Cardiomegaly; Cardiotonic Agents; Disease Models, Animal; GATA4 Transcription Factor; GATA6 Transcription Factor; Gene Expression; HEK293 Cells; Humans; Mice; Myocardium; Myocytes, Cardiac; Primary Cell Culture; Protein Binding; Rats; Rats, Sprague-Dawley; Stilbenes

Hydroxylated phenylpropanoid compounds (e.g., esculetin, piceatannol, and eriodictyol) have been proved to possess important biological activities and pharmacological properties. These compounds exist at low abundance in nature, which hampers their cost-effective isolation, and broad application. Meanwhile, regiospecific hydroxylation of complex aromatic compounds is still quite challenging for chemical synthesis. In past decades, biocatalytic hydroxylation of plant phenylpropanoids was achieved due to the identification and engineering of some cytochrome P450 hydroxylases; however, the conversion efficiency was still too low for scale-up production use. In this work, we identify a non-P450 monooxygenase (HpaBC) from Escherichia coli, which is able to catalyze the efficient ortho-hydroxylation towards plant phenylpropanoids umbelliferone and resveratrol; meanwhile it also exhibits activity towards naringenin. On this basis, whole-cell biocatalysis enables the production of esculetin and piceatannol at high titers (2.7 and 1.2 g/L, respectively, in shake flasks) and high yields (close to 100%). To our knowledge, this work reports the highest titers and yields for biotechnological production of esculetin and piceatannol, representing a promising hydroxylation platform.

Topics: Escherichia coli; Metabolic Engineering; Resveratrol; Stilbenes; Umbelliferones

A novel dimer of piceatannol glycoside, named rheumaustralin (1) was isolated from the underground parts of the ethnomedicinal plant Rheum austral (Polygonaceae) collected from Tibet together with 17 known compounds, including rheumin (2), 2,5-dimethyl-7-hydroxychromone (3), 2,5-dimethylchromone-7-O-β-D-glucopyranoside (4), 7-hydroxy-2-(2'-hydroxypropyl)-5-methylchromone (5), torachrysone (6) torachrysone-8-O-β-D-glucopyranoside (7), 4-(4'-hydroxyphenyl)-2-butanone-4'-O-β-D-glucopyranoside (8), amabiloside (9), N-trans-feruloyl tyramine (10), chrysophanol (11), aloe-emodin (12), emodin (13), physcion (14), physcion-1-O-β-D-glucopyranoside (15), emodin-8-O-β-D-glucopyranoside (16), D-catechin (17) and gallic acid (18). Their structures were determined by combined spectroscopic methods and by comparison of their spectral data with those reported in literature. Compounds 1-10 were tested for their ability to scavenge 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical.

Topics: Antioxidants; Dimerization; Free Radical Scavengers; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Plant Extracts; Rheum; Stilbenes

Chronic lymphocytic leukemia (CLL) is characterized by the progressive accumulation of clonal B lymphocytes. Proliferation occurs in lymphoid tissues upon interaction of leukemic cells with a supportive microenvironment. Therefore, the mobilization of tissue-resident CLL cells into the circulation is a useful therapeutic strategy to minimize the reservoir of tumor cells within survival niches. Because the exit of normal lymphocytes from lymphoid tissues depends on the presence of sphingosine-1 phosphate (S1P) and the regulated expression of S1P receptor-1 (S1PR1), we investigated whether the expression and function of S1PR1 can be modulated by key microenvironment signals. We found that activation of CLL cells with CXCL12, fibroblast CD40L(+), BCR cross-linking, or autologous nurse-like cells reduces their S1PR1 expression and the migratory response toward S1P. Moreover, we found that S1PR1 expression was reduced in the proliferative/activated subset of leukemic cells compared with the quiescent subset from the same patient. Similarly, bone marrow-resident CLL cells expressing high levels of the activation marker CD38 showed a lower expression of S1PR1 compared with CD38(low) counterparts. Finally, given that treatment with BCR-associated kinase inhibitors induces a transient redistribution of leukemic cells from lymphoid tissues to circulation, we studied the effect of the Syk inhibitors piceatannol and R406 on S1PR1 expression and function. We found that they enhance S1PR1 expression in CLL cells and their migratory response toward S1P. Based on our results, we suggest that the regulated expression of S1PR1 might modulate the egress of the leukemic clone from lymphoid tissues.

Topics: ADP-ribosyl Cyclase 1; Adult; Aged; Aged, 80 and over; Animals; B-Lymphocytes; CD40 Ligand; Cell Movement; Chemokine CXCL12; Female; Gene Expression; Gene Expression Regulation, Neoplastic; Humans; Intracellular Signaling Peptides and Proteins; Leukemia, Lymphocytic, Chronic, B-Cell; Lysophospholipids; Male; Membrane Glycoproteins; Mice; Middle Aged; Oxazines; Protein-Tyrosine Kinases; Proto-Oncogene Proteins c-bcr; Pyridines; Receptors, CXCR4; Receptors, Lysosphingolipid; Sphingosine; Sphingosine-1-Phosphate Receptors; Stilbenes; Syk Kinase; Tumor Cells, Cultured; Tumor Microenvironment

Piceatannol, a naturally occurring analog of resveratrol, has been confirmed as an antitumor agent by inhibiting proliferation, migration, and metastasis in diverse cancer. However, the effect and mechanisms of piceatannol on colorectal cancer (CRC) have not been well understood. This study aimed to test whether piceatannol could inhibit growth of CRC cells and reveal its underlying molecular mechanism. MTT assay was used to detect the cell viability in HCT116 and HT29 cells. Flow cytometry analysis was employed to measure apoptosis of CRC cells. Bcl-2, Bax and caspase-3 levels were analyzed by Western blot and miR-129 levels were determined by real-time RT-PCR. Our study showed that piceatannol inhibited HCT116 and HT29 cells growth in a concentration- and time-dependent manner. Piceatannol induced apoptosis by promoting expression of miR-129, and then inhibiting expression of Bcl-2, an known target for miR-129. Moreover, knock down of miR-129 could reverse the reduction of cell viability induced by piceatannol in HCT116 and HT29 cells. Taken together, our study unraveled the ability of piceatannol to suppress colorectal cancer growth and elucidated the participation of miR-129 in the anti-cancer action of piceatannol. Our findings suggest that piceatannol can be considered to be a promising anticancer agent for CRC.

Topics: Antineoplastic Agents, Phytogenic; Caspase 3; Cell Survival; Gene Expression Regulation, Neoplastic; HCT116 Cells; HT29 Cells; Humans; MicroRNAs; Proto-Oncogene Proteins c-bcl-2; RNA, Small Interfering; Signal Transduction; Stilbenes

Resveratrol was glucosylated to its 3- and 4'-β-glucosides by cultured cells of Phytolacca americana. On the other hand, cultured P. americana cells glucosylated pterostilbene to its 4'-β-glucoside. P. americana cells converted piceatannol into its 4'-β-glucoside. The 3- and 4'-β-glucosides of resveratrol were further glucosylated to 3- and 4'-β-maltosides of resveratrol, 4'-β-maltoside of which is a new compound, by cyclodextrin glucanotransferase. Resveratrol 3-β-glucoside and 3-β-maltoside showed low 2,2-diphenyl-1-picrylhydrazyl free-radical-scavenging activity, whereas other glucosides had no radical-scavenging activity. Piceatannol 4'-β-glucoside showed the strongest inhibitory activity among the stilbene glycosides towards histamine release from rat peritoneal mast cells. Pterostilbene 4'-β-glucoside showed high phosphodiesterase inhibitory activity.

Topics: Animals; Anti-Allergic Agents; Biphenyl Compounds; Cell Line; Chemistry Techniques, Synthetic; Free Radical Scavengers; Glycosides; Histamine Release; Male; Neuroprotective Agents; Phosphodiesterase Inhibitors; Picrates; Rats; Resveratrol; Stilbenes

Microbial biotransformation is a great model system to produce drugs and biologically active compounds. In this study, we elucidated the fermentation and production of an anti-cancer agent from a microbial process for regiospecific hydroxylation of resveratrol. Among the strains examined, a potent strain showed high regiospecific hydroxylation activity to produce piceatannol. In a 5 L (w/v 3 L) jar fermentation, this wild type Streptomyces sp. in the batch system produced 205 mg of piceatannol (i.e., 60% yields) from 342 mg of resveratrol in 20 h. Using the product, an in vitro anti-cancer study was performed against a human cancer cell line (HeLa). It showed that the biotransformed piceatannol possessed a significant anticancer activity. This result demonstrates that a biotransformation screening method might be of therapeutic interest with respect to the identification of anti-cancer drugs.

Topics: Antineoplastic Agents; Biotransformation; Fermentation; Gas Chromatography-Mass Spectrometry; HeLa Cells; Humans; Hydroxylation; Neoplasms; Resveratrol; Stilbenes; Streptomyces

A large variety of soluble phenolic compounds, including phenolic acids (hydroxybenzoic acids, ethyl protocatechuate, and hydroxycinnamic acids, as well as phenylacetic acid and phenyllactic acid), stilbenes (trans-piceatannol and trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene), flavan-3-ols (e.g., (-)-epicatechin, (+)-catechin, (-)-epiafzelechin, and their polymers (the proanthocyanidins, PACs)), other flavonoids (e.g., isoflavones, flavanols, and flavones), and biflavonoids, were released from esters and glycosides by base/acid hydrolysis and identified in acetonic extracts of dry-blanched peanut skins (PS). Reversed-phase high-performance liquid chromatography (RP-HPLC) coupled with electrospray ionization mass spectrometry (ESI-MS(n)) was applied to separate and identify the phenolic constituents. Tentative identification of the separated phenolics was based on molecular ions and MS(n) fragmentation patterns acquired by ESI-MS in the negative-ion mode. Identification of free phenolic acids, stilbenes, and flavonoids was also achieved by commercial standards and by published literature data. Quantification was performed on the basis of peak areas of the UV signals from the HPLC chromatograms and calibration curves of the commercial standards. The flavonoids of PS exist mostly in glycoside-bound forms, but the aglycones can be liberated upon acid hydrolysis. PS contain significantly more PACs compared to free phenolic compounds: PAC monomers to tetramers constituted 92.0% of esterified phenolic compounds. The PAC monomer ((+)-catechin) and dimers are the main phenolics released from glycosides and account for 31.7 and 59.1%, respectively, of the total glycoside-bound phenolic compounds.

Topics: Arachis; Chromatography, Liquid; Chromatography, Reverse-Phase; Coumaric Acids; Flavonoids; Glycosides; Hydroxybenzoates; Phenols; Phenylacetates; Plant Extracts; Spectrometry, Mass, Electrospray Ionization; Stilbenes

Piceatannol is a phytochemical that is present in large amounts in passion fruit (Passiflora edulis) seeds, and is an analog of resveratrol. Recently, the absorption and metabolism of piceatannol were investigated in rats, and isorhapontigenin, O-methyl piceatannol, was detected as a piceatannol metabolite in rat plasma. To elucidate the function of piceatannol and its metabolites, we investigated the expression of sirtuin 1 (SIRT1) in THP-1 monocytic cells after treatment with piceatannol and its metabolites, and compared their effects with those of resveratrol and its metabolites. Piceatannol and resveratrol upregulated the expression levels of SIRT1 mRNA and SIRT1 protein. An extract of passion fruit seeds, which contained high levels of piceatannol, also upregulated SIRT1 mRNA expression. As for the metabolites, isorhapontigenin upregulated SIRT1 mRNA expression, whereas resveratrol glucuronides and sulfate did not affect SIRT1 expression. These findings indicate that after intake of piceatannol, not only piceatannol itself, but also its metabolite, isorhapontigenin, contributed to the upregulation of SIRT1 expression.

Topics: Cell Line; Humans; Monocytes; Passiflora; Plant Extracts; Resveratrol; RNA, Messenger; Seeds; Sirtuin 1; Stilbenes; Up-Regulation

The present study was aimed at elucidating the molecular mechanisms of anti-inflammatory activity of piceatannol (trans-3,4,3',5'-tetrahydroxystilbene) in mouse skin in vivo.. Female HR-1 hairless mice were topically treated with 12-O-tetradecanoylphorbol-13-acetate (TPA) with or without piceatannol pretreatment. Epidermal protein expression was assessed by Western blot analysis. The cyclooxygenase-2 (COX-2) expression was detected by immunohistochemistry. The DNA binding of nuclear factor-kappaB (NF-κB) and activator protein-1 (AP-1) was examined by the electrophoretic mobility gel shift assay. The catalytic activity of IκBα kinase-β (IKKβ) was measured by in vitro kinase assay.. Pretreatment with piceatannol attenuated TPA-induced expression of COX-2 and inducible nitric oxide synthase (iNOS) in mouse skin. Piceatannol diminished nuclear translocation and the DNA binding of NF-κB through the blockade of phosphorylation and subsequent degradation of IκBα. Piceatannol attenuated the catalytic activity of IKKβ and inhibited the phosphorylation of mitogen-activated protein (MAP) kinases in TPA-treated mouse skin. In addition, piceatannol decreased TPA-induced expression of c-Fos and the DNA binding of AP-1.. Piceatannol inhibits TPA-induced COX-2 and iNOS expression by blocking the activation of NF-κB and AP-1 via suppression of the IKKβ activity and phosphorylation of MAP kinases, which provides a mechanistic basis of its anti-inflammatory effects in mouse skin.

Topics: Animals; Catalysis; Catalytic Domain; Cyclooxygenase 2; Female; I-kappa B Kinase; Immunohistochemistry; Inflammation; Mice; NF-kappa B; Nitric Oxide Synthase Type II; Phosphorylation; Protein Binding; Proto-Oncogene Proteins c-fos; Skin; Stilbenes; Tetradecanoylphorbol Acetate; Transcription Factor AP-1

To enhance the anticancer efficacy of gemcitabine in the treatment of non-small cell lung cancer (NSCLC), the potential synergistic effect of piceatannol on gemcitabine cytotoxicity was investigated in the human NSCLC A459 cell line. The MTT cell viability assay showed that piceatannol significantly enhanced the cytotoxic effects of gemcitabine by lowering the gemcitabine IC50 value. Flow cytometry analysis revealed that piceatannol exerted its pharmacological effect mainly by increasing the late apoptotic population. Western blot analysis showed that gemcitabine induced the expression of the proapoptotic proteins Bad and Bak, and pretreatment with piceatannol further increased Bak expression, leading to an increased number of cells undergoing late apoptosis. The findings from this study show that piceatannol can enhance the cytotoxic effects of gemcitabine by enhancing expression of the proapoptotic protein Bak, thereby providing the rational basis for a novel combination strategy for the treatment of NSCLC.

Topics: Antineoplastic Combined Chemotherapy Protocols; Apoptosis; bcl-2 Homologous Antagonist-Killer Protein; bcl-Associated Death Protein; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cell Survival; Deoxycytidine; Dose-Response Relationship, Drug; Drug Synergism; Gemcitabine; Humans; Inhibitory Concentration 50; Lung Neoplasms; Stilbenes; Up-Regulation

The sim fruit (Rhodomyrtus tomentosa) has long been used in folk medicine to treat diarrhoea, dysentery, and to boost the immune system. The purpose of this work was to determine its phenolic profile and to evaluate the changes of content during maturation, as well as the variations induced by environmental conditions. Using HPLC-ESI-HR-MS, 19 phenolic compounds (PCs) were tentatively characterised and included stilbenes and ellagitannins as major components, followed by anthocyanins, flavonols, and gallic acid. PCs were then further quantified by HPLC-DAD. Piceatannol, a promising health-promoting stilbene component, was the major PC in the fruit with a concentration of 2.3mg/g dry weight at full maturity stage. This concentration is 1000-2000 times higher than that of red grapes, a major source of stilbene in the human diet. During maturation, the contents in piceatannol and other stilbenes, ellagitannins, and flavonols decreased while the anthocyanin content increased. Shade-grown sim fruits showed significantly higher piceatannol levels than sun-exposed fruits. Taken together, these findings highlight the potential of sim, an under-utilised plant species from South-East Asia, as a source of health-promoting fruits.

Topics: Chromatography, High Pressure Liquid; Fruit; Mass Spectrometry; Myrtaceae; Phenols; Plant Extracts; Stilbenes

Piceatannol is a phenolic stilbenoid and a metabolite of resveratrol which is found in red wine. Piceatannol (PIC) commonly exhibits anti-inflammatory, antiplatelet and antiproliferative activity. In the present study, the anti-allergic and anti-inflammatory mechanisms of PIC were investigated by examining the effects of PIC on pro‑inflammatory cytokine release and phosphorylation of mitogen-activated protein (MAP) kinases (ERK, JNK and p38) in a human mast cell line. PIC dose-dependently inhibited compound 48/80-induced systemic anaphylaxis and immunoglobulin E-mediated local allergic reactions. PIC reduced the immunoglobulin E (IgE)-mediated local allergic reaction and attenuated histamine release from rat peritoneal mast cells. Histamine and β-hexosaminidase release was markedly decreased dose-dependently by PIC treatment in RBL-2H3 cells. PIC treatments of HMC-1 cells definitely reduced mRNA expression and the release of the pro‑inflammatory cytokines, tumor necrosis factor-α and interleukin-8. MAP kinase phosphorylation was also strongly decreased dose-dependently following PIC treatment. PIC regulated the production of cytokines and histamine in phorbol 12-myristate 13-acetate plus A23187-stimulated mast cells. Thus, PIC may alleviate allergic inflammation and may be a useful therapeutic agent for allergic diseases.

Topics: Anaphylaxis; Animals; Anti-Inflammatory Agents; beta-N-Acetylhexosaminidases; Cell Line; Cell Survival; Cytokines; Extracellular Signal-Regulated MAP Kinases; Histamine; Humans; Male; Mast Cells; Mice; Mice, Inbred ICR; p-Methoxy-N-methylphenethylamine; Signal Transduction; Stilbenes

Synthesis of the naturally occurred C- and O-prenylated tetrahydroxystilbenes and O-prenylated cinnamates was carried out by decarbonylative Heck reaction and selenium dioxide catalysed oxidation, respectively. In the decarbonylative Heck synthetic route, fusion of benzoyl chloride and styrene derivatives was catalysed by an N-heterocyclic carbene system generated in situ by palladium acetate and 1,3-bis(2,6-diisopropylphenyl)imidazolinium chloride to form a E-tetrahydroxystilbene derivative. Formation of allyl ether was subsequently carried out by reaction of the deprotected OH in the A phenyl ring of the stilbene with 3,3-dimethylallyl bromide and a base (sodium hydride) to form O-prenylated tetrahydroxystilbene derivatives. [1,5]-Rearrangement of the isoprenyl unit from O- to C-position in the A ring was carried out at elevated temperature in the presence of magnesium silicate (Florisil) to form the corresponding C-prenylated tetrahydroxystilbene. Formation of O-prenylated cinnamate was first carried out by base catalysed allyl ether formation between 3,3-dimethylallyl bromide and hydroxycinnamic acid methyl ester. The methyl group of the isoprenyl unit was subsequently oxidized using selenium dioxide to form a terminal hydroxyl group. The prenylated tetrahydroxystilbenes and cinnamate synthesized in this study were novel derivatives of piceatannol and methyl 4-(3'-methylbut-2'-enyloxy)cinnamate isolated from propolis in Kangaroo Island, South Australia. The synthetic compounds were tested against K562 cancer cells and potent growth inhibitory activity was observed for E-1-[5-hydroxy-3-methoxy-2-(3-methyl-2-butenyl)phenyl]-2-[4-hydroxy-3-methoxyphenyl]ethene, IC50 = 0.10 μM.

Topics: Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cinnamates; Dose-Response Relationship, Drug; Humans; Inhibitory Concentration 50; K562 Cells; Models, Chemical; Molecular Structure; Prenylation; Propolis; Stilbenes; Structure-Activity Relationship

Piceatannol is one of resveratrol derivatives having health promoting potential. However, its low water-solubility and bioavailability could limit its use in both food and pharmaceutical fields. The aim of this work is the study of piceatannol complexation by β-cyclodextrin (β-CD) in aqueous media. The complex formed could improve the bioavailability, the solubility and the stability of piceatannol. The method used was based on RP-HPLC in which, β-CD was added to methanol/water mixtures mobile phases. The apparent formation constant of piceatannol/β-cyclodextrin complex was determined. Within the concentration interval studied (0-4 mM), whenever the concentration of β-CD increased, retention time of piceatannol decreased; indicating an enhancement of solubility due to the formation of the piceatannol/β-CD complex. The formation constants (KF) of the piceatannol/β-CD complex varied significantly with both the methanol concentration in the water-methanol mixture and the temperature. Moreover, in all the physicochemical conditions tested, the stoichiometry of piceatannol/β-CD complex was 1:1. Finally, the thermodynamic parameters were determined: ΔG°=-13.123 kJ mol(-1), ΔH°=-33. 265 kJ mol(-1) and ΔS°=-67.559 J mol(-1) K(-1).

Topics: beta-Cyclodextrins; Chromatography, High Pressure Liquid; Resveratrol; Stilbenes; Thermodynamics

Bioassay-guided fractionation of the leaves of Eugenia rigida yielded three stilbenes, (Z)-3,4,3',5'-tetramethoxystilbene (1), (E)-3,4,3',5'-tetramethoxystilbene (2), and (E)-3,5,4'-trimethoxystilbene (3). Their structures were determined using 1D- and 2D-NMR spectroscopy and HRESIMS. The sterically hindered Z-stereoisomer 1, a new natural product, was prepared by time-dependent photoisomerization of the E-isomer (2) under UV irradiation at λ254 nm, while 2,3,5,7-tetramethoxyphenanthrene (5) was identified at λ365 nm by UHPLC/APCI-MS and NMR spectroscopy. Compounds 1-3 were tested against a panel of luciferase reporter gene assays that assess the activity of many cancer-related signaling pathways, and the Z-isomer (1) was found to be more potent than the E-isomer (2) in inhibiting the activation of Stat3, Smad3/4, myc, Ets, Notch, and Wnt signaling, with IC50 values between 40 and 80 μM. However, both compounds showed similar inhibition against Ap-1 and NF-κB signaling. In addition, 1 demonstrated cytotoxic activity toward human leukemia cells, solid tumor cells of epidermal, breast, and cervical carcinomas, and skin melanoma, with IC50 values between 3.6 and 4.3 μM, while 2 was weakly active against leukemia, cervical carcinoma, and skin melanoma cells. Interestingly, 2 showed antioxidant activity by inhibition of ROS generation to 50% at 33.3 μM in PMA-induced HL-60 cells, while 1 was inactive at 100 μM (vs Trolox 1.4 μM).

Topics: Antineoplastic Agents, Phytogenic; Antioxidants; Drug Screening Assays, Antitumor; Female; HL-60 Cells; Humans; Inhibitory Concentration 50; Molecular Structure; NF-kappa B; Nitric Oxide Synthase Type II; Nuclear Magnetic Resonance, Biomolecular; Plant Leaves; Puerto Rico; Reactive Oxygen Species; Signal Transduction; Stereoisomerism; Stilbenes; Syzygium

The use of naturally occurring botanicals with substantial antioxidant activity to prevent photoageing is receiving increasing attention. We have previously identified piceatannol and scirpusin B, which is a dimer of piceatannol, as strong antioxidants that are present in passion fruit (Passiflora edulis) seeds. In the present study, the effects of passion fruit seed extract, piceatannol, and scirpusin B on human keratinocytes were investigated. The passion fruit seed extract and piceatannol upregulated the glutathione (GSH) levels in keratinocytes in a dose-dependent manner, indicating that piceatannol is an active component of the passion fruit seed extract in keratinocytes. The pretreatment with piceatannol also suppressed the UVB-induced generation of reactive oxygen species (ROS) in the keratinocytes. In addition, the transfer of the medium from the UVB-irradiated keratinocytes to non-irradiated fibroblasts enhanced matrix-metalloproteinase (MMP)-1 activity, and this MMP-1 induction was reduced when the keratinocytes were pretreated with piceatannol. These results suggest that piceatannol attenuates the UVB-induced activity of MMP-1 along with a reduction of ROS generation in keratinocytes. Thus, piceatannol and passion fruit seed extract containing high amounts of piceatannol are potential anti-photoageing cosmetic ingredients.

Topics: Benzofurans; Cell Line; Cells; Glutathione; Humans; Keratinocytes; Matrix Metalloproteinase 1; Passiflora; Plant Extracts; Radiation-Protective Agents; Reactive Oxygen Species; Seeds; Skin Aging; Stilbenes; Ultraviolet Rays

Resveratrol (Res) is recognized as a promising cancer chemoprevention dietary polyphenol with antioxidative, anti-inflammatory, and anticancer properties. However, the role of its analogues in prostate cancer (PCa) chemoprevention is unknown.. We synthesized several natural and synthetic analogues of Res and characterized their effects on PCa cells in vitro using a cell proliferation assay. A colony formation assay and in vitro validation of luciferase (Luc) activity was done for LNCaP-Luc cells that were consequently used for in vivo studies. The efficacy of Res, trimethoxy-resveratrol (3M-Res) and piceatannol (PIC) was studied in a subcutaneous (s.c.) model of PCa using oral gavage. Tumor progression was monitored by traditional caliper and bioluminescent imaging. The levels of cytokines in serum were examined by ELISA, and the levels of compounds in serum and tumor tissues were determined by gas chromatography-mass spectrometry.. We examined the anti-proliferative activities of Res/analogues in three PCa cell lines. We further compared the chemopreventive effects of oral Res, 3M-Res, and PIC in LNCaP-Luc-xenografts. We found that 2 weeks pretreatment with the compounds diminished cell colonization, reduced tumor volume, and decreased tumor growth in the xenografts. Both 3M-Res and PIC demonstrated higher potency in inhibiting tumor progression compared to Res. Notably, 3M-Res was the most active in inhibiting cell proliferation and suppressing colony formation, and its accumulation in both serum and tumor tissues was the highest.. Our findings offer strong pre-clinical evidence for the utilization of dietary stilbenes, particularly 3M-Res, as novel, potent, effective chemopreventive agents in PCa.

Topics: Administration, Oral; Animals; Antineoplastic Agents; Cell Line, Tumor; Growth Inhibitors; Male; Mice; Mice, Nude; Prostatic Neoplasms; Resveratrol; Stilbenes; Xenograft Model Antitumor Assays

Neuronal cell death caused by oxidative stress is common in a variety of neural diseases and can be investigated in detail in cultured HT22 neuronal cells, where the amino acid glutamate at high concentrations causes glutathione depletion by inhibition of the glutamate/cystine antiporter system, intracellular accumulation of reactive oxygen species (ROS) and eventually oxidative stress-induced neuronal cell death. Using this paradigm, we have previously reported that resveratrol (3,5,4'-trans-trihydroxystilbene) protects HT22 neuronal cells from glutamate-induced oxidative stress by inducing heme oxygenase (HO)-1 expression. Piceatannol (3,5,4',3'-trans-trihydroxystilbene), which is a hydroxylated resveratrol analog and one of the resveratrol metabolites, is estimated to exert neuroprotective effect similar to that of resveratrol. The aim of this study, thus, is to determine whether piceatannol, similarly to resveratrol, would protect HT22 neuronal cells from glutamate-induced oxidative stress. Glutamate at high concentrations induced neuronal cell death and ROS formation. Piceatannol reduced glutamate-induced cell death and ROS formation. The observed cytoprotective effect was much higher when HT22 neuronal cells were pretreated with piceatannol for 6 or 12 h prior to glutamate treatment than when pretreated for 0.5 h. Piceatannol also increased HO-1 expression and HO activity via its activation of nuclear factor-E2-related factor 2 (Nrf2). Interestingly, neuroprotective effect of piceatannol was partly (but not completely) abolished by either down-regulation of HO-1 expression or blockage of HO-1 activity. Taken together, our results suggest that piceatannol, similar to resveratrol, is capable of protecting HT22 neuronal cells against glutamate-induced cell death, at least in part, by inducing Nrf2-dependent HO-1 expression.

Topics: Animals; Cell Line; Cell Survival; Cytoprotection; Glutamates; Heme Oxygenase-1; Membrane Proteins; Mice; Neurons; Neuroprotective Agents; NF-E2-Related Factor 2; Oxidative Stress; Reactive Oxygen Species; Resveratrol; RNA Interference; RNA, Small Interfering; Stilbenes

Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen, which is the major cause of severe chronic lung infection in cystic fibrosis patients. It is also responsible for systemic infections in immunocompromised individuals and those presenting with significant pulmonary conditions in intensive care units. This microorganism has the capacity to initiate severe inflammation in infected lungs resulting in detrimental tissue damage. We have hypothesized that Syk protein tyrosine kinase mediates lung epithelial cellular responses to P. aeruginosa infection, and that a naturally occurring non-toxic Syk inhibitor piceatannol can protect infected human cells against the deleterious effects associated with this infection. We infected Syk-positive H292 or Syk-negative A549 human lung epithelial cell lines with P. aeruginosa and assessed the resulting cellular responses, i.e. production of proinflammatory cytokines, adhesion molecule expression, generation of reactive oxygen species, and apoptosis of infected cells, utilizing a multiplex bead-based immunoassay and flow cytometry. We also studied the internalization of P. aeruginosa using the gentamicin exclusion assay. We found that the piceatannol treatment significantly suppressed inflammation, oxidative stress and apoptosis in H292, but not in A549 cells implicating Syk participation in the regulation of the pathological processes induced by P. aeruginosa infection. Intriguingly, piceatannol was able to down-regulate the internalization of P. aeruginosa by both Syk-positive and Syk-negative cell lines, implying that the mechanisms of action of this compound extend beyond Syk inhibition. As piceatannol can interfere with several mechanisms of bacterial pathogenesis this natural compound deserves further study as a potential therapeutic option in P. aeruginosa infection.

Topics: Apoptosis; Cell Line; Cell Separation; Cytokines; Endocytosis; Flow Cytometry; Humans; Inflammation Mediators; Intercellular Adhesion Molecule-1; Intracellular Signaling Peptides and Proteins; Lung; Oxidative Stress; Protein-Tyrosine Kinases; Pseudomonas aeruginosa; Pseudomonas Infections; Respiratory Mucosa; Stilbenes; Syk Kinase

Endothelial cells produce nitric oxide (NO) by activation of constitutive nitric oxide synthase (NOS) and transcription of inducible NO synthase (iNOS). We explored the effect of tetramethylpyrazine (TMP), a compound derived from chuanxiong, on tumor necrosis factor (TNF)-α-induced iNOS in human umbilical vein endothelial cells (HUVECs) and explored the signal pathways involved by using RT-PCR and Western blot. TMP suppressed TNF-α-induced expression of iNOS by inhibiting IκB kinase (IKK) phosphorylation, IκB degradation and nuclear factor κB (NF-κB) nuclear translocation, which were required for NO gene transcription. Exposure to wortmannin abrogated IKK/IκB/NF-κB-mediated iNOS expression, suggesting activation of such a signal pathway might be phosphoinositide-3-kinase (PI3K) dependent. Spleen tyrosine kinase (Syk) inhibitor piceatannol significantly inhibited NO production. Furthermore, piceatannol obviously suppressed TNF-α-induced IκB phosphorylation and the downstream NF-κB activation, suggesting that Syk is an upstream key regulator in the activation of PI3K/IKK/IκB-mediated signaling. TMP significantly inhibited TNF-α-induced phosphorylation of Syk and PI3K. Our data indicate that TMP might repress iNOS expression, at least in part, through its inhibitory effect of Syk-mediated PI3K phosphorylation in TNF-α-stimulated HUVECs.

Topics: Cell Nucleus; Endothelial Cells; Endothelium, Vascular; Human Umbilical Vein Endothelial Cells; Humans; I-kappa B Kinase; I-kappa B Proteins; Intracellular Signaling Peptides and Proteins; NF-kappa B; Nitric Oxide Synthase Type II; Phosphatidylinositol 3-Kinases; Phosphorylation; Protein Transport; Protein-Tyrosine Kinases; Proteolysis; Pyrazines; Signal Transduction; Stilbenes; Syk Kinase; Transcription, Genetic; Tumor Necrosis Factor-alpha

Resistance to cisplatin (CDDP) in ovarian cancer (OVCA) arises from the dysregulation of tumor suppressors and survival signals. During genotoxic challenge, these factors can be influenced by secondary agents that facilitate the induction of apoptosis. Piceatannol is a natural metabolite of the stilbene resveratrol found in grapes and is converted from its parent compound by the enzyme CYP1BA1 p450. It has been hypothesized to exert specific effects against various cellular targets; however, its ability to influence CDDP resistance in cancer cells has not been investigated to date. Here, we show that piceatannol is a potent enhancer of CDDP sensitivity in OVCA, and this effect is achieved through the modulation of several major determinants of chemoresistance. Piceatannol enhances p53-mediated expression of the pro-apoptotic protein NOXA, increases XIAP degradation via the ubiquitin-proteasome pathway, and enhances caspase-3 activation. This response is associated with an increase in Drp1-dependent mitochondrial fission, leading to more effective induction of apoptosis. In vivo studies using a mouse model of OVCA reveal that a number of these changes occur in association with a greater overall reduction in tumor weight when mice are treated with both piceatannol and CDDP, in comparison to treatment with either agent alone. Taken together, these findings demonstrate the potential application of piceatannol to enhance CDDP sensitivity in OVCA, and it acts on p53, XIAP, and mitochondrial fission.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Caspase 3; Cell Line, Tumor; Cell Proliferation; Cisplatin; Disease Models, Animal; Drug Resistance, Neoplasm; Dynamins; Female; Humans; Mice; Mitochondrial Dynamics; Models, Biological; Ovarian Neoplasms; Proteasome Endopeptidase Complex; Proteolysis; Proto-Oncogene Proteins c-bcl-2; Signal Transduction; Stilbenes; Tumor Suppressor Protein p53; Ubiquitination; X-Linked Inhibitor of Apoptosis Protein

Prion diseases are a group of transmissible fatal neurodegenerative disorders of humans and animals, including bovine spongiform encephalopathy, scrapie, and Creutzfeldt-Jakob disease. Microglia, the resident macrophages of the central nervous system, are exquisitely sensitive to pathological tissue alterations, altering their morphology and phenotype to adopt a so-called activated state and perform immunological functions in response to pathophysiological brain insults. Although recent findings have provided valuable insights into the role microglia play in the proinflammatory events observed in prion, the intracellular signaling molecules responsible for the initiation of these responses remain to be elucidated. It seems that microglial activation involve PrP106-126 binding and the activation of cell surface immune and adhesion molecules such as CD36 and integrins, with the subsequent recruitment of Src family tyrosine kinases such as Fyn, Lyn, and Syk kinases. In the present study, we show that CD36 is involved in PrP106-126-induced microglial activation and that PP2 and piceatannol (Pic) can abrogate neurotoxic prion peptides-induced inducible nitric oxide synthase activation in microglia. These findings unveil a previously unrecognized role of PP2 and Pic as Src family kinase Fyn and the tyrosine kinase Syk inhibitor involved in neurotoxic prion peptides-microglia interactions, thus providing new insights into mechanisms underlying the activation of microglia by neurotoxic prion peptides.

Topics: Animals; CD36 Antigens; Cell Line; Enzyme Activation; Gene Expression; Immunoblotting; Interleukin-1beta; Lipopolysaccharides; Mice; Microglia; Nitric Oxide Synthase Type II; Peptide Fragments; Prions; Pyrimidines; Reverse Transcriptase Polymerase Chain Reaction; src-Family Kinases; Stilbenes; Tumor Necrosis Factor-alpha

Metastasis is one of the most threatening features of the oncogenic process and the main cause of cancer-related mortality. Several studies have demonstrated that matrix metalloproteinases (MMPs) are critical for tumor invasion and metastasis. Resveratrol (3,5,4'-trihydroxystilbene), a phenolic compound of red wine, has been reported to be a natural chemopreventive agent. However, the cancer preventive effects of piceatannol (3,5,3',4'-tetrahydroxystilbene), a metabolite of resveratrol and the underlying molecular mechanisms have not yet been fully elucidated. In this study, we report that piceatannol inhi-bits H-ras-induced MMP-2 activity and the invasive phenotype of MCF10A human breast epithelial cells harboring mutated H-ras (H-ras MCF10A cells) more effectively than resveratrol. Piceatannol attenuated the H-ras-induced phosphorylation of Akt in a time- and dose-dependent manner, whereas resveratrol, at the same concentrations, did not exert an inhibitory effect. In vitro kinase assays demonstrated that piceatannol significantly inhibited phosphatidylinositol 3-kinase (PI3K) activity and suppressed phospha-tidylinositol (3,4,5)-trisphosphate (PIP3) expression in the H-ras MCF10A cells. Ex vivo pull-down assays revealed that piceatannol directly bound to PI3K, inhibiting PI3K activity. Data from molecular docking suggested that piceatannol is a more tight-binding inhibitor than resveratrol due to the additional hydrogen bond between the hydroxyl group and the backbone amide group of Val882 in the ATP-binding pocket of PI3K.

Topics: Antineoplastic Agents; Breast Neoplasms; Cell Line, Tumor; Cell Survival; Epithelial Cells; Female; Gene Expression Regulation; Genes, ras; Humans; Matrix Metalloproteinase 2; Mutation; Neoplasm Metastasis; Phosphatidylinositol 3-Kinases; Phosphorylation; Proto-Oncogene Proteins c-akt; Resveratrol; Stilbenes; Wine

Anti-inflammatory effect of piceatannol, a naturally occurring polyphenol and a potent free radical scavenger, on ocular inflammation is not known. We examined the anti-inflammatory role of piceatannol in ocular inflammatory response due to endotoxin-induced uveitis (EIU) in rats. EIU was induced in Lewis rats by subcutaneous injection of lipopolysaccharide (LPS; 150 ug/rat). Piceatannol (30mg/kg body wt, i.p) was injected either 2h prior to or 1h post LPS induction. A significant increase in the number of infiltrating cells, total protein, and various cytokines and chemokines in AqH were observed in the EIU rat eyes as compared to control groups. However, pre- or post-treatment of piceatannol significantly blocked the LPS-induced changes. Further, piceatannol also suppressed the expression of cyclooxygenase-2 (Cox-2), inducible nitric oxide synthase (iNOS) and activation of NF-κB in the ciliary bodies as well as retina. Further, piceatannol also inhibited the expression of Cox-2, iNOS, and phosphorylation of NF-κB in primary human non-pigmented ciliary epithelial cells (HNPECs) treated with LPS. Similarly, piceatannol also diminished LPS-induced level of NO and prostaglandin E2 in HNPECs. Thus our results demonstrate an anti-inflammatory role of piceatannol in suppressing ocular inflammation induced by endotoxin in rats.

Topics: Animals; Aqueous Humor; Cells, Cultured; Cyclooxygenase 2; Cytokines; Disease Models, Animal; Free Radical Scavengers; Gene Expression Regulation; Humans; Male; NF-kappa B; Nitric Oxide Synthase Type II; Rats; Rats, Inbred Lew; Retina; Shock, Septic; Stilbenes; Uveitis

The genome of the ascomycete Neurospora crassa encodes CAO-1 and CAO-2, two members of the carotenoid cleavage oxygenase family that target double bonds in different substrates. Previous studies demonstrated the role of CAO-2 in cleaving the C40 carotene torulene, a key step in the synthesis of the C35 apocarotenoid pigment neurosporaxanthin. In this work, we investigated the activity of CAO-1, assuming that it may provide retinal, the chromophore of the NOP-1 rhodopsin, by cleaving β-carotene. For this purpose, we tested CAO-1 activity with carotenoid substrates that were, however, not converted. In contrast and consistent with its sequence similarity to family members that act on stilbenes, CAO-1 cleaved the interphenyl Cα-Cβ double bond of resveratrol and its derivative piceatannol. CAO-1 did not convert five other similar stilbenes, indicating a requirement for a minimal number of unmodified hydroxyl groups in the stilbene background. Confirming its biological function in converting stilbenes, adding resveratrol led to a pronounced increase in cao-1 mRNA levels, while light, a key regulator of carotenoid metabolism, did not alter them. Targeted Δcao-1 mutants were not impaired by the presence of resveratrol, a phytoalexin active against different fungi, which did not significantly affect the growth and development of wild-type Neurospora. However, under partial sorbose toxicity, the Δcao-1 colonies exhibited faster radial growth than control strains in the presence of resveratrol, suggesting a moderate toxic effect of resveratrol cleavage products.

Topics: Amino Acid Sequence; Molecular Sequence Data; Mutation; Neurospora crassa; Oxygenases; Phylogeny; Phytoalexins; Resveratrol; RNA, Messenger; Sesquiterpenes; Sorbose; Stilbenes

A new plant source, sugarcane, was used to produce the stilbenes piceatannol and resveratrol. Both stilbenes were identified in sugarcane billet stalks (12 mm) after incubation at room temperature for 3 days. Low concentrations of piceatannol (30.6 μg/g) and resveratrol (12.3 μg/g) were detected at day 3. At day 7 of incubation higher concentrations of piceatannol (1659 μg/g) and resveratrol (73 μg/g) were produced. Sugarcane juice obtained from billets that were incubated for 7 days contained high levels of piceatannol (8.5 mg/L) and resveratrol (1.2 mg/L). Although high stilbene concentrations were determined in the sugarcane variety L 97-128, two other varieties (Ho 95-988 and LCP 85-384) displayed lower stilbene concentrations after incubation for 7 days. The total phenolic content (TPC) and antioxidant activities of incubated sugarcane extracts were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and ferric reducing antioxidant power (FRAP). The TPC and antioxidant activities were highest in sugarcane extracts that were incubated for 7 days. This study details a postharvest method to produce stilbene-enriched sugarcane with increased levels of piceatannol and resveratrol.

Topics: Antioxidants; Phenols; Plant Extracts; Resveratrol; Saccharum; Stilbenes; Time Factors

To obtain information on anti-prostate cancer (CaP) activities of piceatannol, a metabolite biotransformed from resveratrol by cytochrome P450 CYP1B, CWR22Rv1 cells were incubated with increasing dose of piceatannol. Proliferation and apoptosis assays in exposed cells showed that piceatannol produced inhibition comparable to resveratrol. To determine whether quinone reductase 2 (NQO2) plays a role in the observed effects, in silico analysis was performed. Piceatannol interacted with NQO2 at the same site as resveratrol forming hydrogen bond with asparagine-161 (ASN161). NQO2 mediated anti-CaP effects of piceatannol were also tested and supported by the attenuation of anti-proliferative activity and reduction in extent of inhibition of NQO2 activity by piceatannol in NQO2-knockdown cells relative to NQO2- expressing cells, and by the copious expression of CYP1B in CWR22Rv1 cells. These results show that NQO2 is an intracellular target for piceatannol, suggesting that CaP prevention by resveratrol may be partially attributed to its conversion to piceatannol.

Topics: Apoptosis; Aryl Hydrocarbon Hydroxylases; Binding Sites; Cell Line, Tumor; Cell Proliferation; Cytochrome P-450 CYP1B1; Humans; Molecular Docking Simulation; NAD(P)H Dehydrogenase (Quinone); Protein Structure, Tertiary; Quinone Reductases; Resveratrol; RNA Interference; RNA, Small Interfering; Stilbenes

Grapevine canes are rich in resveratrol and its complex derivatives. These compounds have many biological activities and are needed mainly for health purposes. Canes, which are often wasted, can be used to produce these high-value compounds at low cost. We studied sixteen Vitis vinifera L. cultivars among the most widely cultivated ones worldwide. Polyphenols were extracted from their canes and identified by liquid chromatography-nuclear magnetic resonance spectroscopy. We accurately determined the content of E-ε-viniferin, E-resveratrol, E-piceatannol, and vitisin B and, for the first time, that of hopeaphenol and miyabenol C. The canes did not contain these major stilbene compounds in similar proportions, and their abundance and order of abundance varied according to the cultivar. For instance, Pinot noir has very high levels of E-resveratrol and E-ε-viniferin; Gewurztraminer has very high levels of vitisin B, and Carignan and Riesling have very high levels of hopeaphenol. These findings suggest that the right cultivar should be used to obtain the highest yield of a polyphenol of interest.

Topics: Benzofurans; Chromatography, Liquid; Phenols; Plant Stems; Polyphenols; Resveratrol; Species Specificity; Stilbenes; Vitis

Accumulating evidence shows that post-ischemic inflammation originated by Toll-like receptors (TLR) plays critical roles in ischemic stroke. However, the functions of other innate immune receptors are poorly understood in cerebral ischemia. Macrophage-inducible C-type lectin, Mincle, is one of the innate immune receptor C-type lectin-like receptor (CLR) to response against dying cells. In the present study, we showed that Mincle, its ligand SAP130, and its downstream phospho-Syk/Syk were upregulated after ischemia, and that Mincle is expressed in immune and non-immune cells in the ischemic brains of mice and human. We treated mice with piceatannol, a Syk inhibitor, and consequently the infarct volume and swelling were suppressed by piceatannol. The levels of phospho-Syk, MMP9 and ICAM-1 were downregulated, and the level of Claudin5 was uplegurated in piceatannol-treated groups. These data indicate that innate immune system, such as Mincle and Syk plays a pivotal role in the pathogenesis after the ischemia and reperfusion.

Topics: Animals; Brain; Down-Regulation; Humans; Immunity, Innate; In Vitro Techniques; Intercellular Adhesion Molecule-1; Intracellular Signaling Peptides and Proteins; Ischemia; Lectins, C-Type; Male; Matrix Metalloproteinase 9; Membrane Proteins; Mice; Protective Agents; Protein-Tyrosine Kinases; Stilbenes; Stroke; Syk Kinase; Up-Regulation

Recent investigations have shown that the Wnt signaling pathway is constitutively activated in multiple myeloma (MM), thereby promoting an exaggerated cell proliferation. Thus, influencing the Wnt pathway might represent a promising target in myeloma treatment.. The present study investigated whether a combination of ethacrynic acid (EA) and ciclopirox olamine (CIC) with piceatannol (PIC) would influence the Wnt pathway and viability of human and murine myeloma cell lines by using DiOC6 and propidium iodide (PI) staining, flow cytometry and immunoblotting.. The combination of EA with PIC as well as the combination of CIC with PIC had a significant additive effect on the vitality of myeloma cells compared to single-agent application, while healthy cells remained mainly unaffected. Additionally, EA and CIC altered the expression of β-catenin itself and its downstream factors.. A combination of Wnt inhibitors could lead to novel treatment options for MM patients.

Topics: Animals; Antifungal Agents; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; beta Catenin; Blotting, Western; Cell Proliferation; Cells, Cultured; Ciclopirox; Colon; Diuretics; Drug Synergism; Ethacrynic Acid; Flow Cytometry; Humans; Mice; Multiple Myeloma; Protein-Tyrosine Kinases; Pyridones; Stilbenes; Wnt Proteins

Neutrophils are able to release cytotoxic substances and inflammatory mediators, which, along with their delayed apoptosis, have a potential to maintain permanent inflammation. Therefore, treatment of diseases associated with chronic inflammation should be focused on neutrophils; formation of reactive oxygen species and apoptosis of these cells represent two promising targets for pharmacological intervention. Piceatannol, a naturally occurring stilbenoid, has the ability to reduce the toxic action of neutrophils. This substance decreased the amount of oxidants produced by neutrophils both extra- and intracellularly. Radicals formed within neutrophils (fulfilling a regulatory role) were reduced to a lesser extent than extracellular oxidants, potentially dangerous for host tissues. Moreover, piceatannol did not affect the phosphorylation of p40(phox)-a component of NADPH oxidase, responsible for the assembly of functional oxidase in intracellular (granular) membranes. The stilbenoid tested elevated the percentage of early apoptotic neutrophils, inhibited the activity of protein kinase C (PKC)-the main regulatory enzyme in neutrophils, and reduced phosphorylation of PKC isoforms α , β II, and δ on their catalytic region. The results indicated that piceatannol may be useful as a complementary medicine in states associated with persisting neutrophil activation and with oxidative damage of tissues.

Topics: Adult; Apoptosis; Biological Products; Cell Separation; Humans; Luminescent Measurements; Male; Middle Aged; Neutrophils; Phosphoproteins; Phosphorylation; Protein Kinase C; Respiratory Burst; Stilbenes; Young Adult

Piceatannol (3, 3', 4, 5'-tetrahydroxy-trans-stilbene) is a naturally occurring phytochemical found in passion fruit (Passiflora edulis) seeds. Previously, we demonstrated that piceatannol has acute vasorelaxant effects in rat thoracic aorta. It was suggested that endothelial NO synthase (eNOS) might be involved in piceatannol-induced acute vasorelaxation. Here, we investigated the expression of eNOS in EA.hy926 human umbilical vein cells after long-term treatment with piceatannol, and compared this effect with that of resveratrol, an analog of piceatannol. Long-term treatment with piceatannol up-regulated eNOS mRNA expression and increased eNOS protein expression in a dose-dependent manner. Moreover, piceatannol increased the levels of phosphorylated eNOS. Treatment with resveratrol also increased eNOS expression, but to a lesser degree than piceatannol. These findings indicate that piceatannol may improve vascular function by up-regulating eNOS expression.

Topics: Cells, Cultured; Human Umbilical Vein Endothelial Cells; Humans; Nitric Oxide Synthase Type III; Resveratrol; RNA, Messenger; Stilbenes

To investigate the mechanisms underlying the biological activity of piceatannol (PCT), a hydroxystilbene natural product that has anti-colitic properties, we examined whether PCT could modulate hypoxia-inducible factor (HIF)-1 activity in human colon carcinoma cells. PCT induced HIF-1α protein, leading to induction of its target gene products, vascular endothelial growth factor and heme oxygenase-1, which are involved in amelioration of colitis. PCT induction of HIF-1α resulted from HIF-1α protein stabilization, which occurred through inhibition of HIF-prolyl hydroxylase-2 (HPH-2). PCT inhibition of HPH-2 was reversed by addition of ascorbate, a cofactor of HPH-2, but not the cosubstrate, 2-ketoglutarate, to the reaction mixture of an in vitro von Hippel-Lindau (VHL) capture assay, and pretreatment with ascorbate abrogated PCT induction of cellular HIF-1α. Moreover, PCT prevented hydroxylation of cellular HIF-1α and attenuated coimmunoprecipitation of Flag-VHL protein and HA-HIF-1α over-expressed in human embryonic kidney 293 cells. Structural analysis using derivatives of PCT revealed that the catechol moiety in PCT was required for the stabilization of HIF-1α protein. Taken together, PCT activation of HIF-1 resulting from inhibition of HPH-2 may be a molecular mechanism for an anti-colitic effect of the natural product.

Topics: Ascorbic Acid; Cell Line, Tumor; Colitis; Colonic Neoplasms; HEK293 Cells; Heme Oxygenase-1; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Hypoxia-Inducible Factor-Proline Dioxygenases; Procollagen-Proline Dioxygenase; Stilbenes; Vascular Endothelial Growth Factor A

We present stilbenoid profiles of canes from 16 grapevines. Fifteen stilbenoids were obtained through isolation and structure identification using MS, NMR, and [α](D) or as commercial standards. An HPLC-UV method for the simultaneous quantification of nine of these stilbenoids was developed and applied to canes of Vitis amurensis, Vitis arizonica, Vitis berlandieri, Vitis betulifolia, Vitis cinerea, Vitis × champini, Vitis × doaniana, Vitis labrusca, Vitis candicans (syn. Vitis mustangensis), Vitis riparia, Vitis rupestris, Vitis vinifera, Muscadinia rotundifolia, and a V. vinifera × M. rotundifolia hybrid. In these species, E-ampelopsin E, E-amurensin B, E-piceid, E-piceatannol, E-resveratrol, E-resveratroloside, E-ε-viniferin, E-ω-viniferin, and E-vitisin B were quantified, when found in sufficient amounts. Total concentrations ranged from ~2.2 to 19.5 g/kg of dry weight. Additional stilbenoids, E-3,5,4'-trihydroxystilbene 2-C-glucoside, Z-ampelopsin E, Z-trans-miyabenol C, E-trans-miyabenol C, scirpusin A, and Z-vitisin B, were identified but not quantified. Our results indicate that canes, particularly those of non-vinifera species, have substantial quantities of valuable, health-promoting stilbenoids.

Topics: Benzofurans; Chromatography, High Pressure Liquid; Flavonoids; Glucosides; Magnetic Resonance Spectroscopy; Phenols; Resveratrol; Stilbenes; Vitis

Piceatannol (trans-3,4,3',5'-tetrahydroxystilbene) is a polyphenol detected in grapes, red wine and Rheum undulatum; it has also been demonstrated to exert anticarcinogenic effects. In this study, in order to determine whether piceatannol inhibits the lung metastasis of prostate cancer cells, MAT-Ly-Lu (MLL) rat prostate cancer cells expressing luciferase were injected into the tail veins of male nude mice. The oral administration of piceatannol (20 mg/kg) significantly inhibited the accumulation of MLL cells in the lungs of these mice. In the cell culture studies, piceatannol was demonstrated to inhibit the basal and epidermal growth factor (EGF)-induced migration and invasion of DU145 cells, in addition to the migration of MLL, PC3 and TRAMP-C2 prostate cancer cells. In DU145 cells, piceatannol attenuated the secretion and messenger RNA levels of matrix metalloproteinase-9, urokinase-type plasminogen activator (uPA) and vascular endothelial growth factor (VEGF). Piceatannol increased the protein levels of tissue inhibitor of metalloproteinase-2 in a concentration-dependent fashion. Additionally, piceatannol inhibited the phosphorylation of signal transducer and activator of transcription (STAT) 3. Furthermore, piceatannol effected reductions in both basal and EGF-induced interleukin (IL)-6 secretion. An IL-6 neutralizing antibody inhibited EGF-induced STAT3 phosphorylation and EGF-stimulated migration of DU145 cells. Interleukin-6 treatment was also shown to enhance the secretion of uPA and VEGF, STAT3 phosphorylation and the migration of DU145 cells; these increases were suppressed by piceatannol. These results demonstrate that the inhibition of IL-6/STAT3 signaling may constitute a mechanism by which piceatannol regulates the expression of proteins involved in regulating the migration and invasion of DU145 cells.

Topics: Animals; Cell Line, Tumor; Epidermal Growth Factor; Gene Expression Regulation; Humans; Interleukin-6; Male; Matrix Metalloproteinase 9; Mice; Mice, Inbred BALB C; Neoplasm Metastasis; Phosphorylation; Prostatic Neoplasms; Signal Transduction; STAT3 Transcription Factor; Stilbenes; Urokinase-Type Plasminogen Activator; Vascular Endothelial Growth Factor A

Numerous studies have shown the potential of dietary polyphenols as anticarcinogenic agents. The aim of the present study was to evaluate the apoptotic effects of piceatannol and myricetin, naturally occurring polyphenols in red wine, alone or in combination, in two human cell lines: HL-60 (leukemia) and HepG2 (hepatoma). Apoptotic cells were identified by chromatin condensation, poly(ADP-ribose) polymerase cleavage and flow cytometry analysis. Results from TUNEL assay showed that piceatannol or myricetin alone induced apoptotic cell death in a concentration- and time-dependent manners in HL-60 cells. Furthermore, in combined treatment the percentage of apoptotic HL-60 cells was significantly higher. Nevertheless, the percentage of TUNEL positive HepG2 cells only was significant after piceatannol treatment and in combined treatment was even lower than in cells treated with piceatannol alone. Moreover, we also studied the relative reactive oxygen species (ROS) production. Our results indicate that apoptosis induced by piceatannol or myricetin occurs through an ROS-independent cell death pathway. In conclusion, piceatannol and myricetin synergistically induced apoptosis in HL-60 cells but not in HepG2 cells. These findings suggest that the potential anticarcinogenic properties of dietary polyphenols depend largely on the cell line used. The relevance of these data needs to be verified in human epidemiological studies.

Topics: Anticarcinogenic Agents; Apoptosis; Blotting, Western; Cell Culture Techniques; Cell Survival; Flavonoids; Flow Cytometry; Hep G2 Cells; HL-60 Cells; Humans; In Situ Nick-End Labeling; Polyphenols; Reactive Oxygen Species; Stilbenes

C-reactive protein (CRP) was reported to be a predictor for left ventricular (LV) remodeling. Matrix metalloproteinase (MMP)-10 participates in the LV remodeling process. However, the intrinsic relationship between CRP and MMP-10 in cardiomyocytes remains unclear. The purpose of this study is to observe whether CRP may promote MMP-10 expression, and if so, to clarify signaling pathways to be involved in CRP-induced MMP-10 expression in cardiomyocytes. We observed in cultured cardiomyocytes that CRP at a dose of 5 μg/ml increased MMP-10 expression and activity in a time-dependent manner, as measured by real-time polymerase chain reaction (PCR), western blots, and casein zymography analysis. We hypothesized that signal pathways of mitogen-activated protein kinases (MAPKs) and Janus kinases (JAKs)/signal transducers and activators of transcription (STATs) might be involved in CRP-induced MMP-10 expression. Our results showed that CRP markedly activated c-Raf/MEK/ERK and JAK1/ERK signaling pathways but not JAK1/STAT3 signaling pathway by using the phosphor-specific antibodies against these pathways, and blockages of c-Raf/MEK/ERK and JAK1/ERK signaling pathways by the specific ERK1/2 inhibitor U0126 and JAK1 inhibitor piceatannol could significantly decrease CRP-induced MMP-10 expression. In addition, we demonstrated that the DNA binding sites of AP-1 and STAT3 in the nucleus of cardiomyocytes mediated CRP-induced MMP-10 expression. In conclusion, we demonstrated that CRP promoted MMP-10 expression and activity in cardiomyocytes, and clarified that c-Raf/MEK/ERK and JAK1/ERK signaling pathways were involved in MMP-10 expression regulation via activation of DNA binding sites for AP-1 and STAT3 in cardiomyocytes. Our findings suggest that CRP acts as a predictor for LV remodeling might be associated with its promotion effect on MMP-10 expression and activity.

Topics: Animals; Butadienes; C-Reactive Protein; Cells, Cultured; Janus Kinase 1; Matrix Metalloproteinase 10; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases; Myocytes, Cardiac; Nitriles; Proto-Oncogene Proteins c-raf; Rats; Rats, Sprague-Dawley; RNA Interference; RNA, Small Interfering; Signal Transduction; STAT3 Transcription Factor; Stilbenes; Transcription Factor AP-1

Type I interferons (IFN) exert multiple effects on both the innate and adaptive immune system in addition to their antiviral and antiproliferative activities. Little is known, however about the direct effects of type I IFNs on germinal center (GC) B cells, the central components of adaptive B cell responses. We used Burkitt's lymphoma (BL) lines, as a model system of normal human GC B cells, to examine the effect of type I IFNs on the expression of BCL-6, the major regulator of the GC reaction. We show that type I IFNs, but not IFNγ, IL-2 and TNFα rapidly down-regulate BCL-6 protein and mRNA expression, in cell lines derived from endemic, but not from sporadic BL. IFNα-induced down-regulation is specific for BCL-6, independent of Epstein-Barr virus and is not accompanied by IRF-4 up-regulation. IFNα-induced BCL-6 mRNA down-regulation does not require de novo protein synthesis and is specifically inhibited by piceatannol. The proteasome inhibitor MG132 non-specifically prevents, while inhibitors of alternate type I IFN signaling pathways do not inhibit IFNα-induced BCL-6 protein downregulation. We validate our results with showing that IFNα rapidly down-regulates BCL-6 mRNA in purified mouse normal GC B cells. Our results identify type I IFNs as the first group of cytokines that can down-regulate BCL-6 expression directly in GC B cells.

Topics: Adaptor Proteins, Signal Transducing; Animals; B-Lymphocytes; Burkitt Lymphoma; Cell Line, Transformed; DNA-Binding Proteins; Down-Regulation; Gene Expression Regulation, Neoplastic; Germinal Center; Herpesvirus 4, Human; Humans; Interferon Regulatory Factors; Interferon-alpha; Interferon-gamma; Interleukin-2; Kinetics; Leupeptins; Mice; Protein Biosynthesis; Proto-Oncogene Proteins c-bcl-6; RNA-Binding Proteins; RNA, Messenger; Signal Transduction; Stilbenes; Transcription Factors; Tumor Necrosis Factor-alpha

Accurate quantum-chemical calculations based on the second-order Møller-Plesset perturbation method (MP2) and density functional theory (DFT) were performed for the first time to investigate the electronic structures of trans-resveratrol and trans-piceatannol, as well as to study the stacking interaction between trans-resveratrol molecules. Ab initio MP2 calculations performed with using standard split-valence Pople basis sets led us to conclude that these compounds have structures that deviate strongly from planarity, whereas the DFT computations for the same basis sets revealed that the equilibrium geometries of these bioactive polyphenols are planar. Furthermore, the results obtained at the MP2(full)/aug-cc-pVTZ and B3LYP/aug-cc-pVTZ levels indicated that the geometries of trans-resveratrol and trans-piceatannol are practically planar at their absolute energy minima. The relative energies of the equilibrium geometries of trans-resveratrol on its potential energy surface were computed at the MP2(full)/aug-cc-pVTZ level. According to the results obtained, a T-shaped (edge-to-phase) conformer of trans-resveratrol dimer is the most stable in vacuum. This T-shaped conformer is mainly stabilized by strong hydrogen bonding and weak C-H...π interactions. Stacked structures with parallel-displaced trans-stilbene skeletons were also found to be energetically stable. The vertical separation and twist angle dependencies of the stacking energy were investigated at the MP2(full)/aug-cc-pVTZ, B3LYP/aug-cc-pVTZ, and HF/aug-cc-pVTZ levels. The standard B3LYP functional and the Hartree-Fock method neglect long-range attractive dispersion interactions. The MP2 computations revealed that the London dispersion energy cannot be neglected at long or short distances. The stacked model considered here may be useful for predicting the quantum nature of the interactions in π-stacked systems of other naturally occurring stilbenoids, and can help to enhance our understanding of the antioxidant and anticancer activities of trans-resveratrol.

Topics: Dimerization; Hydrogen Bonding; Models, Chemical; Models, Molecular; Quantum Theory; Resveratrol; Stilbenes

Piceatannol, a natural stilbene, is an analog and a metabolite of resveratrol. Despite a well documented health benefit of resveratrol in intervention of the development of obesity, the role of piceatannol in the development of adipose tissue and related diseases is unknown. Here, we sought to determine the function of piceatannol in adipogenesis and elucidate the underlying mechanism. We show that piceatannol inhibits adipogenesis of 3T3-L1 preadipocytes in a dose-dependent manner at noncytotoxic concentrations. This anti-adipogenic property of piceatannol was largely limited to the early event of adipogenesis. In the early phase of adipogenesis, piceatannol-treated preadipocytes displayed a delayed cell cycle entry into G(2)/M phase at 24 h after initiation of adipogenesis. Furthermore, the piceatannol-suppressed mitotic clonal expansion was accompanied by reduced activation of the insulin-signaling pathway. Piceatannol dose-dependently inhibited differentiation mixture-induced phosphorylation of insulin receptor (IR)/insulin receptor substrate-1 (IRS-1)/Akt pathway in the early phase of adipogenesis. Moreover, we showed that piceatannol is an inhibitor of IR kinase activity and phosphatidylinositol 3-kinase (PI3K). Our kinetics study of IR further identified a K(m) value for ATP of 57.8 μm and a K(i) value for piceatannol of 28.9 μm. We also showed that piceatannol directly binds to IR and inhibits IR kinase activity in a mixed noncompetitive manner to ATP, through which piceatannol appears to inhibit adipogenesis. Taken together, our study reveals an anti-adipogenic function of piceatannol and highlights IR and its downstream insulin signaling as novel targets for piceatannol in the early phase of adipogenesis.

Topics: 3T3-L1 Cells; Adenosine Triphosphate; Adipocytes; Adipogenesis; Animals; Cell Division; Cell Survival; Gene Expression Regulation; Insulin; Mice; Models, Molecular; Phenols; Phosphatidylinositol 3-Kinases; Phosphorylation; Protein Conformation; Proto-Oncogene Proteins c-akt; Receptor, Insulin; Signal Transduction; Stilbenes; Time Factors; Transcription Factors

L-selectin functions as an important adhesion molecule that mediates tethering and rolling of lymphocytes by binding to high endothelial venule (HEV)-expressed ligands during recirculation. Subsequent lymphocyte arrest and transmigration require activation through binding of HEV-decorated homeostatic chemokines such as secondary lymphoid tissue chemokine (SLC; CCL21) to its counterreceptor, CCR7. Importantly, L-selectin also functions as a signaling molecule. In this study, signaling induced by ligation of L-selectin using mAb or endothelial cell-expressed ligand significantly enhanced the chemotaxis of murine T cells and B cells to SLC but not to other homeostatic chemokines. Consistent with the expression levels of L-selectin in different lymphocyte subsets, L-selectin-mediated enhancement of chemotaxis to SLC was observed for all naive lymphocytes and effector/memory CD8(+) T cells, whereas only a subpopulation of effector/memory CD4(+) T cells responded. During in vivo mesenteric lymph node migration assays, the absence of L-selectin on lymphocytes significantly attenuated both their ability to migrate out of the HEV and their chemotaxis away from the vessel wall. Notably, ligation of L-selectin and/or CCR7 did not result in increased CCR7 expression levels, internalization, or re-expression. Pharmacologic inhibitor studies showed that L-selectin-mediated enhanced chemotaxis to SLC required intact intracellular kinase function. Furthermore, treatment of lymphocytes with the spleen tyrosine kinase family inhibitor piceatannol reduced their ability to migrate across the HEV in peripheral lymph nodes. Therefore, these results suggest that "cross-talk" in the signaling pathways initiated by L-selectin and CCR7 provides a novel mechanism for functional synergy between these two molecules during lymphocyte migration.

Topics: Animals; Antibodies, Monoclonal; Cells, Cultured; Chemokine CCL21; Chemotaxis, Leukocyte; Endothelial Cells; Immunologic Memory; Intracellular Signaling Peptides and Proteins; L-Selectin; Lymph Nodes; Mesentery; Mice; Mice, Inbred C57BL; Mice, Knockout; Protein Kinase Inhibitors; Protein-Tyrosine Kinases; Receptors, CCR7; Receptors, CXCR4; Signal Transduction; Specific Pathogen-Free Organisms; Stilbenes; Syk Kinase; T-Lymphocyte Subsets

Cancer invasion and metastasis are the main causes of treatment failure and death in cancer patients. Piceatannol (3,3',4,5'-tetrahydroxy-trans-stilbene) is a natural analogue of resveratrol. This study investigated the anti-invasive mechanisms of piceatannol in MDA-MB-231 cells. Piceatannol significantly reduced serum-induced cell invasion and migration as well as adhesion without affecting the viability of cells. Furthermore, piceatannol markedly inhibited matrix metalloproteinase-9 (MMP-9) activity and expression at both protein and mRNA levels. Piceatannol attenuated phosphoinisitide-3-kinase (PI3K) and phosphorylation of AKT and mammalian target of rapamycin (mTOR), whereas phosphatase and tensin homologue (PTEN) was increased. Moreover, piceatannol inhibited nuclear factor kappa B (NF-κB) transcriptional activity and DNA binding of NF-κB on MMP-9 promoter. In addition, piceatannol diminished NF-κB nuclear translocation through blocking the inhibitor of NF-κB alpha (IκBα) phosphorylation in the cytoplasm. These results proposed piceatannol as a potential anti-invasive agent by inhibiting MMP-9 involved in PI3K/AKT and NF-κB pathways.

Topics: Antineoplastic Agents, Phytogenic; Breast Neoplasms; Cell Line, Tumor; Cell Movement; Down-Regulation; Female; Gene Expression Regulation, Neoplastic; Humans; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; NF-kappa B; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Signal Transduction; Stilbenes

Piceatannol is a stilbenoid, a metabolite of resveratrol found in red wine. Piceatannol and sera from rats orally given piceatannol were found to dose-dependently suppress both the proliferation and invasion of AH109A hepatoma cells in culture. Its antiproliferative effect was based on cell cycle arrest at lower concentration (25~50 μM) and on apoptosis induction at higher concentration (100 μM). Piceatannol suppressed reactive oxygen species-potentiated invasive capacity by scavenging the intracellular reactive oxygen species. These results suggest that piceatannol, unlike resveratrol, has a potential to suppress the hepatoma proliferation by inducing cell cycle arrest and apoptosis induction. They also suggest that the antioxidative property of piceatannol, like resveratrol, may be involved in its anti-invasive action. Subsequently, piceatannol was found to suppress the growth of solid tumor and metastasis in hepatoma-bearing rats. Thus, piceatannol may be a useful anticancer natural product.

Topics: Animals; Apoptosis; Cell Cycle Checkpoints; Cell Growth Processes; Cell Line, Tumor; Hydrogen Peroxide; Liver Neoplasms, Experimental; Male; Neoplasm Invasiveness; Neoplasms, Experimental; Peroxides; Rats; Stilbenes; Vitis; Wine

Recently, we have shown that the antiangiogenic pigment epithelium-derived factor (PEDF) can bind the catalytic β-subunit of F1-ATP synthase and inhibit endothelial cell surface ATP synthase activity. This factor can additionally restrict tumor growth, invasion and metastasis, and can directly induce death on several tumor cell types. Active cell surface ATP synthase is also present in certain tumor cells and its ATP product is considered a stimulus for tumor growth. The present study aimed to elucidate the biological implications of the interactions between the extracellular PEDF and tumor cell surface ATP synthase. Incubation of T24 human urinary bladder carcinoma cells in media containing human recombinant PEDF protein for 48-96 h dramatically decreased cell viability in a concentration-dependent fashion as monitored by real-time cell impedance with a microelectronic system, microscopic imaging and biomarkers of live cells. Intact tumor cells exhibited cell surface ATP synthesis activity, which was inhibited by piceatannol, a specific inhibitor of F1/F0-ATP synthase. Immunoblotting revealed that the β subunit of F1-ATP synthase was present in plasma membrane fractions of these cells. Interestingly, pre-incubation of tumor cells with PEDF inhibited the activity of cell surface ATP synthase in a concentration-dependent fashion. The PEDF-derived peptide 34-mer decreased tumor cell viability and inhibited extracellular ATP synthesis to the same extent as full-length PEDF. Moreover, ATP additions attenuated both the PEDF-mediated decrease in tumor cell viability and the inhibition of endothelial cell tube formation. The results lead to conclude that PEDF is a novel inhibitor of tumor cell surface ATP synthase activity that exhibits a cytotoxic effect on tumor cells, and that the structural determinants for these properties are within the peptide region 34-mer of the PEDF polypeptide. The data strongly suggest a role for the interaction between the 34-mer region of PEDF and tumor cell-surface ATP synthase in promoting tumor cell death.

Topics: Adenosine Triphosphate; Angiogenesis Inhibitors; Cell Line, Tumor; Cell Membrane; Cell Proliferation; Cell Survival; Eye Proteins; Humans; Mitochondrial Proton-Translocating ATPases; Nerve Growth Factors; Peptide Fragments; Protein Subunits; Serpins; Stilbenes

The skeletal muscle cells are one of the main sites of glucose uptake through glucose transporter 4 (GLUT4) in response to insulin. In muscle cells, 5' adenosine monophosphate-activated protein kinase (AMPK) is known as another GLUT4 translocation promoter. Natural compounds that activate AMPK have a possibility to overcome insulin resistance in the diabetic state. Piceatannol is a natural analog and a metabolite of resveratrol, a known AMPK activator. In this study, we investigate the in vitro effect of piceatannol on glucose uptake, AMPK phosphorylation and GLUT4 translocation to plasma membrane in L6 myocytes, and its in vivo effect on blood glucose levels in type 2 diabetic model db/db mice. Piceatannol was found to promote glucose uptake, AMPK phosphorylation and GLUT4 translocation by Western blotting analyses in L6 myotubes under a condition of insulin absence. Promotion by piceatannol of glucose uptake as well as GLUT4 translocation to plasma membrane by immunocytochemistry was also demonstrated in L6 myoblasts transfected with a glut4 cDNA-coding vector. Piceatannol suppressed the rises in blood glucose levels at early stages and improved the impaired glucose tolerance at late stages in db/db mice. These in vitro and in vivo findings suggest that piceatannol may be preventive and remedial for type 2 diabetes and become an antidiabetic phytochemical.

Topics: AMP-Activated Protein Kinase Kinases; Animals; Blood Glucose; Cell Line; Cell Membrane; Diabetes Mellitus, Type 2; Disease Models, Animal; Enzyme Activation; Glucose; Glucose Transporter Type 4; Mice; Molecular Imaging; Muscle Cells; Protein Kinases; Rats; Resveratrol; Stilbenes

In observations of single molecule behavior under V(max) conditions with minimal load, the F(1) sector of the ATP synthase (F-ATPase) rotates through continuous cycles of catalytic dwells (∼0.2 ms) and 120° rotation steps (∼0.6 ms). We previously established that the rate-limiting transition step occurs during the catalytic dwell at the initiation of the 120° rotation. Here, we use the phytopolyphenol, piceatannol, which binds to a pocket formed by contributions from α and β stator subunits and the carboxyl-terminal region of the rotor γ subunit. Piceatannol did not interfere with the movement through the 120° rotation step, but caused increased duration of the catalytic dwell. The duration time of the intrinsic inhibited state of F(1) also became significantly longer with piceatannol. All of the beads rotated at a lower rate in the presence of saturating piceatannol, indicating that the inhibitor stays bound throughout the rotational catalytic cycle. The Arrhenius plot of the temperature dependence of the reciprocal of the duration of the catalytic dwell (catalytic rate) indicated significantly increased activation energy of the rate-limiting step to trigger the 120° rotation. The activation energy was further increased by combination of piceatannol and substitution of γ subunit Met(23) with Lys, indicating that the inhibitor and the β/γ interface mutation affect the same transition step, even though they perturb physically separated rotor-stator interactions.

Topics: Amino Acid Sequence; Antioxidants; Binding Sites; Catalysis; Enzyme Activation; Escherichia coli; Escherichia coli Proteins; Molecular Sequence Data; Mutagenesis; Polyphenols; Protein Subunits; Proton-Translocating ATPases; Quercetin; Stilbenes; Temperature; Thermodynamics

To address the mechanism of piceatannol in inhibiting TNFα-mediated pathway, studies on piceatannol-treated human leukemia U937 cells were conducted. Piceatannol treatment reduced TNFα shedding and NFκB activation and decreased the release of soluble TNFα into the culture medium of U937 cells. Moreover, ADAM17 expression was down-regulated in piceatannol-treated cells. Over-expression of ADAM17 abrogated the ability of piceatannol to suppress TNFα-mediated NFκB activation. Piceatannol-evoked β-TrCP up-regulation promoted Sp1 degradation, thus reducing transcriptional level of ADAM17 gene in U937 cells. Piceatannol treatment induced p38 MAPK phosphorylation but inactivation of Akt and ERK. In contrast to p38 MAPK inhibitor or restoration of ERK activation, transfection of constitutive active Akt abolished the effect of piceatannol on β-TrCP, Sp1 and ADAM17 expression. Piceatannol-elicited down-regulation of miR-183 expression was found to cause β-TrCP up-regulation. Inactivation of Akt resulted in Foxp3 down-regulation and reduced miR-183 expression in piceatannol-treated cells. Knock-down of Foxp3 and chromatin immunoprecipitating revealed that Foxp3 genetically regulated transcription of miR-183 gene. Taken together, our data indicate that suppression of Akt/Foxp3-mediated miR-183 expression blocks Sp1-mediated ADAM17 expression in piceatannol-treated U937 cells. Consequently, piceatannol suppresses TNFα shedding, leading to inhibition of TNFα/NFκB pathway.

Topics: ADAM Proteins; ADAM17 Protein; Base Sequence; Chromatin Immunoprecipitation; DNA Primers; Down-Regulation; Enzyme-Linked Immunosorbent Assay; Flow Cytometry; Forkhead Transcription Factors; Humans; Leukemia; MicroRNAs; NF-kappa B; Proto-Oncogene Proteins c-akt; RNA Interference; Sp1 Transcription Factor; Stilbenes; Tumor Necrosis Factor-alpha; U937 Cells

Synthesis of four water-soluble resveratrol and piceatannol derivatives bearing symmetrically branched glyceryl trimer (BGL003) with a non-biocleavable linkage, and their biological evaluation as a mitochondrial fusion-inducing agent with cellular fat-reducing effect from cells, is described. The effect of Piceatannol-BGL003 conjugate was as high as that of original stilbenoids.

Topics: Glycerol; Mitochondria; Resveratrol; Solubility; Stilbenes; Water

Secreted tyrosinase from melanin-forming Streptomyces avermitilis MA4680 was involved in both ortho-hydroxylation and further oxidation of trans-resveratrol, leading to the formation of melanin. This finding was confirmed by constructing deletion mutants of melC(2) and melD(2) encoding extracellular and intracellular tyrosinase, respectively; the melC2 deletion mutant did not produce piceatannol as well as melanin, whereas the melD2 deletion mutant oxidized resveratrol and synthesized melanin with the same yields, suggesting that MelC2 is responsible for ortho-hydroxylation of resveratrol. Extracellular tyrosinase (MelC2) efficiently converted trans-resveratrol into piceatannol in the presence of either tyrosinase inhibitors or reducing agents such as catechol, NADH, and ascorbic acid. Reducing agents slow down the dioxygenase reaction of tyrosinase. In the presence of catechol, the regio-specific hydroxylation of trans-resveratrol was successfully performed by whole cell biotransformation, and further oxidation of trans-resveratrol was efficiently blocked. The yield of this ortho-hydroxylation of trans-resveratrol was dependent upon inhibitor concentration. Using 1.8 mg of wild-type Streptomyces avermitilis cells, the conversion yield of 100 μM trans-resveratrol to piceatannol was 78% in 3 h in the presence of 1 mM catechol, indicating 14 μM piceatannol h(-1) DCW mg(-1) specific productivity, which was a 14-fold increase in conversion yield compared to that without catechol, which is a remarkably higher reaction rate than that of P450 bioconversion. This method could be generally applied to biocatalysis of various dioxygenases.

Topics: Catechol Oxidase; Catechols; Hydroxylation; Melanins; Monophenol Monooxygenase; Mutation; Plasmids; Reducing Agents; Resveratrol; Stereoisomerism; Stilbenes; Streptomyces

Resveratrol is a polyphenol contained in red wine that has been amply investigated for its beneficial effects on organismal metabolism, in particular in the context of the so-called "French paradox," i.e., the relatively low incidence of coronary heart disease exhibited by a population with a high dietary intake of cholesterol and saturated fats. At least part of the beneficial effect of resveratrol on human health stems from its capacity to promote autophagy by activating the NAD-dependent deacetylase sirtuin 1. However, the concentration of resveratrol found in red wine is excessively low to account alone for the French paradox. Here, we investigated the possibility that other mono- and polyphenols contained in red wine might induce autophagy while affecting the acetylation levels of cellular proteins. Phenolic compounds found in red wine, including anthocyanins (oenin), stilbenoids (piceatannol), monophenols (caffeic acid, gallic acid) glucosides (delphinidin, kuronamin, peonidin) and flavonoids (catechin, epicatechin, quercetin, myricetin), were all capable of stimulating autophagy, although with dissimilar potencies. Importantly, a robust negative correlation could be established between autophagy induction and the acetylation levels of cytoplasmic proteins, as determined by a novel immunofluorescence staining protocol that allows for the exclusion of nuclear components from the analysis. Inhibition of sirtuin 1 by both pharmacological and genetic means abolished protein deacetylation and autophagy as stimulated by resveratrol, but not by piceatannol, indicating that these compounds act through distinct molecular pathways. In support of this notion, resveratrol and piceatannol synergized in inducing autophagy as well as in promoting cytoplasmic protein deacetylation. Our results highlight a cause-effect relationship between the deacetylation of cytoplasmic proteins and autophagy induction by red wine components.

Topics: Acetylation; Autophagy; Cell Line, Tumor; Cytoplasm; Enzyme Activation; Gene Expression; Humans; Microscopy, Fluorescence; Polyphenols; Resveratrol; Sirtuin 1; Stilbenes

Heparin-binding protein (HBP), an evolutionary ancient and biologically highly important molecule in inflammation, is an inactive serine protease due to mutations in the catalytic triad. The histidine (position 41) in the conserved sequence TAAHC is mutated to serine and this sequence (TAASC) plays a crucial role when HBP binds to monocytes. We synthesized a 20-44 HBP peptide, cyclicized by a sulphur bridge, which encompasses this amino acid and functions as full-length HBP. Using a human monocyte cell line, we have shown that lipopolysaccharide (LPS)-triggered secretion of IL-6 is enhanced up to 10-fold when full-length HBP or the peptide are present in low-to-moderate concentrations. A monoclonal antibody neutralizing HBP also neutralizes the peptide, indicating that the ligand for the HBP receptor is located near serine in position 41 on the HBP surface. A 'back mutated' 20-44 peptide (serine→histidine) has some, but not significant, stimulatory effect on monocytes. Normally, HBP production and release is ascribed to neutrophil granulocytes, but here we find that also monocytes secrete HBP when stimulated with LPS. Furthermore, a small amount of HBP can be demonstrated when monocytes are incubated in medium alone. Our efforts to identify a suggested HBP receptor on monocytes has failed so far.

Topics: Antibodies, Monoclonal; Antimicrobial Cationic Peptides; Blood; Blood Proteins; Carrier Proteins; CD18 Antigens; Cell Line; Culture Media; Humans; Interleukin-6; Intracellular Signaling Peptides and Proteins; Lipopolysaccharides; Monocytes; Peptide Fragments; Peptidoglycan; Protein Interaction Domains and Motifs; Protein-Tyrosine Kinases; Stilbenes; Syk Kinase

INTRODUATION: Resveratrol, a phytoestrogen present at a high concentration in red wine, has been reported to possess many health benefit effects that are protective against age-related diseases. Protein S (PS), an important anticoagulant factor in the protein C (PC) anticoagulant pathway, is mainly synthesized by hepatocytes, and its plasma level is decreased in high-estrogen conditions such as pregnancy and oral contraceptive use. The aim of this study was to investigate whether resveratrol affects PS expression in HepG2 cells.. The secreted and intracellular levels of PS were determined by an enzyme-linked ligandsorbent assay and Western blotting. The mRNA expressions of PS, PC and β chain of C4b-binding protein (C4BP-β) were analyzed by reverse transcription-polymerase chain reaction. The PS gene promotor activities in HepG2 cells transiently expressing estrogen receptor (ER) α were examined by a luciferase reporter assay.. Resveratrol dose- and time-dependently down-regulated the PS expression in HepG2 cells at a transcriptional level, resulting in a significant decrease in secreted PS; however, the PC and C4BP-β mRNA expressions were not affected. This action of resveratrol was not mediated through either the ER signaling or those of mitogen-activated protein kinases and protein kinase C. Piceatannol, a hydroxylated metabolite of resveratrol, and genistein, an isoflavone found in soy products, also down-regulated the PS expression.. Resveratrol down-regulates the PS expression in HepG2 cells in an ER-independent manner, and the two phenolic hydroxyls at carbon-3 and -5 of resveratrol may be involved in this function.

Topics: Blood Proteins; Blotting, Western; Carcinoma, Hepatocellular; Dose-Response Relationship, Drug; Down-Regulation; Enzyme-Linked Immunosorbent Assay; Estrogen Receptor alpha; Gene Expression Regulation, Neoplastic; Genistein; Hep G2 Cells; Histocompatibility Antigens; Humans; Liver Neoplasms; Molecular Structure; Phytoestrogens; Promoter Regions, Genetic; Protein C; Protein S; Resveratrol; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Stilbenes; Structure-Activity Relationship; Time Factors; Transcription, Genetic; Transfection; Wine

Ustilago maydis, the causative agent of corn smut disease, contains two genes encoding members of the carotenoid cleavage oxygenase family, a group of enzymes that cleave double bonds in different substrates. One of them, Cco1, was formerly identified as a β-carotene cleaving enzyme. Here we elucidate the function of the protein encoded by the second gene, termed here as Ustilago maydis Resveratrol cleavage oxygenase 1 (Um Rco1). In vitro incubations of heterologously expressed and purified UM Rco1 with different carotenoid and stilbene substrates demonstrate that it cleaves the interphenyl Cα-Cβ double bond of the phytoalexin resveratrol and its derivative piceatannol. Um Rco1 exhibits a high degree of substrate specificity, as suggested by the lack of activity on carotenoids and the other resveratrol-related compounds tested. The activity of Um Rco1 was confirmed by incubation of U. maydis rco1 deletion and over-expression strains with resveratrol. Furthermore, treatment with resveratrol resulted in striking alterations of cell morphology. However, pathogenicity assays indicated that Um rco1 is largely dispensable for biotrophic development. Our work reveals Um Rco1 as the first eukaryotic resveratrol cleavage enzyme identified so far. Moreover, Um Rco1 represents a subfamily of fungal enzymes likely involved in the degradation of stilbene compounds, as suggested by the cleavage of resveratrol by homologs from Aspergillus fumigatus, Chaetomium globosum and Botryotinia fuckeliana.

Topics: Carotenoids; Gene Deletion; Gene Expression; Oxygenases; Phylogeny; Recombinant Proteins; Resveratrol; Sequence Homology, Amino Acid; Stilbenes; Substrate Specificity; Ustilago

Although piceatannol (PIC) is known to mediate anti-cancer, anti-inflammatory, and anti-oxidant activities, little is known about the mechanism of PIC in terms of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis. In this study, we examined whether combined treatment with PIC and TRAIL synergistically induces apoptosis in THP-1 leukemia cells. Results indicate that PIC substantially enhances TRAIL-induced cell death including DNA fragmentation and poly(ADP-ribose) polymerase cleavage. Consistent with TRAIL-induced apoptosis, PIC significantly increased the mRNA and protein expression levels of DR5, a death receptor of TRAIL. Further, PIC enhanced DR5 promoter activity via Sp1 activation. Interestingly, the DR5 chimera antibodies significantly suppressed PIC and TRAIL-mediated apoptosis. The inhibitor of ERK also decreased PIC and TRAIL-induced apoptosis by blocking DR5 expression. In conclusion, our results suggest that PIC sensitizes TRAIL-induced-apoptosis via Sp1- and ERK-dependent DR5 up-regulation.

Topics: Antineoplastic Agents; Apoptosis; Blotting, Western; Cell Survival; Chromatin Immunoprecipitation; DNA Fragmentation; Drug Synergism; Extracellular Signal-Regulated MAP Kinases; HL-60 Cells; Humans; Leukemia; Phosphorylation; Receptors, TNF-Related Apoptosis-Inducing Ligand; Sp1 Transcription Factor; Stilbenes; TNF-Related Apoptosis-Inducing Ligand; U937 Cells; Up-Regulation

Platelet-derived growth factor BB (PDGF-BB) regulates vascular smooth muscle cells (VSMCs) by activating signaling cascades that promote vasoconstriction and growth, but the underlying mechanisms remain incompletely characterized. In this study, we aimed at investigating the role of spleen tyrosine kinase (Syk) in the proliferation and phenotypes in rat pulmonary arterial VSMCs. Our results demonstrate that PDGF-BB or Syk-adenovirus led to a substantial increase of proliferation of VSMCs and cytoskeleton rearrangement in rat VSMCs. Consistently, these cells underwent phenotype changes. Notably, Syk inhibitor piceatannol significantly inhibited those biological effects induced by PDGF-BB. Thus, we conclude that Syk plays an important role in vascular remodeling through the modulation of proliferation and phenotypes of VSMCs.

Topics: Actins; Animals; Becaplermin; Blotting, Western; Cell Proliferation; Cells, Cultured; Cytoskeleton; Dose-Response Relationship, Drug; Intracellular Signaling Peptides and Proteins; Male; Microscopy, Confocal; Microscopy, Electron; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Platelet-Derived Growth Factor; Protein-Tyrosine Kinases; Proto-Oncogene Proteins c-sis; Rats; Rats, Sprague-Dawley; Stilbenes; Syk Kinase

Glucose-induced oxidative stress is involved in endothelial dysfunction. Dimethylarginine dimethylaminohydrolase (DDAH) and arginase are regulators of the endothelial NO synthase (eNOS). This study aimed to compare the effect of two polyphenolic antioxidants, resveratrol and piceatannol, on DDAH and arginase pathways in bovine aortic endothelial cells under 25 mM glucose for 24 h. DDAH activity and expression were decreased in these cells as compared to control cells, whereas arginase activity was unchanged. DDAH inhibition led to intracellular accumulation of asymmetric dimethylarginine (ADMA), a natural inhibitor of eNOS. Under these conditions, cell pre-treatment with resveratrol (0.1-10 μM) restored basal DDAH activity and ADMA level with a dose-dependent effect. Piceatannol acted as resveratrol on DDAH pathway but at 10-fold lower concentrations. Resveratrol and piceatannol restored DDAH activity even in the presence of splitomicin, a specific inhibitor of Sirtuin 1. These results suggest potential therapeutic intervention targeting resveratrol or piceatannol administration to improve endothelial dysfunction.

Topics: Amidohydrolases; Animals; Antioxidants; Aorta; Arginase; Arginine; Blotting, Western; Cattle; Cell Line; Endothelial Cells; Glucose; Hyperglycemia; Immunoprecipitation; Naphthalenes; Nitric Oxide Synthase; Oxidative Stress; Pyrones; Resveratrol; Sirtuin 1; Stilbenes

Serotonin (5-hydroxytryptamine, 5-HT) is a neurotransmitter involved in the regulation of numerous neuro-physiological processes. The circulating level of 5-HT is regulated by the membrane transporter SERT present both in the presynaptic nerve terminals and blood platelets. 5-HT transport is a process tightly regulated by a variety of factors including protein phosphorylation. Aim of this study was to ascertain if also the SERT Tyr-phosphorylation mediated by Syk-kinase concurs to the regulation of SERT activity. Indeed we found that 5-HT uptake decreased upon platelet exposure to piceatannol or Syk-inhibitor II, two structurally unrelated inhibitors of the tyrosine-kinase Syk. Tyr-phosphorylation of anti-SERT-immuno-stained proteins in membrane extracts and in anti-SERT-immuno-precipitates, decreased upon platelet treatment with piceatannol, in parallel with a reduction of Syk-activity. Syk was immuno-revealed in the anti-SERT immuno-precipitates, which displayed a piceatannol-sensitive kinase activity towards SERT itself and the Syk-substrate α-sinuclein. Syk inhibitors also caused a decrease of the monensin-induced 5-HT-efflux from platelets and of imipramine binding to them. It is concluded that, in addition to the phosphorylation of SERT mediated by various other kinases, also that catalyzed by Syk might play an important role in the 5-HT transport, likely favoring the transporter conformation exposing the neurotransmitter binding sites.

Topics: Antidepressive Agents, Tricyclic; Blood Platelets; Humans; Imipramine; Intracellular Signaling Peptides and Proteins; Phosphorylation; Protein Binding; Protein-Tyrosine Kinases; Serotonin; Serotonin Plasma Membrane Transport Proteins; Stilbenes; Syk Kinase

Mantle cell lymphoma (MCL) is currently an incurable entity, and new therapeutic approaches are needed. We have applied a high-throughput phospho-proteomic technique to MCL cell lines to identify activated pathways and we have then validated our data in both cell lines and tumor tissues.. PhosphoScan analysis was performed on MCL cell lines. Results were validated by flow cytometry and western blotting. Functional validation was performed by blocking the most active pathway in MCL cell lines.. PhosphoScan identified more than 300 tyrosine-phosporylated proteins, among which many protein kinases. The most abundant peptides belonged to proteins connected with B-cell receptor (BCR) signaling. Active BCR signaling was demonstrated by flow cytometry in MCL cells and by western blotting in MCL tumor tissues. Blocking BCR signaling by Syk inhibitor piceatannol induced dose/time-dependent apoptosis in MCL cell lines, as well as several modifications in the phosphorylation status of BCR pathway members and a collapse of cyclin D1 protein levels.. Our data support a pro-survival role of BCR signaling in MCL and suggest that this pathway might be a candidate for therapy. Our findings also suggest that Syk activation patterns might be different in MCL compared to other lymphoma subtypes.

Topics: Blotting, Western; Cell Line, Tumor; Cell Survival; Enzyme Activation; Flow Cytometry; Fluorescent Antibody Technique; Humans; Isoenzymes; Lymphoma, Mantle-Cell; Models, Biological; Phosphoproteins; Phosphorylation; Proteomics; Receptor Protein-Tyrosine Kinases; Receptors, Antigen, B-Cell; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Stilbenes; Tyrosine

Aside from being an integral protein involved in the synthesis and hydrolysis of ATP, Ecto-F1-ATPase plays a role in cholesterol homeostasis. We demonstrated the presence of autoantibodies to ecto-F1-ATPase (ASabs) in sera and cerebrospinal fluids from patients with Alzheimer's disease (AD). Herein we show that ASabs, unlike irrelevant antibodies, can increase cellular uptake of HDL, a risk factor for the development of AD, via a mechanism involving the prototypical function of ecto-F1-ATPase: the generation of ADP due to the hydrolysis of ATP. Piceatannol, a specific inhibitor ecto-F1-ATPase, completely hindered these effects. We hypothesize that ASabs could exert a pathogenetic role in AD.

Topics: Adenosine Diphosphate; Adenosine Triphosphate; Aged; Aged, 80 and over; Alzheimer Disease; Antibody Specificity; Apoptosis; Autoantibodies; Cell Line; Cholesterol, HDL; Enzyme Inhibitors; Extracellular Space; Female; Fluorescent Dyes; Humans; Male; Middle Aged; Proton-Translocating ATPases; Stilbenes

Although astringinin administration under adverse circulatory conditions is known to be protective, the mechanism by which astringinin produces the salutary effects remains unknown. We hypothesize that astringinin administration in males following trauma-hemorrhage decreases cytokine production and protects against hepatic injury. Male Sprague-Dawley rats underwent trauma-hemorrhage (mean blood pressure: 40 mmHg for 90 min, then resuscitation). Different doses of astringinin (0.01, 0.03, 0.1, 0.3 mg/kg of body weight) or vehicle were administered intravenously during resuscitation. Concentrations of plasma aspartate aminotransferase (AST) with alanine aminotransferase (ALT) and various hepatic parameters were measured (n = 8 rats/group) at 24 h after resuscitation. One-way ANOVA and Tukey testing were used for statistical analysis. Trauma-hemorrhage significantly increased plasma AST and ALT levels at 24 h postresuscitation; there was a dose-related benefit when astringinin was administered at doses of 0.01 to 0.3 mg/kg. In astringinin-treated (0.3 mg/kg) rats subjected to trauma-hemorrhage, there were significant improvements in liver myeloperoxidase (MPO) activity (237.80 +/- 45.89 vs. 495.95 +/- 70.64 U/mg protein, P < 0.05), interleukin-6 (IL-6) levels (218.54 +/- 34.52 vs. 478.60 +/- 76.21 pg/mg protein, P < 0.05), cytokine-induced neutrophil chemoattractant (CINC)-1 (88.32 +/- 20.33 vs. 200.70 +/- 32.68 pg/mg protein, P < 0.05), CINC-3 (110.83 +/- 26.63 vs. 290.14 +/- 76.82 pg/mg protein, P < 0.05) and intercellular adhesion molecule (ICAM)-1 concentrations (1,868.5 +/- 211.5 vs. 3,645.0 +/- 709.2 pg/mg protein, P < 0.05), as well as in histology. Results show that astringinin significantly attenuates proinflammatory responses and hepatic injury after trauma-hemorrhage. In conclusion, the salutary effects of astringinin administration on attenuation of hepatic injury following trauma-hemorrhage are likely due to reduction of pro-inflammatory mediator levels.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Chemokine CXCL1; Dose-Response Relationship, Drug; Humans; Intercellular Adhesion Molecule-1; Interleukin-6; Liver; Liver Diseases; Male; Peroxidase; Rats; Rats, Sprague-Dawley; Resuscitation; Shock, Hemorrhagic; Stilbenes

Psoriasis, an immunological skin disease, is characterized by epidermal hyperproliferation, chronic inflammation, and an accumulation of infiltrating T cells. IL-17A is a key cytokine that has a critical role in the pathogenesis of psoriasis. Keratin 17 (K17) is strongly expressed in psoriatic lesions but not in normal skin. Thus, K17 expression is regarded as a hallmark of psoriasis. We previously reported that the K17/T cells/cytokine autoimmune loop was involved in psoriasis. However, the relationship between IL-17A and K17 has yet to be determined. In the present study, IL-17A-induced K17 expression was confirmed in cultured keratinocytes in both mRNA and protein levels. In addition, increased K17 expression was found in the epidermis of IL-17A-injected mouse skin. The regulatory mechanism of K17 expression was further investigated. We found that both the signal transducer and activator of transcription (STAT) 1 and STAT3 pathways were involved in the upregulation of K17 expression induced by IL-17A, and that such regulation could be partially suppressed by STAT1 or STAT3 small interfering RNA and inhibitor. Our data suggest that IL-17A can upregulate K17 expression in keratinocytes in a dose-dependent manner through STAT1- and STAT3-dependent mechanisms. The results indicate that IL-17A might be an important cytokine in the K17/T cells/cytokine autoimmune loop associated with psoriasis.

Topics: Animals; Cell Line; Enzyme Inhibitors; Humans; Interleukin-17; Keratin-17; Keratinocytes; Mice; RNA, Small Interfering; Signal Transduction; STAT1 Transcription Factor; STAT3 Transcription Factor; Stilbenes; Vidarabine

Stilbenes, especially those oligomers, have great potential to be antihyperglycemic agents. In this study, eight stilbene dimers, including five new ones, were obtained by biotransformation of piceatannol using Momordica charantia peroxidase (MCP) for the first time. Their structures were established on the basis of spectroscopic evidences. These piceatannol dimers displayed potential α-glucosidase inhibitory activities, and trans double bond, tetrahydrofuran ring, and free adjacent phenolic dihydroxyls were found to be important for their activities. Enzymatic biotransformation of stilbenes by M.charantia peroxidase (MCP) was showed to be a prominent way to produce oligomeric stilbenes for antihyperglycemic development.

Topics: alpha-Glucosidases; Biocatalysis; Biotransformation; Dimerization; Enzyme Activation; Enzyme Inhibitors; Glycoside Hydrolase Inhibitors; Hypoglycemic Agents; Molecular Conformation; Momordica charantia; Peroxidase; Stilbenes

Tyrosine kinases such as SRC family kinases (SFKs) as well as the mammalian target of rapamycin (mTOR) serine/threonine kinase are often constitutively activated in acute myeloid leukemia (AML) and hence constitute potential therapeutic targets. Here we demonstrate that the epidermal growth factor receptor (EGFR) inhibitor erlotinib, which has previously been shown to mediate antiproliferative/cytotoxic off-target effects in myelodysplastic syndrome (MDS) and AML blasts, reduces SFK overactivation. Erlotinib induced an arrest in the G 1 phase of the cell cycle that, in cells with constitutive SFK activation, could be recapitulated by chemical inhibition of SFKs with 3-(4-chlorophenyl)1-(1,1-dimethylethyl)-1H-pyrazolo[3,4-α]pyrimidin-4-amine (PP2). Moreover, erlotinib inhibited the phosphorylation of mTOR targets like p70 (SK6) , stimulated the maturation of the autophagic marker LC3 and promoted the formation of autophagosomes. Notably, PP2 and the mTOR inhibitor rapamycin had a similar cell cycle-arresting activity to erlotinib, but neither of these compounds alone induced significant levels of cell death. Altogether, these results suggest that the therapeutic off-target effect of erlotinib may be linked to, yet cannot be entirely explained by, the inhibition of oncogenic signaling via SFKs and mTOR. Thus, combination therapies with erlotinib and rapamycin might be beneficial for MDS and AML patients.

Topics: Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Autophagy; Biomarkers, Tumor; Enzyme Activation; Erlotinib Hydrochloride; Flow Cytometry; G1 Phase Cell Cycle Checkpoints; HL-60 Cells; Humans; Leukemia, Myeloid, Acute; Microscopy, Electron; Microscopy, Fluorescence; Microtubule-Associated Proteins; Phosphorylation; Pyrimidines; Quinazolines; Signal Transduction; Sirolimus; src-Family Kinases; Stilbenes; TOR Serine-Threonine Kinases

Astringinin can attenuate organ injury following trauma-hemorrhage, the mechanism remains unknown. Protein kinase B/hemeoxygenase-1 (Akt/HO-1) pathway exerts potent anti-inflammatory effects in various tissues. The aim of this study is to elucidate whether Akt/HO-1 plays any role in astringinin-mediated attenuation of hepatic injury following trauma-hemorrhage. For study this, male Sprague-Dawley rats underwent trauma-hemorrhage (mean blood pressure 35-40 mmHg for 90 min) followed by fluid resuscitation. A single dose of astringinin (0.3 mg/kg body weight) with or without a PI3K inhibitor (wortmannin) or a HO antagonist (chromium-mesoporphyrin) was administered during resuscitation. Various parameters were measured at 24 h post-resuscitation. Results showed that trauma-hemorrhage increased plasma aspartate and alanine aminotransferases (AST and ALT) concentrations and hepatic myeloperoxidase activity, cytokine induced neutrophil chemoattractant (CINC)-1, CINC-3, intercellular adhesion molecule-1, and interleukin-6 levels. These parameters were significantly improved in the astringinin-treated rats subjected to trauma-hemorrhage. Astringinin treatment also increased hepatic Akt activation and HO-1 expression as compared with vehicle-treated trauma-hemorrhaged rats. Co-administration of wortmannin or chromium-mesoporphyrin abolished the astringinin-induced beneficial effects on post-resuscitation pro-inflammatory responses and hepatic injury. These findings collectively suggest that the salutary effects of astringinin administration on attenuation of hepatic injury after trauma-hemorrhage are likely mediated via Akt dependent HO-1 up-regulation.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Chemokine CXCL1; Chemokine CXCL2; Heme Oxygenase-1; Hemorrhage; Intercellular Adhesion Molecule-1; Interleukin-6; Liver; Male; Peroxidase; Phosphorylation; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Signal Transduction; Stilbenes; Wounds and Injuries

Excess reactive oxygen species (ROS) generated from ionizing radiation (IR) or endogenous sources like cellular respiration and inflammation produce cytotoxic effects that can lead to carcinogenesis. Resveratrol (RSV), a polyphenol with antioxidant and anticarcinogenic capabilities, has shown promise as a potential radiation modifier. The present study focuses on examining the effects of RSV or RSV metabolites as a radiation modifier in normal tissue. RSV or a RSV metabolite, piceatannol (PIC) did not protect human lung fibroblasts (1522) from the radiation-induced cell killing. Likewise, neither RSV nor PIC afforded protection against lethal total body IR in C3H mice. Additional research has shown protection in cells against hydrogen peroxide when treated with RSV. Therefore, clonogenic survival was measured in 1522 cells with RSV and RSV metabolites. Only the RSV derivative, piceatannol (PIC), showed protection against hydrogen peroxide mediated cytotoxicity; whereas, RSV enhanced hydrogen peroxide sensitivity at a 50 µM concentration; the remaining metabolites evaluated had little to no effect on survival. PIC also showed enhancement to peroxide exposure at a higher concentration (150 µM). A potential mechanism for RSV-induced sensitivity to peroxides could be its ability to block 1522 cells in the S-phase, which is most sensitive to hydrogen peroxide treatment. In addition, both RSV and PIC can be oxidized to phenoxyl radicals and quinones, which may exert cytotoxic effects. These cytotoxic effects were abolished when HBED, a metal chelator, was added. Taken together RSV and many of its metabolic derivatives are not effective as chemical radioprotectors and should not be considered for clinical use.

Topics: Animals; Antioxidants; Cell Cycle; Cell Survival; Dose-Response Relationship, Drug; Edetic Acid; Female; Fibroblasts; Humans; Hydrogen Peroxide; Mice; Mice, Inbred C3H; Oxidative Stress; Phenols; Quinones; Radiation-Protective Agents; Resveratrol; Stilbenes; tert-Butylhydroperoxide; Whole-Body Irradiation

For understanding of signaling molecules important in lung cancer growth and progression, IL-1beta effect was analyzed on iNOS expression and key signaling molecules in human lung carcinoma A549 cells and established the role of specific signaling molecules by using specific chemical inhibitors. IL-1beta exposure (10 ng/ml) induced strong iNOS expression in serum starved A549 cells. Detailed molecular analyses showed that IL-1beta increased expression of phosphorylated STAT1 (Tyr701 and Ser727) and STAT3 (Tyr705 and Ser727) both in total cell lysates and nuclear lysates. Further, IL-1beta exposure strongly activated MAPKs (ERK1/2, JNK1/2 and p38) and Akt as well as increased nuclear levels of NF-kappaB and HIF-1alpha in A549 cells. Use of specific chemical inhibitors for JAK1 kinase (piceatannol), JAK2 kinase (AG-490), MEK1/2 (PD98059) and JNK1/2 (SP600125) revealed that IL-1beta-induced iNOS expression involved signaling pathways in addition to JAK-STAT and ERK1/2-JNK1/2 activation. Overall, these results suggested that instead of specific pharmacological inhibitors, use of chemopreventive agents with broad spectrum efficacy to inhibit IL-1beta-induced signaling cascades and iNOS expression would be a better strategy towards lung cancer prevention and/or treatment.

Topics: Carcinoma; Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Humans; Janus Kinase 1; Lung Neoplasms; MAP Kinase Signaling System; Nitric Oxide Synthase Type II; Signal Transduction; STAT1 Transcription Factor; STAT3 Transcription Factor; Stilbenes

Estrogenic procarcinogenic effects of piceatannol (PIC) contrast reports about anticarcinogenic activities of PIC. To explain this contradiction, we investigated PIC in estrogen-dependent MCF-7 breast cancer cells and elucidated those cellular mechanisms that correlated with the observed cell effects induced by PIC. Low PIC concentrations (50 nM) induced c-Myc that depended on progesterone receptor (PR) and estrogen receptor (ER). PR-mediated c-Myc induction by PIC was independent of nuclear PR activity but depended on mitogen-activated protein kinase (MAPK) signaling and was associated with an acceleration of cancer cell proliferation. In contrast, 25 μM PIC inhibited deoxynucleotide triphosphate synthesis, activated Chk2 and p38-MAPK and this was accompanied by an attenuation of cancer cell growth. Apoptosis was most probably inhibited due to activation of Akt; however, high PIC concentrations (>100 μM) permitted apoptosis-like cell death in consequence to disruption of orchestrated mitotic signaling. The presented results show for the first time that nanomolar PIC concentrations signal through PR and Erk1/2 and provide a mechanistic explanation why moderate wine consumption-but not other alcoholic beverages-increases the breast cancer risk in women. In contrast, higher PIC concentrations in the micromolar range are considered for adjuvant anticancer therapeutic concepts.

Topics: Animals; Anticarcinogenic Agents; Apoptosis; Breast Neoplasms; Carcinogens; Cell Line, Tumor; CHO Cells; Cricetinae; Cricetulus; Dose-Response Relationship, Drug; Extracellular Signal-Regulated MAP Kinases; Female; Genes, myc; Humans; Receptors, Estrogen; Receptors, Progesterone; Stilbenes; Wine

Vav1 plays an important role in the all-trans retinoic acid (ATRA)-induced completion of the differentiation program of acute promyelocytic leukemia (APL)-derived cells, in which it strengthens the drug effects and is involved in the regulation of maturation-related proteins, such as the CD11b surface antigen. In both myeloid and lymphoid cells, accumulating data attribute to the multidomain protein Vav1 a functional relevance in the control of gene expression, by direct interaction with chromatin remodeling and/or transcriptional proteins. The present study provides evidence that, in the APL-derived NB4 cell line, Vav1 and the transcription factor PU.1 cooperate in regulating the ATRA-induced CD11b expression. Both chromatin immunoprecipitation (ChIP) experiments and electrophoretic mobility shift assays (EMSA) indicate that Vav1 and PU.1 are recruited to CD11b promoter. Even if the two proteins may participate in diverse protein/DNA complexes, the amounts of complexes including PU.1 seem to be dependent on the interaction of this transcription factor with tyrosine-phosphorylated Vav1. The reported data suggest that the ATRA-induced increase of Vav1 expression and tyrosine phosphorylation may be involved in recruiting PU.1 to its consensus sequence on the CD11b promoter and, ultimately, in regulating CD11b expression during the late stages of neutrophil differentiation of APL-derived promyelocytes.

Topics: CD11b Antigen; Cell Differentiation; Cell Line, Tumor; Cell Nucleus; Chromatin Immunoprecipitation; DNA; Electrophoretic Mobility Shift Assay; Gene Expression Regulation, Neoplastic; Granulocyte Precursor Cells; Humans; Intracellular Signaling Peptides and Proteins; Leukemia, Promyelocytic, Acute; Neutrophils; Phosphorylation; Promoter Regions, Genetic; Protein Binding; Protein Kinase Inhibitors; Protein-Tyrosine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-vav; RNA, Small Interfering; Stilbenes; Syk Kinase; Trans-Activators; Tretinoin

A simple and sensitive HPLC-UV method was developed and validated for the quantification of piceatannol analog trans-3,5,3',4'-tetramethoxystilbene (M-PIC) in rat plasma. Following protein precipitation with three volumes of acetonitrile, the analytes were separated on a RP-HPLC column, which was protected by a guard column through gradient delivery of a mixture of acetonitrile-water at 40 degrees C. The UV absorbance at 325nm was recorded to quantify M-PIC. The retention time of M-PIC and trans-3,5-dimethoxystilbene (internal standard) was 7.4 and 8.4min, respectively. The calibration curves were linear (R(2)>0.9989) with a lower limit of quantification of 15ng/ml. The intra- and inter-day precisions, in terms of RSD, were all lower than 7.5%. The average analytical recovery ranged from 97.0 to 104.3% while the average absolute recovery ranged from 101.8 to 105.0%. This reliable HPLC method was subsequently applied to assess the pharmacokinetic profile of M-PIC in Sprague-Dawley rats using 2-hydroxypropyl-beta-cyclodextrin as a dosing vehicle. The terminal elimination half-life (t(1/2lambdaz)) and clearance (Cl) of M-PIC were 313+/-20min and 33.1+/-3.9ml/min/kg, respectively; and its absolute oral bioavailability was as high as 50.7+/-15.0%. M-PIC appeared to have a favorable pharmacokinetic profile and further pharmacological investigation on this phyto-stilbene was warranted.

Topics: Animals; Chemistry, Pharmaceutical; Chromatography, High Pressure Liquid; Drug Evaluation, Preclinical; Male; Rats; Rats, Sprague-Dawley; Spectrophotometry, Ultraviolet; Stilbenes

Resveratrol (3,4',5-trihydroxystilbene) is a naturally occurring polyphenolic compound found in a variety of foods and over-the-counter health products. It has gained wide public use due to its potential health properties, and is available over-the-counter at health product stores. Although the safety profile of resveratrol has been minimally investigated in humans, resveratrol has been associated with observations of toxicity in vitro, and has been identified as a mechanism-based inhibitor of cytochrome P450 3A4. In addition, resveratrol has been rationally hypothesized to form reactive quinone methide metabolites, despite experimental evidence supporting this assumption. This work evaluates the potential for resveratrol to form glutathione-trapped reactive intermediates in human liver microsomes utilizing liquid chromatography and electrospray tandem mass spectrometry, and has resulted in the identification of several in vitro products including two hydroxylated metabolites (piceatannol and metabolite 2), and two pairs of regioisomeric glutathione adducts. The parallel metabolism of resveratrol to piceatannol and metabolite 2 (a putative quinone methide) are demonstrated to result in the formation of two putative quinone methide intermediates resulting in divergent mechanisms for formation of each pair of regioisomeric glutathione adducts.

Topics: Antioxidants; Catalase; Chromatography, High Pressure Liquid; Epoxide Hydrolases; Free Radical Scavengers; Glutathione; Humans; Indolequinones; Metabolic Networks and Pathways; Microsomes, Liver; Resveratrol; Spectrometry, Mass, Electrospray Ionization; Stilbenes; Superoxide Dismutase

Abnormal migration and proliferation of human aortic smooth muscle cells (HASMCs) to the intima causes intimal thickening of the aorta, which is strongly related to the development of atherosclerosis. Previous studies have suggested that red wine polyphenols, particularly resveratrol, have great protective effects against cardiovascular diseases. Here, we compared the anti-atherosclerotic effect of piceatannol, a metabolite of resveratrol, and its underlying mechanisms.. We demonstrated that piceatannol inhibited platelet-derived growth factor (PDGF)-BB-induced cell migration using a modified Boyden chamber assay and wound healing assay. Western blot analysis showed that PDGF-BB-induced phosphorylation of Akt, p70S6K, and p38 was inhibited by piceatannol, but not resveratrol. In vitro and ex vivo phosphoinositide 3-kinase (PI3K) assays demonstrated that piceatannol suppressed PI3K activity more effectively than resveratrol. PDGF-BB-induced migration and proliferation of HASMCs were inhibited by treatment with a commercial PI3K inhibitor, LY294002. Both in vitro and ex vivo pull-down assays revealed that piceatannol directly binds with sepharose 4B-PI3K beads in an ATP-competitive manner.. The results of the present study demonstrate that piceatannol directly binds with PI3K in an ATP-competitive manner and suppresses PI3K activity with anti-atherosclerotic effects.

Topics: Adenosine Triphosphate; Angiogenesis Inducing Agents; Aorta; Becaplermin; Binding, Competitive; Cell Division; Cell Movement; Cells, Cultured; Drug Interactions; Enzyme Inhibitors; Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating); Humans; Intracellular Signaling Peptides and Proteins; MAP Kinase Signaling System; Muscle, Smooth, Vascular; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Platelet-Derived Growth Factor; Protein-Tyrosine Kinases; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-sis; Resveratrol; Ribosomal Protein S6 Kinases, 70-kDa; Stilbenes; Syk Kinase

The anticancer dug arsenic trioxide (ATO) is known to be toxic for human mononuclear and neutrophil cell populations by a mechanism that needs to be further investigated. Due to the well-characterized role of Syk kinase in phagocytosis and because activation and involvement of Syk in response to ATO treatment has never been reported in any cells, we decided to determine whether or not Syk is involved in the mode of action of ATO. Human neutrophils were freshly isolated and incubated in vitro with ATO and the role of Syk was evaluated in different neutrophil functions. We found that ATO increased phosphorylation of Syk and this was reversed by piceatannol, a Syk-specific pharmacological inhibitor. In addition, ATO increased the phagocytic ability of neutrophils and degranulation via Syk activation. Finally, using both pharmacological inhibition and cellular depletion of Syk via an antisense approach, we found that this kinase is involved in apoptosis. We conclude that Syk activation is an important step in the mode of action of ATO in mature immune cells such as neutrophils and is involved in rapid, intermediate and lengthy biological processes. This is the first study to report that Syk is activated by ATO.

Topics: Antineoplastic Agents; Antisense Elements (Genetics); Apoptosis; Arsenic Trioxide; Arsenicals; Cell Adhesion; Cell Degranulation; Cell Separation; Enzyme Activation; Enzyme Inhibitors; Humans; In Vitro Techniques; Intracellular Signaling Peptides and Proteins; Membrane Proteins; Neutrophils; Oxides; Phagocytosis; Phosphorylation; Protein-Tyrosine Kinases; Spleen; Stilbenes; Syk Kinase

Macrophage proliferation can be stimulated by phagocytosis and by cross-linking of Fcgamma receptors (FcgammaR). In this study, we investigated the role of FcgammaR and the signaling cascades that link FcgammaR activation to cell cycle progression. This effect was mediated by the activating FcgammaR, including FcgammaRI and III, via their Fcgamma subunit. Further investigation revealed that the cell cycle machinery was activated by FcgammaR cross-linking through downstream signaling events. Specifically, we identified the extracellular signal-regulated kinase (ERK) signaling pathway as a mediator of signals from FcgammaR activation to cyclin D1 expression, because cyclin D1 expression associated with FcgammaR cross-linking was attenuated by specific inhibitors of the ERK1/2 signaling pathway, PD98059 and U0126 and the spleen tyrosine kinase (Syk) inhibitor, Piceatannol. Our findings establish a link between the ERK activation and cell cycle signaling pathways, thus providing a causal mechanism by which FcgammaR activation produces a mitogenic effect that stimulates macrophage proliferation. Macrophage mitosis following FcgammaR activation could potentially affect the outcome of macrophage interactions with intracellular pathogens. In addition, our results suggest the possibility of new treatment options for certain infectious diseases, chronic inflammatory diseases, and leukemias based on interference with FcgammaR-stimulated macrophage cell proliferation.

Topics: Animals; Blotting, Western; Bone Marrow Cells; Butadienes; Cell Cycle; Cell Line; Cell Proliferation; Cyclin D1; Enzyme Inhibitors; Extracellular Signal-Regulated MAP Kinases; Flavonoids; Flow Cytometry; Intracellular Signaling Peptides and Proteins; Macrophages; MAP Kinase Signaling System; Mice; Mice, Inbred C57BL; Mice, Knockout; Nitriles; Protein-Tyrosine Kinases; Receptors, IgG; Stilbenes; Syk Kinase

Erucylphosphohomocholine (ErPC3, Erufosine) was reported previously to induce apoptosis in otherwise highly apoptosis-resistant malignant glioma cell lines while sparing their non-tumorigenic counterparts. We also previously found that the mitochondrial 18 kDa Translocator Protein (TSPO) is required for apoptosis induction by ErPC3. These previous studies also suggested involvement of reactive oxygen species (ROS). In the present study we further investigated the potential involvement of ROS generation, the participation of the mitochondrial respiration chain, and the role of the mitochondrial F(O)F(1)-ATP(synth)ase in the pro-apoptotic effects of ErPC3 on U87MG and U118MG human glioblastoma cell lines. For this purpose, cells were treated with the ROS chelator butylated hydroxyanisole (BHA), the mitochondrial respiration chain inhibitors rotenone, antimycin A, myxothiazol, and the uncoupler CCCP. Also oligomycin and piceatannol were studied as inhibitors of the F(O) and F(1) subunits of the mitochondrial F(O)F(1)-ATP(synth)ase, respectively. BHA was able to attenuate apoptosis induction by ErPC3, including mitochondrial ROS generation as determined with cardiolipin oxidation, as well as collapse of the mitochondrial membrane potential (Deltapsi(m)). Similarly, we found that oligomycin attenuated apoptosis and collapse of the Deltapsi(m), normally induced by ErPC3, including the accompanying reductions in cellular ATP levels. Other inhibitors of the mitochondrial respiration chain, as well as piceatannol, did not show such effects. Consequently, our findings strongly point to a role for the F(O) subunit of the mitochondrial F(O)F(1)-ATP(synth)ase in ErPC3-induced apoptosis and dissipation of Deltapsi(m) as well as ROS generation by ErPC3 and TSPO.

Topics: Adenosine Triphosphate; Antineoplastic Agents; Apoptosis; Brain Neoplasms; Butylated Hydroxyanisole; Caspases; Cell Line, Tumor; Cyclosporine; Electron Transport; Enzyme Inhibitors; Erucic Acids; Glioblastoma; Humans; Membrane Potential, Mitochondrial; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Oligomycins; Phosphorylcholine; Proton-Translocating ATPases; Reactive Oxygen Species; Receptors, GABA; Stilbenes

trans-Resveratrol (3,5,4'-trihydroxystilbene) is a natural polyphenolic compound that exhibits antioxidant properties. Our study aimed at studying the HO*-induced oxidation of resveratrol (100 micromol.L(-1)) in aerated aqueous solutions. Gamma radiolysis of water was used to generate HO*/O(2)(*-) free radicals (I = 10 Gy.min(-1), dose = 400 Gy). Oxidation products were identified by direct infusion mass spectrometry and high-performance liquid chromatography/mass spectrometry. For each product, structural elucidation was based on simple mass spectra, fragmentation spectra and deuterium/hydrogen exchange spectra; the comparison with mass spectra of synthetic products provided valuable information allowing the complete identification of the oxidation products. Four products resulting from the direct attack of HO* radicals towards resveratrol were identified respectively as piceatannol (trans-3,5,3',4'-tetrahydroxystilbene), 3,5-dihydroxybenzoic acid, 3,5-dihydroxybenzaldehyde and 4-hydroxybenzaldehyde.

Topics: Benzaldehydes; Chromatography, Liquid; Gamma Rays; Hydroxybenzoates; Oxidation-Reduction; Resorcinols; Resveratrol; Spectrometry, Mass, Electrospray Ionization; Stilbenes; Water

Twelve phenolic compounds, including three stilbenes, two flavonoids, two coumarins, one neolignan, and four lignans, isolated from Euphorbia and Pycnanthus species or obtained by derivatization, were assayed for their potential antineoplastic efficacy in three human cancer cell lines: gastric (EPG85-257), pancreatic (EPP85-181), and colon (HT-29) carcinomas as well as derived multidrug-resistant sublines. In each case, two different multidrug-resistant variants, i.e., cell lines with classical and atypical MDR phenotype, were used. The majority of the MDR cancer sublines showed increased sensitivities to the studied compounds when compared to the parental sublines. The most active compound was the flavonoid naringenin, found to be 15-fold more effective against the atypical MDR subline of gastric carcinoma than in parental drug-sensitive cells. Furthermore, the stilbene trans-3,5,3',4'-tetramethoxypiceatannol and the lignans 4'-hydroxy-3,3',4-trimethoxylignan and heliobuphthalmin also exhibited high antineoplasic activities against the classical MDR subline derived from gastric carcinoma. The results of this study suggest that some phenolic compounds might be valuable for the treatment of multidrug-resistant cancer cells.

Topics: Antineoplastic Agents, Phytogenic; Cell Line, Tumor; Colonic Neoplasms; Drug Resistance, Multiple; Euphorbia; Flavanones; Humans; Lignans; Magnoliopsida; Myristicaceae; Neoplasms; Pancreatic Neoplasms; Phenols; Phytotherapy; Plant Extracts; Stilbenes; Stomach Neoplasms

The signal transduction protein SmTK4 from Schistosoma mansoni belongs to the family of Syk kinases. In vertebrates, Syk kinases are known to play specialized roles in signaling pathways in cells of the hematopoietic system. Although Syk kinases were identified in some invertebrates, their role in this group of animals has not yet been elucidated. Since SmTK4 is the first Syk kinase from a parasitic helminth, shown to be predominantly expressed in the testes and ovary of adult worms, we investigated its function. To unravel signaling cascades in which SmTK4 is involved, yeast two-/three-hybrid library screenings were performed with either the tandem SH2-domain, or with the linker region including the tyrosine kinase domain of SmTK4. Besides the Src kinase SmTK3 we identified a new Src kinase (SmTK6) acting upstream of SmTK4 and a MAPK-activating protein, as well as mapmodulin acting downstream. Their identities and colocalization studies pointed to a role of SmTK4 in a signaling cascade regulating the proliferation and/or differentiation of cells in the gonads of schistosomes. To confirm this decisive role we performed biochemical and molecular approaches to knock down SmTK4 combined with a novel protocol for confocal laser scanning microscopy for morphological analyses. Using the Syk kinase-specific inhibitor Piceatannol or by RNAi treatment of adult schistosomes in vitro, corresponding phenotypes were detected in the testes and ovary. In the Xenopus oocyte system it was finally confirmed that Piceatannol suppressed the activity of the catalytic kinase domain of SmTK4. Our findings demonstrate a pivotal role of SmTK4 in gametogenesis, a new function for Syk kinases in eukaryotes.

Topics: Animals; Enzyme Inhibitors; Gene Knockdown Techniques; Immunoprecipitation; In Situ Hybridization; Intracellular Signaling Peptides and Proteins; Microscopy, Confocal; Oogenesis; Protein-Tyrosine Kinases; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; Schistosoma mansoni; Signal Transduction; Spermatogenesis; Stilbenes; Syk Kinase; Transfection; Two-Hybrid System Techniques; Xenopus

Arginase competitively inhibits nitric oxide synthase (NOS) via use of the common substrate L-arginine. Arginase II has recently reported as a novel therapeutic target for the treatment of cardiovascular diseases such as atherosclerosis. Here, we demonstrate that piceatannol-3'-O-beta-D-glucopyranoside (PG), a potent component of stilbenes, inhibits the activity of arginase I and II prepared from mouse liver and kidney lysates, respectively, in a dose-dependent manner. In human umbilical vein endothelial cells, incubation of PG markedly blocked arginase activity and increased NOx production, as measured by Griess assay. The PG effect was associated with increase of eNOS dimer ratio, although the protein levels of arginase II or eNOS were not changed. Furthermore, isolated mice aortic rings treated with PG showed inhibited arginase activity that resulted in increased nitric oxide (NO) production upto 78%, as measured using 4-amino-5-methylamino-2',7'-difluorescein (DAF-FM) and a decreased superoxide anions up to 63%, as measured using dihydroethidine (DHE) in the intact endothelium. PG showed IC((50)) value of 11.22 microM and 11.06 microM against arginase I and II, respectively. PG as an arginase inhibitor, therefore, represents a novel molecule for the therapy of cardiovascular diseases derived from endothelial dysfunction and may be used for the design of pharmaceutical compounds.

Topics: Animals; Aorta; Arginase; Dose-Response Relationship, Drug; Endothelial Cells; Enzyme Activation; Glucosides; Humans; Mice; Mice, Inbred C57BL; Nitrates; Nitric Oxide; Nitric Oxide Synthase Type III; Nitrites; Reactive Oxygen Species; Rheum; Stilbenes

Piceatannol (3,4,3',5'-tetrahydroxy-trans-stilbene), derived from the seeds of Euphorbia lagascae, has been reported to have anti-proliferative, anti-inflammatory, and antioxidant properties. However, the mechanisms underlying its chemoprotective effects remain largely unresolved. In the present study, we found that piceatannol treatment (30 microM) significantly upregulated the expression of the antioxidant enzyme heme oxygenase-1 (HO-1) and its mRNA transcript at 6h and 3h, respectively in human breast epithelial (MCF10A) cells. A redox-sensitive transcription factor NF-E2-related factor (Nrf2) plays a pivotal role in induced expression of many cytoprotective enzymes including HO-1. Piceatannol induced translocation of Nrf2 into the nucleus and its transcriptional activities when treated to the MCF10A cells for 6h. Upregulation of HO-1 expression by piceatannol through direct binding of Nrf2 to antioxidant response element (ARE) was verified by the chromatin immunoprecipitation (ChIP) assay. siRNA knock down of Nrf2 gene abolished piceatannol-induced HO-1 expression. In addition, piceatannol-induced activation of Nrf2 and/or HO-1 expression was abrogated by the pharmacological inhibitor (LY294002) as well as the kinase-dead form of Akt. In an attempt to elucidate the molecular mechanisms underlying cytoprotective or chemoprotective activity exerted by piceatannol, we examined its effect on the signaling pathways responsible for induction of HO-1 expression. We hypothesize that an electrophilic quinone formed as a consequence of oxidation of piceatannol bearing the catechol moiety may bind directly to Kelch-like ECH-associated protein 1 (Keap1), an inhibitory protein that sequesters Nrf2 in the cytoplasm. This will diminish the affinity of Keap1 for Nrf2. The thiol reducing agents, dithiothreitol (100 microM) or beta-mercaptoethanol (1.4 microM), attenuated piceatannol-induced Nrf2 activation and HO-1 expression. It is hence likely that piceatannol modifies specific cysteine residues of Keap1, which allows Nrf2 to translocate into the nucleus and bind to ARE, leading to enhancement of the expression of HO-1. The characteristic catechol moiety of piceatannol appears to be critical for induction of Nrf2 activation and subsequent upregulation of HO-1.

Topics: Active Transport, Cell Nucleus; Anticarcinogenic Agents; Antioxidants; Base Sequence; Breast; Cell Line; Chromones; Cysteine; Epithelial Cells; Euphorbia; Female; Heme Oxygenase-1; Humans; Intracellular Signaling Peptides and Proteins; Kelch-Like ECH-Associated Protein 1; Morpholines; NF-E2-Related Factor 2; Proto-Oncogene Proteins c-akt; RNA, Small Interfering; Signal Transduction; Stilbenes; Up-Regulation

To verify whether piceatannol-induced death of leukemia cells was associated with Fas-mediated death pathway, the present study was conducted. Piceatannol-induced apoptotic death of human leukemia U937 cells was characterized by increase in intracellular Ca(2+) concentration ([Ca(2+)]i), ERK inactivation, p38 MPAK activation, degradation of procaspase-8 and production of t-Bid. Piceatannol treatment increased Fas and FasL protein expression, and up-regulated transcription of Fas and FasL mRNA. Down-regulation of FADD blocked piceatannol-induced procaspase-8 degradation and rescued viability of piceatannol-treated cells. Abolition of piceatannol-induced increase in [Ca(2+)]i abrogated p38 MAPK activation and up-regulation of Fas and FasL expression, but restored ERK activation and viability of piceatannol-treated cells. Suppression of p38alpha MAPK or transfection of constitutively active MEK1 abolished piceatannol-induced Fas and FasL up-regulation. Piceatannol treatment repressed ERK-mediated c-Fos phosphorylation but evoked p38alpha MAPK-mediated c-Jun and ATF-2 phosphorylation. Knockdown of c-Fos, c-Jun and ATF-2 by siRNA reflected that c-Fos attenuated the effect of c-Jun and ATF-2 on Fas/FasL up-regulation. Taken together, our data indicate that Fas/FasL up-regulation in piceatannol-treated U937 cells is elicited by Ca(2+)/p38alpha MAPK-mediated activation of c-Jun and ATF-2, and suggest that autocrine Fas-mediated apoptotic mechanism is involved in piceatannol-induced cell death.

Topics: Activating Transcription Factor 2; Calcium; Cells, Cultured; Enzyme Activators; Fas Ligand Protein; fas Receptor; Gene Expression Regulation; Humans; Proto-Oncogene Proteins c-jun; RNA Interference; Signal Transduction; Stilbenes; U937 Cells; Up-Regulation

There are multiple lines of evidence supporting that chronic inflammation is linked to carcinogenesis. Nuclear factor-kappaB (NF-kappaB), a major redox-sensitive transcription factor responsible for the induction of a wide array of pro-inflammatory genes, is frequently overactivated in many tumors. Moreover, constitutive activation of IkappaB kinase (IKK), a key regulator of NF-kappaB signaling, has been implicated in inflammation-associated tumorigenesis. Piceatannol (trans-3,4,3',5'-tetrahydroxystilbene; PIC) derived from grapes, rhubarb and sugarcane exhibits immunosuppressive and antitumorigenic activities in several cell lines, but the underlying mechanisms are poorly understood. In the present study, we found that PIC inhibited migration and anchorage-independent growth of human mammary epithelial cells (MCF-10A) treated with the prototypic tumor promoter, 12-O-tetradecanoylphorbol-13-aceate (TPA). PIC treatment suppressed the TPA-induced activation of NF-kappaB and expression of cyclooxygenase-2 (COX-2) in MCF-10A cells. We speculate that an electrophilic quinone formed as a consequence of oxidation of PIC bearing the catechol moiety may directly interact with critical cysteine thiols of IKKbeta, thereby inhibiting its catalytic activity. In support of this speculation, the reducing agent dithiothreitol abrogated the inhibitory effects of PIC on TPA-induced activation of NF-kappaB signaling and expression of COX-2. In addition, the inhibitory effects of PIC on NF-kappaB activation and COX-2 induction were blunted in cells expressing mutant IKKbeta (C179A) in which cysteine 179 was replaced by alanine. In conclusion, our results show that direct modification of IKKbeta by PIC, presumably at the cysteine 179 residue, blocks NF-kappaB activation signaling and COX-2 induction in TPA-treated MCF-10A cells and also migration and transformation of these cells.

Topics: Anticarcinogenic Agents; Blotting, Western; Breast; Breast Neoplasms; Cell Culture Techniques; Cell Division; Cell Line, Tumor; Cyclooxygenase 2; Cysteine; Epithelial Cells; Female; Flavonoids; Gene Expression Regulation, Enzymologic; Humans; I-kappa B Kinase; NF-kappa B; Phenols; Phorbol Esters; Polyphenols; Resveratrol; Stilbenes; Wound Healing

Phytoalexins t-resveratrol and t-piceatannol, the well-known health-promoting active components in plants, are secondary metabolites generated upon biotic or abiotic stresses. We have reported UV-irradiated peanut callus is a potent means to produce these compounds (J. Agric. Food Chem. 2005, 53, 3877). In this work, the effects of fungi and chemical elicitors on induction of t-resveratrol and t-piceatannol were examined. Results showed the investigated fungi Botryodiplodia theobromae and Reishi Ganoderma lucidum were generally more effective than chemical stress methyl jasmonate, salicylic acid, and sucrose. As high as 15.46+/-9.85 microg of t-resveratrol and 6.93+/-2.03 microg of t-piceatannol could be elicited in each gram of callus by sterilized G. lucidum mycelium (80 mg). Although much more sterilized G. ludicum mycelia was required to induce similar level of t-resveratrol and t-piceatannol in comparison to the sterilized B. theobromae mycelia (1 mg), uptake of the G. ludicum mycelium may provide a variety of health-promoting effects. Our findings suggest G. ludicum mycelium-treated peanut callus is a good source of bioactive components.

Topics: Arachis; Chromatography, High Pressure Liquid; Reishi; Resveratrol; Stilbenes

It is well-known that the invasion of microbes such as fungi in some plants, including peanut, can induce the biosynthesis of stilbenoids such as trans-resveratrol and trans-piceatannol. However, in a recent study it was found that not all kinds of microorganisms possessed such potential. The Gram-negative bacterium Pseudochrobactrum asaccharolyticum isolated from the peanut callus failed to act as an elicitor. After systematic investigation, the different inductive effects between fungi and Gram-negative bacteria were attributed to the chitin content of the cell wall. Results showed significantly more trans-resveratrol and trans-piceatannol was induced by fungi (8.92-16.35 and 2.15-7.01 microg/g of fresh calluses, respectively) than by bacteria (1.77-2.72 and 0.16-0.52 microg/g of fresh calluses, respectively), regardless of species and viability. Such great differences prompted the direct utilization of chitin, the distinctive component of fungal cell wall, as an elicitor. The results that trans-resveratrol induced by chitin was about two-thirds the amount induced by sterilized fungi, whereas trans-piceatannol (2.55+/-0.60 microg/g) was close to that by sterilized fungi, revealed chitin is not only an important fungal constituent responsible for the induction of trans-resveratrol and trans-piceatannol but also an efficient elicitor by itself. These findings suggested sterilized fungi and chitin can be used as a safe and fast elicitor, as far as the risk of viable microbes is concerned, to induce trans-resveratrol and trans-piceatannol in the well-controlled peanut tissue culture.

Topics: Anti-Infective Agents; Arachis; Chitin; Microbial Sensitivity Tests; Resveratrol; Stilbenes

P-selectin glycoprotein ligand-1 (PSGL-1) not only functions as an anchor molecule to capture monocytes and other leukocytes to endothelial cells in ischemic tissue by its interaction with P-selectin, but also transduces signals to initiate firm adhesion. Endothelial progenitor cells are derived from monocytes and play a very important role in neovascularization. Transplantation of endothelial progenitor cells is a promising therapeutic strategy to improve treatment of ischemic disease such as myocardial and cerebral infarction; however, its efficacy is now limited by the fact that few of the transplanted cells adhere to and accumulate in the ischemic tissue. In this study we aimed to investigate whether the overexpression of PSGL-1 gene promotes endothelial progenitor cells adhesion activity and explore the underlying mechanisms. We found that after transfection with human PSGL-1 gene, endothelial progenitor cells exhibited higher affinity to activated human umbilical vein endothelial cells or recombined P-selectin/ICAM-1 monolayer. The overexpression of PSGL-1-enhanced beta2-integrin expression on endothelial progenitor cells surface, and this effect was Syk dependent. The specific Syk inhibitor abolished the elevating effect of overexpression of PSGL-1 on surface beta2-integrin expression and the adhesive affinity of endothelial progenitor cells. These results suggested that Syk plays a key role in signal transduction downstream of PSGL-1 in endothelial progenitor cells, and the overexpression of PSGL-1 improves endothelial progenitor cells adhesive properties through enhanced activation of Syk and following integrin activation.

Topics: Animals; Antibodies; Blotting, Western; Cell Adhesion; Cell Line; Cells, Cultured; Endothelial Cells; Enzyme Activation; Integrins; Intercellular Adhesion Molecule-1; Intracellular Signaling Peptides and Proteins; Male; Membrane Glycoproteins; P-Selectin; Phosphorylation; Protein-Tyrosine Kinases; Rats; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction; Stem Cells; Stilbenes; Syk Kinase; Transfection

Piceatannol, a dietary polyphenol present in grapes and wine, is known for its promising anticancer and anti-inflammatory activity. The aim of this study was to analyse the concentration-dependent glucuronidation of piceatannol in vitro.. To determine the glucuronidation of piceatannol, experiments were conducted with human liver microsomes as well as using a panel of 12 recombinant UDP-glucuronosyltransferase isoforms. Furthermore, the chemical structures of novel glucuronides were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS).. Along with piceatannol it was possible to identify three metabolites whose structures were identified by LC-MS/MS as piceatannol monoglucuronides (M1-M3). Formation of M1 and M3 exhibited a pattern of substrate inhibition, with apparent K(i) and V(max)/K(m) values of 103 +/- 26.6 microm and 3.8 +/- 1.3 microl/mg protein per min, respectively, for M1 and 233 +/- 61.4 microm and 19.8 +/- 9.5 microl/mg protein per min, respectively, for M3. In contrast, formation of metabolite M2 followed classical Michaelis-Menten kinetics, with a K(m) of 18.9 +/- 8.1 microm and a V(max) of 0.21 +/- 0.02 nmol/mg protein per min. Incubation in the presence of human recombinant UDP-glucuronosyltransferases (UGTs) demonstrated that M1 was formed nearly equally by UGT1A1 and UGT1A8. M2 was preferentially catalysed by UGT1A10 and to a lesser extent by UGT1A1 and UGT1A8. The formation of M3, however, was mainly catalysed by UGT1A1 and UGT1A8.. Our results elucidate the importance of piceatannol glucuronidation in the human liver, which must be taken into account in humans after dietary intake of piceatannol.

Topics: Aged; Chromatography, Liquid; Female; Glucuronides; Glucuronosyltransferase; Humans; Isoenzymes; Male; Microsomes, Liver; Middle Aged; Stilbenes; Tandem Mass Spectrometry

The effect of passion fruit, the fruit of Passiflora edulis , on melanin inhibition and collagen synthesis was studied using cultured human melanoma and fibroblast cells. Passion fruit was divided into three parts, rind (PF-R), pulp (PF-P), and seed (PF-S), and each part was extracted using 80% ethanol. The concentration of polyphenols was higher in PF-S than in PF-R or PF-P. Treatment of melanoma cells with PF-S led to inhibition of melanogenesis. In addition, the production of total soluble collagen was elevated in dermal fibroblast cells cultured in the presence of PF-S. PF-R and PF-P did not yield these effects. Furthermore, the removal of polyphenols from PF-S led to the abolishment of the effects described above. We discovered that piceatannol (3,4,3',5'-tetrahydroxy-trans-stilbene) is present in passion fruit seeds in large amounts and that this compound is the major component responsible for the PF-S effects observed on melanogenesis and collagen synthesis.

Topics: Cell Line, Tumor; Collagen; Fruit; Humans; Melanins; Passiflora; Plant Extracts; Seeds; Stilbenes

Resveratrol and kaempferol are natural chemopreventative agents that are also aryl hydrocarbon receptor (AHR) antagonists and estrogen receptor (ER) agonists. In this study we evaluated the role of ERα in resveratrol- and kaempferol-mediated inhibition of AHR-dependent transcription. Kaempferol or resveratrol inhibited dioxin-induced cytochrome P450 1A1 (CYP1A1) and CYP1B1 expression levels and recruitment of AHR, ERα and co-activators to CYP1A1 and CYP1B1. Both phytochemicals induced the expression and recruitment of ERα to gene amplified in breast cancer 1 (GREB1). RNAi-mediated knockdown of ERα in T-47D cells did not affect the inhibitory action of either phytochemical on AHR activity. Both compounds also inhibited AHR-dependent transcription in ERα-negative MDA-MB-231 and BT-549 breast cancer cells. These data show that ERα does not contribute to the AHR-inhibitory activities of resveratrol and kaempferol.

Topics: Antineoplastic Agents, Phytogenic; Aryl Hydrocarbon Hydroxylases; Aryl Hydrocarbon Receptor Nuclear Translocator; Blotting, Western; Breast Neoplasms; Cell Line, Tumor; Cytochrome P-450 CYP1A1; Cytochrome P-450 CYP1B1; Dose-Response Relationship, Drug; Estradiol; Estrogen Receptor alpha; Fulvestrant; Gene Expression Regulation, Neoplastic; Humans; Kaempferols; Polychlorinated Dibenzodioxins; Receptors, Aryl Hydrocarbon; Resveratrol; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; RNA, Messenger; Stilbenes; Teratogens; Transcription, Genetic

The δ subunit of mitochondrial ATP synthase serves as a linker between the F(0) and F(1) sectors. Here, through microarray and quantitative RT-PCR, we found that the δ1 subunit was significantly up-regulated during cotton fibre cell elongation. Both the relative level and duration of GhATPδ1 transcripts correlated positively with the final length of different cotton germplasms. Elongating fibre cells had a significantly elevated ATP/ADP ratio, suggesting that a higher energy input is probably required for primary fibre cell wall formation and elongation. We obtained a putative full-length GhATPδ1 cDNA that shows 37% sequence identity to the Saccharomyces cerevisiae ATP16 at the deduced amino acid level. An almost wild-type growth rate was restored in atp16Δ cells that expressed GhATPδ1, with a resultant ATP/ADP ratio similar to that found in wild-type cells, indicating that the cotton gene was functional in yeast. Mitochondria prepared from 10 dpa wild-type fibre cells showed significantly higher ATP synthase activity in comparison to ovule samples from wild type and leaf samples. Exogenous application of piceatannol (PA) or oligomycin (OM), inhibitors of ATP synthase F(1) or F(0) subunits, respectively, in ovule culture media resulted in much shorter fibre cells and a significantly lower ATP/ADP ratio. Our data suggest that GhATPδ1 is important for activity of mitochondrial ATP synthase and is probably related to cotton fibre elongation.

Topics: Adenosine Diphosphate; Adenosine Triphosphate; Cell Enlargement; Cotton Fiber; Gene Expression Profiling; Gene Expression Regulation, Plant; Genetic Complementation Test; Gossypium; Mitochondria; Mitochondrial Proton-Translocating ATPases; Oligomycins; Oligonucleotide Array Sequence Analysis; Ovule; Plant Proteins; Saccharomyces cerevisiae; Stilbenes; Tissue Culture Techniques

The practical synthesis of important natural polyphenolic stilbenes, including resveratrol, piceatannol and oxyresveratrol, through Perkin methodology is described. Starting from 3,5-dihydoxyacetophenone (1), the common intermediate 3,5-dimethoxyphenylacetic acid (3) can be obtained via methylation and Willgerodt-Kindler reaction. Perkin condensations between (3) and substituted phenylaldehydes 4 furnished E-2,3-diarylacrylic acids 5, followed by decarboxylation in Cu/quinoline giving stilbene intermediates 6 which bear the Z-configuration. Finally, through a simultaneous demethylation/isomerization process in AlI₃/CH₃CN system, the target compounds 7a-c can be obtained respectively in good to high overall yields. The synthetic method proved to be more concise, trans-specific, mild, economical and commonly applicable.

Topics: Antineoplastic Agents, Phytogenic; Antioxidants; Fallopia japonica; Flavonoids; Molecular Structure; Moraceae; Phenols; Plant Extracts; Plants; Polyphenols; Protein-Tyrosine Kinases; Resveratrol; Stilbenes

To investigate the role of spleen tyrosine kinase (Syk) in rat pulmonary vascular smooth muscle cells (PVSMCs) proliferation induced by platelet-derived growth factor-BB (PDGF-BB).. PVSMCs from male Sprague-Dawley rats were cultured in vitro and the cells of passages 3-5 were used in the experiment. PVSMCs were stimulated by PDGF-BB and were treated with three different doses of piceatannol, a Syk selective inhibitor. Cell proliferation was assessed by methyl thiazolyl tetrazolium (MTT) assay. DNA synthesis was measured by ³H-thymidine incorporation (³H-TdR). Cellular cycle was observed by flow cytometry. Syk mRNA and protein expression were detected using real-time quantitative PCR and Western blot, respectively.. The expression of Syk protein of PVSMCs was significantly up-regulated following PDGF-BB stimulation. PDGF-BB stimulation dramatically increased PVSMCs proliferation. After piceatannol treatment, both Syk mRNA and protein expression decreased and the proliferation of PVSMCs was inhibited in a dose-dependent manner.. Syk may promote PVSMCs proliferation induced by PDGF-BB.

Topics: Animals; Becaplermin; Cell Proliferation; Cells, Cultured; Hypertension, Pulmonary; Intracellular Signaling Peptides and Proteins; Male; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Platelet-Derived Growth Factor; Protein-Tyrosine Kinases; Proto-Oncogene Proteins c-sis; Pulmonary Artery; Rats; Rats, Sprague-Dawley; Stilbenes; Syk Kinase

Nuclear factor (NF)-kappaB activation is a critical step in the triggering of inflammatory responses by macrophages. Although numerous investigations have been reported, the precise regulatory mechanisms controlling inflammatory responses mediated by NF-kappaB remain unclear. In this study, we investigated the early signaling events responsible for modulating NF-kappaB activation using various parameters, such as the expression of pro-inflammatory genes and the phosphorylation levels of inhibitor of kappaB alpha (IkappaB alpha) and its upstream kinases. Lipopolysaccharide (LPS) treatment biphasically induced activation of IkappaB alpha phosphorylation at 5 and 30 min, which induced subsequent pro-inflammatory gene expression that was maximized at 45 and 90 min. Of the intracellular signals tested, a series of signaling cascades composed of spleen tyrosine kinase (Syk), phosphoinositide-3-kinase (PI3K), and Akt (protein kinase B) were involved in regulating early phosphorylation of IkappaB alpha, according to biochemical and pharmacological analyses. Therefore, our data suggests that Syk-mediated activation of intracellular signaling in response to LPS may play an important role in LPS-induced inflammatory signaling events. Thus, Syk may be a potential target for the development of potent anti-inflammatory drugs.

Topics: Animals; CSK Tyrosine-Protein Kinase; Enzyme Activation; Gene Expression Regulation, Enzymologic; I-kappa B Proteins; Intracellular Signaling Peptides and Proteins; Lipopolysaccharides; Macrophages, Peritoneal; Male; Mice; Mice, Inbred C57BL; Mice, Inbred ICR; NF-kappa B; NF-KappaB Inhibitor alpha; Phosphatidylinositol 3-Kinases; Phosphorylation; Protein-Tyrosine Kinases; Proto-Oncogene Proteins c-akt; RNA, Small Interfering; Signal Transduction; src-Family Kinases; Stilbenes; Syk Kinase; Transfection

The aim of this study was to investigate the concentration-dependent sulfation of piceatannol, a dietary polyphenol present in grapes and wine and known for its promising anticancer and anti-inflammatory activity.. Sulfation of piceatannol was investigated in human liver cytosol as well as using a panel of recombinant sulfotransferase isoforms. Furthermore, the chemical structures of novel sulfates were identified by liquid chromatography/mass spectrometry (LC/MS).. In the presence of 3'-phosphoadenosine-5'-phosphosulfate, three metabolites could be detected whose structures were identified by LC/MS/MS as piceatannol disulfate (M1) and two monosulfates (M2, M3). The kinetics of M1 formation exhibited a pattern of substrate inhibition with a Ki of 21.8 +/- 11.3 microm and a Vmax/Km of 7.63 +/- 1.80 microl/mg protein per min. Formation of M2 and M3 showed sigmoidal kinetics with apparent Km and Vmax values of 27.1 +/- 2.90 microm and 118.4 +/- 4.38 pmol/mg protein per min, respectively, for M2; and 35.7 +/- 2.70 microm and 81.8 +/- 2.77 pmol/mg protein per min, respectively, for M3. Incubation in the presence of human recombinant sulfotransferases (SULTs) demonstrated that M1 was formed equally by SULT1A1*1 and SULT1B1 and to a lesser extent by SULT1A1*2. M2 was preferentially catalysed by SULT1A1*2, 1A3 and 1E1. The formation of M3, however, was mainly catalysed by SULT1A2*1 and SULT1A3.. Our results elucidate the importance of piceatannol sulfation in human liver, which must be taken into account in humans after dietary intake of piceatannol.

Topics: Administration, Oral; Arylsulfotransferase; Chromatography, High Pressure Liquid; Cytosol; Dietary Supplements; Dose-Response Relationship, Drug; Flavonoids; Hepatocytes; Humans; Kinetics; Mass Spectrometry; Molecular Structure; Phenols; Phosphoadenosine Phosphosulfate; Polyphenols; Recombinant Proteins; Stilbenes; Sulfates; Sulfotransferases

House dust mite (HDM) induces allergic asthma in sensitized individuals, although the mechanisms by which HDM is sensed and recognized by the airway mucosa, leading to dendritic cell (DC) recruitment, activation, and subsequent T(H)2-mediated responses, are unknown.. We sought to define the pathways by which HDM activates respiratory epithelium to induce allergic airway responses.. Using a human airway epithelial cell line (16HBE14o-), we studied secretion of the DC chemokine CCL20 after exposure to HDM or other allergens, investigated components of the HDM responsible for the induction of chemokine release, and examined activation of signaling pathways. Central findings were also confirmed in primary human bronchial cells.. We demonstrate that exposure of airway epithelium to HDM results in specific and rapid secretion of CCL20, a chemokine attractant for immature DCs. The induction of CCL20 secretion is dose and time dependent and quite specific to HDM because other allergens, such as ragweed pollen and cockroach antigen, fail to significantly induce CCL20 secretion. Induction of CCL20 secretion is not protease or Toll-like receptor 2/4 dependent but, interestingly, relies on beta-glucan moieties within the HDM extract, as evidenced by the ability of other beta-glucans to competitively inhibit its secretion and by the fact that disruption of these structures by treatment of HDM with beta-glucanase significantly reduces subsequent chemokine secretion.. Taken together, our results describe a novel mechanism for specific pattern recognition of HDM-derived beta-glucan moieties, which initiates allergic airway inflammation and, through recruitment of DCs, might link innate pattern recognition at the airway surface with adaptive immune responses.

Topics: Adult; Allergens; Animals; Antigens, Dermatophagoides; Arthropod Proteins; beta-Glucans; Cell Line; Cells, Cultured; Chemokine CCL20; Cysteine Endopeptidases; Dendritic Cells; Humans; Immunity, Innate; Intracellular Signaling Peptides and Proteins; Peptide Hydrolases; Protein-Tyrosine Kinases; Pyroglyphidae; Respiratory Mucosa; Stilbenes; Syk Kinase; Toll-Like Receptors

Activated phospholipase C1, produced in response to tyrosine phosphorylation, appears to play an important role during uterine contractions. These studies sought to determine which non-receptor protein tyrosine kinases are involved in the activation of phospholipase C1 in rat uterine tissue. In vitro contraction studies were performed utilizing isoform specific protein tyrosine kinase inhibitors. Western blots were performed utilizing antibodies to phosphotyrosine-phospholipase C1, total phospholipase C1, c-Src kinase and Lck kinase. Spontaneous, stretch-stimulated, and bpV(phen) (tyrosine phosphatase inhibitor) enhanced uterine contractions were significantly suppressed in response to Damnacanthal (Lck kinase inhibitor) and PP1 (c-Src kinase inhibitor). Damnacanthal and PP1 also significantly suppressed bpV(phen)-enhanced tyrosine phosphorylation of phospholipase C1. Western blots confirmed expression of Lck kinase and c-Src kinase in uterine tissue. In conclusion, the Lck and c-Src kinases appear to play an important role in regulating tyrosine phosphorylation of phospholipase C1 and contractile activity in the rat uterus.

Topics: Animals; Anthraquinones; Blotting, Western; Female; In Vitro Techniques; Indoles; Lymphocyte Specific Protein Tyrosine Kinase p56(lck); Organometallic Compounds; Phenanthrolines; Phospholipase C gamma; Phosphorylation; Phosphotyrosine; Protein Kinase Inhibitors; Protein Tyrosine Phosphatases; Proto-Oncogene Proteins pp60(c-src); Pyrazoles; Pyrimidines; Rats; Rats, Sprague-Dawley; Stilbenes; Sulfonamides; Time Factors; Uterine Contraction; Uterus

In recent studies, the wild-type and mutant forms of cytochrome P450 (P450) BM3 (CYP102A1) from Bacillus megaterium were found to metabolize various drugs through reactions similar to those catalyzed by human P450 enzymes. Therefore, it was suggested that CYP102A1 can be used to produce large quantities of the metabolites of human P450-catalyzed reactions. trans-Resveratrol (3,4',5-trihydroxystilbene), an anticancer-preventive agent, is oxidized by human P450 1A2 to produce two major metabolites, piceatannol (3,5,3',4'-tetrahydroxystilbene) and another hydroxylated product. In this report, we show that the oxidation of trans-resveratrol, a human P450 1A2 substrate, is catalyzed by wild-type and a set of CYP102A1 mutants. One major hydroxylated product, piceatannol, was produced as a result of the hydroxylation reaction. Other hydroxylated products were not produced. Piceatannol formation was confirmed by high-performance liquid chromatography and gas chromatograph-mass spectrometry by comparing the metabolite with the authentic piceatannol compound. These results demonstrate that CYP102A1 mutants can be used to produce piceatannol, a human metabolite of resveratrol.

Topics: Anticarcinogenic Agents; Bacterial Proteins; Carbon Monoxide; Cytochrome P-450 Enzyme System; Gas Chromatography-Mass Spectrometry; Humans; Hydroxylation; Kinetics; Mutagenesis, Site-Directed; Mutation; NADPH-Ferrihemoprotein Reductase; Oxidation-Reduction; Resveratrol; Stilbenes

Piceatannol is a naturally occurring bioactive stilbene with documented antileukemic properties. It has been extensively used as a Syk-selective protein tyrosine kinase inhibitor for the study of various signaling pathways. Herein, we show that the hydroxystilbene, piceatannol, and related catechol ring-containing compounds are able to induce the loss of the Cbl family of proteins. Normal cellular Cbl-regulatory mechanisms were not involved in this process. Screening of a small library of piceatannol-like compounds indicated that aromaticity and a catechol ring were required for the induction of Cbl loss. Further examination of these two chemical properties showed that the oxidative conversion of the catechol ring of piceatannol into a highly reactive O-benzoquinone was the cause of piceatannol-induced Cbl loss. Characterization of the Cbl selectivity of piceatannol-induced protein loss revealed that this compound was also able to induce the functional loss of specific Cbl-associated proteins involved in signaling pathways commonly associated with cancer. This work uncovers a new, piceatannol-dependent effect and shows a novel way in which this phenomenon can be exploited to inhibit disease-associated signaling pathways.

Topics: 3T3 Cells; Adaptor Proteins, Signal Transducing; Animals; Antineoplastic Agents, Phytogenic; Cells, Cultured; Humans; K562 Cells; Mice; Models, Biological; Neoplasms; Oxidation-Reduction; Protein Binding; Protein Processing, Post-Translational; Proto-Oncogene Proteins c-cbl; Signal Transduction; Stilbenes

Piceatannol is more potent than resveratrol in free radical scavenging in association with antiarrhythmic and cardioprotective activities in ischaemic-reperfused rat hearts. The present study aimed to investigate the antiarrhythmic efficacy and the underlying ionic mechanisms of piceatannol in rat hearts.. Action potentials and membrane currents were recorded by the whole-cell patch clamp techniques. Fluo-3 fluorimetry was used to measure cellular Ca2+ transients. Antiarrhythmic activity was examined from isolated Langendorff-perfused rat hearts.. In rat ventricular cells, piceatannol (3-30 micromol.L(-1)) prolonged the action potential durations (APDs) and decreased the maximal rate of upstroke (V(max)) without altering Ca2+ transients. Piceatannol decreased peak I(Na) and slowed I(Na) inactivation, rather than induced a persistent non-inactivating current, which could be reverted by lidocaine. Resveratrol (100 micromol.L(-1)) decreased peak I(Na) without slowing I(Na) inactivation. The inhibition of peak I(Na) or V(max) was associated with a negative shift of the voltage-dependent steady-state I(Na) inactivation curve without altering the activation threshold. At the concentrations more than 30 micromol.L(-1), piceatannol could inhibit I(Ca,L), I(to), I(Kr), Ca2+ transients and Na+-Ca2+ exchange except I(K1). Piceatannol (1-10 micromol.L(-1)) exerted antiarrhythmic activity in isolated rat hearts subjected to ischaemia-reperfusion injury.. The additional hydroxyl group on resveratrol makes piceatannol possessing more potent in I(Na) inhibition and uniquely slowing I(Na) inactivation, which may contribute to its antiarrhythmic actions at low concentrations less than 10 micromol.L(-1).

Topics: Aconitine; Action Potentials; Animals; Anti-Arrhythmia Agents; Arrhythmias, Cardiac; Caffeine; Calcium Channel Blockers; Calcium Channels, L-Type; Cell Line; Electric Stimulation; ERG1 Potassium Channel; Ether-A-Go-Go Potassium Channels; Free Radical Scavengers; Humans; In Vitro Techniques; Male; Myocardial Reperfusion Injury; Myocytes, Cardiac; Patch-Clamp Techniques; Rats; Rats, Sprague-Dawley; Resveratrol; Sodium Channel Agonists; Sodium Channel Blockers; Sodium Channels; Stilbenes

We have studied the inhibitory effect of five polyphenols namely, resveratrol, piceatannol, quercetin, quercetrin, and quercetin-3-beta-D glucoside on Escherichia coli ATP synthase. Recently published X-ray crystal structures of bovine mitochondrial ATP synthase inhibited by resveratrol, piceatannol, and quercetin, suggest that these compounds bind in a hydrophobic pocket between the gamma-subunit C-terminal tip and the hydrophobic inside of the surrounding annulus in a region critical for rotation of the gamma-subunit. Herein, we show that resveratrol, piceatannol, quercetin, quercetrin, or quercetin-3-beta-d glucoside all inhibit E. coli ATP synthase but to different degrees. Whereas piceatannol inhibited ATPase essentially completely ( approximately 0 residual activity), inhibition by other compounds was partial with approximately 20% residual activity by quercetin, approximately 50% residual activity by quercetin-3-beta-D glucoside, and approximately 60% residual activity by quercetrin or resveratrol. Piceatannol was the most potent inhibitor (IC(50) approximately 14 microM) followed by quercetin (IC(50) approximately 33 microM), quercetin-3-beta-D glucoside (IC(50) approximately 71 microM), resveratrol (IC(50) approximately 94 microM), quercitrin (IC(50) approximately 120 microM). Inhibition was identical in both F(1)F(o) membrane preparations as well as in isolated purified F(1). In all cases inhibition was reversible. Interestingly, resveratrol and piceatannol inhibited both ATPase and ATP synthesis whereas quercetin, quercetrin or quercetin-3-beta-d glucoside inhibited only ATPase activity and not ATP synthesis.

Topics: ATP Synthetase Complexes; Escherichia coli; Inhibitory Concentration 50; Models, Molecular; Molecular Structure; Proton Pumps; Quercetin; Resveratrol; Stilbenes

We have examined whether and by what mechanism piceatannol inhibits cell cycle progression in DU145 cells. The treatment of cells with piceatannol for 24h resulted in an increase in the percentage of cells in G1 phase and dose-dependent decreases in [(3)H]thymidine incorporation, as well as in protein levels of cyclin A, cyclin D1, and cyclin-dependent kinase (CDK)2 and CDK4. Piceatannol exerted no effect on the levels of p21(WAF1/CIP1) or p27(KIP1). Piceatannol reduced CDK4 and CDK2 activity. These results indicate that delaying G1 cell cycle progression contributes to the piceatannol-mediated inhibition of DU145 cell growth, which may be mediated via the inhibition of CDK activity.

Topics: Antineoplastic Agents; Cell Cycle; Cell Line, Tumor; Cyclin-Dependent Kinases; Flow Cytometry; Humans; Immunoblotting; Immunoprecipitation; Male; Prostatic Neoplasms; Stilbenes

Resveratrol and piceatannol are plant-derived polyphenols possessing extremely wide range of biological activities such as cancer chemopreventive, cardio- and neuroprotective, antioxidant, anti-inflammatory, anticancer and lifespan extending properties. Despite great interest in these stilbenes, their interactions with lipid bilayers have not been extensively studied. In the present work, the interaction of both resveratrol and piceatannol with model membranes composed of phosphatidylcholine (DMPC and DPPC) was investigated by means of fluorescence spectroscopy, differential scanning calorimetry (DSC) and electron spin resonance spectroscopy (ESR). Generalized polarization of two fluorescent probes Laurdan and Prodan measured in pure lipid and lipid:stilbene mixtures revealed that resveratrol and piceatannol changed bilayer properties in both gel-like and liquid crystalline phase and interacted with lipid headgroup region of the membrane. These findings were corroborated by DSC experiments in which the stilbene-induced decrease of lipid melting temperature and transition cooperativity were recorded. Resveratrol and piceatannol restricted also the ESR-measured mobility of spin probes GluSIN18, 5DSA and 16DSA with nitroxide group localized at different depths. Since the most pronounced effect was exerted on the spin probe located near membrane surface, we concluded that also ESR results pointed to the preferential interaction of resveratrol and piceatannol with headgroup region of lipid bilayer.

Topics: Calorimetry, Differential Scanning; Electron Spin Resonance Spectroscopy; Liposomes; Membranes, Artificial; Resveratrol; Spectrometry, Fluorescence; Stilbenes; Thermodynamics

We have previously described an analog peptide of type II collagen (CII) that can suppress collagen-induced arthritis (CIA). This analog peptide represents CII(245-270), the immunodominant epitope of CII, but with substitutions at 260, 261, and 263 - CII(245-270) (A(260), B(261), and N(263)) (A9). To elucidate the mechanisms responsible for suppression, we used mice transgenic for a collagen-specific T cell receptor (TCR). When we found that APCs pulsed with A9 failed to induce T cell phosphorylation of TCR-zeta and ZAP-70, we explored alternative signaling pathways. We determined that A9 instead induced phosphorylation of spleen tyrosine kinase (Syk). The importance of Syk was confirmed by the use of chemical Syk inhibitors, which blocked both cytokine secretion and activation of GATA-3 mediated by peptide A9. In summary, T cells use an alternative pathway in response to A9 that involves Syk. This novel T cell pathway may represent an important means for altering T cell phenotypes.

Topics: Animals; Antigen-Presenting Cells; Arthritis, Experimental; CD4-Positive T-Lymphocytes; Collagen Type II; Cytokines; Extracellular Signal-Regulated MAP Kinases; GATA3 Transcription Factor; Intracellular Signaling Peptides and Proteins; JNK Mitogen-Activated Protein Kinases; Mice; Mice, Inbred DBA; Mice, Transgenic; Oligopeptides; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Protein-Tyrosine Kinases; Receptors, Antigen, T-Cell; Signal Transduction; Stilbenes; Sulfonamides; Syk Kinase

Piceatannol (3,5,3',4'-tetrahydroxy- trans-stilbene), a resveratrol analogue, is a polyphenol present in the skins of grapes and in wine and other foods. The present study aimed to investigate for the first time the cardioprotective effects of piceatannol on vascular smooth muscle cells (VSMC). The treatment of cells with piceatannol inhibited cell proliferation by reducing extracellular signal-regulated kinase (ERK) 1/2 and JNK activity in cultured VSMC in the presence of tumor necrosis factor-alpha (TNF-alpha). These inhibitory effects were also associated with G1 cell cycle arrest, and resulted in a decrease in cyclin-dependent kinases (CDKs) and cyclins. Piceatannol treatment strongly induced the expression of p21WAF1 via independence of p27KIP and p53 expression. The effect of piceatannol was not restricted to cell proliferation, as TNF-alpha-induced invasion and migration was also suppressed in VSMC. Moreover, piceatannol treatment strongly decreased matrix metalloproteinase-9 (MMP-9) expression and promoter activity in a dose-dependent manner in response to TNF-alpha. It was further demonstrated that piceatannol abrogated the transcriptional activity of nuclear factor kappa B (NF-kappaB), an important nuclear transcription factor involved in MMP-9 expression. Overall, these results demonstrate that piceatannol inhibits proliferation and migration of VSMC treated with TNF-alpha. Therefore, piceatannol may be an effective therapeutic approach to treat atherosclerosis.

Topics: Animals; Cardiotonic Agents; Cell Movement; Cell Proliferation; Cyclin-Dependent Kinase Inhibitor Proteins; Cyclin-Dependent Kinases; Cyclins; Extracellular Signal-Regulated MAP Kinases; G1 Phase; JNK Mitogen-Activated Protein Kinases; Male; Matrix Metalloproteinase 9; Mice; Muscle, Smooth, Vascular; NF-kappa B; Phosphorylation; Stilbenes; Tumor Necrosis Factor-alpha

Alzheimer's disease (AD) is an age-related neurodegenerative disorder in which apoptosis plays a potentially important role. 4-Hydroxynonenal (HNE) is a major lipid peroxidation product produced by oxidative stress, and its level is elevated in the AD brain. In the present study, piceatannol (but not resveratrol) at the concentration of 20 micromol/L inhibited HNE-induced PC12 cell death. Treatment with HNE induced nuclear condensation in PC12 cells, and this was attenuated by piceatannol treatment. HNE induced poly(ADP-ribose) polymerase cleavage and decreased Bcl-2 expression, with both of these effects being attenuated by piceatannol. Piceatannol also inhibited the phosphorylation of c-Jun N-terminal kinase, which is a key regulator of HNE-induced PC12 cell death. These results indicate that piceatannol has therapeutic potential in the prevention of AD.

Topics: Aldehydes; Animals; Apoptosis; Blotting, Western; Cell Nucleus; Cell Proliferation; Cross-Linking Reagents; Dose-Response Relationship, Drug; Enzyme Activation; JNK Mitogen-Activated Protein Kinases; Microscopy, Fluorescence; PC12 Cells; Phosphorylation; Poly(ADP-ribose) Polymerases; Proto-Oncogene Proteins c-bcl-2; Rats; Stilbenes

Although Syk has been reported to be associated with IL-2R beta [corrected] and IL-15R alpha in some hematopoietic cells, its association has never been investigated in the IL-4/IL-4R system. In this study, we demonstrate for the first time that Syk is constitutively associated with IL-4R(alpha)in human polymorphonuclear neutrophils (PMNs) and that IL-4 stimulation increases the amount of Syk associated with IL-4R(alpha). Moreover, upon IL-4 treatment, a pool of Syk associated with IL-4R(alpha) is phosphorylated. We also report that such association is not unique to PMNs because Syk associates with IL-4R(alpha) in Raji and in PBMC cells. Stimulation of PMNs by IL-4 increased the amount of Syk associated with PLC-gamma2, pAkt, and alpha-tubulin. Pretreatment of cells with the Syk-selective inhibitor piceatannol or Syk inhibitor II, significantly inhibited the ability of IL-4 to enhance phagocytosis and cell adhesion and to delay apoptosis, and these results correlate with the ability of piceatannol to reduce Syk activation and its association with IL-4R(alpha). Down-regulation of Syk by antisense techniques demonstrates the importance of Syk in the antiapoptotic effect of IL-4. We conclude that association of Syk to IL-4R(alpha) is of biological significance and that IL-4R(alpha) is a new candidate to be added to the few cytokine receptor components which associate with Syk.

Topics: Adjuvants, Immunologic; Androstadienes; Apoptosis; Cell Adhesion; Cell Line; Cells, Cultured; Humans; Interleukin-4; Interleukin-4 Receptor alpha Subunit; Intracellular Signaling Peptides and Proteins; Neutrophils; Phagocytosis; Phosphatidylinositol 3-Kinases; Phospholipase C gamma; Protein Kinase Inhibitors; Protein-Tyrosine Kinases; Proto-Oncogene Proteins c-akt; Stilbenes; Syk Kinase; Tubulin; Wortmannin

Polyphenolic natural products from green tea and red wine have been identified as metalloproteinase inhibitors. Members from the flavonoid and stilbene families found to possess metalloproteinase inhibitory activities include (-)-epigallocatechin gallate, (-)-epicatechin gallate and piceatannol, but their minimally active pharmacophores have not been evaluated. The present study has examined compounds that are structural components of or structurally related to (-)-epigallocatechin gallate, (-)-epicatechin gallate and piceatannol for inhibition of aggrecanases and four representative matrix metalloproteinases. Piceatannol and pyrogallol were found to inhibit all aggrecanases and matrix metalloproteinases studied, indicating a crucial reliance on multiple hydroxyl groups for (-)-epigallocatechin gallate, (-)-epicatechin gallate and piceatannol activity. Differences in K(i) values for pyrogallol as determined with two structurally distinct substrates indicated the likelihood that this compound binds in a non-competitive modality. Further analysis showed that pyrogallol acts as an exosite inhibitor, consistent with the action of (-)-epigallocatechin gallate. In contrast, piceatannol was shown to be a competitive binding inhibitor and showed no differences in apparent K(i) values as determined by distinct substrates, illustrating the benefits of using two structurally distinct substrates to assist the analysis of protease inhibitors. The compounds identified here could be utilized to develop novel metalloproteinase probes or as fragment components of more active inhibitors.

Topics: ADAM Proteins; ADAMTS4 Protein; ADAMTS5 Protein; Amino Acid Sequence; Antioxidants; Catechin; Enzyme Activation; Enzyme Inhibitors; Flavonoids; Humans; Matrix Metalloproteinase Inhibitors; Matrix Metalloproteinases; Molecular Sequence Data; Molecular Structure; Peptides; Procollagen N-Endopeptidase; Stilbenes

Piceatannol (trans-3,4,3',5'-tetrahydroxystilbene) is a polyphenol that is found in grapes, red wine, Rheum undulatum, and the seeds of Euphorbia lagascae. It has been previously reported that piceatannol inhibits the proliferation of a variety of cancer cell types. In the present study, we assessed the effects of piceatannol on the growth of androgen-insensitive DU145 prostate cancer cells at concentrations of 1-10 micromol/L. Piceatannol reduced the viable numbers and increased the numbers of apoptotic DU145 cells in a dose-dependent manner. Western blot analysis revealed that piceatannol increased the protein levels of cleaved caspase-8, -9, -7, and -3 and cleaved poly(ADP-ribose) polymerase (PARP). Piceatannol increased mitochondrial membrane permeability and cytochrome c release from the mitochondria to the cytosol. Piceatannol induced an increase in the levels of truncated Bid, Bax, Bik, Bok, and Fas but caused a decrease in the levels of Mcl-1 and Bcl-xL. Caspase-8 and -9 inhibitors mitigated piceatannol-induced apoptosis. The caspase-8 inhibitor suppressed the piceatannol-induced cleavage of Bid, caspase-3, and PARP. These results indicate that piceatannol induces apoptosis via the activation of the death receptor and mitochondrial-dependent pathways in prostate cancer cells.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cytochromes c; Dose-Response Relationship, Drug; Humans; Intracellular Signaling Peptides and Proteins; Male; Mitochondrial Membranes; Mitochondrial Proteins; Phytotherapy; Plant Extracts; Poly(ADP-ribose) Polymerases; Prostatic Neoplasms; Signal Transduction; Stilbenes; Vitis

Piceatannol (E-3,5,3',4'-tetrahydroxystilbene) is a phytoalexin synthesized in grapes in response to stress conditions. It exhibits strong antioxidant and antileukaemic activities due to the presence of the catechol moiety. To modify some physical properties like solubility, and miscibility in non-aqueous media some new previously unreported piceatannol derivatives having lipophilic chains on the A-ring were prepared in good yields by a simple and efficient procedure. The key step was a chemo- and regioselective aromatic hydroxylation with 2-iodoxybenzoic acid (IBX). The new compounds showed antioxidant activity and seemed promising for possible applications as multifunctional emulsifiers in food, cosmetic and pharmaceutical fields.

Topics: Antioxidants; Iodobenzenes; Iodobenzoates; Molecular Structure; Stilbenes; Structure-Activity Relationship

Inflammatory tissue injury has been implicated in tumor promotion and progression. 3,5,4'-trihydroxy-trans-stilbene (resveratrol) and 3,4,3', 5'-tetrahydroxy-trans-stilbene (piceatannol), 2 structurally related plant polyphenols, have been reported to possess antioxidant, anti-inflammatory, and chemopreventive properties. This study was aimed at investigating the possible protective effects of resveratrol and piceatannol against dextran sulfate sodium (DSS)-induced inflammation in mouse colonic mucosa. Administration of DSS (2.5%) in drinking water for 7 days to male ICR mice resulted in colitis and elevated expression of inducible nitric oxide synthase (iNOS) and activation of nuclear factor-kappa B (NF-kappaB), a major transcription factor known to upregulate proinflammatory gene expression. Phosphorylation of extracellular signal-regulated kinase (ERK) and signal transducer and activator of transcription-3 (STAT3) was also enhanced after DSS treatment. Oral administration of resveratrol or piceatannol (10 mg/kg body weight each) for 7 constitutive days attenuated the DSS-induced inflammatory injury, upregulation of iNOS expression, and activation of NF-kappaB, STAT3, and ERK.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Colitis; Colonic Neoplasms; Dextran Sulfate; DNA-Binding Proteins; Down-Regulation; Drug Therapy, Combination; Extracellular Signal-Regulated MAP Kinases; I-kappa B Kinase; Inflammatory Bowel Diseases; Male; Mice; Mice, Inbred ICR; NF-kappa B; Nitric Oxide Synthase Type II; Phosphorylation; Resveratrol; STAT3 Transcription Factor; Stilbenes; Time Factors

There are multiple lines of evidence supporting that inflammation is causally linked to carcinogenesis. Abnormal upregulation of cyclooxygenase-2 (COX-2), a rate-limiting enzyme in the prostaglandin biosynthesis, has been implicated in carcinogenesis. Trans-3,4,3',5'-tetrahydroxystilbene (piceatannol), a naturally occurring hydroxylated stilbene with potent anti-inflammatory and antioxidative activities, has been shown to inhibit the proliferation of several cancer cells by inducing apoptosis or blocking cell cycle progression. In this study, we examined the effect of piceatannol on activation of the nuclear transcription factor NF-kappa B, one of the major transcription factors that regulate proinflammatory COX-2 gene transcription, in human mammary epithelial (MCF-10A) cells treated with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). When pretreated to MCF-10A cells, piceatannol markedly inhibited TPA-induced NF-kappa B DNA binding to a greater extent than resveratrol and oxyresveratrol, stilbene analogs structurally related to piceatannol. Piceatannol also inhibited TPA-induced phosphorylation and degradation of Ikappa Balpha as well as nuclear translocation of the phosphorylated form of p65, the functionally active subunit of NF-kappa B. Likewise, TPA-induced expression of COX-2 was abrogated by piceatannol pretreatment. The thiol reducing agent dithiothreitol abolished the inhibitory effects of piceatannol on NF-kappa B DNA binding activity, suggesting that piceatannol may directly modify NF-kappa B or its regulator through reaction with the cysteine thiol(s).

Topics: Anti-Inflammatory Agents; Antioxidants; Breast; Breast Neoplasms; Carcinogens; Cell Line; Cell Transformation, Neoplastic; Cyclooxygenase 2; DNA-Binding Proteins; Dose-Response Relationship, Drug; Down-Regulation; Epithelial Cells; Female; Humans; I-kappa B Kinase; NF-kappa B; Phosphorylation; Protein Transport; Stilbenes; Tetradecanoylphorbol Acetate

Chronic Beryllium Disease (CBD) is a delayed-type hypersensitivity immune reaction that leads to granuloma formation in the lungs and potentially severe loss of pulmonary function. Although the molecular mechanisms that mediate beryllium (Be)-stimulated granuloma formation are not well understood, cell adhesion molecules are likely to play a key role in the migration of immune cells to sites of inflammation. In this study, we examined the role of the cell adhesion molecule I-CAM1 in Be-stimulated small airway epithelial cells (SAECs). These epithelial cells line the airway and represent the first point of contact for inhaled foreign substances. We find that Be exposure specifically induced I-CAM1 expression on the cell surface of SAEC and release of soluble I-CAM1 into the extracellular medium. Furthermore, anti-I-CAM1 antibodies inhibited Be-stimulated adhesion of SAEC to the macrophage cell-line THP1, indicating that the Be-induced adhesive properties of SAEC are at least partly due to I-CAM1 expression. These studies support a model in which I-CAM1 cell adhesion functions may play a role in directing immune cells to the lung and activating a Be-specific immune response in Be hypersensitivity disease.

Topics: Antibodies, Blocking; Beryllium; Bronchi; Cell Adhesion; Cells, Cultured; Humans; Immunity, Mucosal; Intercellular Adhesion Molecule-1; Respiratory Mucosa; RNA, Messenger; Stilbenes; Up-Regulation

This study investigated the in vitro protective effects of three derivatives of resveratrol, i.e., piceatannol (trans-3,5,3',4'-tetrahydroxystilbene), PDM2 (1,3-dichloro-5-[(1E)-2-(4-chlorophenyl)ethenyl]-benzene) and PDM11 ((E)-5-[2-(4-chlorophenyl)ethenyl]-1,3-dimethoxyphenyl-ethene), compared with resveratrol as reference compound, against oxidation of linoleate micelles (10(-2)M) initiated by radiolysis-generated hydroxyl radicals. Lipid peroxidation was monitored by conjugated dienes (differential absorbance at 234nm), and by hydroperoxides (reverse phase HPLC with chemiluminescence detection). The higher the concentration of resveratrol or piceatannol (from 10(-5)M to 10(-4)M), the stronger the antioxidant ability. Piceatannol, with the presence of an additional hydroxyl group, showed a better antioxidant effect than resveratrol for a given concentration (competition with the fatty acid to scavenge lipid peroxyl radicals LOO), whereas PDM2 and PDM11, without any hydroxyl group, did not exhibit any significant protective effect. A lower limit for the LOO rate constant has been estimated for piceatannol (>/=1.4x10(5)M(-1)s(-1)) and for resveratrol (>/=0.3x10(5)M(-1)s(-1)).

Topics: Chemistry, Physical; Chromatography, High Pressure Liquid; Dose-Response Relationship, Radiation; Free Radical Scavengers; Hydrogen-Ion Concentration; Hydroxyl Radical; Linoleic Acid; Lipid Peroxidation; Micelles; Models, Chemical; Oxidation-Reduction; Oxygen; Resveratrol; Stilbenes

The roots of three varieties of Polygonum cuspidatum were analyzed for resveratrol and its analogs. The powder of the dried roots was extracted with aqueous ethanol (60% v/v) and the extracts obtained were analyzed using RP HPLC with coulometric detection. A simple HPLC method with a multichannel CoulArray detector was developed for the determination of four stilbenes: resveratrol, its glucoside piceid, piceatannol, and its glucoside astringin. Analyses were carried out on a LiChrospher C18 (125 x 4.6 mm id, particle size 5 microm) column with a mobile phase of ammonium acetate (pH 3) and ACN in gradient mode. Four compounds were monitored by a CoulArray electrochemical detector. Potentials of eight electrochemical cells in series were set in the range of 200-900 mV. Optimization of the mobile phase pH was performed. Calibration curves showed good linearity with correlation coefficients (r(2))--more than 0.9975.

Topics: Chromatography, High Pressure Liquid; Electrochemistry; Fallopia japonica; Glucosides; Hydrogen-Ion Concentration; Plant Roots; Resveratrol; Stilbenes

Piceatannol (3,5,3',4'-tetrahydroxy-trans-stilbene; PIC) is a polyphenol found in grapes. It is known as a protein kinase inhibitor that modifies multiple cellular targets, exerting immunosuppressive and antitumorigenic activities in several cell lines. The purpose of the present work was to evaluate the anti-inflammatory effect of PIC on dextran sulfate sodium (DSS)-induced colitis. Experimental colitis was induced in BALB/c mice by dissolving 5% DSS in their drinking water for 7 days. PIC (1, 2.5, 5, or 10 mg/kg body weight) was administrated daily per oral route for 7 days. A significant blunting of weight loss and clinical signs was observed in DSS-exposed, PIC-treated mice when compared to vehicle-treated mice. This was associated with a remarkable amelioration of the disruption of the colonic architecture, a significant reduction in colonic myeloperoxidase (MPO) activity, and a decrease in production of inflammatory mediators such as nitric oxide (NO), prostaglandin (PG) E2, and pro-inflammatory cytokines. The present data indicate that further evaluation of the potential of PIC as an agent for the prevention and/or treatment of inflammatory bowel diseases in human clinical studies is warranted.

Topics: Animals; Colitis; Colon; Dextran Sulfate; Female; Immunohistochemistry; Inflammation Mediators; Mice; Mice, Inbred BALB C; NF-kappa B; Peroxidase; STAT3 Transcription Factor; Stilbenes; Vitis

Piceatannol (3,3',4,5'-tetrahydroxy-trans-stilbene; PCA) is a naturally occurring metabolite of resveratrol (3,4',5-trihydroxy-trans-stilbene; RV). In this study, we identified additional biochemical targets of PCA in human HL-60 promyelocytic leukemia cells. Incubation with PCA led to a significant proportion of apoptotic cells and caused an arrest in the G2-M phase of the cell cycle. PCA depleted intracellular dCTP and dGTP pools, and inhibited the incorporation of 14C-labeled cytidine into DNA. PCA significantly abolished all NTP pools, and sequential treatment with PCA and Ara-C yielded synergistic growth inhibitory effects because of remarkably increased Ara-CTP formation after PCA preincubation. Due to these promising results, PCA may support conventional chemotherapy of human malignancies and therefore, deserves further preclinical and in vivo testing.

Topics: Antimetabolites, Antineoplastic; Antineoplastic Agents; Cell Cycle; Cytarabine; Drug Screening Assays, Antitumor; Drug Synergism; Enzyme Inhibitors; HL-60 Cells; Humans; Leukemia, Promyelocytic, Acute; Models, Chemical; Propidium; Ribonucleotide Reductases; Stilbenes; Time Factors

The mechanism by which the naturally occurring polyphenolic compounds resveratrol (RES), C(14)H(12)O(3), and its metabolite piceatannol (PIC), C(14)H(12)O(4), scavenge free radicals is studied using experimental and density functional theory (DFT) methods. PIC's crystal structure shows a strong intermolecular hydrogen bond network, which, through a concerted motion of the hydroxyl hydrogen atoms, can produce a second hydrogen bond chain. This reorganization offers a low-energy pathway for the transfer of hydrogen atoms and is a contributing factor to PIC's biological activity. Additionally, DFT calculations describing the entire reaction mechanism of RES, PIC, and 3,3',4',5,5'-pentahydroxystilbene with hydroxyl and peroxyl radicals agree with experimental results, showing that increased hydroxylation aids in scavenging activity. PIC is more efficient than RES because (i) by sharing its 3'-OH hydrogen atom with its adjacent neighbor, O-4', the abstraction and transfer of the 4'-H atom to the free radical becomes easier and (ii) the resulting PIC semiquinone radical is more stable. As a result of the reaction with OH(*), both RES and PIC form water; with the peroxyl radical, both RES and PIC form hydrogen peroxide. Also, docking of PIC onto the protein transthyretin suggests better performance than RES and confirms its possible application in neurodegenerative conditions such as Alzheimer's disease.

Topics: Crystallization; Crystallography, X-Ray; Free Radical Scavengers; Hydrogen Bonding; Hydroxyl Radical; Molecular Structure; Peroxides; Prealbumin; Resveratrol; Stilbenes

Resveratrol (3,5,4'-trihydroxystilbene) and piceatannol (3,4,3',5'-tetrahydroxy-trans-stilbene) are phytoalexins present in red grapes and wines. In vitro studies have revealed that piceatannol blocks LMP2A, a viral protein-tyrosine kinase implicated in leukemia, non-Hodgkin's lymphoma and other diseases associated with the Epstein-Barr virus, and has an antimelanoma effect on human melanoma cells. Resveratrol has several beneficial effects on human health, such as anticancer, cardioprotection, antioxidant, inhibition of platelet aggregation and anti-inflammatory activity. In this investigation, the collisional behaviour of deprotonated resveratrol and piceatannol obtained under electrospray conditions is described. The mechanisms involved in the fragmentation pattern of [M-H](-) species of the two compounds were investigated by performing MS(n) experiments, deuterium labelling and accurate mass measurements.

Topics: Deuterium; Deuterium Exchange Measurement; Molecular Weight; Phytoalexins; Resveratrol; Sesquiterpenes; Spectrometry, Mass, Electrospray Ionization; Stilbenes; Terpenes

Myeloid dendritic cells (mDC) activated with a B7-DC-specific cross-linking IgM Ab (B7-DC XAb) take up and retain Ag and interact with T cell compartments to affect a number of biologic changes that together cause strong antitumor responses and blockade of inflammatory airway disease in animal models. The molecular events mediating the initial responses in mDC remain unclear. In this study we show that B7-DC XAb caused rapid phosphorylation of the adaptor protein DAP12 and intracellular kinases Syk and phospholipase C-gamma1. Pretreatment of mDC with the Syk inhibitor piceatannol blocked B7-DC XAb-induced Ag uptake with a concomitant loss of tumor protection in mice. Vaccination with tumor lysate-pulsed wild-type B7-DC XAb-activated mDC, but not TREM-2 knockout XAb-activated mDC, protected mice from lethal melanoma challenge. Multimolecular caps appeared within minutes of B7-DC XAb binding to either human or mouse mDC, and FRET analysis showed that class II, CD80, CD86, and TREM-2 are recruited in tight association on the cell surface. When TREM-2 expression was reduced in wild-type mDC using short hairpin RNA or by using mDC from TREM-2 knockout mice, in vitro DC failed to take up Ag after B7-DC XAb stimulation. These results directly link TREM-2 signaling with one change in the mDC phenotype that occurs in response to this unique Ab. The parallel signaling events observed in both human and mouse mDC support the hypothesis that B7-DC cross-linking may be useful as a therapeutic immune modulator in human patients.

Topics: Adaptor Proteins, Signal Transducing; Animals; Antibodies; Antigens; B7-1 Antigen; B7-2 Antigen; Dendritic Cells; Gene Expression Regulation; Histocompatibility Antigens Class II; Humans; Immunologic Capping; Inflammation; Intracellular Signaling Peptides and Proteins; Melanoma; Membrane Glycoproteins; Membrane Proteins; Mice; Mice, Knockout; Myeloid Cells; Neoplasms, Experimental; Phospholipase C gamma; Phosphorylation; Protein-Tyrosine Kinases; Receptors, Immunologic; Respiration Disorders; Signal Transduction; Stilbenes; Syk Kinase; T-Lymphocytes

With a view to elucidating the structural requisites for effective antinitrosating properties in plant polyphenolics and their metabolites, we have undertaken a comparative investigation of the nitrite scavenging effects of representative catechol derivatives of dietary relevance in the 2,3-diaminonaphthalene (DAN) nitrosation and tyrosine nitration assays. Compounds tested included caffeic acid (1), chlorogenic acid (2), piceatannol (3), hydroxytyrosol (4), and the corresponding S-glutathionyl conjugates 5-8, which were prepared using either tyrosinase (5 and 6) or a novel, o-iodoxybenzoic acid (IBX)-based oxygenation/ conjugation methodology (7b and 8). In the DAN nitrosation assay at pH 4.0, the rank order of inhibitory activities was found to be 5-S-glutathionylpiceatannol (7b) > 3 > 1 > 2 > 2-S-glutathionylcaffeic acid (5) > 2-S-glutathionylchlorogenic acid (6) > 4 approximately 5-S-glutathionylhydroxytyrosol (8). Quite unexpectedly, in the tyrosine nitration assay in 0.5 M HCl, 2 was the most efficient inhibitor followed by 1 > 4 > 3 > 7b approximately 5 > 8 > 6. Under the assay conditions, the glutathionyl conjugates were usually consumed at faster rates than the parent catechols (decomposition rates: 3 > 1 > 4 > 2). The 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) assay indicated that the most effective hydrogen donors were 4 > 7b > 1 approximately 3. Overall, these results indicated that catechol compounds and their glutathionyl conjugates may exhibit profoundly different inhibitory properties depending on the specific conditions of the assay, including especially pH, and that their antinitrosating properties do not correlate tout-court with their hydrogen donor capacity. The glutathionyl-piceatannol conjugate 7b was found to be one of the most potent inhibitors in the physiologically relevant DAN assay and may provide a new structural lead for the design of effective antinitrosating agents based on dietary polyphenolic compounds.

Topics: 2-Naphthylamine; Caffeic Acids; Catechols; Chlorogenic Acid; Free Radical Scavengers; Glutathione; Nitrosation; Phenylethyl Alcohol; Plant Extracts; Reactive Nitrogen Species; Stilbenes

There is mounting evidence implicating the accumulation of intracellular reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the pathogenesis of neurodegenerative disorders, including Alzheimer's disease. Recently, considerable attention has been focused on identifying naturally occurring antioxidants that are able to reduce excess ROS and RNS, thereby protecting against oxidative stress and neuron death. The present study investigated the possible protective effects of piceatannol (trans-3,4,3',5'-tetrahydroxystilbene), which is present in grapes and other foods, on hydrogen-peroxide- and peroxynitrite-induced oxidative cell death. PC12 rat pheochromocytoma (PC12) cells treated with hydrogen peroxide or SIN-1 (a peroxynitrite-generating compound) exhibited apoptotic death, as determined by nucleus condensation and cleavage of poly(ADP-ribose)polymerase (PARP). Piceatannol treatment attenuated hydrogen-peroxide- and peroxynitrite-induced cytotoxicity, apoptotic features, PARP cleavage and intracellular ROS and RNS accumulation. Treatment of PC12 cells with hydrogen peroxide or SIN-1 led to down-regulation of Bcl-X(L) and activation of caspase-3 and -8, which were also inhibited by piceatannol treatment. Hydrogen peroxide or SIN-1 treatment induced phosphorylation of the c-Jun-N-terminal kinase (JNK), which was inhibited by piceatannol treatment. Moreover, SP600125 (a JNK inhibitor) significantly inhibited hydrogen-peroxide- and peroxynitrite-induced PC12 cell death, revealing inactivation of the JNK pathway as a possible molecular mechanism for the protective effects of piceatannol against hydrogen-peroxide- and peroxynitrite-induced apoptosis of PC12 cells. Collectively, these findings suggest that the protective effect of piceatannol against hydrogen-peroxide- and peroxynitrite-induced apoptosis of PC12 cells is associated with blocking the activation of JNK and the down-regulation of Bcl-XL.

Topics: Animals; Anthracenes; Apoptosis; bcl-X Protein; Caspase 3; Caspase 8; Cell Survival; Down-Regulation; Enzyme Activation; Hydrogen Peroxide; JNK Mitogen-Activated Protein Kinases; PC12 Cells; Peroxynitrous Acid; Poly(ADP-ribose) Polymerases; Rats; Stilbenes

In the present study, we characterized OXSI-2 [3-(1-Methyl-1H-indol-3-yl-methylene)-2-oxo-2, 3-dihydro-1H-indole-5-sulfonamide], a putative inhibitor of Syk, and determined its specificity and selectivity in platelets. We found that OXSI-2 completely abolished convulxin-induced platelet functional responses. In order to determine whether OXSI-2 inhibited Src family kinase-mediated platelet responses, we evaluated its effect on Src family kinase (SFK)-mediated signaling events in platelets, viz. Lyn-mediated phosphorylation of Y352 on Syk, LAT-Y191 phosphorylation by Syk, and protease-activated receptor (PAR)-mediated phosphorylation of ERK. In the present work, we report that convulxin mediated Syk tyrosine 352 phosphorylation is not inhibited by OXSI-2, whereas piceatannol and PP2 abolished it. Syk-mediated Y191 LAT phosphorylation is abolished by all the three inhibitors. AYPGKF-induced phosphorylation of ERK was marginally inhibited by OXSI-2, whereas treatment with PP2 and piceatannol completely abolished it. However, PAR-mediated thromboxane generation (an event mediated by ERK) was potentiated by OXSI-2 whereas PP2 and piceatannol brought thromboxane to basal levels. Protein kinase C (PKC) inhibitors are known to potentiate PAR-mediated thromboxane generation in platelets. In contrast, OXSI-2, unlike PKC inhibitors, did not inhibit secretion. Therefore, we conclude that OXSI-2 is not a Syk-selective inhibitor in platelets because of its unexplained non-specific effects.

Topics: Adaptor Proteins, Signal Transducing; Blood Platelets; Blotting, Western; Crotalid Venoms; Cytoplasmic Granules; Dose-Response Relationship, Drug; Enzyme Inhibitors; Extracellular Signal-Regulated MAP Kinases; Humans; Indoles; Intracellular Signaling Peptides and Proteins; Lectins, C-Type; Maleimides; Membrane Proteins; Oligopeptides; Phospholipase C gamma; Phosphorylation; Platelet Function Tests; Protein Kinases; Protein-Tyrosine Kinases; Signal Transduction; src-Family Kinases; Stilbenes; Sulfonamides; Syk Kinase; Thromboxanes; Tyrosine

In the search for biologically active compounds from Euphorbia lagascae Spreng, an herbaceous plant native to southeast of Iberic Peninsula, a stilbene, two coumarins and two 12-deoxyphorbol diterpene esters were isolated by chromatographic methods, from the methanol extracts of its defatted seeds. The structures of these compounds were elucidated by a combination of physical and spectral data (IR, MS and high-resolution (1)H-NMR and (13)C-NMR spectroscopy utilizing COSY, HMBC, HMQC and NOESY experiments). The stilbene, piceatannol, was screened for its antileishmanial activity against promastigotes as an extracellular form of Leishmania donovani, Leishmania infantum and Leishmania major, and amastigotes of Leishmania donovani as an intracellular form. Pentostan (sodium stibogluconate), the first line clinical drug, was used as a standard reference. Piceatannol was moderately active against the extracellular forms of the three tested Leishmania species, and more active than the reference compound against the intracellular form of Leishmania donovani.

Topics: Animals; Antiprotozoal Agents; Coumarins; Euphorbia; Leishmania; Leishmania donovani; Leishmania infantum; Magnetic Resonance Spectroscopy; Molecular Structure; Plant Extracts; Seeds; Stilbenes

Cystic fibrosis is mainly caused by mutations that interfere with the biosynthetic folding of the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The aim of this study was to find cellular proteins interacting with CFTR and regulating its processing. We have used a genetic screen in yeast to identify such proteins and identified CSN5 that interacted with the third cytoplasmic loop of CFTR. CSN5 is the 5th component of the COP9 signalosome, a complex of eight subunits that shares significant homologies to the lid subcomplex of the 26S proteasome and controls the stability of many proteins. The present study shows that CSN5 associates with the core-glycosylated form of CFTR and suggests that this association targets misfolded CFTR to the degradative pathway. Identifying CSN5 as a new component of the degradative pathway is an important step towards the goal of unraveling the sorting between misfolded and correctly folded CFTR proteins.

Topics: Blotting, Western; COP9 Signalosome Complex; Cystic Fibrosis Transmembrane Conductance Regulator; Glycosylation; HeLa Cells; Humans; Immunoprecipitation; Intracellular Signaling Peptides and Proteins; Kidney; Peptide Hydrolases; Protein Binding; Protein Folding; Protein-Tyrosine Kinases; Saccharomyces cerevisiae; Stilbenes; Subcellular Fractions; Two-Hybrid System Techniques

Targeting of tumor tissues is one of the most powerful approaches to accelerate the efficiency of anticancer treatments. The investigation of effective targets, including proteins specifically and abundantly expressed in abnormal regions, has been one of the most important research topics in cancer therapy. In this study, we performed a proteomic analysis on human breast carcinoma tissues to investigate the tumor-specific protein expression in breast carcinoma. Our study showed that ATP synthase was up-regulated in tumor tissues and was present on the plasma membrane of breast cancer cells. Furthermore, we treated the breast cancer cells with ATP synthase inhibitors and examined the inhibitory efficiency. Aurovertin B, an ATP synthase inhibitor, has strong inhibition on the proliferation of several breast cancer cell lines, but little influence on the normal cell line MCF-10A. Aurovertin B inhibits proliferation of breast cancer cells by inducing apoptosis and arresting cell cycle at the G0/G1 phase. This study showed aurovertin B can be used as an antitumorigenic agent and may be exploited in cancer chemotherapy.

Topics: Apoptosis; Aurovertins; Breast Neoplasms; Cell Line; Cell Line, Tumor; Cell Proliferation; Cell Survival; Enzyme Inhibitors; Female; Humans; Inhibitory Concentration 50; Membrane Proteins; Mitochondrial Proton-Translocating ATPases; Models, Molecular; Resveratrol; Stilbenes; Up-Regulation

Piceatannol is a polyphenol that is found in abundant quantities in grapes and wine. Although recent experimental data revealed the proapoptotic potency of piceatannol, the molecular mechanisms underlying the anti-leukemic activity have not yet been studied in detail. This study examined the effects of piceatannol on the growth of the human leukemia cell line U937. The results showed that piceatannol inhibits the viability of U937 cells by inducing apoptosis, as evidenced by the formation of apoptotic bodies, DNA fragmentation and the accumulation of the sub-G1 phase. RT-PCR and immunoblotting data showed that treating the cells with piceatannol caused the down-regulation of anti-apoptotic Bcl-2 and cIAP-2 expression. Piceatannol-induced apoptosis was also associated with the proteolytic activation of caspase-3, and the degradation/cleavage of poly (ADP-ribose) polymerase protein. z-DEVD-fmk, a caspase-3-specific inhibitor, blocked the activation of caspase-3 and increased the survival of the piceatannol-treated U937 cells, suggesting that caspase-3 activation is essential for piceatannol-induced apoptosis.

Topics: Antineoplastic Agents; Apoptosis; Caspase 3; Caspase 9; Cell Survival; Down-Regulation; Enzyme Activation; Humans; Poly(ADP-ribose) Polymerases; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-bcl-2; Stilbenes; U937 Cells

Piceatannol (3,3',4,5'-Tetrahydroxy-trans-stilbene) is a polyphenol present in grapes and wine. Piceatannol is a protein kinase inhibitor that modifies multiple cellular targets exerting immunosuppressive, antileukemic, and antitumorigenic activities in several cell lines and animal models. In this study, the antiproliferative activity of piceatannol was investigated. The results showed that piceatannol inhibited the proliferation of T24 and HT1376 human bladder cancer cells by blocking cell cycle progression in the G0/G1 phase and inducing apoptosis. ELISA showed that the G0/G1 phase arrest is due to an increased in the expression of p21/WAF1. An enhancement in Fas/APO-1 and membrane-bound Fas ligand (mFasL) might be responsible for the apoptotic effect induced by piceatannol. Our study reports the novel finding, that the induction of p21/WAF1 and activity of the Fas/mFasL apoptotic system may participate in the antiproliferative activity of piceatannol in T24 and HT1376 cells.

Topics: Apoptosis; Cell Cycle; Cell Division; Cell Line, Tumor; Cell Membrane; Fas Ligand Protein; Humans; Protein-Tyrosine Kinases; Stilbenes; Tumor Suppressor Protein p53; Urinary Bladder Neoplasms; Vitis; Wine

Resveratrol, the main active polyphenol in red wine, has been demonstrated to show benefits against skin disorders. The bioavailability of orally administered resveratrol is insufficient to permit high enough drug concentrations for systemic therapy. In this study, we examined the feasibility of the topical/transdermal delivery of resveratrol. The effects of vehicles on the in vitro permeation and skin deposition from saturated solutions such as aqueous buffers and soybean oil were investigated. The general trend for the delivery from solutions was: pH 6 buffer=pH 8 buffer>10% glycerol formal in pH 6 buffer>pH 9.9 buffer>pH 10.8 buffer>soybean oil. A linear relationship was established between the permeability coefficient (K(p)) and drug accumulation in the skin reservoir. Viable epidermis/dermis served as the predominant barrier for non-ionic resveratrol permeation. On the other hand, both the stratum corneum (SC) and viable skin acted as barriers to anionic resveratrol. Several prototype hydrogel systems were also studied as resveratrol vehicles. The viscosity but not the polarity of the hydrogels controlled resveratrol permeation/deposition. Piceatannol, a derivative of resveratrol with high pharmacological activity, showed 11.6-fold lower skin permeation compared to resveratrol. The safety profiles of resveratrol suggested that the hydrogel caused no SC disruption or skin erythema. It was concluded that delivery via a skin route may be a potent way to achieve the therapeutic effects of resveratrol. This is the first report to establish the permeation profiles for topically applied resveratrol.

Topics: Adhesives; Administration, Topical; Animals; Antioxidants; Chromatography, High Pressure Liquid; Female; Flavonoids; Hydrogels; Mice; Mice, Nude; Pharmaceutical Solutions; Pharmaceutical Vehicles; Phenols; Polyphenols; Resveratrol; Skin Absorption; Solutions; Stilbenes; Viscosity; Water Loss, Insensible; Wine

In patients with atopic diseases, cationic-charged eosinophil proteins are deposited in inflamed tissues. Although the role of cytokines in cell activation is well established, the presence of cationic-charged tissue can also be an important factor in inflammatory cell function.. We sought to determine whether increased cationic charge seen in an atopic microenvironment plays a role in the activation of eosinophils.. Human eosinophils were incubated with Sepharose beads coated with cationic or anionic compounds in the presence and absence of a cytokine cocktail (IL-3, IL-5, and GM-CSF) to simulate the milieu of inflammation. Eosinophil peroxidase and eosinophil-derived neurotoxin (EDN) release were compared with eosinophil morphology and expression of CD18, as determined by means of confocal microscopy.. Cytokines with positively charged beads caused greater eosinophil peroxidase release (lysine coated, 44.2 nmol/L; compound 48/80, 40.0 nmol/L; or EDN coated, 49.1 nmol/L) than cytokines alone (14.9 nmol/L). Beads coated with heparin, dextran sulfate, and aspartic acid did not show this effect. EDN release was also induced by lysine-coated beads with cytokines (67.1 ng/100 microL) and blocked by heparin. Eosinophil incubation with wortmannin, genistein, and the src kinase inhibitor PP1 blocked cationic signaling. Eosinophils adherent to cationic-charged beads but not anionic-charged beads show polarization of CD18 expression toward the bead's surface.. Cationic-charged surfaces induce increased eosinophil mediator release by increasing the density of CD18 expression available at the target surface.

Topics: Androstadienes; Cations; CD18 Antigens; Cell Adhesion; Cell Degranulation; Cell Polarity; Cytokines; Dextran Sulfate; Eosinophil Cationic Protein; Eosinophil Peroxidase; Eosinophil-Derived Neurotoxin; Eosinophils; Genistein; Heparin; Humans; Protein Kinase Inhibitors; Protein Kinases; Receptors, Neuropeptide Y; Signal Transduction; Stilbenes; Wortmannin

Piceatannol and its parent compound, trans-resveratrol, decreased the in vitro catalytic activity of rat CYP1A1 and CYP1A2 by mixed inhibition. trans-Resveratrol was not a mechanism-based inactivator of rat CYP1A in vitro and the administration of this compound (50 mg/kg) to rats did not affect hepatic microsomal CYP1A-mediated enzyme activity.

Topics: Animals; Cytochrome P-450 CYP1A1; Cytochrome P-450 CYP1A2 Inhibitors; Enzyme Inhibitors; Male; Microsomes, Liver; Rats; Rats, Sprague-Dawley; Resveratrol; Stilbenes

Although few epidemiological studies have demonstrated that C-reactive protein (CRP) is related to insulin resistance, no study to date has examined the molecular mechanism. Here, we show that recombinant CRP attenuates insulin signaling through the regulation of spleen tyrosine kinase (Syk) on small G-protein RhoA, jun N-terminal kinase (JNK) MAPK, insulin receptor substrate-1 (IRS-1), and endothelial nitric oxide synthase in vascular endothelial cells. Recombinant CRP suppressed insulin-induced NO production, inhibited the phosphorylation of Akt and endothelial nitric oxide synthase, and stimulated the phosphorylation of IRS-1 at the Ser307 site in a dose-dependent manner. These events were blocked by treatment with an inhibitor of RhoA-dependent kinase Y27632, or an inhibitor of JNK SP600125, or the transfection of dominant negative RhoA cDNA. Next, anti-CD64 Fcgamma phagocytic receptor I (FcgammaRI), but not anti-CD16 (FcgammaRIIIa) or anti-CD32 (FcgammaRII) antibody, partially blocked the recombinant CRP-induced phosphorylation of JNK and IRS-1 and restored, to a certain extent, the insulin-stimulated phosphorylation of Akt. Furthermore, we identified that recombinant CRP modulates the phosphorylation of Syk tyrosine kinase in endothelial cells. Piceatannol, an inhibitor of Syk tyrosine kinase, or infection of Syk small interference RNA blocked the recombinant CRP-induced RhoA activity and the phosphorylation of JNK and IRS-1. In addition, piceatannol also restrained CRP-induced endothelin-1 production. We conclude that recombinant CRP induces endothelial insulin resistance and dysfunction, and propose a new mechanism by which recombinant CRP induces the phosphorylation of JNK and IRS-1 at the Ser307 site through a Syk tyrosine kinase and RhoA-activation signaling pathway.

Topics: Animals; C-Reactive Protein; Cattle; Cells, Cultured; Endothelial Cells; Endothelin-1; Endothelium, Vascular; Insulin; Insulin Receptor Substrate Proteins; Insulin Resistance; Intracellular Signaling Peptides and Proteins; MAP Kinase Kinase 4; MAP Kinase Signaling System; Mice; Nitric Oxide; Nitric Oxide Synthase Type III; Oncogene Protein v-akt; Phosphoproteins; Phosphorylation; Protein-Tyrosine Kinases; Receptors, IgG; Recombinant Proteins; rhoA GTP-Binding Protein; Signal Transduction; Stilbenes; Syk Kinase

The chemokine receptor CXCR3 is critical for the function of activated T cells. We studied the molecular mechanisms of CXCR3 signalling. The addition of CXCR3 ligands to normal human T cells expressing CXCR3 led to the tyrosine phosphorylation of multiple proteins. Addition of the same ligands to Jurkat T cells engineered to express CXCR3 induced tyrosine phosphorylation of proteins with molecular weights similar to those in normal cells. Immunoblotting with phosphotyrosine-specific antibodies identified Zeta-associated protein of 70,000 molecular weight (ZAP-70), linker for the activation of T cells (LAT), and phospholipase-C-gamma1 (PLCgamma1) to be among the proteins that become phosphorylated upon CXCR3 activation. ZAP-70 was phosphorylated on tyrosine 319, LAT on tyrosines 171 and 191, and PLCgamma1 on tyrosine 783. The ZAP-70 inhibitor piceatannol reduced CXCR3-mediated tyrosine phosphorylation of ZAP-70, LAT, PLCgamma1 and mitogen-activated protein kinase Erk and it reduced CXCL10-mediated chemotaxis of both CXCR3-transfected Jurkat T cells and normal T cells expressing CXCR3. These results are consistent with the involvement of ZAP-70 in CXCR3-mediated protein tyrosine phosphorylation and CXCR3-induced T-cell chemotaxis. Studies with the Lck-deficient Jurkat T-cell line, JCAM1.6, demonstrated that phosphorylation of ZAP-70 after CXCR3 activation is a Lck-dependent process. Finally, stimulating CXCR3-expressing Jurkat T cells and normal T cells expressing CXCR3 through the T-cell receptor attenuated CXCR3-induced tyrosine phosphorylation and CXCR3-mediated T-cell migration, indicating the occurrence of cross-talk between T-cell receptor and CXCR3-signalling pathways. These results shed light on the mechanisms of CXCR3 signalling. Such information could be useful when designing therapeutic strategies to regulate T-cell function.

Topics: Adaptor Proteins, Signal Transducing; Cells, Cultured; Chemotaxis, Leukocyte; Humans; Jurkat Cells; Ligands; Lymphocyte Activation; Membrane Proteins; Phospholipase C gamma; Phosphorylation; Protein-Tyrosine Kinases; Receptors, Antigen, T-Cell; Receptors, Chemokine; Receptors, CXCR3; Signal Transduction; Stilbenes; ZAP-70 Protein-Tyrosine Kinase

Here we investigated the role of spleen tyrosine kinase (Syk) in the migration induced by platelet-derived growth factor (PDGF) in rat aortic smooth muscle cells (RASMC).. Cell migration was determined using a Boyden chamber, by wound-healing, and by aortic ring assays. Activity of Syk, mitogen-activated protein kinase (MAPK), and heat shock protein 27 (HSP27) were tested using immunoblotting with kinase inhibitors and small interference RNAs.. PDGF-BB induced binding of Syk to the PDGFbeta receptor and increased the phosphorylation of Syk and migration in RASMC. These effects of PDGF-BB were inhibited by piceatannol, an inhibitor of Syk. PDGF-BB increased the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, p38 MAPK, and HSP27, which were significantly inhibited by piceatannol and in Syk-knockdown cells. The p38 MAPK inhibitor SB203580 and ERK1/2 inhibitor PD98059 inhibited the migration, which was further inhibited by the combination of these inhibitors. SB203580, but not PD98059, inhibited the phosphorylation of HSP27 induced by PDGF-BB in RASMC. PDGF-BB-induced migration was attenuated in HSP27-knockdown cells. Kinase inhibitors and Syk-knockdown diminished PDGF-BB-induced sprout outgrowth in the aortic ring assay.. These results imply that Syk is an upstream signal of the p38 MAPK/HSP27 and ERK1/2 pathways that contributes to PDGF-BB-mediated migration in RASMC.

Topics: Animals; Aorta; Becaplermin; Cell Movement; Cells, Cultured; Enzyme Activation; Enzyme Inhibitors; Flavonoids; Imidazoles; Immunoblotting; Immunoprecipitation; Intracellular Signaling Peptides and Proteins; MAP Kinase Signaling System; Mitogen-Activated Protein Kinases; Myocytes, Smooth Muscle; Phosphorylation; Platelet-Derived Growth Factor; Protein-Tyrosine Kinases; Proto-Oncogene Proteins c-sis; Pyridines; Rats; Receptor, Platelet-Derived Growth Factor beta; RNA Interference; RNA, Small Interfering; Stilbenes; Syk Kinase; Transfection

Biological activities of peanut stilbenoids, mainly resveratrol and its derivatives, have attracted increased attention and interest because of peanut being a potent producer and a dietary channel to convey these polyphenols to the human body. As arachidin-1 and piceatannol are structurally close to resveratrol, it is worthy to investigate their immunological activities on inhibition of lipopolysaccharide (LPS)-induced production of PGE2 and NO and mediation of the related transcription factors (NF-kappaB and C/EBP) of RAW 264.7 macrophage cells. Productions of PGE2 and NO were inhibited by all the test stilbenoids in a dose-dependent manner while gene and protein expressions of COX-2 and iNOS were not inhibited. As shown by NF-kappaB-driven luciferase assay, LPS-induced NF-kappaB activities were also reduced by the stilbenoids. In further, when these stilbenoids were subjected to monitoring their inhibitory effectiveness on LPS-induced transcription factor expressions of C/EBPdelta and C/EBPbeta, only C/EBPdelta expressions were reduced. Thus, these stilbenoids were effective in inhibition of PGE2- or NO-mediated inflammation and NF-kappaB- or C/EBPdelta-mediated inflammatory gene expression. In comparison, the highest inhibitory activity on LPS-induced PGE2/NO production, C/EBPdelta gene expression, and NF-kappaB activation was piceatannol which was followed in order by arachidin-1 and resveratrol. The observed anti-inflammatory activities of these peanut stilbenoids are of merit in further consideration for nutraceutical applications.

Topics: Animals; Anti-Inflammatory Agents; Arachis; Cell Line; Inflammation; Lipopolysaccharides; Macrophages; Mice; Resveratrol; Stilbenes

Disturbances in energy homeostasis can result in obesity and other metabolic diseases. Here we report a metabolic pathway present in normal human skeletal muscle myoblasts that is activated by the small polyphenolic molecule kaempferol (KPF). Treatment with KPF leads to an approximately 30% increase in skeletal myocyte oxygen consumption. The mechanism involves a several-fold increase in cyclic AMP (cAMP) generation and protein kinase A activation, and the effect of KPF can be mimicked via treatment with dibutyryl cAMP. Microarray and real-time PCR studies identified a set of metabolically relevant genes influenced by KPF including peroxisome proliferator-activated receptor gamma coactivator-1alpha, carnitine palmitoyl transferase-1, mitochondrial transcription factor 1, citrate synthase, and uncoupling protein-3, although KPF itself is not a direct mitochondrial uncoupler. The cAMP-responsive gene for type 2 iodothyronine deiodinase (D2), an intracellular enzyme that activates thyroid hormone (T3) for the nucleus, is approximately threefold upregulated by KPF; furthermore, the activity half-life for D2 is dramatically and selectively increased as well. The net effect is an approximately 10-fold stimulation of D2 activity as measured in cell sonicates, with a concurrent increase of approximately 2.6-fold in the rate of T3 production, which persists even 24 h after KPF has been removed from the system. The effects of KPF on D2 are independent of sirtuin activation and only weakly reproduced by other small polyphenolic molecules such as quercetin and fisetin. These data document a novel mechanism by which a xenobiotic-activated pathway can regulate metabolically important genes as well as thyroid hormone activation and thus may influence metabolic control in humans.

Topics: Animals; Cell Line; Chalcones; Cyclic AMP; Cyclic AMP-Dependent Protein Kinase Type II; Cyclic AMP-Dependent Protein Kinases; Dose-Response Relationship, Drug; Energy Metabolism; Gene Expression Profiling; Gene Expression Regulation; Humans; Iodide Peroxidase; Iodothyronine Deiodinase Type II; Kaempferols; Myoblasts; Oxygen Consumption; Rats; Resveratrol; RNA Interference; Stilbenes; Triiodothyronine

Beta-amyloid (Abeta) is a main component of senile plaques in Alzheimer's disease (AD) that induces neuronal cell death. Since reactive oxygen species (ROS) have been implicated in Abeta-induced neurotoxicity, considerable attention has recently been focused on identifying naturally occurring antioxidative phenolic phytochemicals that are able to decrease ROS levels. Piceatannol (trans-3,4,3',5'-tetrahydroxystilbene), which has a structure homologous to resveratrol, is an anti-inflammatory and antiproliferative stilbene compound derived from plants. This article investigated the possible protective effects of piceatannol on Abeta-induced PC12 neuronal cell death, and found that piceatannol exerted much stronger protective effects than did resveratrol. Piceatannol treatment attenuated the intracellular accumulation of ROS induced by treatment of PC12 cells with Abeta, inhibited Abeta-induced apoptotic features including internucleosomal DNA fragmentation, nucleus condensation, cleavage of poly(ADP-ribose) polymerase (PARP), and activation of caspase-3. These results suggest that piceatannol blocks Abeta-induced accumulation of ROS, thereby protecting PC12 cells from oxidative stress.

Topics: Amyloid beta-Peptides; Animals; Apoptosis; Dose-Response Relationship, Drug; Neurons; Neuroprotective Agents; PC12 Cells; Peptide Fragments; Rats; Resveratrol; Stilbenes

Piceatannol, compared with the renowned resveratrol, is a better anticancer agent and a superior agent with other biological activities. However, as there are only few plants reported to contain minute quantity of piceatannol, the scarcity of sources greatly impedes the piceatannol-related researches. To explore new sources of piceatannol, we established a sample preparation approach for screening the piceatannol in plants using HPLC-UV-fluorescence detection. When the HPLC is coupled with UV and fluorescence detectors, the decrease of signals in interferences and increase of signal in piceatannol in the fluorescence chromatogram mark clearly the position of the piceatannol peak; ultimately, it allows identification without standards. In this study, we systematically evaluated the factors affecting the extraction efficiency of piceatannol in sample preparation. Of the sample preparation strategies studied, direct solvent extraction and liquid nitrogen treatment followed by solvent extraction gave satisfactory recoveries for both piceatannol and resveratrol. These approaches avoided time-consuming lyophilization procedure. In addition, all procedures must be done in the dark to avoid negative impact of irradiation from fluorescence light on the recoveries of piceatannol and resveratrol. With the present method, we re-examined the plants previously claimed to contain only resveratrol for their piceatannol contents. The species examined included Polygonum cuspidatum, Arachis hypogaea, Vitis thunbergii, and Ampelopsis brevipedunculaata. The results showed, for the first time, all these plants contain piceatannol. The finding implies that the resveratrol-containing plants may also contain piceatannol. The results demonstrate the feasibility of these sample preparation approaches and may further the understanding for the distribution of piceatannol in plants.

Topics: Antineoplastic Agents; Arachis; Chromatography, High Pressure Liquid; Fallopia japonica; Plant Extracts; Reproducibility of Results; Resveratrol; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Stilbenes; Vitis

Although spleen tyrosine kinase (Syk) has crucial roles in various cells, its function on vascular smooth muscle contraction has not been determined. In the present study, we performed experiments to determine if Syk contributes to the endothelin-1 (ET-1)-mediated contraction in rat aortic smooth muscle. ET-1-induced contraction of aortic strips was inhibited by piceatannol, PD98059, and SB203580, inhibitors of Syk, extracellular signal-regulated kinase 1/2 (ERK1/2), and p38 mitogen-activated protein kinase (MAPK), respectively. Piceatannol also attenuated high K(+)-induced contraction. ET-1 dose-dependently enhanced the activity of Syk and this was inhibited by piceatannol in both rat aortic strip and rat aortic smooth muscle cells. The phosphorylation of p38 MAPK and heat shock protein 27 (HSP27), but not that of ERK1/2, in response to ET-1 was inhibited by both piceatannol and SB203580. These results suggest that Syk may play an important role in the regulation of aortic smooth muscle contraction induced by ET-1, which may be mediated by the p38 MAPK/HSP27 signaling pathway.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Aorta; Calcium-Calmodulin-Dependent Protein Kinases; Cells, Cultured; Dose-Response Relationship, Drug; Endothelin-1; Enzyme Inhibitors; Flavonoids; Imidazoles; Immunoblotting; Immunoprecipitation; In Vitro Techniques; Intracellular Signaling Peptides and Proteins; Male; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Protein-Tyrosine Kinases; Pyridines; Rats; Rats, Sprague-Dawley; Stilbenes; Syk Kinase; Vasoconstriction

To evaluate the effects of the anti-inflammatory hydroxystilbene, resveratrol, on Propionibacterium acnes growth.. Three different strains of P. acnes were tested against resveratrol at concentrations between 0 and 200 mg/L. Piceatannol was included as a second hydroxystilbene to compare with resveratrol, and erythromycin and benzoyl peroxide were used as positive controls.. After 24 h of treatment with resveratrol, the average 50% inhibitory concentration (IC(50)) was 73 mg/L and the average 100% inhibitory concentration (IC(100)) was 187 mg/L for the three strains of P. acnes tested. The IC(50) and IC(100) of piceatannol were 123 and 234 mg/L, respectively. The highest concentration of resveratrol tested (200 mg/L) was bactericidal, whereas lower concentrations were bacteriostatic.. Resveratrol, an anti-inflammatory hydroxystilbene, is capable of inhibiting P. acnes growth.

Topics: Anti-Bacterial Agents; Anti-Inflammatory Agents, Non-Steroidal; Benzoyl Peroxide; Dose-Response Relationship, Drug; Erythromycin; Keratolytic Agents; Microbial Sensitivity Tests; Propionibacterium acnes; Resveratrol; Stilbenes

Dectin-1 is a fungal pattern recognition receptor that binds to beta-glucans and triggers cytokine production by facilitating interaction with TLR2 or by directly activating spleen tyrosine kinase (Syk). To assess the possible role of Dectin-1 in the innate response to mycobacteria, we used an in vitro system in which IL-12p40 production is measured in splenic dendritic cells (SpDC) following exposure to live Mycobacterium tuberculosis bacilli. Treatment of SpDC with laminarin or glucan phosphate, two molecules known to block Dectin-1-dependent activity, led to a reduction in M. tuberculosis-induced IL-12p40 as well as IL-12p70 production. Moreover, SpDC from Dectin-1-/- chimeric mice displayed reduced IL-12p40 production in response to mycobacteria when compared with Dectin-sufficient DC. Laminarin treatment also inhibited mycobacterial-induced IL-12p40 production in DC from TLR2-/- mice, arguing that Dectin-1 functions independently of TLR2 signaling in this system. Importantly, a Dectin-1 fusion protein was found to directly bind to live mycobacteria in a laminarin-inhibitable manner indicating the presence of ligands for the receptor in the bacterium and laminarin pretreatment resulted in reduced association of mycobacteria to SpDC. In additional experiments, mycobacterial stimulation was shown to be associated with increased phosphorylation of Syk and this response was inhibited by laminarin. Furthermore, pharmacologic inhibition of Syk reduced the M. tuberculosis-induced IL-12p40 response. Together, these findings support a role for Dectin-1 in promoting M. tuberculosis-induced IL-12p40 production by DC in which the receptor augments bacterial-host cell interaction and enhances the subsequent cytokine response through an unknown mechanism involving Syk signaling.

Topics: Adjuvants, Immunologic; Animals; CD11b Antigen; Dendritic Cells; Female; Glucans; Hypolipidemic Agents; Interleukin-12; Interleukin-12 Subunit p40; Intracellular Signaling Peptides and Proteins; Lectins, C-Type; Male; Membrane Proteins; Mice; Mice, Inbred C57BL; Mice, Knockout; Mycobacterium tuberculosis; Nerve Tissue Proteins; Polysaccharides; Protein Kinase Inhibitors; Protein-Tyrosine Kinases; Receptors, Immunologic; Spleen; Stilbenes; Syk Kinase; Toll-Like Receptor 2

In this study, we clarified the intracellular mechanism of angiotensin II (Ang II) in promoting migration in rat aortic smooth muscle cells (RASMCs). RASMC migration was measured with the Boyden chamber assay, and the result was confirmed with an aortic sprout assay. The activities of kinases were investigated by western blot analysis. Ang II enhanced RASMC migration, which was chemotaxis directed, and induced the phosphorylation of p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase 1/2 (ERK1/2), and heat shock protein 27 (Hsp27). Ang II-enhanced cell migration was inhibited by SB203580 (a p38 MAPK inhibitor) and piceatannol (a spleen tyrosine kinase inhibitor), but only partially by PD98059 (an ERK inhibitor) and PP2 (a Src inhibitor). The Ang II-stimulated phosphorylation of p38 MAPK and Hsp27 in RASMCs was inhibited by piceatannol and SB203580. The phosphorylation of ERK1/2 stimulated by Ang II was suppressed by PD98059, piceatannol, and PP2. Ang II increased the sprout outgrowth from aortic rings and this response was attenuated by pretreatment with SB203580, PD98059, PP2, or piceatannol. These results suggest that p38 MAPK contributes to the regulation of the Ang II-induced chemotactic migration of vascular smooth muscle cells, which is mediated by Hsp27 phosphorylation.

Topics: Actins; Angiotensin II; Animals; Aorta; Calcium-Calmodulin-Dependent Protein Kinases; Cell Movement; Cell Proliferation; Cells, Cultured; Dose-Response Relationship, Drug; Enzyme Inhibitors; Flavonoids; Imidazoles; Intracellular Signaling Peptides and Proteins; Male; Mitogen-Activated Protein Kinase 1; Muscle, Smooth, Vascular; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Protein-Tyrosine Kinases; Pyridines; Pyrimidines; Rats; Rats, Sprague-Dawley; Signal Transduction; Stilbenes; Syk Kinase; Vasoconstrictor Agents

The cytotoxicity of resveratrol and of piceatannol, a structural analog of resveratrol, was examined in cultured cells. Using a MTT-based assay, which measures the conversion of 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) to a colored formazan product in living cells, resveratrol was found to inhibit the viability of transformed mouse macrophages, tumor-derived human T cells and human epidermoid carcinoma cells in a concentration-dependent manner, with the effect decreasing in the order: T cells (LC50 approximately 27 micromol L(-1), 24 h; approximately 9 micromol L(-1); 48 h)>macrophages (LC50 approximately 29 micromol L(-1), 24 h; 39 micromol L(-1), 48 h)>skin cells (LC50 approximately 91 micromol L(-1), 24 h; approximately 66 micromol L(-1), 48 h). Paradoxically, a high concentration of resveratrol (50 micromol L(-1)) inhibited the proliferation of all three cell types, and a low concentration (5 micromol L(-1)) stimulated the proliferation of macrophages. The viability of macrophages was also decreased by piceatannol in a concentration-dependent manner. The stimulation of macrophages with zymosan lowered the cytotoxicity of both resveratrol and piceatannol. Scanning electron microscopy of cells treated with resveratrol revealed changes in cellular morphology that were consistent with toxicity. In macrophages and skin cells, resveratrol (50 micromol L(-1)) induced a time-dependent increase in reduced glutathione levels but did not alter the background levels of thiobarbituric acid-reactive substances. Taken together, the present data indicate that resveratrol is toxic to cultured macrophages, T cells and skin cells at concentrations>or=25 micromol L(-1), and that the cytotoxicity occurs via a mechanism that does not involve oxidative stress. Furthermore, the degree of toxicity of both resveratrol and piceatannol towards macrophages depends on the activation status of these cells, with zymosan-activated cells appearing more resistant than nonstimulated cells.

Topics: Animals; Antioxidants; Cell Proliferation; Cell Survival; Glutathione; Humans; Lipid Peroxidation; Macrophages; Mice; Resveratrol; Skin; Stilbenes; T-Lymphocytes; Tumor Cells, Cultured

We previously reported that piceatannol isolated from the rhizome extract of RHEUM UNDULATUM has a potent vasorelaxant activity. In the present study, the mechanisms underlying the direct vascular relaxant effect of piceatannol were investigated in isolated rat aorta. Piceatannol induced a concentration-dependent relaxation in aortic preparations precontracted with phenylephrine (EC (50) : 2.4 +/- 0.4 microM), which was completely inhibited by endothelial removal, N(omega)-nitro- L-arginine (nitric oxide synthase inhibitor), methylene blue and 1 H- oxadiazolo [4,3- A]quinoxalin-1-one (guanylyl cyclase inhibitor). The piceatannol-induced relaxation was also blocked by raising the extracellular K (+) (45 mM), 4-aminopyridine (voltage-sensitive K (+) channel blocker) and tetraethylammonium [the non-selective Ca (2+)-activated K (+) (K (Ca)) channel blocker] but not by indomethacin (cyclooxygenase inhibitor), atropine (muscarinic receptor antagonist), propranolol (beta-adrenoceptor antagonist), verapamil and nifedipine (L-type voltage-gated Ca (2+) channel blocker), barium chloride (inward rectifier K (+) channel inhibitor) and glibenclamide (ATP-sensitive K (+) channel blocker). In further studies investigating the role of Ca (2+)-activated K (+) (K (Ca)) channels, piceatannol-induced relaxant responses were decreased by charybdotoxin [large (BK (Ca))- and intermediate (IK (Ca))-conductance K (Ca) channel blocker], iberiotoxin (selective BK (Ca) channels blocker), but not by apamin [small-conductance K (Ca) (SK (Ca)) channel blocker], TRAM-34 [intermediate-conductance K (Ca) (IK (Ca)) channel blocker]. The present results demonstrate that piceatannol-induced vascular relaxation in rat aorta may be mediated by an endothelium-dependent nitric oxide signaling pathway, at least partially, through the activation of BK (Ca).

Topics: Animals; Aorta; Electric Conductivity; Molecular Structure; Potassium Channels, Calcium-Activated; Rats; Rats, Sprague-Dawley; Rheum; Rhizome; Stilbenes; Vasodilation

In our efforts to find new skin lightening agents, piceatannol (PICE) was investigated for its antioxidative property and ability to inhibit melanogenesis. In this study, PICE's effect on inhibition of mushroom tyrosinase, and tyrosinase inhibiting activity and melanin content were assessed utilizing the B16F10 melanoma cell (B16 cell) culture system. Results indicated that PICE has a strong antityrosinase activity (IC(50)=1.53 microM). To evaluate the relative efficacy of PICE compared to other tyrosinase inhibitors, its inhibitory effect was compared and showed that PICE was significantly stronger than kojic acid (IC(50)=50.1 microM) and resveratrol (IC(50)=63.2 microM). Furthermore, PICE was shown to down-regulate melanin content. To document PICE's antioxidative property, which is known to influence melanogenic activity, we assessed reactive species (RS) generation, reduced glutathione (GSH) and oxidized glutathione (GSSG) levels in these B16 cells. The results showed that PICE suppressed RS generation and enhanced the GSH/GSSG ratio. In conclusion, our results indicated that the antimelanogenic action of PICE is likely exhibited by the combined effect of PICE's antioxidative property and its ability to suppress RS generation while increasing the GSH/GSSG ratio.

Topics: Animals; Antioxidants; Cell Line, Tumor; Dose-Response Relationship, Drug; Down-Regulation; Glutathione; Glutathione Disulfide; Inhibitory Concentration 50; Melanins; Melanocytes; Melanoma, Experimental; Mice; Molecular Structure; Monophenol Monooxygenase; Pyrones; Reactive Oxygen Species; Resveratrol; Stilbenes

Studies of patients with congenital immunodeficiency due to mutation of the NF-kappaB essential modulator (NEMO) gene have demonstrated that NEMO integrity is required for NK cell cytotoxicity. Thus, we have studied the physiology of NF-kappaB activation in NK cells during the cytolytic program. In resting ex vivo human NK cells or cell lines, IkappaB was degraded after 10 min exposure to PMA and ionomycin, or TNF and was maximally degraded by 30 min. Ligation of several NK cell activation receptors including NKp30 induced a similar response and was blocked by pretreatment with the proteosome inhibitor MG132. There was no short-term effect on p100 processing, the signature of noncanonical NF-kappaB activation. NK cell IkappaB degradation corresponded to increases in nuclear NF-kappaB as detected by EMSA. Supershift of stimulated NK cells and fluorescence microscopy of individual NK cells in cytolytic conjugates demonstrated that the p65/p50 heterodimer was the primary NF-kappaB used. NF-kappaB function was evaluated in NK92 cells transduced with a kappaB GFP reporter, and their conjugation with K562 cells or ligation of NKp30 ligation resulted in rapid GFP accumulation. The latter was prevented by the Syk inhibitor piceatannol. Thus, NK cell activation signaling specifically induces transcriptional activation and synthesis of new NF-kappaB dependent proteins during the initiation of cytotoxicity.

Topics: Cell Line; Green Fluorescent Proteins; Humans; Ionomycin; K562 Cells; Killer Cells, Natural; Leupeptins; Natural Cytotoxicity Triggering Receptor 3; NF-kappa B; Receptors, Immunologic; Signal Transduction; Stilbenes; Tetradecanoylphorbol Acetate; Tumor Necrosis Factor-alpha

Glycoprotein (GP)VI, that binds collagen, together with GPIb-IX-V which binds vonWillebrand factor, forms an adheso-signalling complex on platelets that initiates thrombus formation in haemostasis and thrombosis. In this study, we show that two snake venom metalloproteinases, crotarhagin and alborhagin, induce ectodomain shedding of GPVI by a mechanism that involves activation of endogenous platelet metalloproteinases. Alborhagin is a viper venom metalloproteinase from Trimeresurus albolabris, while crotarhagin is a previously undescribed toxin from the rattlesnake Crotalus horridus horridus ( approximately 60-kDa non-reduced and reduced). Like alborhagin, crotarhagin induces aggregation in human platelet-rich plasma (maximal activity, approximately 0.3 microg/ml). Aggregation of washed platelets was inhibited by soluble GPVI ectodomain expressed as an Fc-fusion protein, confirming crotarhagin targeted GPVI. Treating washed platelets with crotarhagin or alborhagin resulted in time-dependent loss of surface GPVI and the appearance of an approximately 55-kDa soluble GPVI fragment in supernatants. Crotarhagin also induced shedding in GPVItransfected RBL-2H3 cells. Crotarhagin-induced shedding was metalloproteinase-dependent (inhibited by EDTA), but also blocked by inhibitors of GPVI signalling (Src kinase inhibitors, PP1 or PP2, or Syk inhibitor, piceatannol), indicating shedding required GPVI-dependent platelet activation. Together, the data suggest that the rattlesnake metalloproteinase, crotarhagin, and the viper toxin alborhagin, induce GPVI shedding by a mechanism involving activation of endogenous platelet metalloproteinases rather than direct cleavage of GPVI.

Topics: Animals; Blood Platelets; Cell Line; Crotalid Venoms; Dose-Response Relationship, Drug; Edetic Acid; Enzyme Activation; Humans; In Vitro Techniques; Intracellular Signaling Peptides and Proteins; Metalloendopeptidases; Metalloproteases; Peptide Fragments; Platelet Aggregation; Platelet Membrane Glycoproteins; Protease Inhibitors; Protein Kinase Inhibitors; Protein Structure, Tertiary; Protein-Tyrosine Kinases; Pyrazoles; Pyrimidines; Rats; Receptors, Collagen; Recombinant Fusion Proteins; Signal Transduction; src-Family Kinases; Stilbenes; Syk Kinase; Time Factors; Transfection; Viper Venoms

Piceatannol is an anti-inflammatory and anti-proliferative plant-derived stilbene. Heme oxygenase-1 (HO-1) is a cytoprotective enzyme to activate by various phytochemicals. In this study, we examined the ability of piceatannol to upregulate HO-1 expression in endothelial cells. We found piceatannol at micromolar (10-50 microM) concentrations dramatically increased HO-1 protein levels in a time-dependent manner. Piceatannol was similarly potent in the induction of HO-1 as hemin, arsenate, and 15d-PGJ2, and was more potent than some other phytochemicals including curcumin, EGCG, baicalein, and quercetin. In contrast, the similar chemical structure compounds, trans-stilbene, stilbene oxide, and resveratrol had no HO-1-inducing effects, suggesting a critical role for the hydroxyl groups in HO-1 induction. No cytotoxicity and superoxide production was observed after 10-50 microM piceatannol treatments. Piceatannol-mediated HO-1 induction was abrogated in the presence of N-acetylcysteine and glutathione, but not by other antioxidants. Induction of HO-1 by piceatannol was further enhanced by using buthionine sulfoximine. In addition, we determined that tyrosine kinase was involved in the induction of HO-1 by using tyrosine kinase inhibitors, herbimycin A, erbstatin, and genistein; in contrast, no significant changes in the pretreatment of PI3 kinase or MAP kinase inhibitors was determined. HO-1 induction was blocked by the protein kinase C inhibitors calphostin C, rottlerin, and long PMA pretreatment, whereas conventional PKC inhibitors, Go6976, and Ca2+ chelator BAPTA/AM, had no effect. Elevated HO-1 protein levels were associated with the inhibition of tumor necrosis factor-alpha (TNFalpha)-induced intercellular adhesion molecule-1 (ICAM-1) expression. Treating ECs with zinc protoporphyrin, an HO-1 inhibito blocked the anti-inflammatory effect of piceatannol. In summary, this study identified piceatannol as a novel phytochemical inducer of HO-1 expression and identified the mechanisms involved in this process.

Topics: Animals; Blotting, Western; Cattle; Cell Survival; Cells, Cultured; Endothelium, Vascular; Enzyme Induction; Gene Expression Regulation, Enzymologic; Heme Oxygenase-1; Intercellular Adhesion Molecule-1; Luminescent Measurements; Protein Kinase C; Protein-Tyrosine Kinases; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Stilbenes; Superoxides; Tumor Necrosis Factor-alpha; Up-Regulation

Shiga toxin (Stx) is composed of an A-moiety that inhibits protein synthesis after translocation into the cytosol, and a B-moiety that binds to Gb3 at the cell surface and mediates endocytosis of the toxin. After endocytosis, Stx is transported retrogradely to the endoplasmic reticulum, and then the A-fragment enters the cytosol. In this study, we have investigated whether toxin-induced signaling is involved in its entry. Stx was found to activate Syk and induce rapid tyrosine phosphorylation of several proteins, one protein being clathrin heavy chain. Toxin-induced clathrin phosphorylation required Syk activity, and in cells overexpressing Syk, a complex containing clathrin and Syk could be demonstrated. Depletion of Syk by small interfering RNA, expression of a dominant negative Syk mutant (Syk KD), or treatment with the Syk inhibitor piceatannol inhibited not only Stx-induced clathrin phosphorylation but also endocytosis of the toxin. Also, Golgi transport of Stx was inhibited under all these conditions. In conclusion, our data suggest that Stx regulates its entry into target cells.

Topics: Clathrin Heavy Chains; Endocytosis; Enzyme Activation; Genistein; Golgi Apparatus; HeLa Cells; Humans; Intracellular Signaling Peptides and Proteins; Multiprotein Complexes; Phosphorylation; Protein Binding; Protein Transport; Protein-Tyrosine Kinases; Shiga Toxin; Stilbenes; Syk Kinase; Tyrosine

Among B-cell lymphomas mantle cell lymphoma (MCL) has the worst prognosis. By using a combination of genomic and expression profiling (Affymetrix GeneChip Mapping 10k Xba131 and U133 set), we analysed 26 MCL samples to identify genes relevant to MCL pathogenesis and that could represent new therapeutic targets. Recurrent genomic deletions and gains were detected. Genes were identified as overexpressed in regions of DNA gain on 3q, 6p, 8q, 9q, 16p and 18q, including the cancer genes BCL2 and MYC. Among the transcripts with high correlation between DNA and RNA, we identified SYK, a tyrosine kinase involved in B-cell receptor signalling. SYK was amplified at DNA level, as validated by fluorescence in situ hybridisation (FISH) analysis, and overexpressed at both RNA and protein levels in the JeKo-1 cell line. Low-level amplification, with protein overexpression of Syk was demonstrated by FISH in a small subset of clinical samples. After treatment with low doses of the Syk inhibitor piceatannol, cell proliferation arrest and apoptosis were induced in the cell line overexpressing Syk, while cells expressing low levels of Syk were much less sensitive. A combination of genomic and expression profiling suggested Syk inhibition as a new therapeutic strategy to be explored in lymphomas.

Topics: Apoptosis; B-Lymphocytes; Cell Division; Cell Line, Tumor; DNA, Neoplasm; Enzyme Precursors; Gene Deletion; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Genes, Neoplasm; Humans; Immunohistochemistry; In Situ Hybridization, Fluorescence; Intracellular Signaling Peptides and Proteins; Lymphoma, Mantle-Cell; Neoplasm Proteins; Protein-Tyrosine Kinases; RNA, Neoplasm; Stilbenes; Syk Kinase; Transcription, Genetic

Piceatannol (1) was found to be more effective than caffeic acid, an established antinitrosating agent, in inhibiting N-nitrosation of 2,3-diaminonaphthalene. Product analysis of the reaction mixture of 1 (20 microM) with nitrite ions (80 microM) at pH 3.0 and at 37 degrees C showed conversion to a single major nitration product, (E)-3,3',4,5'-tetrahydroxy-beta-nitrostilbene (2) (68% yield). This would result from an unexpected nitration at the double bond sector via the 4-phenoxyl radical, which was analyzed at the unrestricted DFT level.

Topics: Antioxidants; Caffeic Acids; Catechols; Ions; Molecular Conformation; Naphthalenes; Nitrates; Nitrites; Nitrosation; Phenols; Plant Oils; Stilbenes

Formation of ATP from ADP on the external surface of vascular endothelial cells has been attributed to plasma membrane ATP synthase, ectoadenylate kinase (ecto-AK), and/or ectonucleoside diphosphokinase. These enzymes or their catalytic products have been causatively linked to the elaboration of vascular networks and the regulation of capillary function. The amount of ATP generated extracellularly is small, requiring sensitive analytical methods for quantification. Human umbilical vein endothelial cells were used to revisit extracellular ATP synthesis using a reliable tetrazolium reduction assay and multiwell plate cultures. Test conditions compatible with AK stability were established. Extracellular AK activity was found to be <1% of the total (intracellular and extracellular), raising the possibility that the external enzyme could have leaked from living cells and/or a few dying cells. To determine whether AK inadvertently leaked from the cells, the activity of another cytoplasmic enzyme, glucose-6-phosphate dehydrogenase (G6PD), was also measured. G6PD is present in the cytoplasm in similar abundance to AK. The activity ratio of G6PD (extracellular/total) was found to be similar to that of AK. Because G6PD in the medium was probably due to leakage, other cytoplasmic macromolecules, including AK, should be released proportionately from the cells. The role of plasma membrane ATP synthase in extracellular ATP formation was examined using Hanks' balanced salt solution with and without selective inhibitors of AK and ATP synthase activities. With P(1),P(5)-di(adenosine 5')-pentaphosphate (inhibitor of AK activity), no extracellular ATP synthesis was detected, whereas with oligomycin, piceatannol, and aurovertin (inhibitors of F(1)F(0)-ATP synthase and F(1)-ATPase activities), no inhibition of extracellular ATP synthesis was observed. AK activity alone could account for the observed extracellular ATP synthesis. The possible impact of ADP impurity in the assays is discussed.

Topics: Adenylate Kinase; Animals; Aurovertins; Cattle; Cell Membrane; Cytoplasm; Endothelial Cells; Enzyme Inhibitors; Humans; Kinetics; Oligomycins; Proton-Translocating ATPases; Rabbits; Stilbenes

Streptococcus pneumoniae is the most common organism responsible for community acquired pneumonia and meningitis. In pneumococcal pneumonia, a strong local inflammatory cytokine response reduces the frequency of bacteremia and increases survival. The initiation of this cytokine response by innate recognition of bacterial cell wall components through TLR has been described, but the role of soluble innate mediators has received limited attention. C-reactive protein (CRP) is an acute phase protein that binds phosphocholine residues on S. pneumoniae cell walls. CRP interacts with phagocytic cells through FcgammaRI and FcgammaRII and activates the classical complement pathway. CRP is protective in mouse pneumococcal bacteremia by increasing complement-dependent clearance and killing of bacteria. We studied the cytokine response of PBMC stimulated with CRP-opsonized S. pneumoniae to determine the effect of CRP interaction with FcgammaR. CRP dramatically increased the production of TNF-alpha and IL-1beta in response to S. pneumoniae. These increases were blocked by phosphocholine, which inhibits CRP binding to S. pneumoniae, by inhibitors of FcgammaR signaling, and by mAb to FcgammaRI and FcgammaRII. A mutated rCRP with decreased FcgammaR binding had a decreased ability to stimulate TNF-alpha release, compared with wild-type CRP. Individuals who were homozygous for the R-131 allele of FcgammaRIIA, which has a higher affinity for CRP, showed higher responses to CRP-opsonized bacteria than did individuals homozygous for the H-131 allele, further implicating this receptor. The results indicate that CRP recognition of S. pneumoniae and binding to FcgammaR may enhance the early protective cytokine response to infection.

Topics: Alleles; Androstadienes; Antibodies, Blocking; Antibodies, Monoclonal; C-Reactive Protein; Cells, Cultured; Cytokines; Humans; Interleukin-1; Leukocytes, Mononuclear; Ligands; Mutagenesis, Site-Directed; Opsonin Proteins; Polymorphism, Genetic; Protein Binding; Receptors, IgG; Signal Transduction; Stilbenes; Streptococcus pneumoniae; Tumor Necrosis Factor-alpha; Up-Regulation; Wortmannin

From stem bark of Callistemon rigidus (Myrtaceae), piceatannol and scirpusin B were isolated as components that exhibit inhibitory effects on alpha-amylase activity in isolated mouse plasma. In particular, scirpusin B also inhibited alpha-amylase in mouse gastrointestinal tract. Thus, we expect the depressive effect on the elevation of postprandial blood glucose may be a new medicinal use of this compound as well as the plant itself.

Topics: Administration, Oral; alpha-Amylases; Animals; Benzofurans; Blood Glucose; Enzyme Inhibitors; Gastrointestinal Tract; Hypoglycemic Agents; Male; Mice; Mice, Inbred Strains; Molecular Structure; Myrtaceae; Plant Bark; Plant Extracts; Plant Stems; Stilbenes

Postharvest treatment of seedless white table grapes (var. 'Superior') with different gas ozone concentrations (3.88 and 1.67 g/h) for 1, 3, and 5 h induced an increase in stilbenoid biosynthesis [trans-resveratrol, piceatannol, and viniferinas (resveratrol dehydrodimers and dehydrotrimers)] during storage at 22 degrees C and 95% relative humidity. The maximal resveratrol concentration was reached after 2 days of storage, and this amount was similar to that induced by optimized UV-C treatments (1 min, 510 W, 40 cm). Although similar resveratrol concentrations accumulated in grapes after both UV-C and O3 treatments (maximum ozone production and time), the ozone treatment was more efficient in inducing viniferins accumulation in grape berries. A sequence in the biosynthesis of stilbenoids was observed, starting with the resveratrol monomer, continuing with the resveratrol dehydrodimers epsilon-viniferin and delta-viniferin, and ending with four different resveratrol dehydrotrimers. These trimers were different from alpha-viniferin, a trimer previously reported to be induced in grapes after biotic and abiotic stresses. Two alpha-viniferin isomers were also detected in the ozone-treated grapes, although at very low concentrations that prevented their quantification.

Topics: Fruit; Ozone; Resveratrol; Stilbenes; Ultraviolet Rays; Vitis

trans-Resveratrol (t-RES) is one of the most relevant and extensively investigated stilbenes with a broad spectrum of biological activities. In contrast to the detailed knowledge of t-RES activities in biological systems, much less is known about the effects of higher hydroxylated stilbenes. Therefore, the aim of this study was to evaluate the protective effects (antioxidant activities) of t-RES and two analogues: the natural metabolite piceatannol (PCA) and the synthesized 3,3',4,4',5,5'-hexahydroxy-trans-stilbene (HHS) against H2O2-induced DNA damage in leukemic L1210, K562 and HL-60 cells using single-cell gel electrophoresis (SCGE). After 24 h pre-treatment of cells all compounds investigated significantly inhibited the incidence of DNA single strand breaks induced by H2O2. The protective effects of PCA and HHS in L1210 cells and of HHS in HL-60 cells were significantly higher compared to the activity of t-RES (+P < 0.05). In K562 cells the differences of the antioxidant activities of PCA and HHS, and of PCA in HL-60 cells were of much higher significance when compared to t-RES (++P < 0.01). In conclusion, we can prove that all stilbenes investigated, t-RES, PCA, and HHS, manifested potent antioxidant effects on three leukemic cell lines and the presence of ortho-dihydroxy structures enhanced the protective effect against DNA damage caused by .OH radicals.

Topics: Animals; Antineoplastic Agents, Phytogenic; Antioxidants; Cell Survival; DNA Damage; HL-60 Cells; Humans; Hydrogen Peroxide; K562 Cells; Leukemia; Mice; Oxidants; Protein-Tyrosine Kinases; Resveratrol; Ribonucleotide Reductases; Stilbenes

Instead of blocking oocyte maturation as it does in most animals, cAMP causes oocytes of marine nemertean worms to initiate maturation (=germinal vesicle breakdown, "GVBD"). To characterize cAMP-induced GVBD in nemerteans, inhibitors of tyrosine kinase signaling were tested on Cerebratulus sp. oocytes that had been incubated in cAMP-elevating drugs versus seawater (SW) alone. Such tests yielded similar results for Src-like tyrosine kinase blockers, as the inhibitors prevented mitogen-activated protein kinase (MAPK) activation without stopping either GVBD or maturation-promoting factor (MPF) activation in both SW and cAMP-elevating treatments. Alternatively, genistein, a general tyrosine kinase antagonist, and piceatannol, an inhibitor of the tyrosine kinase Syk, reduced GVBD and MAPK/MPF activities in SW-, but not cAMP-induced maturation. Similarly, inhibitors of the human epidermal growth factor receptor-2 (HER-2) tyrosine kinase prevented GVBD and MAPK/MPF activations in oocytes treated with SW, but not with cAMP-elevating drugs. Antagonists of either protein tyrosine phosphatases (PTPs) or the dual-specificity phosphatase Cdc25 also reduced GVBD and MAPK/MPF activities in SW-treated oocytes without generally affecting cAMP-induced maturation. Collectively, these data suggest cAMP triggers GVBD via pathways that do not require MAPK activation or several components of tyrosine kinase signaling. In addition, such differences in tyrosine kinase cascades, coupled with the dissimilar patterns of Ser/Thr kinase signaling described in the accompanying study, indicate that nemertean oocytes are capable of utilizing multiple mechanisms to activate MPF during GVBD.

Topics: Animals; Annelida; Butadienes; cdc25 Phosphatases; Cyclic AMP; Eukaryotic Cells; Genistein; Intracellular Signaling Peptides and Proteins; Maturation-Promoting Factor; Mitogen-Activated Protein Kinases; Models, Biological; Nitriles; Oocytes; Protein Tyrosine Phosphatases; Protein-Tyrosine Kinases; Receptor Protein-Tyrosine Kinases; Receptor, ErbB-2; Seawater; src-Family Kinases; Stilbenes; Syk Kinase

The mammalian target of rapamycin (mTOR) is emerging as a promising target for antitumor therapy. However, the mechanism that contributes to its regulation in B lymphomas remains unknown. This study shows that in follicular lymphoma (FL) cells, mTOR is active because the cells displayed rapamycin-sensitive phosphorylation of p70S6 kinase and 4E-BP1. Moreover, immunohistochemistry applied on lymph node tissue sections obtained from patients with FL revealed that, in most cases, p70S6 kinase was highly phosphorylated compared to normal tonsillar tissue. In FL cells, mTOR was under control of both phospholipase D (PLD) and phosphatidylinositol 3-kinase (PI3K). Moreover, we demonstrated that Syk plays a central role in mTOR activation because we found that both expression and activity are elevated compared to normal or chronic lymphocytic leukemia B cells. We also provide evidence that Syk operates through PLD- and PI3K-independent pathways. Finally, Syk inhibition by piceatannol or by siRNA plasmids resulted in a potent inhibition of mTOR activity in FL cells, as well as in mantle cell lymphoma, Burkitt lymphoma, and diffuse large B-cell lymphoma. These findings suggest that the Syk-mTOR pathway has a critical function in FL survival, and therefore, that Syk could be a promising new target for B-lymphoma therapy.

Topics: Burkitt Lymphoma; Cell Line, Tumor; Enzyme Activation; Humans; Intracellular Signaling Peptides and Proteins; Leukemia, Lymphocytic, Chronic, B-Cell; Lymph Nodes; Lymphoma, B-Cell; Lymphoma, Follicular; Lymphoma, Mantle-Cell; Neoplasm Proteins; Palatine Tonsil; Phosphatidylinositol 3-Kinases; Phospholipase D; Protein Kinases; Protein-Tyrosine Kinases; Ribosomal Protein S6 Kinases, 70-kDa; RNA, Small Interfering; Signal Transduction; Stilbenes; Syk Kinase; TOR Serine-Threonine Kinases

Resveratrol has been shown to have anticarcinogenic activity. We previously found that resveratrol inhibited growth and induced apoptosis in 2 human melanoma cell lines. In this study we determined whether resveratrol would inhibit human melanoma xenograft growth. Athymic mice received control diets or diets containing 110 micromol/L or 263 micromol/L resveratrol, 2 wk prior to subcutaneous injection of the tumor cells. Tumor growth was measured during a 3-wk period. Metabolism of resveratrol was assayed by bolus gavage of 75 mg/kg resveratrol in tumor-bearing and nontumor-bearing mice. Pellets containing 10-100 mg resveratrol were implanted into the mice, next to newly palpated tumors, and tumor growth determined. We also determined the effect of a major resveratrol metabolite, piceatannol, on experimental lung metastasis. Resveratrol, at any concentration tested, did not have a statistically significant effect on tumor growth. The higher levels of resveratrol tested (0.006% in food or 100 mg in slow-release pellets) tended to stimulate tumor growth (P = 0.08-0.09). Resveratrol and its major metabolites, resveratrol glucuronide and piceatannol, were found in serum, liver, skin, and tumor tissue. Piceatannol did not affect the in vitro growth of a murine melanoma cell line, but significantly stimulated the number of lung metastases when these melanoma cells were directly injected into the tail vein of the mouse. These results suggest that resveratrol is not likely to be useful in the treatment of melanoma and that the effects of phytochemicals on cell cultures may not translate to the whole animal system.

Topics: Animals; Anticarcinogenic Agents; Cell Division; Cell Line, Tumor; Chromatography, High Pressure Liquid; Delayed-Action Preparations; Diet; Drug Implants; Humans; Lung Neoplasms; Male; Melanoma; Mice; Mice, Inbred C57BL; Mice, Nude; Neoplasm Metastasis; Neoplasm Transplantation; Oxidation-Reduction; Resveratrol; Stilbenes; Transplantation, Heterologous

Caveolae and its structural protein caveolin-1 (Cav-1) are abundant in vascular endothelial cells (ECs) and have been suggested to contribute to cell signaling and cholesterol trafficking. This study investigated the effect of cholesterol on the movement of caveolae-related proteins in human umbilical vein ECs with use of caveolae functional proteomics. After cholesterol exposure to ECs for 2 to 4 h, caveolae were isolated and separated on 2-D protein gels. Among 40 protein spots revealed in caveolae fractions, the ATP synthase beta subunit (ATPS-beta), one of the 3 proteins enriched by cholesterol in caveolae, was confirmed by western blotting and confocal microscopy. Further, cholesterol exposure increased the level of ATPS-beta, along with Cav-1 and cholesterol in caveolae. These effects could be blocked by cytochalasin B, an actin cytoskeleton disruptor. ATPS-beta was physically associated with Cav-1, as demonstrated by co-immunoprecipitation and GST-Cav-1 fusion protein pull-down assay. Cholesterol increased the extracellular ATP release mediated by ATPS-beta, since this action could be blocked by piceatannol or oligomycin, ATPS inhibitors. Thus, the ectopic localization of ATPS-beta may participate in the energy balance of cells in response to the change in intracellular cholesterol levels.

Topics: Caveolae; Caveolin 1; Cell Membrane; Cells, Cultured; Cholesterol; Cytochalasin B; Endothelium, Vascular; Humans; Mitochondrial Proton-Translocating ATPases; Oligomycins; Protein Subunits; Protein Transport; Proteomics; Stilbenes

Piceatannol (3,3',4,5'-tetrahydroxy-trans-stilbene) is a polyphenol present in grapes and wine. By means of alkaline phosphatase activity and osteocalcin enzyme-linked immunosorbent assay (ELISA), we have shown that piceatannol exhibits a significant induction of differentiation in immortalized fetal osteoblasts (hFOB), and osteosarcoma cells (MG-63). Alkaline phosphatase and osteocalcin are phenotypic markers for early-stage differentiated osteoblasts and terminally differentiated osteoblasts, respectively, our results indicate that piceatannol stimulate osteoblast differentiation at various stages (from maturation to terminally differentiated osteoblasts). Induction of differentiation by piceatannol was associated with increased bone morphogenetic protein-2 (BMP-2) production. Addition of purified BMP-2 protein did not increase the upregulation of alkaline phosphatase activity and osteocalcin secretion by piceatannol, whereas the BMP-2 antagonist noggin blocked piceatannol and BMP-2-mediated alkaline phosphatase activity, and osteocalcin secretion enhancement, indicating that BMP-2 production is required in piceatannol-mediated osteoblast maturation and differentiation. In conclusion, piceatannol increased BMP-2 synthesis, and this effect may contribute to its action on the induction of osteoblasts maturation and differentiation, followed by an increase of bone mass. Decreases in new bone formation, followed by estrogen deficiency or various pathologic factors, may contribute to the mechanisms involved in postmenopausal osteoporosis.

Topics: Alkaline Phosphatase; Bone Density Conservation Agents; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Calcification, Physiologic; Carrier Proteins; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Collagen Type I; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Humans; Osteoblasts; Osteocalcin; Osteogenesis; Protein Biosynthesis; RNA, Messenger; Stilbenes; Time Factors; Transcription, Genetic; Transforming Growth Factor beta; Up-Regulation

Proinflammatory mediators, such as prostaglandin E(2) (PGE(2)), nitric oxide (NO), and proinflammatory cytokines [interlukin (IL)-1beta, IL-6, and tumor necrosis factor (TNF)-alpha] play pivotal roles in brain injuries. Anti-inflammatory responses are associated with significant downregulation of these proinflammatory mediators following brain injury. In the present study, we investigated the effects of piceatannol (PIC) on the production of proinflammatory mediators in lipopolysaccharide (LPS)-stimulated BV2 microglia. PIC significantly inhibited the release of NO, PGE(2), and proinflammatory cytokines in a dose-dependent manner. PIC also attenuated the expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 mRNA and protein levels. Moreover, PIC prevented NF-kappaB p65 nuclear translocation. Our data also indicate that PIC exhibits anti-inflammatory properties by suppressing the transcription of proinflammatory cytokine genes through the NF-kappaB signaling pathway. The anti-inflammatory properties of PIC may be useful for attenuating inflammatory diseases and LPS-stimulated microglial activation.

Topics: Animals; Blotting, Western; Cell Line; Cell Survival; Cyclooxygenase 2; Cytokines; Dinoprostone; Dose-Response Relationship, Drug; Enzyme Inhibitors; Enzyme-Linked Immunosorbent Assay; Inflammation Mediators; Lipopolysaccharides; Luciferases; Mice; Microglia; NF-kappa B; Nitric Oxide; Nitric Oxide Synthase Type II; Nitrites; Reverse Transcriptase Polymerase Chain Reaction; RNA; Stilbenes

We have recently found that Syk is widely expressed in lung epithelial cells (EC) and participates in beta1 integrin signaling. In this study, we assessed the role of Syk in regulation of NO production. Stimulation of human bronchial EC line HS-24 by TNF caused an increased expression of inducible nitric oxide synthase (iNOS). Inhibition of Syk using siRNA or piceatannol down-regulated the iNOS expression and reduced NO production. This effect occurred in EC simultaneously stimulated via beta1 integrins, suggesting that TNF and beta1 integrins provide co-stimulatory signals. Inhibition of Syk down-regulated TNF-induced p38 and p44/42 MAPK phosphorylation and nuclear translocation of p65 NF-kappaB. Thus, TNF-induced activation of pro-inflammatory signaling in EC leading to enhanced expression of iNOS and NO production was dependent on Syk. Syk-mediated signaling regulates NO production at least partly via activating the MAPK cascade. Understanding the role of Syk in airway EC may help in developing new therapeutic tools for inflammatory lung disorders.

Topics: Bronchi; Cell Line; Down-Regulation; Enzyme Activation; Epithelial Cells; Extracellular Signal-Regulated MAP Kinases; Humans; Integrin beta1; Intracellular Signaling Peptides and Proteins; Nitric Oxide; Nitric Oxide Synthase Type II; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Protein-Tyrosine Kinases; Respiratory Mucosa; RNA, Small Interfering; Signal Transduction; Stilbenes; Syk Kinase; Transcription Factor RelA; Tumor Necrosis Factor-alpha

The pharmacokinetics of piceatannol, pinosylvin and rhapontigenin were characterized in male Sprague-Dawley rats after single intravenous doses of 10 mg kg(-1) of each stilbene. Serial blood samples were collected via a catheter inserted into the right jugular vein and plasma samples were analysed for the selected stilbenes concentrations using reverse phase HPLC methods. After an acute intravenous dose of piceatannol, plasma AUC, urine t(1/2), CL and V(d) were 8.48+/-2.48 micro g h mL(-1), 19.88+/-5.66 h, 2.13+/-0.92 Lh(-1) kg(-1) and 10.76+/-2.88 L kg(-1)(mean+/-s.e.m.), respectively. The acute intravenous dose of pinosylvin yielded the plasma AUC, urine t(1/2), CL and V(d) values of 5.23+/-1.20 micro g h mL(-1), 13.13+/-2.05 h, 1.84+/-0.44 Lh(-1) kg(-1) and 2.29+/-0.56 L kg(-1)(mean+/-s.e.m.), respectively. Rhapontigenin intravenous dosing yielded the plasma AUC, urine t(1/2), CL and V(d) values of 8.39+/-0.10 micro g h mL(-1), 25.31+/-1.46 h, 1.18+/-0.035 Lh(-1) kg(-1) and 11.05+/-0.17 L kg(-1)(mean+/-s.e.m.), respectively. Each stilbene was extensively glucuronidated. These stilbenes were predominantly eliminated via non-urinary routes. All three stilbenes were highly distributed into tissues and were highly extracted by the liver. The detectable plasma half-lives of these xenobiotics appear to be relatively short. However, utilizing urinary concentration-time data, much longer elimination half-lives were evident. The estimates of oral bioavailability characterize these stilbenes as poorly bioavailable compounds.

Topics: Animals; Area Under Curve; Biological Availability; Chromatography, High Pressure Liquid; Half-Life; Injections, Intravenous; Male; Mass Spectrometry; Rats; Rats, Sprague-Dawley; Stilbenes; Tissue Distribution

In patients with chronic heart failure (CHF) increased plasma concentrations of proinflammatory cytokines are found. For example, the plasma interleukin-6 (IL-6) concentration correlates with disease severity. Beside IL-6 cardiotrophin-1 (CT-1), a member of the IL-6 superfamily, is also increased in CHF. We examined whether CT-1 is able to induce IL-6 in human umbilical vein endothelial cells (HUVEC) and characterised the underlying pathway. IL-6 mRNA was determined by real-time PCR and by RT-PCR in HUVEC which were stimulated with different CT-1 concentrations and for different time periods. IL-6 concentration in the supernatant was determined by ELISA. For the pathway determination following inhibitors were used: piceatannol (signal transducer and activation of transcription (STAT)3 phosphorylation), wortmannin (phosphatiylinositol 3-kinase (PI3K)), SB203580 (p38 mitogen-activated protein kinase (MAPK)), AG490 (Janus kinase (JAK)2), PD98059 (mitogen-activated protein kinase kinase (MEK) 1/2), parthenolide (nuclear factor kappaB) and cycloheximide (protein biosynthesis). CT-1 caused a concentration- and time-dependent increase in IL-6 mRNA in HUVEC with a maximal induction seen after 6 h (2-fold compared to control) with 100 ng/ml CT-1. In the supernatant of HUVEC a concentration- and time-dependent increase of IL-6 protein was found. A maximum effect with 100 ng/ml CT-1 was found after 24 h (11-fold compared to control). AG490, SB203580, piceatannol, parthenolide and cycloheximide inhibit CT-1 induced IL-6 mRNA and protein expression whereas wortmannin and PD98059 did not inhibit IL-6 expression. CT-1 induced both IL-6 mRNA and protein in a concentration- and time-dependent manner in HUVEC. The underlying pathway includes activation of JAK2, STAT3, p38 and NFkappaB. CT-1 induced IL-6 expression and requires protein synthesis and IL-6 is not stored intracellularly. We speculate that in CHF CT-1 might be in part responsible for increased IL-6 plasma concentrations. Modulation of the CT-1 pathway may be a further strategy in CHF treatment.

Topics: Antibodies, Monoclonal; Cells, Cultured; Cycloheximide; Cytokines; Dose-Response Relationship, Drug; Endothelial Cells; Enzyme Inhibitors; Enzyme-Linked Immunosorbent Assay; Gene Expression; Humans; Imidazoles; Interleukin-6; Janus Kinase 2; Kinetics; NF-kappa B; p38 Mitogen-Activated Protein Kinases; Pyridines; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sesquiterpenes; STAT3 Transcription Factor; Stilbenes; Tyrphostins; Umbilical Cord

The gene product of spleen tyrosine kinase (SYK) has been implicated in the suppression of breast cancer invasion. We previously reported that SYK expression is lost in a subset of breast cancer; primarily by methylation-mediated gene silencing. In our study, we explored the possibility of using a DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine (AZA), to suppress breast cancer cell invasion by restoring SYK expression. We found that AZA treatment reestablished the expression of SYK(L) that was accompanied by suppression of the invasion capacity of SYK-negative cells. This invasion inhibition was not due to global cellular toxicity since this treatment did not affect overall cell proliferation. This decreased invasiveness by AZA treatment was diminished by piceatannol, a SYK inhibitor, suggesting that SYK play a significant role in AZA-inducible invasion suppression. SYK promoter hypermethylation was found infrequent in pathologically normal mammary tissues or benign lesions (<5%). In contrast, SYK methylation was frequently identified in ductal carcinoma in situ ( approximately 45%) and invasive ductal carcinoma (47% in node-negative and 40% in node-positive cases), indicating that the hypermethylation of SYK occurs at a stage prior to the development of invasion phenotypes. All these results suggested a potential use of SYK methylation as a valuable biomarker to detect early cancerous lesions and support the use of AZA as a new reagent to the management of advanced breast cancer.

Topics: Antimetabolites, Antineoplastic; Azacitidine; Breast; Breast Neoplasms; Carcinoma, Ductal; Carcinoma, Intraductal, Noninfiltrating; Cell Proliferation; Decitabine; DNA Methylation; DNA Modification Methylases; Enzyme Precursors; Female; Gene Expression Regulation, Neoplastic; Gene Silencing; Humans; Intracellular Signaling Peptides and Proteins; Neoplasm Invasiveness; Phenotype; Protein-Tyrosine Kinases; Stilbenes; Syk Kinase

High-resolution crystallographic studies of a number of inhibited forms of bovine F1-ATPase have identified four independent types of inhibitory site: the catalytic site, the aurovertin B-binding site, the efrapeptin-binding site and the site to which the natural inhibitor protein IF1 binds. Hitherto, the binding sites for other inhibitors, such as polyphenolic phytochemicals, non-peptidyl lipophilic cations and amphiphilic peptides, have remained undefined. By employing multiple inhibition analysis, we have identified the binding sites for these compounds. Several of them bind to the known inhibitory sites. The amphiphilic peptides melittin and synthetic analogues of the mitochondrial import pre-sequence of yeast cytochrome oxidase subunit IV appear to mimic the natural inhibitor protein, and the polyphenolic phytochemical inhibitors resveratrol and piceatannol compete for the aurovertin B-binding site (or sites). The non-peptidyl lipophilic cation rhodamine 6G acts at a separate unidentified site, indicating that there are at least five inhibitory sites in the F1-ATPase. Each of the above inhibitors has significantly different activity against the bacterial Bacillus PS3 alpha3beta3gamma subcomplex compared with that observed with bovine F1-ATPase. IF1 does not inhibit the bacterial enzyme, even in the absence of the epsilon-subunit. An understanding of these inhibitors may enable rational development of therapeutic agents to act as novel antibiotics against bacterial ATP synthases or for the treatment of several disorders linked to the regulation of the ATP synthase, including ischaemia-reperfusion injury and some cancers.

Topics: Animals; ATPase Inhibitory Protein; Aurovertins; Bacillus; Binding Sites; Binding, Competitive; Cattle; Inhibitory Concentration 50; Melitten; Mitochondria, Heart; Mitochondrial Proton-Translocating ATPases; Models, Molecular; Molecular Structure; Peptides; Proteins; Resveratrol; Rhodamines; Stilbenes

Upon exposure to hypotonic medium, skate red blood cells swell and then reduce their volume by releasing organic osmolytes and associated water. The regulatory volume decrease is inhibited by stilbenes and anion exchange inhibitors, suggesting involvement of the red blood cell anion exchanger skAE1. To determine the role of tyrosine phosphorylation, red blood cells were volume expanded with and without prior treatment with the tyrosine kinase inhibitor piceatannol. At the concentration used, 130 microM, piceatannol nearly completely inhibits p72(syk), a tyrosine kinase previously shown to phosphorylate skAE1 (M. W. Musch, E. H. Hubert, and L. Goldstein. J Biol Chem 274: 7923-7928, 1999). Hyposmotic-induced volume expansion stimulated association of p72(syk) with a light membrane fraction of skate red blood cells. Piceatannol did not inhibit this association but decreased hyposmotically stimulated increased skAE1 tyrosine phophorylation. Movement of skAE1 from an intracellular to a surface detergent-resistant membrane domain and tetramer formation were not inhibited by piceatannol treatment. Two effects of hyposmotic-induced volume expansion, decreased band 4.1 binding and increased ankyrin, were both inhibited by piceatannol. These results suggest that at least one event requiring p72(syk) activation is pivotal for hyposmotic-induced increased transport; however, steps that do not require tyrosine phosphorylation may also play a role.

Topics: Animals; Anion Exchange Protein 1, Erythrocyte; Ankyrins; Blood Volume; Blotting, Western; Cell Membrane; Electrophoresis, Polyacrylamide Gel; Enzyme Inhibitors; Enzyme Precursors; Erythrocytes; Immunoprecipitation; Intracellular Signaling Peptides and Proteins; Membranes; Osmolar Concentration; Phosphorylation; Plasma Substitutes; Protein-Tyrosine Kinases; Skates, Fish; Stilbenes; Syk Kinase; Taurine

The protein tyrosine kinase Syk is critically involved in immunoreceptor signaling in hematopoietic cells. Recent studies demonstrate Syk expression in nonhematopoietic cells, including fibroblasts, endothelial cells, hepatocytes, and breast epithelium. However, the role of Syk in these cells is uncertain. We hypothesized that Syk is expressed in respiratory epithelial cells (EC) and that it functions as a signaling molecule involved in inflammatory responses in the epithelium. With the use of immunohistochemistry, Western blot, PCR, and laser scanning confocal microscopy, Syk was detected in human, rat, and mouse bronchial epithelium in situ and in cultured human bronchial EC in primary cells and the cell lines HS-24 and BEAS-2B. Syk-dependent signaling pathways in EC were initiated by engagement of beta1-integrin receptors. Stimulation of beta1-integrin receptors by fibronectin or antibody cross-linking caused redistribution of Syk from a cytoplasmic to plasma membrane localization. In stimulated cells, Syk and beta1-integrin colocalized. In addition, following beta1-integrin receptor engagement, tyrosine phosphorylation of Syk was observed. Expression of the intercellular adhesion molecule-1 (ICAM-1) and production of IL-6, both important molecules in lung inflammation, was downregulated in EC treated with Syk small interfering RNA or Syk inhibitor piceatannol. We propose that Syk is involved in signaling pathways induced by integrin engagement in airway EC. Syk-mediated signaling regulates IL-6 and ICAM-1 expression and may be important in the pathophysiology of lung inflammation.

Topics: Animals; Bronchi; Cells, Cultured; Cross-Linking Reagents; Down-Regulation; Epithelial Cells; Humans; Inflammation Mediators; Integrin alpha5beta1; Integrin beta1; Intercellular Adhesion Molecule-1; Interleukin-6; Male; Mice; Mice, Inbred C57BL; Protein-Tyrosine Kinases; Rats; Rats, Inbred BN; Signal Transduction; Stilbenes; Tissue Distribution; Tumor Necrosis Factor-alpha; ZAP-70 Protein-Tyrosine Kinase

The molecular stimuli involved in receptor-induced integrin activation are still poorly defined. We have investigated the role of receptors for the Fc portion of immunoglobulin G molecules (Fc gammaR) on activation of integrins in human neutrophils. Cross-linking of Fc gammaRIIA induced an increase in surface expression of beta2 integrins but had no effect on beta1 integrins. In contrast, cross-linking of Fc gammaRIIIB not only increased beta2 integrins on the cell surface but also induced beta1 integrin activation, as indicated by an increase in binding to fibronectin and the appearance of an activation epitope detected by the monoclonal antibody 15/7. The Fc gammaRIIIB-induced increase of beta2 integrins required Src-family tyrosine kinases, Syk kinase, and phosphatidylinositol-3 kinase (PI-3K), as the corresponding, specific inhibitors, PP2, Piceatannol, and LY294002, completely blocked it. Contrary to this, Fc gammaRIIIB-induced beta1 integrin activation was not blocked by PP2 or LY294002. It was, however, enhanced by Piceatannol. After Fc gammaRIIIB cross-linking, colocalization of Fc gammaRIIIB and active beta1 integrins was detected on the neutrophil membrane. These data show, for the first time, that cross-linking of Fc gammaRIIIB induces an inside-out signaling pathway that leads to beta1 integrin activation. This activation is independent of Src-family kinases, and PI-3K and may be induced in part by the interaction of Fc gammaRIIIB with beta1 integrins.

Topics: Adult; Antigens, CD; Chromones; Cross-Linking Reagents; Enzyme Inhibitors; GPI-Linked Proteins; Humans; Integrin beta1; Morpholines; Neutrophil Activation; Neutrophils; Protein-Tyrosine Kinases; Receptors, IgG; Signal Transduction; Stilbenes; Up-Regulation

Vascular endothelial growth factor (VEGF), a potent angiogenesis factor, likely contributes to airway remodeling in asthma. We sought to examine the effects and mechanism of action of IL-6 family cytokines on VEGF release from human airway smooth muscle (HASM) cells. Oncostatin M (OSM), but not other IL-6 family cytokines, increased VEGF release, and IL-1beta enhanced OSM-induced VEGF release. OSM increased VEGF mRNA expression and VEGF promoter activity, whereas IL-1beta had no effect. IL-1beta did not augment the effects of OSM on VEGF promoter activity but did augment OSM-induced VEGF mRNA expression and mRNA stability. The STAT3 inhibitor piceatannol decreased both OSM-induced VEGF release and synergy between OSM and IL-1beta, without affecting responses to IL-1beta alone. Piceatannol also inhibited OSM-induced VEGF mRNA expression. In contrast, inhibitors of MAPK pathway had no effect on OSM or OSM plus IL-1beta-induced VEGF release. OSM increased type 1 IL-1 receptor (IL-1R1) mRNA expression, as measured by real-time PCR, and piceatannol attenuated this response. Consistent with the increase in IL-1R1 expression, OSM markedly augmented IL-1beta-induced VEGF, MCP-1, and IL-6 release. In summary, our data indicate OSM causes VEGF expression in HASM cells by a transcriptional mechanism involving STAT3. IL-1beta also synergizes with OSM to increase VEGF release, likely as a result of effects of IL-1beta on VEGF mRNA stability as well as effects of OSM on IL-1R1 expression. This is the first description of a role for OSM on IL-1R1 expression in any cell type. OSM may contribute to airway remodeling observed in chronic airway disease.

Topics: Cells, Cultured; Chemokine CCL2; DNA-Binding Proteins; Drug Synergism; Enzyme Inhibitors; Growth Inhibitors; Humans; Inflammation Mediators; Interleukin-1; Interleukin-6; Lung; Mitogen-Activated Protein Kinases; Muscle, Smooth; Oncostatin M; Peptides; Phosphorylation; Protein-Tyrosine Kinases; Receptors, Interleukin-1; Receptors, Interleukin-1 Type I; RNA, Messenger; Signal Transduction; STAT3 Transcription Factor; Stilbenes; Trans-Activators; Vascular Endothelial Growth Factor A

Inflammatory processes are involved in the etiology of diseases. We analyzed the effect of resveratrol, piceatannol, synthetic tri-acetoxystilbene (TAS), and genistein (Bonistein(TM)) on the production of inflammatory mediators including prostaglandin E2 (PGE2), tumor necrosis factor-alpha (TNF-alpha), interleukins, and chemokines, which participate in the progression of inflammation. In order to induce inflammatory responses, human peripheral blood mononuclear and/or polymorphonuclear leukocytes were stimulated with lipopolysaccharide (LPS) and interferon-gamma (IFN(gamma)) and the production of PGE2, interleukin-8 (IL-8), and TNF-alpha was determined. In response to the stimuli, genes were substantially activated within < 2 h (e. g., TNF-alpha, IL-1alpha), or at a later stage, (e. g., COX-2, IL-6, IL-8). Unlike genistein, resveratrol and related compounds dose-dependently reduced PGE2 production. Genistein, piceatannol, and TAS diminished secretion of TNF-alpha, and IL-8. TAS reduced mRNA levels of COX-2, TNF-alpha, IL-8, IL-6, and IL-1alpha, while resveratrol impaired early expression of IL-8 and TNF-alpha. Piceatannol out-performed resveratrol, yet without matching TAS. Genistein downregulated TNF-alpha and IL-8 expression. These substances altered the LPS/IFNgamma-induced gene expression in mononuclear cells rather than in polymorphonuclear leukocytes. Immunoblot analyses corroborated the distinct activity pattern of resveratrol and genistein. In conclusion, resveratrol and their derivatives attenuated the inflammatory response of PBLs at several levels, whereas genistein acts on cytokines and pro-inflammatory interleukins.

Topics: Cell Survival; Cyclooxygenase 2; Dinoprostone; Gene Expression; Genistein; Humans; Inflammation; Interferon-gamma; Interleukin-1; Interleukin-6; Interleukin-8; Leukocytes; Leukocytes, Mononuclear; Lipopolysaccharides; Membrane Proteins; Neutrophils; Prostaglandin-Endoperoxide Synthases; Resveratrol; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Stilbenes; Tumor Necrosis Factor-alpha

Piceatannol is an anti-inflammatory, immunomodulatory, and antiproliferative stilbene that has been shown to interfere with the cytokine signaling pathway. Dendritic cells (DCs) play a pivotal in the initiation of T-cell-mediated immune responses, making them an attractive cellular adjuvant for use in cancer vaccines. This study investigated the effect of piceatannol on the phenotypic and functional maturation of human monocyte-derived DCs in vitro. Human monocytes were cultured with GM-CSF and IL-4 for 6 days, followed by another 2 days in the presence of piceatannol or LPS. DCs harvested on day 8 were examined using functional assays. The expression levels of CD1a, CD80, CD83, and CD86 as expressed by mean fluorescence intensity (MFI) on DCs differentiated from immature DCs after culture with 1 muM of piceatannol for 2 days were enhanced and decreased endocytic activity. Piceatannol-treated DCs also displayed enhanced T-cell stimulatory capacity in a MLR, as measured by T-cell proliferation. Similar results were obtained with DCs differentiated with LPS from immature DCs. However, piceatannol did not inhibit phenotypic and functional maturation induced by LPS from immature DCs. Piceatannol-treated DCs induced the differentiation of naive T cells towards a helper T-cell type 1 (Th1) response at DCs/T (1:5) cells ratio depending on IL-12 secretion. These results demonstrate that piceatannol may be used on DC-based vaccine for cancer immunotherapy.

Topics: Antibodies, Monoclonal; Cell Differentiation; Coculture Techniques; Culture Media; Cytokines; Dendritic Cells; Fluorescent Antibody Technique; Humans; Interleukin-12; Lipopolysaccharides; Lymphocyte Culture Test, Mixed; Monocytes; Phenotype; Platelet Aggregation Inhibitors; Stilbenes; T-Lymphocytes; T-Lymphocytes, Helper-Inducer

Vav is one of the genetic markers that correlate with the differentiation of hematopoietic cells. In T and B cells, it appears crucial for both development and functions, while, in non-lymphoid hematopoietic cells, Vav seems not involved in cell maturation, but rather in the response of mature cells to agonist-dependent proliferation and phagocytosis. We have previously demonstrated that the amount and the tyrosine phosphorylation of Vav are up-regulated in both whole cells and nuclei of tumoral promyelocytes induced to granulocytic maturation by ATRA and that tyrosine-phosphorylated Vav does not display any ATRA-induced GEF activity but contributes to the regulation of PI 3-K activity. In this study, we report that Vav accumulates in nuclei of ATRA-treated APL-derived cells and that the down-modulation of Vav prevents differentiation of tumoral promyelocytes, indicating that it is a key molecule in ATRA-dependent myeloid maturation. On the other hand, the overexpression of Vav induces an increased expression of surface markers of granulocytic differentiation without affecting the maturation-related changes of the nuclear morphology. Consistent with an effect of Vav on the transcriptional machinery, array profiling shows that the inhibition of the Syk-dependent tyrosine phosphorylation of Vav reduces the number of ATRA-induced genes. Our data support the unprecedented notion that Vav plays crucial functions in the maturation process of myeloid cells, and suggest that Vav can be regarded as a potential target for the therapeutic treatment of myeloproliferative disorders.

Topics: Cell Cycle Proteins; Cell Differentiation; Cell Line, Tumor; Enzyme Inhibitors; Gene Expression; Gene Expression Regulation, Leukemic; Granulocytes; HL-60 Cells; Humans; Leukemia, Promyelocytic, Acute; Myeloid Progenitor Cells; Phosphorylation; Protein-Tyrosine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-vav; RNA, Small Interfering; Stilbenes; Transfection; Tretinoin; Tumor Cells, Cultured

A new source to produce a significant quantity of a naturally occurring polyphenol, piceatannol, was investigated in this study. Both resveratrol and piceatannol are recognized as important ingredients in functional foods due to their beneficial health effects. However, unlike resveratrol, the piceatannol concentration in plants is very low. Thus, calluses of peanuts, an easily obtainable source, were chosen as the material to induce piceatannol production under controlled conditions. To induce resveratrol and piceatannol, calluses were exposed to the ultraviolet (UV) irradiation. Significant quantities of resveratrol and piceatannol were produced by calluses upon UV irradiation in both static and suspension culture conditions. The amounts of piceatannol and resveratrol produced in 1 g of calluses ranged from 2.17 to 5.31 microg and from 0.25 to 11.97 microg, respectively, in static culture. In suspension culture, the amounts of induced piceatannol and resveratrol were somewhat lower. The quantities of induced piceatannol and resveratrol reached a maximum at 18 h after UV irradiation treatment in static culture. In contrast, the levels of resveratrol and piceatannol remained almost constant throughout the experiments in suspension culture. The piceatannol produced by calluses in all studies was much higher than the values reported in the literature, whereas the resveratrol produced was comparable to reported values.

Topics: Antineoplastic Agents; Arachis; Chromatography, High Pressure Liquid; Resveratrol; Stilbenes; Tissue Culture Techniques; Ultraviolet Rays

Resveratrol (3,4',5-trihydroxy stilbene), a plant derived polyphenol found in mulberries, grapes and red wine is considered to possess chemopreventive properties against cancer. It is recognized as a naturally occurring antioxidant but also catalyzes oxidative DNA degradation in vitro in the presence of transition metal ions such as copper. Using a cellular system of lymphocytes isolated from human peripheral blood and Comet assay, we have confirmed that resveratrol-Cu(II) system is indeed capable of causing DNA degradation in cells such as lymphocytes. Also, trans-stilbene, which does not have any hydroxyl groups, is inactive in the lymphocyte system. Pre-incubation of lymphocytes with resveratrol indicates that it is capable of either traversing the cell membrane or binding to it. Our results are in partial support of our hypothesis that anticancer properties of various plant derived polyphenols may involve mobilization of endogenous copper and the consequent prooxidant action.

Topics: Antineoplastic Agents; Comet Assay; Copper; DNA; DNA Damage; Humans; Lymphocytes; Molecular Structure; Plasmids; Reactive Oxygen Species; Resveratrol; Stilbenes

CD1d is a non-polymorphic MHC class I-related protein that binds and presents glycolipid antigens to T cell antigen receptors expressed by NK-like T (NKT) cells. CD1d-dependent immune responses play critical roles in infectious disease, autoimmunity, allergy and cancer. We tested the hypothesis that B cell antigen receptor (BCR) targeting of a biotin-modified version of the CD1d-binding antigen alpha-galactosylceramide (biotin-alpha-GalCer) results in enhanced murine CD1d-mediated presentation as compared with presentation of non-targeted biotin-alpha-GalCer. Presentation of BCR-targeted antigen to NKT cells was enhanced 100- to 1000-fold compared with non-targeted antigen. CD1d presentation of BCR-targeted antigen was observed after 4 h treatment, consistent with a requirement for endosomal trafficking. Furthermore, unlike non-targeted antigen, BCR-targeted antigen was not loaded directly onto cell-surface CD1d. Blocking BCR signaling with the Syk tyrosine kinase inhibitor piceatannol inhibited presentation of BCR-targeted antigen but not non-targeted antigen. Piceatannol blocked transport of the BCR to CD1d-containing endosomes, showing that intersection of BCR-targeted antigen with endosomes is required for enhanced mCD1d antigen presentation. Our data suggest that the BCR facilitates capture of low quantities of mCD1d antigens to enhance CD1d-dependent immune responses.

Topics: Animals; Antigen Presentation; Antigens, CD1; Antigens, CD1d; Biotin; Cell Line; Endosomes; Enzyme Precursors; Galactosylceramides; Histocompatibility Antigens Class I; Intracellular Signaling Peptides and Proteins; Killer Cells, Natural; Mice; Protein Transport; Protein-Tyrosine Kinases; Receptors, Antigen, B-Cell; Stilbenes; Syk Kinase; T-Lymphocytes

The nuclear p68 RNA helicase is essential for normal cell growth. The protein plays a very important role in early organ development and maturation. In our previous report, we showed that recombinant p68 RNA helicase was phosphorylated at serine/threonine and tyrosine residue(s). In the present study, we examined the phosphorylation status of p68 in six different cancer cell lines and compared the results with those in cells derived from the corresponding normal tissues. We showed here that p68 was phosphorylated at tyrosine residue(s) in all tested cancer cells but not in the corresponding normal cells/tissues. The tyrosyl phosphorylation of p68 also responded to platelet-derived growth factor. It is thus clear that p68 phosphorylation at tyrosine residue(s) is associated with abnormal cell proliferation and cancer development. The tyrosyl phosphorylation(s) was diminished if the cancer cells were treated with apoptosis agents, such as tumor necrosis factor-alpha, tumor necrosis factor-related apoptosis-inducer ligand, and STI-571. The tyrosyl phosphorylation of p68, however, was not affected by other anticancer drugs, such as piceatannol, etoposide, and taxol. The close correlation between p68 phosphorylations and cancer may provide a useful diagnostic marker and potential therapeutic target for cancer treatment.

Topics: Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Benzamides; Blotting, Western; Caco-2 Cells; Cell Line, Tumor; Cell Proliferation; Etoposide; HeLa Cells; Humans; Imatinib Mesylate; K562 Cells; Neoplasms; Paclitaxel; Phosphorus Radioisotopes; Phosphorylation; Piperazines; Precipitin Tests; Pyrimidines; RNA Helicases; RNA Interference; Stilbenes; Tumor Necrosis Factor-alpha

Resveratrol and its analogs are promising cancer chemoprevention agents, currently under investigation in clinical trials. However, patients administered other plant polyphenols experienced severe diarrhea, likely due to an increase in intracellular cyclic AMP (cAMP). Resveratrol itself raises intracellular cAMP levels in breast cancer cells in vitro. Its future use as a cancer chemopreventive agent could therefore be compromised by its severe side effects. The aim of the study was (a) to define the influence of resveratrol on intestinal Cl(-) secretion and (b) to elucidate possible intracellular transduction pathways involved. Resveratrol caused a dose- and time-dependent increase in DeltaIsc in T(84) cells. The specificity of resveratrol was confirmed by using piceatannol 100 mumol/L, the hydroxylated resveratrol analog, which did not alter DeltaIsc. A significant elevation of [cAMP](i) by resveratrol was assessed in T(84) cells. In mouse jejunum, resveratrol induced a time- and dose-dependent increase in DeltaIsc as well. In bilateral Cl(-)-free medium, as well as after inhibition of protein kinase A, resveratrol-induced DeltaIsc was reduced significantly. Preincubation of T(84) cells with butyrate 2 mmol/L (24 and 48 hours) significantly inhibited resveratrol as well as forskolin-induced Cl(-) secretion. In summary, the main mechanism of action of resveratrol in intestinal epithelia is cAMP-induced chloride secretion which can be suppressed by butyrate. It can therefore be suggested that in cancer chemoprevention, both agents should be combined to reduce an undesired side effect such as diarrhea and to benefit from the known agonistic effect of both agents on differentiation of colon cancer cells.

Topics: Animals; Anticarcinogenic Agents; Butyrates; Cell Differentiation; Cell Line, Tumor; Chlorides; Colforsin; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Dose-Response Relationship, Drug; Electrophysiology; Humans; In Vitro Techniques; Jejunum; Male; Mice; Mice, Inbred BALB C; Resveratrol; Signal Transduction; Stilbenes; Time Factors

Caragana tibetica KOM. (Fabaceae) is a medicinal plant that has been traditionally used in western part of China. In the course of our screening study on antioxidant activity of medicinal plants, the 70% acetone extract of the stems of C. tibetica was found to have a potent superoxide anion scavenging activity. Tibeticanol (1), a new piceatannol dimer possessing antioxidant activity, was isolated along with eleven known aromatic compounds. Their structures were elucidated on the basis of NMR and MS data. Enzyme oxidation of monomeric stilbene, piceatannol (3), with horseradish peroxidase and hydrogen peroxide yielded cassigarol E (5) and G (6) as major products. Most of the isolated compounds exhibited superoxide anion scavenging activity.

Topics: Acetylation; Antioxidants; Caragana; Carbohydrate Conformation; Free Radical Scavengers; Horseradish Peroxidase; Hydrogen Peroxide; Magnetic Resonance Spectroscopy; Oxidation-Reduction; Plant Stems; Spectrometry, Mass, Fast Atom Bombardment; Stilbenes; Superoxides

Previous epidemiological reports have suggested that red wine intake is associated with beneficial health effects due to the ability of certain phytochemical components to exert estrogen-like activity. It has been also documented that estrogens induce the proliferation of hormone-dependent breast cancer cells by binding to and transactivating estrogen receptor (ER) alpha, which in turn interacts with responsive DNA sequences located within the promoter region of target genes. In order to provide further insight into the positive association between wine consumption and the incidence of breast carcinoma in postmenopausal women, we have evaluated the estrogenic properties of two abundant wine-derived compounds, named piceatannol (PIC) and myricetin (MYR), using as model systems the hormone-sensitive MCF7 and the endocrine-independent SKBR3 breast cancer cells. On the basis of our experimental evidence PIC and MYR may contribute to the estrogenicity of red wine since: (1) they transactivate endogenous ER alpha; (2) they activate the agonist-dependent activation function (AF) 2 of ER alpha and ER beta in the context of the Gal4 chimeric proteins; (3) they rapidly induce the nuclear immunodetection of ER alpha; (4) they regulate the expression of diverse estrogen target genes; (5) they compete with 17beta-estradiol for binding to ER alpha and ER beta; and--as a biological counterpart of the aforementioned abilities--(6) they exert stimulatory effects on the proliferation of MCF7 cells. Hence, the estrogenic activity of PIC and MYR might be considered at least as a potential factor in the association of red wine intake and breast tumors, particularly in postmenopausal women.

Topics: Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Estradiol; Estrogen Receptor alpha; Estrogen Receptor beta; Female; Flavonoids; Gene Expression Regulation; Genes, Reporter; Humans; Molecular Structure; Phenols; Phytoestrogens; Protein-Tyrosine Kinases; Recombinant Fusion Proteins; Stilbenes; Wine

C-Reactive protein (CRP) can modulate integrin surface expression on monocytes following Fcgamma receptor engagement. We have investigated the signal transduction events causing this phenotypic alteration.. CRP-induced signalling events were examined in THP-1 and primary monocytes, measuring Syk phosphorylation by Western blotting, intracellular Ca(2+) ([Ca(2+)](i)) by Indo-1 fluorescence and surface expression of CD11b by flow cytometry. Cytosolic peroxides were determined by DCF fluorescence.. CRP induced phosphorylation of Syk and an increase in [Ca(2+)](i) both of which were inhibitable by the Syk specific antagonist, piceatannol. Piceatannol also inhibited the CRP-induced increase in surface CD11b. In addition, pre-treatment of primary monoytes with the Ca(2+) mobiliser, thapsigargin, increased CD11b expression; this effect was accentuated in the presence of CRP but was abolished in the presence of the [Ca(2+)](i) chelator, BAPTA. CRP also increased cytosolic peroxide levels; this effect was attenuated by antioxidants (ascorbate, alpha-tocopherol), expression of surface CD11b not being inhibited by antioxidants alone.. CRP induces CD11b expression in monocytes through a peroxide independent pathway involving both Syk phosphorylation and [Ca(2+)](i) release.

Topics: Antioxidants; Blotting, Western; C-Reactive Protein; Calcium; Calcium Signaling; CD11b Antigen; Cell Line, Tumor; Chelating Agents; Egtazic Acid; Enzyme Precursors; Flow Cytometry; Gene Expression Regulation; Humans; Intracellular Signaling Peptides and Proteins; Monocytes; Peroxides; Phosphorylation; Protein-Tyrosine Kinases; Receptors, IgG; Signal Transduction; Stilbenes; Syk Kinase; Thapsigargin

Signal transducers and activators of transcription (STAT) were originally discovered as components of cytokine signal transduction pathways. Persistent activation of one STAT, STAT3, is a common feature of prostate cancer. Activated STAT3 was found in pathology specimens obtained from prostatectomy in the cancerous areas but not in the normal margins. Because the activation of STAT3 is mediated by the action of an upstream Janus kinase (JAK) kinase, usually JAK1 or JAK2, the activation step for STAT3 might itself be a target for therapy in prostate cancer. However, the redundancy of upstream kinases may make this strategy unreliable for therapy. To develop molecular targets for prostate cancer treatment, JAK kinase and STAT3 inhibition of two prostate cancer lines were compared. DU145 and NRP-154 cells were treated with JAK kinase inhibitors, analyzed for onset of apoptosis, and measured by annexin V binding and propidium iodide uptake. Activation of caspases in the cells was determined by measuring cleaved caspase-3 following treatment. For determining the effect on mitochondrial membrane depolarization that accompanies apoptosis, the fluorescent dye JC-1 was used. STAT3 was specifically inhibited by transfecting either a dominant-negative (DN) STAT3 plasmid or antisense STAT3 oligonucleotides into the cells. To look for reduction in STAT3 levels within cells, fixed and permeabilized prostate cancer cells were stained with antibody to STAT3. We found that more than one JAK kinase is involved in STAT3 activation in prostate cancer lines. AG490 (JAK2 specific) induced apoptosis in DU145 but not in NRP-154 prostate cancer lines, whereas piceatannol (JAK1 specific) induced apoptosis in NRP-154 but not in DU145 cells. Next, we demonstrated efficacy of specific STAT3 inhibitors in prostate cancer lines. Both induction of apoptosis and reduction in intracellular STAT3 protein were observed following treatment with antisense STAT3 oligonucleotides, while transfection of a DN-STAT3 plasmid into both prostate cancer cell lines resulted in loss of viability and onset of apoptosis. We conclude that STAT3-specific inhibitors, rather than JAK kinase-specific inhibitors, should be more useful therapeutically in treating androgen-resistant prostate cancer and that STAT3 is an appropriate target in the treatment of prostate cancer.

Topics: Animals; Apoptosis; Cell Line, Tumor; DNA-Binding Proteins; Enzyme Inhibitors; Humans; Janus Kinase 2; Janus Kinase 3; Male; Oligonucleotides, Antisense; Prostate; Prostatic Neoplasms; Protein-Tyrosine Kinases; Proto-Oncogene Proteins; STAT3 Transcription Factor; Stilbenes; Trans-Activators; Transfection; Tyrphostins

Cryptococcus neoformans monoclonal antibody immune complex (IC) induces beta-chemokines and phagocytosis in primary human microglia via activation of Fc receptor for immunoglobulin G (FcgammaR). In this report, we investigated microglial FcgammaR signal-transduction pathways by using adenoviral-mediated gene transfer and specific inhibitors of cell-signaling pathways. We found that Src inhibitor PP2 and Syk inhibitor piceatannol inhibited phagocytosis, macrophage-inflammatory protein-1alpha (MIP-1alpha) release, as well as phosphorylation of extracellular-regulated kinase (ERK) and Akt, consistent with Src/Syk involvement early in FcgammaR signaling. Constitutively active mitogen-activated protein kinase kinase (MEK) induced MIP-1alpha, and Ras dominant-negative (DN) inhibited IC-induced ERK phosphorylation and MIP-1alpha production. These results suggest that the Ras/MEK/ERK pathway is necessary and sufficient in IC-induced MIP-1alpha expression. Neither Ras DN nor the MEK inhibitor U0126 inhibited phagocytosis. In contrast, phosphatidylinositol-3 kinase (PI-3K) inhibitors Wortmannin and LY294002 inhibited phagocytosis without affecting ERK phosphorylation or MIP-1alpha production. Conversely, Ras DN or U0126 did not affect Akt phosphorylation. Together, these results demonstrate distinct roles played by the PI-3K and Ras/MEK/ERK pathways in phagocytosis and MIP-1alpha induction, respectively. Our results demonstrating activation of functionally distinct pathways following microglial FcgammaR engagement may have implications for human central nervous system diseases.

Topics: Adenoviridae; Brain; Butadienes; Chemokine CCL3; Chemokine CCL4; Chemokine CCL5; Cryptococcus neoformans; Enzyme Precursors; Female; Fetus; Genes, Dominant; Humans; Intracellular Signaling Peptides and Proteins; Macrophage Inflammatory Proteins; MAP Kinase Kinase Kinase 1; MAP Kinase Kinase Kinases; Microglia; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases; Nitriles; Phagocytosis; Phosphatidylinositol 3-Kinases; Phosphorylation; Pregnancy; Protein-Tyrosine Kinases; ras Proteins; Receptors, IgG; Signal Transduction; src-Family Kinases; Stilbenes; Syk Kinase

Aggregation of high-affinity receptors for immunoglobulin E (Fc epsilon RI) on the surface of mast cells results in degranulation, a response that is potentiated by binding of stem cell factor (SCF) to its receptor Kit. We observed that one of the major initial signaling events associated with Fc epsilon RI-mediated activation of human mast cells (HuMCs) is the rapid tyrosine phosphorylation of a protein of 25 to 30 kDa. The phosphorylation of this protein was also observed in response to SCF. This protein was identified as non-T-cell activation linker (NTAL), an adaptor molecule similar to linker for activated T cells (LAT). Unlike the Fc epsilon RI response, SCF induced NTAL phosphorylation in the absence of detectable LAT phosphorylation. When SCF and antigen were added concurrently, there was a marked synergistic effect on NTAL phosphorylation, however, SCF did not enhance the phosphorylation of LAT induced by Fc epsilon RI aggregation. Fc epsilon RI- and SCF-mediated NTAL phosphorylation appear to be differentially regulated by Src kinases and/or Kit kinase, respectively. Diminution of NTAL expression by silencing RNA oligonucleotides in HuMCs resulted in a reduction of both Kit- and Fc epsilon RI-mediated degranulation. NTAL, thus, appears to be an important link between the signaling pathways that are initiated by these receptors, culminating in mast cell degranulation.

Topics: Adaptor Proteins, Signal Transducing; Animals; Antigens; Carrier Proteins; Cell Degranulation; Cell Line; Enzyme Activation; Enzyme Inhibitors; Humans; Mast Cells; Membrane Proteins; Mice; Phosphoproteins; Phosphorylation; Proteins; Proto-Oncogene Proteins c-kit; Pyrimidines; Receptors, IgE; RNA, Small Interfering; Signal Transduction; src-Family Kinases; Stem Cell Factor; Stilbenes; Tyrosine

Interferon regulatory factor 3 (IRF3) mediates the transcriptional induction of interferon-stimulated genes (ISGs) in response to viral and bacterial infections. Here we show that the hydroxystilbene piceatannol inhibits the LPS-mediated activation of IRF3 and subsequent ISG induction. Consequently, piceatannol blocks the LPS-induced up-regulation of critical mediators of the inflammatory response such as interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), intercellular adhesion molecule 1 (ICAM-1), and macrophage chemoattractant protein (MCP-1). Furthermore, the LPS-mediated induction of tissue factor (TF), a cell surface protein responsible for initiating the coagulation cascade, is also inhibited by piceatannol. The effectiveness of piceatannol in blocking both the inflammatory response and the coagulation pathway is evidenced by its ability to confer protection against LPS-induced septic shock in a murine model. Thus, IRF3 appears to be a promising target for pharmacologic intervention in the prevention or treatment of septic shock syndrome.

Topics: Animals; Cell Line; Cell Line, Tumor; Chemokine CCL2; DNA-Binding Proteins; Enzyme Inhibitors; Enzyme-Linked Immunosorbent Assay; Humans; Inflammation; Intercellular Adhesion Molecule-1; Interferon Regulatory Factor-3; Interferons; Interleukin-6; Lipopolysaccharides; Mice; Protein-Tyrosine Kinases; Reverse Transcriptase Polymerase Chain Reaction; Ribonucleases; Sepsis; Shock; Stilbenes; Time Factors; Transcription Factors; Transcription, Genetic; Transfection; Tumor Necrosis Factor-alpha

Interleukin-15 (IL-15) is a cytokine that possesses interesting, potential therapeutic properties. However, based on several parameters including activation of neutrophils, it is also recognized as a proinflammatory cytokine. The mechanisms by which IL-15 activates human neutrophil functions are not fully understood. Although these cells express a functional IL-15 receptor (IL-15R) composed of IL-15Ralpha, IL-2/15Rbeta (CD122), and gamma(c) (CD132) subunits, the role of each receptor component has not been investigated in IL-15-induced human neutrophil responses. In the present study, fluorescein-activated cell sorter analysis revealed that the ability of IL-15 to enhance neutrophil phagocytosis is not a result of increased expression of IL-15Ralpha, CD122, or CD132 on the neutrophil cell surface. Pretreatment of neutrophils with specific antibodies to IL-15Ralpha, CD122, or CD132 was found to inhibit phagocytosis of opsonized-sheep red blood cells by nearly 40%, 21%, and 27%, respectively. As expected, pretreatment of neutrophils with anti-IL-2Ralpha (CD25) had no effect. Pretreatment of cells with the Syk inhibitor piceatannol was found to significantly inhibit the ability of IL-15 to enhance phagocytosis. In addition, IL-15 was found to induce tyrosine phosphorylation of Syk that was largely inhibited by pretreating cells with piceatannol. Moreover, we found that Syk kinase is physically associated with IL-15Ralpha. We conclude that IL-15R enhances neutrophil phagocytosis by a Syk-dependent mechanism and that the IL-15Ralpha chain plays a key role in mediating this response, at least by interacting with Syk kinase.

Topics: Animals; Blotting, Western; Cells, Cultured; Enzyme Inhibitors; Enzyme Precursors; Flow Cytometry; Humans; Interleukin-15; Intracellular Signaling Peptides and Proteins; Neutrophil Activation; Neutrophils; Phagocytosis; Phosphorylation; Protein-Tyrosine Kinases; Receptors, Interleukin-15; Receptors, Interleukin-2; Stilbenes; Syk Kinase

There are important differences in signaling between the Fc receptor for immunoglobulin G (IgG) FcgammaRIIA, which uses the Ig tyrosine-activating motif (ITAM) within its own cytoplasmic domain, and FcgammaRI, which transmits signals by means of an ITAM located within the cytoplasmic domain of its associated gamma-chain. For example, in transfected epithelial cells and COS-1 cells, FcgammaRIIA mediates phagocytosis of IgG-coated red blood cells more efficiently than does FcgammaRI/gamma, and enhancement of phagocytosis by Syk kinase is more pronounced for FcgammaRI/gamma than for FcgammaRIIA. In addition, structure/function studies indicate that the gamma-chain ITAM and the FcgammaRIIA ITAM have different requirements for mediating the phagocytic signal. To study the differences between FcgammaRIIA and FcgammaRI/gamma, we examined the interaction of FcgammaRIIA and the FcgammaRI/gamma chimera FcgammaRI-gamma-gamma (extracellular domain-transmembrane domain-cytoplasmic domain) with Syk kinase and with the Src-related tyrosine kinases (SRTKs) Hck and Lyn in transfected COS-1 cells. Our data indicate that FcgammaRIIA interacts more readily with Syk than does FcgammaRI-gamma-gamma and suggest that one consequence may be the greater phagocytic efficiency of FcgammaRIIA compared with FcgammaRI/gamma. Furthermore, individual SRTKs affect the efficiency of phagocytosis differently for FcgammaRI-gamma-gamma and FcgammaRIIA and also influence the ability of these receptors to interact with Syk kinase. Taken together, the data suggest that differences in signaling by FcgammaRIIA and FcgammaRI-gamma-gamma are related in part to interaction with Syk and Src kinases and that individual SRTKs play different roles in FcgammaR-mediated phagocytosis.

Topics: Animals; Antigens, CD; COS Cells; Enzyme Precursors; Humans; Intracellular Signaling Peptides and Proteins; Monocytes; Mutation; Phagocytosis; Protein-Tyrosine Kinases; Receptors, IgG; Signal Transduction; src-Family Kinases; Stilbenes; Syk Kinase; Transfection

Anti-neutrophil cytoplasm antibodies (ANCA) with specificity for myeloperoxidase (MPO) are implicated as pathogenic agents in pauci-immune systemic vasculitis. In agreement with previously published observations we show that human neutrophils incubated with an MPO-specific IgG class monoclonal antibody are pro-adhesive and undergo apoptosis more readily in vitro. If apoptotic neutrophils are incubated with this antibody they are readily phagocytosed by macrophages and we show that 'blocking' antibodies to FcgammaRIIa (CD32) on the macrophage inhibit this process. We also examined the effect of E3MPO, a monoclonal anti-MPO antibody derived from a patient with severe systemic vasculitis. E3MPO is closely related to the cold-agglutinins and bears an epitope recognized by the monoclonal antibody 9G4 which is expressed on antibodies derived from the V4-34 germ-line immunoglobulin gene. In previous studies, we have shown that anti-MPO antibodies present in sera from patients with vasculitis often bear this epitope. In contrast to the IgG-class antibody, incubation of neutrophils with E3MPO inhibited neutrophil adhesion and apoptosis. Apoptotic neutrophils however were phagocytosed more readily by macrophages in the presence of E3MPO. The effects of E3MPO on neutrophil adhesion and apoptosis were inhibited by piceatannol, an inhibitor of Syk-family kinases; activation of which is associated with cross-linking of the beta(2)-integrins. We show that surface-expressed MPO co-localizes with these beta(2)-integrins and suggest that cross-linking of beta(2)-integrin-bound MPO by polyvalent antibodies could result in signaling through these receptors. We have demonstrated that there are different consequences of Fcgamma-receptor-dependent and -independent signaling mediated by ANCA.

Topics: Adenosine; Adenosine A1 Receptor Agonists; Adenosine-5'-(N-ethylcarboxamide); Animals; Antibodies, Antineutrophil Cytoplasmic; Antibodies, Monoclonal; Apoptosis; Autoantigens; Autoimmune Diseases; CD18 Antigens; Cell Adhesion; Enzyme Inhibitors; Enzyme Precursors; Humans; Hyaluronan Receptors; Immunoglobulin G; Immunoglobulin M; Intracellular Signaling Peptides and Proteins; Macrophages; Mice; Neutrophils; Opsonin Proteins; Peroxidase; Phagocytosis; Phenethylamines; Protein-Tyrosine Kinases; Receptors, IgG; Signal Transduction; Stilbenes; Syk Kinase; Vasculitis

Spleen tyrosine kinase (Syk), a nonreceptor protein kinase initially found to be expressed only in hemopoietic cells, has now been shown to be expressed in nonhemopoietic cells and to mediate signaling of various cytokines. Whether Syk plays any role in TNF signaling was investigated. Treatment of Jurkat T cells with TNF activated Syk kinase but not ZAP70, another member of Syk kinase family, and the optimum activation occurred at 10 s and with 1 nM TNF. TNF also activated Syk in myeloid and epithelial cells. TNF-induced Syk activation was abolished by piceatannol (Syk-selective inhibitor), which led to the suppression of TNF-induced activation of c- JNK, p38 MAPK, and p44/p42 MAPK. Jurkat cells that did not express Syk (JCaM1, JCaM1/lck) showed lack of TNF-induced Syk, JNK, p38 MAPK, and p44/p42 MAPK activation, as well as TNF-induced IkappaBalpha phosphorylation, IkappaBalpha degradation, and NF-kappaB activation. TNF-induced NF-kappaB activation was enhanced by overexpression of Syk by Syk-cDNA and suppressed when Syk expression was down-regulated by expression of Syk-small interfering RNA (siRNA-Syk). The apoptotic effects of TNF were reduced by up-regulation of NF-kappaB by Syk-cDNA, and enhanced by down-regulation of NF-kappaB by siRNA-Syk. Immunoprecipitation of cells with Syk Abs showed TNF-dependent association of Syk with both TNFR1 and TNFR2; this association was enhanced by up-regulation of Syk expression with Syk-cDNA and suppressed by down-regulation of Syk using siRNA-Syk. Overall, our results demonstrate that Syk activation plays an essential role in TNF-induced activation of JNK, p38 MAPK, p44/p42 MAPK, NF-kappaB, and apoptosis.

Topics: Apoptosis; Enzyme Precursors; Humans; Intracellular Signaling Peptides and Proteins; Jurkat Cells; Mitogen-Activated Protein Kinases; NF-kappa B; Protein-Tyrosine Kinases; Receptors, Tumor Necrosis Factor; Stilbenes; Syk Kinase; Time Factors; Tumor Necrosis Factor-alpha

A study was conducted to determine the presence of resveratrol, pterostilbene, and piceatannol in Vaccinium berries. Samples representing selections and cultivars of 10 species from Mississippi, North Carolina, Oregon, and Canada were analyzed by gas chromatography/mass spectrometry. Resveratrol was found in Vaccinium angustifolium (lowbush blueberry), Vaccinium arboretum (sparkleberry), Vaccinium ashei (rabbiteye blueberry), Vaccinium corymbosum (highbush blueberry), Vaccinium elliottii (Elliott's blueberry), Vaccinium macrocarpon (cranberry), Vaccinium myrtillus (bilberry), Vaccinium stamineum (deerberry), Vaccinium vitis-ideae var. vitis-ideae (lingonberry), and Vaccinium vitis-ideae var. minor (partridgeberry) at levels between 7 and 5884 ng/g dry sample. Lingonberry was found to have the highest content, 5884 ng/g dry sample, comparable to that found in grapes, 6471 ng/g dry sample. Pterostilbene was found in two cultivars of V. ashei and in V. stamineum at levels of 99-520 ng/g dry sample. Piceatannol was found in V. corymbosum and V. stamineum at levels of 138-422 ng/g dry sample. These naturally occurring stilbenes, known to be strong antioxidants and to have cancer chemopreventive activities, will add to the purported health benefits derived from the consumption of these small fruits.

Topics: Antioxidants; Fruit; Phenols; Resveratrol; Species Specificity; Stilbenes; Vaccinium

The centrosome is the major microtubule organizing center in mammalian cells. During interphase, the single centrosome is duplicated and the progeny centrosomes then serve as the spindle poles during mitosis. Little is known about the signals that drive centrosome doubling. In these studies, various inhibitors and molecular approaches were used to demonstrate a role for the Stat pathway in regulating the events of centrosome doubling. Both piceatannol and a dominant negative behaving Stat3 adenovirus were able to disrupt centrosome duplication in hydroxyurea-arrested Chinese hamster ovary cells, demonstrating that Stat3 is a key signaling molecule in the events of centrosome duplication. Investigation into the role of Stat3 signaling during centrosome production demonstrated that Stat3 does not directly regulate the transcription of the centrosome genes encoding gamma-tubulin and PCM-1. Instead, Stat3 apparently regulated gamma-tubulin levels through post-transcriptional mechanisms whereas PCM-1 levels actually increased when Stat3 was inhibited, suggesting more complex mechanisms for regulating PCM-1 production. These studies demonstrate that Stat3 plays a vital role in centrosome duplication events, although the downstream targets of Stat3 activation leading to centrosome production remain to be established. The proposed signaling pathway utilizes Stat3 as a fundamental signaling molecule that directs the production of the various centrosome proteins indirectly.

Topics: Animals; Cell Cycle; Cell Cycle Proteins; Centrosome; CHO Cells; Cricetinae; DNA-Binding Proteins; Microtubules; Signal Transduction; STAT3 Transcription Factor; Stilbenes; Trans-Activators; Tubulin

The resveratrol analogue piceatannol (3,5,3',4'-tetrahydroxy- trans-stilbene; PICE) is a polyphenol present in grapes and wine. PICE is a protein kinase inhibitor that modifies multiple cellular targets exerting immunosuppressive, antileukemic and antitumorigenic activities in several cell lines and animal models. The present work aims to evaluate the antimelanoma effect of PICE on human melanoma cells for the first time. To this purpose, the pro-apoptotic capacity, uptake and metabolism of PICE as well as its effect on cell cycle and cyclins A, E and B1 expression will be studied.. . Human SK-Mel-28 melanoma cells were incubated with PICE (1-200 microM) for 72 hours. Cell cycle and viability were examined using flow cytometry analysis. Apoptosis was determined using the annexin V assay and also by fluorescence microscopy. Cyclins A, E and B1 were detected by Western blotting. Stability, cellular uptake and metabolism of PICE were evaluated using HPLC-DAD-MS-MS.. The lowest PICE concentration assayed (1 microM) increased about 6-fold over the control the apoptotic population of melanoma cells (10.2% at 8 hours which remained constant during 48 h). 100 microM PICE induced 13% apoptosis at 8 h increasing up to 41.5% at 48 h. The decrease in cell viability was highly correlated with the increase of apoptotic cells ( R = 0.996; P < 0.0001) revealing that significant cytotoxic, unspecific effects did not occur in melanoma cells upon incubation with PICE. Cell cycle was arrested at G(2) phase which was supported by the down-regulation of cyclins A, E and B1. Two methyl-PICE derived metabolites, 3,5,4'-trihydroxy-3'-methoxy- trans-stilbene and 3,5,3'-trihydroxy-4'-methoxy- trans-stilbene (corresponding to 36% of the initially PICE added) were excreted by cells to the medium. The same methyl-PICE derivatives were also found inside the cells (0.01% of the initially PICE added; 0.0183 picograms/cell).. The antimelanoma properties of dietary piceatannol cannot be ruled out taking into account its fast and potent pro-apoptotic capacity at low concentration (1 microM).

Topics: Apoptosis; Cell Cycle; Cell Division; Cell Survival; Dose-Response Relationship, Drug; Down-Regulation; Flow Cytometry; Humans; Melanoma; Stilbenes; Tumor Cells, Cultured; Vitis; Wine

A method of analysis of piceatannol in biological fluids is necessary to study the kinetics of in vitro and in vivo metabolism and determine its concentration in foodstuffs. A novel and simple high-performance liquid chromatographic method was developed for simultaneous determination of piceatannol and products of its metabolism in rat serum and liver microsomes. Serum, or microsomes (0.1 mL), were precipitated with acetonitrile after addition of the internal standard, 4-methylumbelliferone. Separation was achieved on a phenomenex C(18) column (250 x 4.6 mm i.d., 5 microm) equipped with a phenomenex C(18) (4 x 3.0 mm i.d., 5 microm) guardcolumn with fluorescence excitation at 320 nm and emission at 420 nm. Separation was also possible with UV detection at 310 nm. The fluorescent calibration curves were linear ranging from 0.05 to 100 microg/mL. The mean extraction efficiency was >95%. Precision of the assay was <10% (coefficient of variation), and was within 10% at the limit of quantitation (0.05 ng/mL). Bias of the assay was lower than 7%. The limit of detection was 50 ng/mL for a 0.1 mL sample. The assay was applied successfully to the in vitro kinetic study of metabolism of piceatannol in rat liver microsomes and pharmacokinetics in rats. Three metabolites of piceatannol have been identified. .

Topics: Acetonitriles; Animals; Biotransformation; Chemical Precipitation; Chromatography, High Pressure Liquid; Drug Stability; Glucuronosyltransferase; Male; Microsomes, Liver; NADP; Quality Control; Rats; Rats, Sprague-Dawley; Sensitivity and Specificity; Spectrometry, Fluorescence; Stilbenes

Epithelial injury and repair are central consequences of ischemia and reperfusion of the gut. Intestinal mucosal wounds are repaired in part by epithelial restitution. However, the signaling mechanisms regulating restitution remain poorly understood, and few therapies to enhance restitution have been described. Previously we demonstrated that alpha-melanocyte-stimulating hormone (alpha-MSH) protected against postischemic gut injury in the rat. In this report, we tested the effects and mechanisms of alpha-MSH on wound restitution of rat small intestine (IEC-6) cells subjected to H2O2 stress with or without scrape wounding. H2O2 treatment resulted in tyrosine phosphorylation of Syk kinase and its downstream target IkappaBalpha, with subsequent NF-kappaB activation. Alpha-MSH and the Syk kinase inhibitor piceatannol blocked these processes. In scrape-wounded cells, H2O2 inhibited wound restitution, and this was partially restored by cotreatment with alpha-MSH or piceatannol. In contrast, overexpression of NF-kappaB p65 or Syk kinase, but not a dominant-negative mutant of Syk kinase, aggravated H2O2 inhibition of wound restitution, and inhibitors of c-Src tyrosine kinase or phosphatidylinositol-3 kinase were without effect. The results indicate an important role for Syk tyrosine kinase and the NF-kappaB pathway in the response to oxidant stress and the impairment of epithelial restitution in IEC-6 cells. The data also disclose that the beneficial effects of alpha-MSH on gut ischemia/reperfusion injury may relate to its acceleration of epithelial restitution.

Topics: alpha-MSH; Animals; Blotting, Western; Cell Line; Cells, Cultured; Epithelial Cells; Genes, Reporter; Hydrogen Peroxide; I-kappa B Proteins; Immunoprecipitation; NF-kappa B; NF-KappaB Inhibitor alpha; Oxidants; Phosphatidylinositol 3-Kinases; Phosphorylation; Plasmids; Rats; Reperfusion Injury; Signal Transduction; Stilbenes; Transfection; Tyrosine; Wound Healing

The effect of piceatannol on lipopolysaccharide (LPS)-induced nitric oxide (NO) production was examined. Piceatannol significantly inhibited NO production in LPS-stimulated RAW 264.7 cells. The inhibition was due to the reduced expression of an inducible isoform of NO synthase (iNOS). The inhibitory effect of piceatannol was mediated by down-regulation of LPS-induced nuclear factor (NF)-kappaB activation, but not by its cytotoxic action. Piceatannol inhibited IkappaB kinase (IKK)-alpha and beta phosphorylation, and subsequently IkappaB-alpha phosphorylation in LPS-stimulated RAW 264.7 cells. On the other hand, piceatannol did not affect activation of mitogen-activated protein (MAP) kinases including extracellular signal regulated kinase 1/2 (Erk1/2), p38 and stress-activated protein kinase/c-Jun NH2-terminal kinase (SAPK/JNK). Piceatannol inhibited the phosphorylation of Akt and Raf-1 molecules, which regulated the activation of IKK-alpha and beta phosphorylation. The detailed mechanism of the inhibition of LPS-induced NO production by piceatannol is discussed.

Topics: Animals; Cell Line; I-kappa B Kinase; Lipopolysaccharides; Macrophages; Mitogen-Activated Protein Kinases; NF-kappa B; Nitric Oxide; p38 Mitogen-Activated Protein Kinases; Protein Serine-Threonine Kinases; Signal Transduction; Stilbenes

Topics: Animals; Asthma; Butadienes; Calcium-Calmodulin-Dependent Protein Kinases; Enzyme Inhibitors; Guinea Pigs; Imidazoles; Nitriles; Protein-Tyrosine Kinases; Pyrimidines; Signal Transduction; Stilbenes

Protein-tyrosine phosphatase (PTP) inhibitors are potent activators of T lymphocytes, most likely by affecting the early steps of T cell receptor (TCR) signaling. We have analyzed the effect of the PTP inhibitor bisperoxovanadium (bpV) on expression of the human cyclooxygenase 2 (COX-2) gene, which is induced following TCR triggering. Here we show that COX-2 promoter activity is markedly up-regulated following exposure of Jurkat T cells to bpV(pic). Interestingly enough, treatment of Jurkat cells with cyclic AMP-elevating agents such as forskolin, in combination with bpV, resulted in a more important COX-2 transcriptional activation. Such activation is inhibited by the immunosuppressive drugs FK506 and cyclosporin A. The two nuclear factor of activated T cells (NFAT) binding sites located within the COX-2 promoter region are involved in bpV-mediated positive effect on COX-2 promoter. Electromobility shift assays showed that NFAT1 and activator protein-1 are both translocated to the nucleus following bpV treatment. The active participation of p56(lck), ZAP-70, p36(LAT), and calcium in the bpV-dependent signaling cascade leading to COX-2 transcriptional activation was demonstrated using deficient cell lines and specific inhibitors. Although several PTPs are most likely targeted by bpV, our data suggest that the bpV-mediated signaling cascade is initiated by inhibition of SHP-1, which leads to phosphorylation of p56(lck) and ZAP-70 and, ultimately, to NFAT and activator protein-1 nuclear translocation. These results suggest that PTP inhibitors can activate COX-2 gene expression in a manner very similar to the stimulation induced by TCR triggering.

Topics: Active Transport, Cell Nucleus; Adaptor Proteins, Signal Transducing; Binding Sites; Calcineurin; Calcium; Calcium Channel Blockers; Carrier Proteins; CCAAT-Enhancer-Binding Proteins; Cell Line; Cell Nucleus; Colforsin; Cyclooxygenase 2; Cyclosporine; Dose-Response Relationship, Drug; Enzyme Activation; Enzyme Inhibitors; Gallic Acid; Humans; Immunosuppressive Agents; Isoenzymes; Jurkat Cells; Lymphocyte Specific Protein Tyrosine Kinase p56(lck); Membrane Proteins; Mutation; Phosphoproteins; Phosphorylation; Plasmids; Promoter Regions, Genetic; Prostaglandin-Endoperoxide Synthases; Protein Tyrosine Phosphatases; Protein-Tyrosine Kinases; Signal Transduction; Stilbenes; T-Lymphocytes; Tacrolimus; Time Factors; Transcription, Genetic; Transcriptional Activation; Transfection; Vanadates; Vanadium Compounds; ZAP-70 Protein-Tyrosine Kinase

Hematopoietic malignancies have been shown to depend on cytokine growth factor autocrine/paracrine loops for growth and differentiation. This results in the constitutive activation of cytokine-mediated transcription factors like signal transducer and activators of transcription (STAT) 3 in non-Hodgkin's lymphoma (NHL) and multiple myeloma (MM). Recent evidence demonstrates that cytokines also contribute to a drug-resistant phenotype in many tumor cell types. We hypothesized that inhibitors of the STAT3 pathway would sensitize drug-resistant and endogenous cytokine-dependent NHL and MM tumor cells to the cytotoxic effects of chemotherapeutic drugs. We examined an AIDS-related NHL cell line, 2F7, known to be dependent on interleukin (IL)-10 for survival and an MM cell line, U266, known to be dependent on IL-6 for survival. IL-10 and IL-6 signal the cells through the activation of Janus kinase (JAK)1 and JAK2, respectively. Thus, we investigated the effect of two chemical STAT3 pathway inhibitors, namely, piceatannol (JAK1/STAT3 inhibitor) and tyrphostin AG490 (JAK2/STAT3 inhibitor), on the tumor cells for sensitization to therapeutic drugs. We demonstrate by phosphoprotein immunoblotting analysis and electrophoretic mobility shift analysis that piceatannol and AG490 inhibit the constitutive activity of STAT3 in 2F7 and U266, respectively. Furthermore, piceatannol and AG490 sensitize 2F7 and U266 cells, respectively, to apoptosis by a range of therapeutic drugs including cisplatin, fludarabine, Adriamycin, and vinblastine. The specificity of the inhibitors was corroborated in experiments showing that piceatannol had no effect on U266 and, likewise, AG490 has no effect on 2F7. The sensitization observed by these inhibitors correlated with the inhibition of Bcl-2 expression in 2F7 and Bcl-xL expression in U266. Altogether, these results demonstrate that STAT3 pathway inhibitors are a novel class of chemotherapeutic sensitizing agents capable of reversing the drug-resistant phenotype of cytokine-dependent tumor cells.

Topics: Antineoplastic Agents; Apoptosis; bcl-2-Associated X Protein; bcl-Associated Death Protein; bcl-X Protein; Carrier Proteins; Cytokines; DNA Fragmentation; DNA-Binding Proteins; Dose-Response Relationship, Drug; Down-Regulation; Doxorubicin; Humans; Immunoblotting; Interleukin-10; Interleukin-6; Janus Kinase 1; Janus Kinase 2; Lymphoma, Non-Hodgkin; Models, Biological; Multiple Myeloma; Protein-Tyrosine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; STAT3 Transcription Factor; Stilbenes; Time Factors; Trans-Activators; Tumor Cells, Cultured; Tyrphostins; Vinblastine

The use of postharvest controlled irradiation by UV pulses is proposed as a potential method to produce stilbene-enriched red wine. "Monastrell" grapes were UV-C-irradiated to increase stilbene content. The main inducible stilbenes were resveratrol and piceatannol, which are molecules with reported health-beneficial activities. The evolution of both compounds was followed in the different steps of an "analytical" traditional maceration wine-making process. The final wine made from UV-C-irradiated grapes was enriched about 2- and 1.5-fold in resveratrol and piceatannol, respectively, when compared to the control wine. In addition, no difference was detected regarding the standard enological parameters (color, acidity, etc.). It is strongly suggested that, with the use of more susceptible wine grapes to induce bioactive stilbenes upon UV-C irradiation, the stilbene-enrichment of wine can be much higher.

Topics: Chromatography, High Pressure Liquid; Color; Fruit; Hydrogen-Ion Concentration; Mass Spectrometry; Resveratrol; Stilbenes; Ultraviolet Rays; Vitis; Wine

We describe the isolation of a protein, SWAP-70-like adapter of T cells (SLAT), which is expressed at high levels in thymocytes and differentiated Th2 cells. SLAT expression was upregulated in differentiating Th2 cells and downregulated in Th1 cells. Ectopic SLAT expression exerted positive or negative effects on IL-4 versus IFNgamma induction, respectively. TCR signaling induced translocation of SLAT to the immunological synapse and its association with ZAP-70 kinase. SLAT reduced the association of ZAP-70 with TCR-zeta and interfered with ZAP-70 but not Lck signaling. Consistent with these results, pharmacological inhibition of ZAP-70 also induced Th2 skewing. Thus, SLAT is a protein which plays a role in Th2 development and/or activation, perhaps by interfering with ZAP-70 signaling.

Topics: Amino Acid Sequence; Animals; Biological Transport, Active; Cell Differentiation; DNA-Binding Proteins; Enzyme Inhibitors; Genes, T-Cell Receptor; Guanine Nucleotide Exchange Factors; Mice; Mice, Transgenic; Minor Histocompatibility Antigens; Molecular Sequence Data; Nuclear Proteins; Protein-Tyrosine Kinases; Receptors, Antigen, T-Cell; Sequence Homology, Amino Acid; Signal Transduction; Stilbenes; Th2 Cells; ZAP-70 Protein-Tyrosine Kinase

Resveratrol, a constituent of grapes and other foods, has been reported to be a potential cancer chemopreventive agent. Our previous study showed that the antitumor activity of resveratrol occurs through mitogen-activated protein kinases-mediated p53 activation and induction of apoptosis. To develop more effective agents with fewer side effects for the chemoprevention of cancer, we investigated the effect of resveratrol and its structurally related derivatives on epidermal growth factor (EGF)-induced cell transformation. Our results provided the first evidence that one of the resveratrol derivatives exerted a more potent inhibitory effect than resveratrol on EGF-induced cell transformation, but had less cytotoxic effects on normal nontransformed cells. Compared to resveratrol, this compound also caused cell cycle arrest in the G1 phase, but did not induce p53 activation and apoptosis. Furthermore, this compound, but not resveratrol, markedly inhibited EGF-induced phosphatidylinositol-3 kinase (PI-3K) and Akt activation. Collectively, these data suggested that the higher antitumor effect of the compound compared to resveratrol, may act through a different mechanism by mainly targeting PI-3K/Akt signaling pathways.

Topics: Animals; Anticarcinogenic Agents; Apoptosis; Cell Line; Cell Transformation, Neoplastic; Epidermal Growth Factor; G1 Phase; Gene Expression Regulation; Genes, p53; Mice; Resveratrol; Stilbenes

To evaluate the impact of monosodium urate monohydrate (MSUM) crystals on the synthesis of prostaglandin E(2) (PGE(2)) by human neutrophils, and to examine some of the mechanisms underlying these responses.. The amount of PGE(2) released in the supernatants of stimulated human neutrophils was evaluated by enzyme immunoassay, and expression of cyclooxygenase 2 (COX-2) was monitored by immunoblot on cell lysates, as well as by cytofluorometry of buffy-coat cells.. We observed that MSUM crystals rapidly stimulated the synthesis of PGE(2), with levels peaking at 1 hour. This response was decreased by NS-398, a specific inhibitor of COX-2. We also detected a constitutive expression of COX-2 in unstimulated and unprimed neutrophils. This rapid COX-2-dependent PGE(2) accumulation was independent of translation and transcription. We also observed that piceatannol, but not colchicine, blocked the synthesis of PGE(2) stimulated by MSUM crystals.. These results show that the interaction of MSUM crystals with human neutrophils stimulates a significant synthesis of PGE(2) mediated by constitutively expressed COX-2. The results of this study emphasize the potential importance of the neutrophil as a source of PGE(2), which may modulate, positively or negatively, the inflammatory response.

Topics: Arachidonic Acid; Crystallization; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Dinoprostone; Dose-Response Relationship, Drug; Humans; Isoenzymes; Leukotriene B4; Membrane Proteins; Neutrophil Activation; Neutrophils; Nitrobenzenes; Prostaglandin-Endoperoxide Synthases; Stilbenes; Sulfonamides; Uric Acid

A feasibility research was performed to study the possibilities of using a molecularly imprinted polymer as sorbent material in solid-phase extraction for the separation of active inhibitors of epidermal growth factor receptor (EGRF) from Caragana Jubata, a Chinese traditional Tibetan medicine. A molecularly imprinted polymer using quercetin, an active anti-EGFR inhibitor (IC50 = 15 microM), as the template and acrylamide as the functional monomer was prepared. The polymer was evaluated as a selective sorbent in molecularly imprinted solid-phase extraction. The EtOAc extract of Caragana Jubata was loaded on the polymer, and two novel active anti-EGFR inhibitors were found to be selectively retained after washing the polymer with appropriate solvent to disrupt the non-specific interactions occurring between the sample and the polymer matrix, which were identified as (E)-piceatannol (IC50 =4.9 microM) and butein (IC50 = 10 microM). The present work affords us a new potential method for selective separation of bioactive components from herb by using molecularly imprinted polymer as a solid-phase extraction adsorbent.

Topics: Caragana; Chalcone; Chalcones; Chromatography, High Pressure Liquid; ErbB Receptors; Humans; Quercetin; Sensitivity and Specificity; Stilbenes; Tumor Cells, Cultured

Acute myeloid leukemia (AML) cells express the cell surface antigen CD33 that can function as a downregulator of cell growth, mediating growth arrest and apoptosis. The protein kinase Syk is an essential element in several cascades coupling certain antigen receptors to cell responses. Recently we reported that CD33 recruits Syk for its signaling in AML cell lines. In this study, we further investigated the mechanism(s) of Syk engagement in CD33 signaling in primary AML samples.. We investigated 25 primary AML samples for their proliferative response (3H-thymidine incorporation) and biochemical changes (Western blot analysis) to anti-CD33 mAb treatment.. Proliferation studies demonstrated that 14 (56%) of AML samples were responsive (R) while 11 (44%) were nonresponsive (n-R) to inhibitory antibody activity. Seven of 25 AML samples (28%) expressed undetectable levels of Syk. However, cells from two of these patients expressed the ZAP-70 protein kinase. In Syk/ZAP-70(+) samples, CD33 ligation inhibited proliferation in 70% of cases, while none of the Syk/ZAP-70(-) samples was responsive. There were significant biochemical differences between responder and nonresponder AML populations. In responder samples, CD33 ligation induced phosphorylation of CD33 andSyk and formation of the CD33/Syk complex. In nonresponder samples, CD33 was not phosphorylated, and Syk was in complex with the SHP-1 protein phosphatase constitutively.. Syk is an important component in the regulation of proliferation in AML cells. The differential response of AML cells to CD33 ligation is associated with the level of the Syk expression.

Topics: Antibodies, Monoclonal; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Cell Division; Enzyme Precursors; HL-60 Cells; Humans; Intracellular Signaling Peptides and Proteins; Leukemia, Myeloid, Acute; Protein-Tyrosine Kinases; Sialic Acid Binding Ig-like Lectin 3; Stilbenes; Syk Kinase; ZAP-70 Protein-Tyrosine Kinase

On encountering a danger signal, dendritic cells (DCs) undergo a complex maturation process and become specialized in antigen presentation. We previously reported that engagement of major histocompatibility complex (MHC) class II molecules located on immature DCs in membrane rafts by lymphocyte activation gene-3 (LAG-3; CD223) leads to DC maturation. In contrast, exposure of DCs to class II-specific monoclonal antibodies (mAbs) did not lead to maturation. Here, we have investigated the signal transduction pathways involved in the LAG-3-induced maturation of human monocyte-derived DCs. We first show that areas of raft aggregation (both cholesterol rich and CDw78 microdomains) could be visualized using a soluble LAG-3 protein and confocal microscopy. Engagement of class II molecules by both its natural ligand LAG-3 and class II mAb induces rapid protein phosphorylation of phospholipase Cgamma2 (PLCgamma2) and p72syk as well as activation of phosphatidyl inositol 3-kinase/Akt, p42/44 extracellular signal-regulated protein kinase, and p38 mitogen-activated protein kinase pathways. Studies using inhibitors demonstrate that these 3 pathways are all important in inducing the maturation process of LAG-3-stimulated DCs. When class II molecules were ligated with LAG-3 versus specific antibody, differences in the phosphorylation pattern of c-Akt were observed. Thus, MHC class II signaling in DCs involves several pathways that have to be finely regulated to lead to cell activation and maturation.

Topics: Antibodies, Monoclonal; Antigens, CD; Cross-Linking Reagents; Dendritic Cells; Down-Regulation; Enzyme Activation; Enzyme Inhibitors; Enzyme Precursors; Histocompatibility Antigens Class II; Humans; Immunophenotyping; Intracellular Signaling Peptides and Proteins; Ligands; Lymphocyte Activation Gene 3 Protein; Membrane Proteins; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases; Monocytes; p38 Mitogen-Activated Protein Kinases; Phosphatidylinositol 3-Kinases; Phospholipase C gamma; Phosphorylation; Protein Serine-Threonine Kinases; Protein-Tyrosine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Signal Transduction; Stilbenes; Syk Kinase; Type C Phospholipases; Tyrosine

To study the chemical constituents of the stem of Cassia siamea.. The compounds were isolated by chromatography on silica gel, and identified on the basis of spectral analysis.. Five compounds were isolated and identified as: beta-sitosterol (I), sucrose (II), n-octacosanol (III), 2-methyl-5-(2'-hydroxypropyl)-7-hydroxy-chromone-2'-O-beta-D-glucopyranoside (IV) and piceatannol (V).. Compound IV is a new compound. Compounds II, III and V were obtained from this plant for the first time.

Topics: Cassia; Chromones; Fatty Alcohols; Monosaccharides; Plant Stems; Plants, Medicinal; Stilbenes

A fine control of beta(2) integrin (CD11/CD18)-mediated firm adhesion of human neutrophils to the endothelial cell monolayer is required to allow ordered emigration. To elucidate the molecular mechanisms that control this process, intracellular protein tyrosine signaling subsequent to beta(2) integrin-mediated ligand binding was studied by immunoprecipitation and Western blotting techniques. The 72-kDa Syk-kinase, which was tyrosine-phosphorylated upon adhesion, was found to coprecipitate with CD18, the beta-subunit of the beta(2) integrins. Moreover, inhibition of Syk-kinase by piceatannol enhanced adhesion and spreading but diminished N-formyl-Met-Leu-Phe-induced chemotactic migration. The enhancement of adhesiveness was associated with integrin clustering, which results in increased integrin avidity. In contrast, piceatannol had no effect on the surface expression or on the affinity of beta(2) integrins. Altogether, this suggests that Syk-kinase controls alternation of beta(2) integrin-mediated ligand binding with integrin detachment.

Topics: Blotting, Western; CD11 Antigens; CD18 Antigens; Cell Adhesion; Cell Movement; Chemotaxis, Leukocyte; Enzyme Inhibitors; Enzyme Precursors; Humans; Intracellular Signaling Peptides and Proteins; Ligands; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Phosphorylation; Precipitin Tests; Protein Binding; Protein-Tyrosine Kinases; Signal Transduction; Stilbenes; Syk Kinase; Tyrosine

Berries of Vitis vinifera L. cv. Barbera were infected, at veraison and during ripening, by a conidial suspension of A. japonicus, A. ochraceus, A. fumigatus and two isolates of A. carbonarius to control ochratoxin A production and stilbene induced synthesis. The experimental design provided also for intact and punctured berries and incubation temperature of 25 degrees C and 30 degrees C. All the tested fungi, except A. fumigatus, significantly increased trans-resveratrol synthesis over the control, while trans-piceid was not affected; only A. ochraceus significantly elicited the berries to synthesize piceatannol. The two isolates of A. carbonarius produced higher amounts of ochratoxin A than did the other fungi. A positive correlation between ochratoxin A and trans-resveratrol synthesis occurred. trans-Resveratrol and piceatannol showed fungicidal activity against A. carbonarius, being able to completely inhibit fungal growth at a concentration of 300 microg/g and 20 microg/g, respectively.

Topics: Aspergillus; Fruit; Kinetics; Ochratoxins; Phytoalexins; Plant Extracts; Resveratrol; Sesquiterpenes; Stilbenes; Terpenes; Vitis

Extracellular ATP synthesis on human umbilical vein endothelial cells (HUVECs) was examined, and it was found that HUVECs possess high ATP synthesis activity on the cell surface. Extracellular ATP generation was detected within 5 s after addition of ADP and inorganic phosphate and reached a maximal level at 15 s. This type of ATP synthesis was almost completely inhibited by mitochondrial H(+)-ATP synthase inhibitors (e.g., efrapeptins, resveratrol, and piceatannol), which target the F(1) catalytic domain. Oligomycin and carbonyl cyanide m-chlorophenylhydrazone, but not potassium cyanide, also inhibited extracellular ATP synthesis on HUVECs, suggesting that cell surface ATP synthase employs the transmembrane electrochemical potential difference of protons to synthesize ATP as well as mitochondrial H(+)-ATP synthase. The F(1)-targeting H(+)-ATP synthase inhibitors markedly inhibited the proliferation of HUVECs, but intracellular ATP levels in HUVECs treated with these inhibitors were only slightly affected, as shown by comparison with the control cells. Interestingly, piceatannol inhibited only partially the activation of Syk (a nonreceptor tyrosine kinase), which has been shown to play a role in a number of endothelial cell functions, including cell growth and migration. These findings suggest that H(+)-ATP synthase-like molecules on the surface of HUVECs play an important role not only in extracellular ATP synthesis but also in the proliferation of HUVECs. The present results demonstrate that the use of small molecular H(+)-ATP synthase inhibitors targeting the F(1) catalytic domain may lead to significant advances in potential antiangiogenic cancer therapies.

Topics: Adenosine Triphosphate; Carbonyl Cyanide m-Chlorophenyl Hydrazone; Cell Division; Cell Line; Cell Membrane; Dose-Response Relationship, Drug; Endothelial Cells; Enzyme Precursors; Extracellular Space; Humans; Intracellular Signaling Peptides and Proteins; Oligomycins; Peptides; Potassium Cyanide; Protein-Tyrosine Kinases; Proton-Translocating ATPases; Resveratrol; Ribonucleotide Reductases; Stilbenes; Syk Kinase; Umbilical Veins

Resveratrol (3,4',5-trans-trihydroxystilbene) is a dietary polyphenol with chemopreventive properties present in grapes, red wine, peanuts and other edible products. The antiproliferative and proapoptotic effect of resveratrol in breast cancer cells can be traced to the accumulation of ceramide. In this study we demonstrate that resveratrol can also exert antiproliferative/proapoptotic effects in association with the accumulation of endogenous ceramide in the androgen receptor (AR)-negative prostate cancer cell line, PC3. Notably, resveratrol shares with other ceramide-inducing agents a phenolic moiety on its structure. For this reason we hypothesize that the phenolic moiety is critical for the ceramide-associated growth-inhibitory effects of resveratrol. We compared the ability to induce both ceramide increase and growth inhibition in PC3 cells of resveratrol and three resveratrol analogs: piceatannol (3,3',4',5-trans-tetrahydroxystilbene), with an additional hydroxyl group in the 3' position; trans-stilbene, the nonhydroxylated analog; and the semisynthetic 3,4',5-trimethoxy-trans-stilbene (TmS), with methoxyl groups in lieu of the hydroxyl groups. Of the three stilbenoids, only piceatannol (and not stilbene or TmS) produced ceramide-associated growth inhibition. These data point to the phenolic moiety of stilbenoids as a critical structural feature necessary to induce ceramide-associated growth inhibition.

Topics: Anticarcinogenic Agents; Apoptosis; Cell Line, Tumor; Ceramides; Humans; Male; Prostatic Neoplasms; Resveratrol; Stilbenes; Structure-Activity Relationship; Time Factors

Macrophages are known to adhere to a plastic dish via beta2 integrin (CR3) and scavenger receptors. Although their functions such as phagocytosis, endocytosis, and nitric oxide production have been investigated on adherent macrophages in vitro, very little is known about intracellular signals triggered by adhesion to a plastic dish. Recently we reported that the mRNA level of krox-20/egr-2 was significantly increased in rat alveolar macrophages following exposure to fibrous titanium dioxide particles. In the present study we report that up-regulation of krox-20/egr-2 gene expression following adhesion to a plastic dish and homophilic adhesion in rat alveolar macrophages and rat macrophage cell line, NR8383. The mRNA level of krox-20/egr-2 increased with a peak 1 hr after adhesion to a plastic dish in both cell types. Piceatannol inhibited tyrosine-phosphorylation of Syk and decreased both adhesion and krox-20/egr-2 mRNA level. In contrast staurosporine, a serine/threonine kinase inhibitor, increased adherence of macrophages and yet prohibited the adhesion-dependent increase in krox-20/egr-2 gene expression. When NR8383 cells are cultured in suspension, the cells aggregated naturally and produced cell clumps. The mRNA level of krox-20/egr-2 also increased in response to the homophilic intercellular adhesion. The increased mRNA level of krox-20/egr-2 was not caused by inflammatory stimuli, because lipopolysaccharide did not affect the aggregation-dependent up-regulation of krox-20/egr-2 gene. The up-regulation of krox-20/egr-2 gene due to the homophilic cell aggregation was also inhibited either by piceatannol or staurosporine. Those results suggest that krox-20/egr-2 gene expression is triggered by sensing non-specific and homophilic cellular adhesion and the following phosphorylation of signal transducing proteins including Syk and staurosporine-inhibitable kinases.

Topics: Animals; Cell Adhesion; Cell Aggregation; Cell Line; Cells, Cultured; DNA-Binding Proteins; Early Growth Response Protein 2; Enzyme Inhibitors; Lipopolysaccharides; Macrophages; Macrophages, Alveolar; Male; Rats; Rats, Sprague-Dawley; RNA, Messenger; Signal Transduction; Staurosporine; Stilbenes; Transcription Factors; Up-Regulation; Zinc Fingers

Epstein-Barr virus (EBV) is a human herpesvirus that establishes a lifelong latent infection in the majority of the human population. The virus resides in a latent state in B lymphocytes and is associated with a variety of cancers in the human host. In normal individuals, latent infection with EBV typically poses no health risk, but upon immunosuppression, either following organ transplantation or HIV infection, malignancies and lymphoproliferative diseases can result. Latent membrane protein 2A (LMP2A) is a virally encoded membrane protein that is expressed in EBV latent infection and in most of the tumors associated with EBV infection. Previous studies have indicated that LMP2A expression alters the activity of the Src family protein tyrosine kinases, the Syk protein tyrosine kinase, the Btk protein tyrosine kinase, and phosphatidylinositol 3-kinase (PI3-kinase). In this study, inhibitors of each of these kinases were tested using an in vitro system dependent on LMP2A expression for B cell colony formation in IL-7 containing methylcellulose media. Of the inhibitors tested, only piceatannol, a Syk tyrosine kinase inhibitor, demonstrated a specific effect on LMP2A expressing cells and not control cells. These studies provide a basis for targeting LMP2A function in EBV latency and may allow for the identification of novel therapeutics for the treatment or eradication of EBV latent infections and associated proliferative disorders.

Topics: Agammaglobulinaemia Tyrosine Kinase; Amides; Animals; Apoptosis; B-Lymphocytes; Bone Marrow Cells; Chromones; Enzyme Inhibitors; Enzyme Precursors; Herpesvirus 4, Human; Humans; Intracellular Signaling Peptides and Proteins; Mice; Mice, Transgenic; Morpholines; Nitriles; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein-Tyrosine Kinases; src-Family Kinases; Stilbenes; Syk Kinase; Viral Matrix Proteins; Virus Latency

Piceatannol is an anti-inflammatory, immunomodulatory, and anti-proliferative stilbene that has been shown to interfere with the cytokine signaling pathway. Previously, we have shown that resveratrol suppresses the activation of the nuclear transcription factor NF-kappaB. Piceatannol, previously reported as a selective inhibitor of protein tyrosine kinase Syk, is structurally homologous to resveratrol. Whether piceatannol can also suppress NF-kappaB activation was investigated. The treatment of human myeloid cells with piceatannol suppressed TNF-induced DNA binding activity of NF-kappaB. In contrast, stilbene or rhaponticin (another analog of piceatannol) had no effect, suggesting the critical role of hydroxyl groups. The effect of piceatannol was not restricted to myeloid cells, as TNF-induced NF-kappaB activation was also suppressed in lymphocyte and epithelial cells. Piceatannol also inhibited NF-kappaB activated by H(2)O(2), PMA, LPS, okadaic acid, and ceramide. Piceatannol abrogated the expression of TNF-induced NF-kappaB-dependent reporter gene and of matrix metalloprotease-9, cyclooxygenase-2, and cyclin D1. When examined for the mechanism, we found that piceatannol inhibited TNF-induced IkappaBalpha phosphorylation, p65 phosphorylation, p65 nuclear translocation, and IkappaBalpha kinase activation, but had no significant effect on IkappaBalpha degradation. Piceatannol inhibited NF-kappaB in cells with deleted Syk, indicating the lack of involvement of this kinase. Overall, our results clearly demonstrate that hydroxyl groups of stilbenes are critical and that piceatannol, a tetrahydroxystilbene, suppresses NF-kappaB activation induced by various inflammatory agents through inhibition of IkappaBalpha kinase and p65 phosphorylation.

Topics: Active Transport, Cell Nucleus; Anti-Inflammatory Agents, Non-Steroidal; Base Sequence; Cell Line; Ceramides; Cyclin D1; Cyclooxygenase 2; DNA; Enzyme Inhibitors; Enzyme Precursors; Gene Expression; HeLa Cells; Humans; Hydrogen Peroxide; I-kappa B Kinase; Intracellular Signaling Peptides and Proteins; Isoenzymes; Jurkat Cells; Lipopolysaccharides; Matrix Metalloproteinase 9; Membrane Proteins; NF-kappa B; Okadaic Acid; Phosphorylation; Prostaglandin-Endoperoxide Synthases; Protein Serine-Threonine Kinases; Protein-Tyrosine Kinases; Stilbenes; Syk Kinase; Tetradecanoylphorbol Acetate; Transcription Factor RelA; Tumor Necrosis Factor-alpha

The discovery of new immunosuppressive agents has enhanced short-term graft survival. However, current immunosuppressants often induce toxicities that limit their clinical use. Thus, there is a need for new immunosuppressants for use in clinical transplantation. Piceatannol blocks Syk and ZAP-70, tyrosine kinases involved in immune cell activation. We examined whether piceatannol prolongs kidney allograft survival in the stringent ACI-to-Lewis rat model.. Kidney recipients were divided into four groups. Group 1 (n=8) received piceatannol 30 mg/kg per day intravenously and cyclosporine A (CsA) 2 mg/kg per day intramuscularly from day -3 to day 7 after transplantation. At day 8, piceatannol was reduced to 10 mg/kg per day and the combined treatment continued until day 60. Group 2 (n=9) received 2 mg/kg per day CsA alone from day -3 to day 60. Group 3 (n=4) received piceatannol alone as in group 1. Group 4 (n=2) received only the vehicle dimethyl sulfoxide from day -3 to day 60. Graft rejection was defined as either a serum creatinine level more than 2 mg/dL or animal death.. Group 1 animals survived for at least 115 days (n=8, P<0.05), with several animals maintaining their grafts for more than 200 days. In contrast, 8 of 9 animals in group 2 rejected their grafts within 10 days of transplantation; one animal survived for 71 days. Excellent graft function was maintained in group 1 animals despite withdrawal of immunosuppression.. These results are the first to show that piceatannol, when combined with subtherapeutic dosages of CsA, prevents graft rejection, suggesting that targeting Syk and Zap could be useful for preventing graft rejection.

Topics: Animals; Cyclosporine; Dose-Response Relationship, Drug; Drug Therapy, Combination; Graft Survival; Immunosuppressive Agents; Kidney; Kidney Transplantation; Leukocyte Count; Phosphorylation; Rats; Rats, Inbred ACI; Rats, Inbred Lew; Receptors, Antigen, T-Cell; Reference Values; Stem Cells; Stilbenes; T-Lymphocytes; T-Lymphocytes, Cytotoxic; Thymidine; Transplantation, Homologous; Tyrosine

Piceatannol, a naturally occurring analog of resveratrol, was previously identified as the active ingredient in herbal preparations in folk medicine and as an inhibitor of p72(Syk). We studied the effects of piceatannol on growth, proliferation, differentiation and cell cycle distribution profile of the human colon carcinoma cell line Caco-2. Growth of Caco-2 and HCT-116 cells was analyzed by crystal violet assay, which demonstrated dose- and time-dependent decreases in cell numbers. Treatment of Caco-2 cells with piceatannol reduced proliferation rate. No effect on differentiation was observed. Determination of cell cycle distribution by flow cytometry revealed an accumulation of cells in the S phase. Immunoblotting demonstrated that cyclin-dependent kinases (cdk) 2 and 6, as well as cdc2 were expressed at steady-state levels, whereas cyclin D1, cyclin B1 and cdk 4 were downregulated. The abundance of p27(Kip1) was also reduced, whereas the protein level of cyclin E was enhanced. Cyclin A levels were enhanced only at concentrations up to 100 micromol/L. These changes also were observed in studies with HCT-116 cells. On the basis of our findings, piceatannol can be considered to be a promising chemopreventive or anticancer agent.

Topics: Alkaline Phosphatase; Antineoplastic Agents; Blotting, Western; Caco-2 Cells; Cell Cycle; Cell Division; Colorectal Neoplasms; Cyclin-Dependent Kinases; Cyclins; Dose-Response Relationship, Drug; Flow Cytometry; Humans; S Phase; Stilbenes; Time Factors; Tumor Cells, Cultured

Resveratrol is a cancer preventative agent that is found in red wine. Piceatannol is a closely related stilbene that has antileukaemic activity and is also a tyrosine kinase inhibitor. Piceatannol differs from resveratrol by having an additional aromatic hydroxy group. The enzyme CYP1B1 is overexpressed in a wide variety of human tumours and catalyses aromatic hydroxylation reactions. We report here that the cancer preventative agent resveratrol undergoes metabolism by the cytochrome P450 enzyme CYP1B1 to give a metabolite which has been identified as the known antileukaemic agent piceatannol. The metabolite was identified by high performance liquid chromatography analysis using fluorescence detection and the identity of the metabolite was further confirmed by derivatisation followed by gas chromatography-mass spectrometry studies using authentic piceatannol for comparison. This observation provides a novel explanation for the cancer preventative properties of resveratrol. It demonstrates that a natural dietary cancer preventative agent can be converted to a compound with known anticancer activity by an enzyme that is found in human tumours. Importantly this result gives insight into the functional role of CYP1B1 and provides evidence for the concept that CYP1B1 in tumours may be functioning as a growth suppressor enzyme.

Topics: Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Aryl Hydrocarbon Hydroxylases; Chemoprevention; Chromatography, High Pressure Liquid; Cytochrome P-450 CYP1B1; Cytochrome P-450 Enzyme System; Gas Chromatography-Mass Spectrometry; Humans; Neoplasms; Resveratrol; Stilbenes; Tumor Cells, Cultured; Wine

Emerging evidence suggests that NK-activatory receptors use KARAP/DAP12, CD3zeta, and FcepsilonRIgamma adaptors that contain immunoreceptor tyrosine-based activatory motifs to mediate NK direct lysis of tumor cells via Syk tyrosine kinase. NK cells may also use DAP10 to drive natural cytotoxicity through phosphoinositide 3-kinase (PI3K). In contrast to our recently identified PI3K pathway controlling NK cytotoxicity, the signaling mechanism by which Syk associates with downstream effectors to drive NK lytic function has not been clearly defined. In NK92 cells, which express DAP12 but little DAP10/NKG2D, we now show that Syk acts upstream of PI3K, subsequently leading to the specific signaling of the PI3K-->Rac1-->PAK1-->mitogen-activated protein/extracellular signal-regulated kinase (ERK) kinase-->ERK cascade that we earlier described. Tumor cell ligation stimulated DAP12 tyrosine phosphorylation and its association with Syk in NK92 cells; Syk tyrosine phosphorylation and activation were also observed. Inhibition of Syk function by kinase-deficient Syk or piceatannol blocked target cell-induced PI3K, Rac1, PAK1, mitogen-activated protein/ERK kinase, and ERK activation, perforin movement, as well as NK cytotoxicity, indicating that Syk is upstream of all these signaling events. Confirming that Syk does not act downstream of PI3K, constitutively active PI3K reactivated all the downstream effectors as well as NK cytotoxicity suppressed in Syk-impaired NK cells. Our results are the first report documenting the instrumental role of Syk in control of PI3K-dependent natural cytotoxicity.

Topics: Adaptor Proteins, Signal Transducing; Cell Line; Cytoplasmic Granules; Cytotoxicity, Immunologic; Down-Regulation; Enzyme Activation; Enzyme Inhibitors; Enzyme Precursors; Humans; Immunosuppressive Agents; Intracellular Signaling Peptides and Proteins; K562 Cells; Killer Cells, Natural; Ligands; MAP Kinase Kinase Kinase 1; Membrane Glycoproteins; Membrane Proteins; Mitogen-Activated Protein Kinases; p21-Activated Kinases; Perforin; Phosphatidylinositol 3-Kinases; Pore Forming Cytotoxic Proteins; Protein Serine-Threonine Kinases; Protein Transport; Protein-Tyrosine Kinases; rac1 GTP-Binding Protein; Receptors, Immunologic; Signal Transduction; Stilbenes; Syk Kinase; Tumor Cells, Cultured

Tissue plasminogen activator (tPA) and urokinase (uPA) are targets of plasminogen activator inhibitor-1 (PAI-1) inhibition. We have previously shown that both proteases can also induce PAI-1 secretion in rat smooth muscle cells (SMCs). We now report that both proteases appear to use very similar cellular mechanisms for signal transduction. They induced PAI-1 secretion using a pathway(s) involving protein kinase C (PKC). They also activated the Raf/Mek/mitogen-activated protein kinase (MAPK) pathway, which lies downstream of PKC activation. Activation of protein kinase A (PKA), however, lowered PAI-1 secretion induced by uPA and tPA, as a result of an inhibition of the PKC pathway and inhibition of Raf, Mek and MAPK phosphorylations. Src and syk family non-receptor tyrosine kinases (TK) were also involved in PAI-1 induction. The mechanisms of interaction of these tyrosine kinases with other pathways appeared to be quite different: src appeared to act within the PKC and PKA pathways, while syk operated independently of these pathways. Furthermore, whereas src inhibition resulted in inhibition of Raf/Mek/Erk phosphorylations, syk inhibition could only inhibit Mek and Erk phosphorylations but not the phosphorylation of Raf. These multiple pathways utilized by uPA and tPA to modulate PAI-1 secretion might be involved in determining the proteolytic or antiproteolytic potential of the SMCs under different pathophysiological conditions.

Topics: 1-Methyl-3-isobutylxanthine; 8-Bromo Cyclic Adenosine Monophosphate; Animals; Bucladesine; Carbazoles; Cells, Cultured; Cyclic AMP-Dependent Protein Kinases; Enzyme Inhibitors; Flavonoids; Genistein; Indoles; Isoquinolines; MAP Kinase Signaling System; Muscle, Smooth, Vascular; Phosphodiesterase Inhibitors; Phosphorylation; Plasminogen Activator Inhibitor 1; Protein Kinase C; Protein-Tyrosine Kinases; Pyrroles; Rats; Signal Transduction; src-Family Kinases; Stilbenes; Sulfonamides; Tissue Plasminogen Activator; Urokinase-Type Plasminogen Activator

We investigated similarities in the signaling pathways elicited by the F2 isoprostane 8-iso-PGF2alpha and by low doses of U46619 to induce platelet activation. Both 0.01-0.1 micromol/L U46619 and 0.01-1 micromol/L 8-iso-PGF2alpha triggered shape change and filopodia extension, as well as adhesion to immobilized fibrinogen of washed platelets. At these doses the two platelet agonists failed to trigger secretion and aggregation, which were however induced by higher doses of U46619 (0.1-1 micromol/L). SB203580 (1-10 micromol/L), a specific inhibitor of the p38 mitogen activated protein (MAP) kinase blunted platelet shape change and adhesion induced by 0.05-1 micromol/L 8-iso-PGF2alpha and by 0.01 micromol/L U46619. These platelet responses were also inhibited by 20 micromol/L cytochalasin D, an inhibitor of actin polymerization, and 50 micromol/L piceatannol, an inhibitor of the Syk tyrosine kinases. Both 8-iso-PGF2alpha and U46619-induced p38 MAP kinase phosphorylation in suspended platelets and this was inhibited by piceatannol, indicating that Syk activation occurs upstream of p38 MAP kinase phosphorylation. These findings suggest that the signaling pathway triggered by both 8-iso-PGFalpha and low concentrations of U46619 to induce platelet adhesion and shape change implicates Syk, the p38 MAP kinase, and actin polymerization.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Actin Cytoskeleton; Actins; Adult; Antigens, CD; Blood Platelets; Cell Size; Cytochalasin D; Dinoprost; Enzyme Activation; Enzyme Inhibitors; Enzyme Precursors; F2-Isoprostanes; Humans; Imidazoles; Integrin beta3; Intracellular Signaling Peptides and Proteins; MAP Kinase Signaling System; Microscopy, Electron, Scanning; Mitogen-Activated Protein Kinases; P-Selectin; p38 Mitogen-Activated Protein Kinases; Platelet Activation; Platelet Adhesiveness; Platelet Glycoprotein GPIIb-IIIa Complex; Platelet Membrane Glycoproteins; Protein-Tyrosine Kinases; Pseudopodia; Pyridines; Stilbenes; Syk Kinase; Thromboxane A2

Activation of nontransmembrane protein tyrosine kinases, such as Lyn and Syk, has been shown to be the earliest detectable signaling response to Fc receptor (Fc epsilon RI) cross-linking on mast cells leading to mast cell degranulation. The present study examined the effects of piceatannol (3,4,3',5'-tetrahydroxy-trans-stilbene, 10-100 microM), a Syk-selective tyrosine kinase inhibitor, on ovalbumin-induced anaphylactic contraction of isolated guinea pig bronchi and release of histamine and peptidoleukotrienes from chopped lung preparations. Pretreatment with piceatannol slightly suppressed ovalbumin-induced peak anaphylactic bronchial contraction but markedly (P<0.05) facilitated relaxation of the anaphylactically contracted bronchi. Piceatannol did not inhibit direct histamine-, leukotriene D(4)- or KCl-induced bronchial contraction, nor revert an existing anaphylactic bronchial contraction. Piceatannol, at 30 microM and above, significantly (P<0.05) prevented ovalbumin-induced release of both histamine and peptidoleukotrienes from lung fragments. Piceatannol did not inhibit exogenous arachidonic acid-induced release of peptidoleukotrienes from lung fragments. Our data show for the first time that inhibition of Syk tyrosine kinase can attenuate anaphylactic bronchial contraction in vitro, probably via inhibition of mast cell degranulation.

Topics: Airway Obstruction; Anaphylaxis; Animals; Bronchoconstriction; Enzyme Inhibitors; Enzyme Precursors; Enzyme-Linked Immunosorbent Assay; Guinea Pigs; Histamine Release; In Vitro Techniques; Injections, Intraperitoneal; Intracellular Signaling Peptides and Proteins; Leukotrienes; Lung; Male; Ovalbumin; Protein-Tyrosine Kinases; Stilbenes; Syk Kinase

Study on the non-anthraquinone constituents from rhizoma and radix of Rheum sublanceolatum.. The constituents were isolated through column chromatography and identified on the basis of their physiochemical and spectral data.. Six non-anthraquinone constituents were isolated and identified as n-octacosanic acid, sitosterol, daucosterol, 2-methyl-5-carboxymethyl-7-hydroxychromone, piceatannol and 6-hydroxymusizin-8-O-beta-D-glucopyranoside.. All these compounds were firstly isolated from R. sublanceolatum.

Topics: Plant Roots; Plants, Medicinal; Rheum; Rhizome; Sitosterols; Stilbenes

Phosphorylation of the N-terminal domain of I kappa B inhibitory subunits induces activation of the transcription factor NF-kappa B. Although serine phosphorylation has been shown to induce ubiquitination and subsequent proteasome-mediated degradation of I kappa B-alpha, little is known about the mechanisms that lead to release of active NF-kappa B in T cells as a consequence of tyrosine phosphorylation of I kappa B-alpha [Imbert, V., Rupec, R.A., Livolsi, A., Pahl, H.L., Traenckner, B.M., Mueller-Dieckmann, C., Farahifar, D., Rossi, B., Auberger, P., Baeuerle, P. & Peyron, J.F. (1996) Cell 86, 787--798]. The involvement of the tyrosine kinases p56(lck) and ZAP-70 in this reaction is demonstrated here using specific pharmacological inhibitors and Jurkat mutants unable to express these kinases. Although the inhibitors prevented both pervanadate-induced phosphorylation of I kappa B-alpha on Tyr42 and NF-kappa B activation, we observed that, in p56(lck)-deficient Jurkat mutants, NF-kappa B could still associate with I kappa B-alpha despite phosphorylation on Tyr42. Furthermore, the SH2 domain of p56(lck) appeared to be required for pervanadate-induced NF-kappa B activation but not for Tyr42 phosphorylation. These results show that p56(lck) and ZAP-70 are key components of the signaling pathway that leads to phosphotyrosine-dependent NF-kappa B activation in T cells and confirm that tyrosine kinases must control at least two different steps to induce activation of NF-kappa B. Finally, we show that H(2)O(2), which stimulates p56(lck) and ZAP-70 in T cells, is an activator of NF-kappa B through tyrosine phosphorylation of I kappa B-alpha.

Topics: DNA; DNA-Binding Proteins; Enzyme Activation; Humans; Hydrogen Peroxide; I-kappa B Proteins; Jurkat Cells; Lymphocyte Specific Protein Tyrosine Kinase p56(lck); Mutation; NF-kappa B; NF-KappaB Inhibitor alpha; Phosphorylation; Phosphotyrosine; Protein Binding; Protein Tyrosine Phosphatases; Protein-Tyrosine Kinases; Pyrazoles; Pyrimidines; Signal Transduction; src Homology Domains; Stilbenes; T-Lymphocytes; Transcriptional Activation; Vanadates; ZAP-70 Protein-Tyrosine Kinase

Oxidative stress plays an important role in the pathogenesis of myocardial ischemia and infarction. Antioxidants might then be beneficial in the prevention of these diseases. Astringinin (3,3',4',5-tetrahydroxystilbene), a resveratrol (3,4',5-trihydroxystilbene) analogue with considerably higher antioxidative activity and free radical scavenging capacity, was introduced to examine its cardioprotective effects in ischemia or ischemia-reperfusion (I/R) rats. In the present study, the left main coronary artery was occluded by the following procedures: (i) 30 min occlusion, (ii) 5 min occlusion followed by 30 min reperfusion, and (iii) 4 h occlusion. Animals were infused with and without astringinin before coronary artery occlusion. Mortality, and the severity of ischemia- and I/R-induced arrhythmias were compared. Pretreatment of astringinin dramatically reduced the incidence and duration of ventricular tachycardia (VT) and ventricular fibrillation (VF) during either ischemia or I/R period. Astringinin at 2.5 x 10(-5) and 2.5 x 10(-4) g/kg completely prevented the mortality of animals during ischemia or I/R. During the same period, astringinin pretreatment also increased nitric oxide (NO) and decreased lactate dehydrogenase (LDH) levels in the carotid blood. In animals subjected to 4 h coronary occlusion, the cardiac infarct size (expressed as a percentage of occluded zone) was reduced from 44.4 + or - 4.1% to 19.1 + or - 2.4% by astringinin (2.5 x 10(-4) g/kg). We conclude that, astringinin is a potent antiarrhythmic agent with cardioprotective activity in ischemic and ischemic-reperfused rat heart. The beneficial effects of astringinin in the ischemic and ischemic-reperfused hearts may be correlated with its antioxidant activity and upregulation of NO production.

Topics: Animals; Antioxidants; Free Radical Scavengers; Heart; Hemodynamics; L-Lactate Dehydrogenase; Male; Myocardial Infarction; Myocardial Reperfusion Injury; Nitrates; Nitric Oxide; Nitrites; Rats; Resveratrol; Stilbenes; Tachycardia, Ventricular; Ventricular Fibrillation

Our previous data demonstrated that cellular and nuclear tyrosine-phosphorylated Vav associate with phosphoinositide 3-kinase during all-trans-retinoic acid-dependent granulocytic differentiation of HL-60 cells. In this study, aimed to analyze the mechanism by which Vav is recruited and activated, we report that the Src homology 2 domain of Vav interacts with tyrosine-phosphorylated proteins in a differentiation-dependent manner. Two adaptor proteins, Cbl and SLP-76, were identified, showing a discrete distribution inside the cells, with Cbl absent from the nuclei and SLP-76 particularly abundant in the nuclear compartment. Of note, Vav interacts with the tyrosine kinase Syk, which is also present in the nuclear compartment and may phosphorylate Vav in vitro when cells differentiate. Inhibition of Syk activity by piceatannol prevents both in vitro and in vivo Vav tyrosine phosphorylation, its association with the regulatory subunit of phosphoinositide 3-kinase, and the nuclear modifications typically observed during granulocytic differentiation of this cell line. These findings suggest that tyrosine-phosphorylated Vav and its association with phosphoinositide 3-kinase play a crucial role in all-trans-retinoic acid-induced reorganization of the nucleoskeleton, which is responsible for the changes in nuclear morphology observed during granulocytic differentiation of HL-60 cells.

Topics: Adaptor Proteins, Signal Transducing; Cell Compartmentation; Cell Cycle Proteins; Cell Differentiation; Cell Nucleus; Enzyme Inhibitors; Enzyme Precursors; Granulocytes; Hematopoietic Stem Cells; Humans; Intracellular Signaling Peptides and Proteins; Oncogene Protein v-cbl; Phosphatidylinositol 3-Kinases; Phosphoproteins; Phosphorylation; Protein Structure, Tertiary; Protein-Tyrosine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-vav; Retroviridae Proteins, Oncogenic; Stilbenes; Syk Kinase; Tretinoin; Tumor Cells, Cultured; Tyrosine

Neutrophils up-regulate beta2 integrins like CD11b/CD18 in response to lipopolysaccharide (LPS). Up-regulation of beta2 integrins causes neutrophils to adhere to surfaces, and to release superoxide anion (O2-). When neutrophils are exposed to LPS plus plasma under conditions not favorable for adherence (absence of Mg2+), the cells do not spontaneously release O2-, but instead they are primed for enhanced release of O2- after subsequent triggering by fMLP. In the presence of Mg2+, neutrophils adhere in response to LPS but fMLP-triggered O2- release by LPS-primed neutrophils is diminished. To understand why adherence interferes with the response of neutrophils to N-formyl-methionyl-leucyl-phenylalanine (fMLP), beta2 integrins were cross-linked by mouse monoclonal antibodies that had been immobilized by surface-bound anti-mouse antibody. When unprimed neutrophils were trapped on the surface by these cross-linked monoclonal antibodies, O2- release was triggered, and priming by LPS for fMLP-triggered O2- release was diminished, indicating that this cross-linking of beta2 integrins mimicked adherence. Alkaline phosphatase is up-regulated by LPS or tumor necrosis factor-alpha, and this response was also diminished by the cross-linking antibodies. The diminished alkaline phosphatase up-regulation was reversed by genistein, a general inhibitor of tyrosine kinases, and by piceatannol, an inhibitor for Syk kinase. Piceatannol also inhibited the phosphorylation of Syk caused by cross-linking of beta2 integrins. These results suggested that adherence-induced triggering and Syk kinase activation might be responsible for the diminished response of LPS-primed neutrophils to fMLP when neutrophils were adherent.

Topics: Alkaline Phosphatase; Antibodies, Monoclonal; CD18 Antigens; Cell Adhesion; Dose-Response Relationship, Drug; Enzyme Inhibitors; Enzyme Precursors; Genistein; Humans; Intracellular Signaling Peptides and Proteins; Lipopolysaccharides; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Phosphorylation; Protein-Tyrosine Kinases; Stilbenes; Superoxides; Syk Kinase; Time Factors; Tumor Necrosis Factor-alpha

Serum amyloid P component (SAP) is a member of the pentraxin family of proteins. These proteins are characterized by cyclic pentameric structure, calcium-dependent ligand binding, and frequent regulation as acute-phase serum proteins. SAP is the serum precursor of the P component of amyloid. It binds to a broad group of molecules, including autoantigens, through a pattern recognition binding site. The related pentraxin, C-reactive protein (CRP), is a strong acute-phase reactant in man and an opsonin. We previously determined that the binding of CRP to leukocytes occurs through Fc receptors for IgG (FcgammaR). We now report that SAP also binds to FcgammaR and opsonizes particles for phagocytosis by human polymorphonuclear leukocytes (PMN). Specific, saturable binding of SAP to FcgammaRI, FcgammaRIIa, and FcgammaRIIIb expressed on transfected COS cells was detected using SAP-biotin and PE-streptavidin. Zymosan was used to test the functional consequences of SAP and CRP binding to FcgammaR. Both SAP and CRP bound to zymosan and enhanced its uptake by PMN. This enhanced phagocytosis was abrogated by treatment of PMN with wortmannin, a phosphatidylinositol-3 kinase inhibitor, or with piceatannol, a Syk inhibitor, consistent with uptake through FcgammaR. Treatment of PMN with phosphatidylinositol-specific phospholipase C to remove FcgammaRIIIb also decreased phagocytosis of SAP-opsonized zymosan, but not CRP-opsonized zymosan. These results suggest that SAP may function in host defense. In addition, as SAP binds to chromatin, a major immunogen in systemic lupus erythematosus, it may provide a clearance mechanism for this Ag through FcgammaR bearing cells.

Topics: Androstadienes; Animals; COS Cells; Enzyme Inhibitors; Fluorescein-5-isothiocyanate; Humans; Microspheres; Neutrophils; Opsonin Proteins; Phagocytosis; Phosphatidylinositol Diacylglycerol-Lyase; Phosphoinositide Phospholipase C; Protein Binding; Receptors, IgG; Serum Amyloid P-Component; Stilbenes; Transfection; Type C Phospholipases; Wortmannin; Zymosan

The L-type calcium channel is the major calcium influx pathway in vascular smooth muscle and is regulated by integrin ligands, suggesting an important link between extracellular matrix and vascular tone regulation in tissue injury and remodeling. We examined the role of integrin-linked tyrosine kinases and focal adhesion proteins in regulation of L-type calcium current in single vascular myocytes. Soluble tyrosine kinase inhibitors blocked the increase in current produced by alpha(5) integrin antibody or fibronectin, whereas tyrosine phosphatase inhibition enhanced the effect. Cell dialysis with an antibody to focal adhesion kinase or with FRNK, the C-terminal noncatalytic domain of focal adhesion kinase, produced moderate (24 or 18%, respectively) inhibition of basal current but much greater inhibition (63 or 68%, respectively) of integrin-enhanced current. A c-Src antibody and peptide inhibitors of the Src homology-2 domain or a putative Src tyrosine phosphorylation site on the channel produced similar inhibition. Antibodies to the cytoskeletal proteins paxillin and vinculin, but not alpha-actinin, inhibited integrin-dependent current by 65-80%. Therefore, alpha(5)beta(1) integrin appears to regulate a tyrosine phosphorylation cascade involving Src and various focal adhesion proteins that control the function of the L-type calcium channel. This interaction may represent a novel mechanism for control of calcium influx in vascular smooth muscle and other cell types.

Topics: Actinin; Animals; Antibodies, Monoclonal; Binding Sites; Calcium Channels, L-Type; Cell Adhesion; Cytoskeletal Proteins; Cytoskeleton; Dose-Response Relationship, Drug; Enzyme Inhibitors; Extracellular Matrix; Fibronectins; Focal Adhesion Kinase 1; Focal Adhesion Protein-Tyrosine Kinases; Integrins; Ligands; Male; Microscopy, Fluorescence; Myocardium; Patch-Clamp Techniques; Paxillin; Phosphoproteins; Phosphoric Monoester Hydrolases; Phosphorylation; Protein Kinase C; Protein Structure, Tertiary; Protein-Tyrosine Kinases; Rats; Rats, Sprague-Dawley; Receptors, Fibronectin; Signal Transduction; Stilbenes; Time Factors; Tyrosine; Vinculin

Cortactin is an F-actin-binding protein expressed in platelets. During aggregation by thrombin, cortactin associates with Src, is tyrosine phosphorylated, and then translocates to the cytoskeleton. It is also found to associate with Syk during platelet shape change. Since cortactin undergoes tyrosine phosphorylation in platelets activated by thrombopoietin (TPO) that exhibit neither shape change nor aggregation, we investigated whether it could also relocalize to the detergent-insoluble fraction. We demonstrate that cortactin was present as a tyrosine-phosphorylated protein and co-localized with Syk in the Triton X-100-insoluble fraction of TPO-activated platelets. TPO stimulated Syk activation and association with cortactin. Conversely, cortactin associated with the kinases, Syk and Src. Cortactin tyrosine phosphorylation was blocked by Syk kinase inhibitor, piceatannol or Src family kinase inhibitor, PP2, suggesting that it depends on these two kinases. However, piceatannol or PP2 did not prevent cortactin translocation to the detergent-insoluble fraction. These data suggest that tyrosine phosphorylation is not required for cortactin translocation to the detergent-insoluble compartment. Furthermore, TPO activates, through its receptor c-Mpl, a signalling pathway to the cytoskeleton.

Topics: Blood Platelets; Cortactin; Cytoskeleton; Enzyme Activation; Enzyme Precursors; Humans; In Vitro Techniques; Intracellular Signaling Peptides and Proteins; Microfilament Proteins; Octoxynol; Phosphorylation; Protein Transport; Protein-Tyrosine Kinases; Recombinant Proteins; src-Family Kinases; Stilbenes; Syk Kinase; Thrombopoietin; Tyrosine

In contrast to IgG Fc receptor II (Fc gamma RIIa), the function of Src-family kinases, Syk and phosphoinositide 3-kinase (PI3K) in signal transduction of glycosylphosphatidylinositol-anchored Fc gamma RIIIb has not been analyzed in detail. Therefore pharmacological inhibitors were used to define the role of specific kinases in signalling of Fc gamma RIIa and Fc gamma RIIIb in myeloid cells. We demonstrate that the broad tyrosine kinase inhibitor genistein, the Src-family kinase inhibitor PP2, and the Syk kinase inhibitor piceatannol inhibit [Ca2+]i rise induced by both low-affinity Fc gamma R in neutrophils. Genistein and PP2 additionally prevent Fc gamma R-triggered hydrogen peroxide generation. In contrast, wortmannin, a PI3K inhibitor, which blocks Fc gamma RIIIb activation completely, abolishes Fc gamma RIIa-mediated [Ca2+]i flux only in the beginning. In addition, herbimycin A, a further specific inhibitor of Src-family kinases leads to a delayed Fc gamma RIIa-induced [Ca2+]i rise in THP-1 cells. In summary, our data demonstrate differences between both low-affinity IgG Fc receptors, and provide evidence for an essential role of Src-family kinases, Syk and PI3K in Fc gamma RIIIb-mediated signalling.

Topics: Androstadienes; Benzoquinones; Calcium Signaling; Enzyme Inhibitors; Enzyme Precursors; Genistein; Humans; Hydrogen Peroxide; In Vitro Techniques; Intracellular Signaling Peptides and Proteins; Lactams, Macrocyclic; Neutrophils; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein-Tyrosine Kinases; Quinones; Receptors, IgG; Rifabutin; Signal Transduction; Stilbenes; Syk Kinase; Wortmannin

Peripheral human red blood cells (RBCs) are not generally known to become activated and adhesive in response to cell signaling. We show, however, that soluble thrombospondin via integrin-associated protein (IAP; CD47) increases the adhesiveness of sickle RBCs (SS RBCs) by activating signal transduction in the SS RBC. This stimulated adhesion requires occupancy of IAP and shear stress and is mediated by the activation of large G proteins and tyrosine kinases. Reticulocyte-enriched RBCs derived from sickle-cell disease (SCD) patients are most responsive to IAP-induced activation. These studies therefore establish peripheral SS RBCs as signaling cells that respond to a novel synergy between IAP-induced signal transduction and shear stress, suggesting new therapeutic targets in SCD.

Topics: Anemia, Sickle Cell; Antigens, CD; Carrier Proteins; CD47 Antigen; Cell Adhesion; Cells, Cultured; Enzyme Inhibitors; Erythrocytes, Abnormal; Genistein; Humans; Models, Biological; Oligopeptides; Phosphotyrosine; Signal Transduction; Stilbenes; Stress, Physiological; Thrombospondins; Virulence Factors, Bordetella

Development of the chimeric mouse antihuman CD20 antibody, Rituximab, presented a notable advance in the treatment of patients with non-Hodgkin's lymphoma (NHL). Its use allowed the specific targeting of tumor B cells without the systemic toxicity of traditional therapies. The mechanisms by which Rituximab induces its antitumor activity are not fully understood. We have shown previously that Rituximab down-regulates Bcl-2 expression in some B-NHL cell lymphoma lines through an interleukin 10 (IL-10)-dependent autocrine loop, an effect that renders the resistant cells susceptible to chemotherapeutic drugs. The objective of this study was to delineate the signaling pathway by which Bcl-2 is controlled by Rituximab and IL-10. We hypothesized that the down-regulation of IL-10 by Rituximab decreases activation of the signal transducer and activator of transcription 3 (STAT3) protein, which in turn, is responsible for decreased levels of Bcl-2. We demonstrate by phosphoprotein immunoblotting and gel shift analyses that endogenous IL-10 induces activation of STAT3 in the 2F7 cell line. Furthermore, we show that Rituximab and anti-IL-10 antibody treatment decreases the ability of STAT3 to bind to its DNA binding site. The decrease in STAT3 activation by these treatments correlates with a decrease in Bcl-2 expression. Additionally, piceatannol, an inhibitor of STAT3 activation, down-regulates the expression of Bcl-2. Altogether, these results demonstrate that Bcl-2 expression is under the regulation of the STAT3 signaling pathway, which is regulated by endogenously secreted IL-10. Hence, Rituximab-induced down-regulation of IL-10 expression is responsible for the down-regulation of Bcl-2 and sensitization of NHL cells by therapeutic drugs. Furthermore, these findings support the notion that circulating IL-10 in vivo may control the resistance of NHL to drug-mediated cytotoxicity.

Topics: Antibodies; Antibodies, Monoclonal; Antibodies, Monoclonal, Murine-Derived; Antineoplastic Agents; Burkitt Lymphoma; Culture Media, Serum-Free; DNA-Binding Proteins; Down-Regulation; Drug Synergism; Humans; Interleukin-10; Phosphorylation; Proto-Oncogene Proteins c-bcl-2; Rituximab; Signal Transduction; STAT3 Transcription Factor; Stilbenes; Trans-Activators

[structure: see text] Aiphanol (1), a novel stilbenolignan, along with isorhapontigenin (2), piceatannol (3), and luteolin, were isolated by bioassay-guided fractionation from the seeds of Aiphanes aculeata Willd. (Arecaceae). The structure of compound 1 was elucidated by spectroscopic methods. Compound 1 is based on an unprecedented stilbenolignan skeleton in which a stilbene moiety is linked with a phenylpropane unit through a dioxane bridge. Compounds 1 and 2 exhibited significant inhibitory activities against cyclooxygenases-1 and -2.

Topics: Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Flavonoids; Isoenzymes; Luteolin; Magnetic Resonance Spectroscopy; Molecular Structure; Plants, Medicinal; Prostaglandin-Endoperoxide Synthases; Seeds; Stilbenes; Structure-Activity Relationship

The inflammatory response in acute gouty arthritis is in large part a result of the interaction between neutrophils and monosodium urate (MSU) crystals. The tyrosine kinase Syk, which has been largely associated with the phagocytic response by Fc receptors and with spreading mediated by integrins, has been identified as one of the major proteins tyrosine-phosphorylated in human neutrophils upon stimulation by MSU crystals and is known to be mediated in part by the Fc receptor, CD16. This has led to the present examination of the implication of Syk in the activation pathways used by MSU crystals. The tyrosine-phosphorylation patterns induced by MSU crystals and by the ligation of CD16 were inhibited by piceatannol, which, conversely, only slightly delayed but did not diminish the peak of tyrosine phosphorylation induced by cross-linking CD32 or by the addition of fMet-Leu-Phe. Moreover, piceatannol inhibited the activity of Syk as monitored by in vitro kinase assays, by its in situ tyrosine phosphorylation, and by its activity toward exogenous substrates after stimulation by MSU crystals. We also measured the impact of piceatannol on the mobilization of calcium, the production of superoxide anions, and the activity of PLD stimulated by MSU crystals. We noted a distinct inhibition of all these responses by piceatannol. Finally, the morphological changes observed in neutrophils as characteristic of MSU crystal internalization were diminished significantly by piceatannol. The results obtained show that Syk plays a critical and central role in the signal-transduction pathways called upon by MSU crystals subsequent to their interaction with human neutrophils.

Topics: Adult; Antibodies; Cells, Cultured; Crystallization; Enzyme Inhibitors; Enzyme Precursors; Gout; Humans; Intracellular Signaling Peptides and Proteins; N-Formylmethionine Leucyl-Phenylalanine; Neutrophil Activation; Neutrophils; Phospholipase D; Phosphorylation; Phosphotyrosine; Protein-Tyrosine Kinases; Receptors, IgG; Stilbenes; Superoxides; Syk Kinase; Uric Acid

1. Leukotriene B(4) (LTB(4)) stimulation of guinea-pig peritoneal eosinophils, induced a biphasic activation of the NADPH oxidase composed of a rapid (<3 min) phase mediated by non-adherent cells and a sustained (3 - 120 min) phase mediated by CD11b/CD18 adherent eosinophils. Studies were undertaken to compare the intracellular mechanism that mediate these responses. 2. SB 203580 and PP1, inhibitors of p38 mitogen-activated protein (MAP) kinase and the src-family protein tyrosine kinases, respectively caused concentration-dependent attenuation of both the rapid (SB203580: pD(2)=-6.31; PP1: pD(2)=-5.50) and sustained (SB203580: pD(2)=-6.50; PP1: pD(2)=-5.73) phases. Similarly, the MAP kinase kinase-1 inhibitor, PD098059 produced partial inhibition of the both phases of superoxide generation. 3. The protein kinase C (PKC) inhibitors Ro-31 8220, GF 109203X and Gö 6976 attenuated the rapid NADPH oxidase response (pD(2)s=-6.10, -6.72, -6.15 respectively) and, to a lesser extent, (pD(2)s=-5.54, -6.02, -6.51 respectively) the sustained phase. 4. An inhibitor of phosphatidylinositol 3-kinase (PtdIns 3-kinase), wortmannin caused concentration dependent attenuation of the sustained (pD(2)=-8.68) but not rapid phase of superoxide generation. In contrast, the syk kinase inhibitor, piceatannol abolished the rapid (pD(2)=-6.43) but not sustained respiratory responses. 5. This study demonstrates that LTB(4)-induced superoxide generation from adherent and non-adherent eosinophils is mediated via both common (p38 MAP kinase, MEK-1, PKC and the src kinases) and divergent intracellular pathways (syk kinases and PtdIns 3-kinase). This suggests the possibility of therapeutic intervention to selective attenuate activation of adherent tissue eosinophils.

Topics: Androstadienes; Animals; Antibodies; Carbazoles; CD18 Antigens; Cell Adhesion; Dose-Response Relationship, Drug; Enzyme Activation; Enzyme Inhibitors; Enzyme Precursors; Eosinophils; Flavonoids; Guinea Pigs; Imidazoles; Indoles; Integrin beta1; Intracellular Signaling Peptides and Proteins; Leukotriene B4; Macrophage-1 Antigen; Male; Maleimides; Mitogen-Activated Protein Kinases; NADPH Oxidases; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase C; Protein-Tyrosine Kinases; Pyrazoles; Pyridines; Pyrimidines; Rats; src-Family Kinases; Stilbenes; Syk Kinase; Time Factors; Wortmannin

The stilbene phytochemicals resveratrol and piceatannol have been reported to possess substantial antitumorigenic and antileukemic activities, respectively. Although recent experimental data revealed the proapoptotic potency of resveratrol, the molecular mechanisms underlying the antileukemic activity have not yet been studied in detail. In the present study, we show that resveratrol, as well as the hydroxylated analog piceatannol, are potent inducers of apoptotic cell death in BJAB Burkitt-like lymphoma cells with an ED50 concentration of 25 microM. Further experiments revealed that treatment of BJAB cells with both substances led to a concentration-dependent activation of caspase-3 and mitochondrial permeability transition. Using BJAB cells overexpressing a dominant-negative mutant of the Fas-associated death domain (FADD) adaptor protein to block death receptor-mediated apoptosis, we demonstrate that resveratrol- and piceatannol-induced cell death in these cells is independent of the CD95/Fas signaling pathway. To explore the antileukemic properties of both compounds in more detail, we extended our study to primary, leukemic lymphoblasts. Interestingly, piceatannol but not resveratrol is a very efficient inducer of apoptosis in this ex vivo assay with leukemic lymphoblasts of 21 patients suffering from childhood lymphoblastic leukemia (ALL).

Topics: Adolescent; Anticarcinogenic Agents; Antineoplastic Agents; Apoptosis; Burkitt Lymphoma; Caspase 3; Caspases; Cell Nucleus; Child; Child, Preschool; DNA Fragmentation; Dose-Response Relationship, Drug; fas Receptor; Female; Humans; Infant; Leukemia, Lymphoid; Male; Membrane Potentials; Mitochondria; Resveratrol; Signal Transduction; Stilbenes; Tumor Cells, Cultured

Syk kinase is probably an early necessary tyrosine kinase involved in IgE-mediated secretion from human basophils. Causal testing of the role of syk kinase in the secretion requires a selective pharmacological agent. Piceatannol has previously been used to demonstrate the causal role of syk in secretion but its selectively has recently come into question.. To determine whether piceatannol inhibits IgE-mediated signalling events in a manner consistent with its putative inhibitory effects on syk kinase and at concentrations relevant to its inhibition of mediator release.. Human basophils were examined for the effects of piceatannol on mediator release or various signalling steps.. We show that while piceatannol has an IC50 for inhibition of IgE-mediated histamine release of 3-5 microm, these same concentrations inhibit secretion of phorbol 12-myristate 13-acetate (PMA)-induced histamine release (as previously shown) and leukotriene C (LTC)4 release induced by fMLP. Concentrations of piceatannol up to 100 microm also did not inhibit IgE-mediated phosphorylation of shc, a immediate downstream target of syk kinase. Similar concentrations also did not inhibit IgE-mediated cytosolic calcium elevations, another downstream signal thought to be dependent on syk kinase. In contrast, piceatannol did modify the cytosolic calcium response that follows stimulation with formyl methionyl-leucyl-phenylalanine (fMLP).. Taken together with published studies using other cell types, we conclude that piceatannol does not inhibit secretion from human basophils by inhibiting the activity of syk kinase.

Topics: Antibodies, Anti-Idiotypic; Basophils; Calcium; Cells, Cultured; Dose-Response Relationship, Drug; Enzyme Activation; Enzyme Inhibitors; Enzyme Precursors; GTP-Binding Proteins; Histamine Release; Humans; Immunoglobulin E; Intracellular Signaling Peptides and Proteins; Leukotriene C4; N-Formylmethionine Leucyl-Phenylalanine; Protein-Tyrosine Kinases; Receptors, IgE; Stilbenes; Syk Kinase

Phagocytosis is increased by Fcgamma receptors (FcgammaRs), and studies with syk(-/-) macrophages demonstrated that Syk kinase is required for FcgammaR phagocytosis. Similar studies with macrophages lacking the Src family kinases Hck, Fgr, and Lyn showed that these kinases are not required for phagocytosis but that they enhance the rate of particle engulfment. In this report we show that both wild-type and hck(-/-)fgr(-/-) macrophages expressed Fyn, Src, and Yes and that these kinases were activated on ingestion of immunoglobulin G (IgG)-coated particles and redistributed, together with Syk, to actin-rich phagocytic cups and the phagosomal membrane. At doses blocking IgG-dependent phagocytosis, the tyrosine kinase inhibitors PP1 and piceatannol inhibited both Src family kinase and Syk activities, as well as their redistribution to actin-rich phagocytic cups. Hck, Fgr, and Lyn were dispensable for lysosome-phagosome fusion (PLF) induced by IgG-coated particles. However, PP1 or piceatannol hampered unopsonized yeast-induced PLF despite the fact that they did not block yeast internalization.

Topics: Actins; Animals; Biopolymers; Enzyme Inhibitors; Enzyme Precursors; Immunoglobulin G; Intracellular Signaling Peptides and Proteins; Lysosomes; Membrane Fusion; Mice; Mice, Knockout; Microscopy, Confocal; Microscopy, Fluorescence; Microspheres; Opsonin Proteins; Phagocytosis; Phagosomes; Protein-Tyrosine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-fyn; Proto-Oncogene Proteins c-hck; Proto-Oncogene Proteins c-yes; Pyrazoles; Pyrimidines; Receptors, IgG; Saccharomyces cerevisiae; src-Family Kinases; Stilbenes; Syk Kinase

The tyrosine kinase p72(Syk) plays a critical role in platelet signal transduction. It associates with the platelet receptor for the Fc domain of IgGs, FcgammaRII, following stimulation by FcgammaRII cross-linking. Here, we show that p72(Syk) and FcgammaRII tyrosine phosphorylation and association occured following platelet stimulation by: (1) two monoclonal antibodies, which form a bridge between a target antigen and FcgammaRII, and (2) the G-protein-coupled receptor agonist thrombin. The kinetics of the p72(Syk)/FcgammaRII association depended on the signalling pathway (i.e., the antigen targeted or the thrombin receptor). We established a direct relationship between the level of FcgammaRII phosphorylation and the detection of its association with p72(Syk). Inhibition of p72(Syk) by piceatannol resulted in partial or total inhibition of FcgammaRII phosphorylation, after immunological activation or addition of thrombin, respectively, suggesting that p72(Syk) participates in FcgammaRII phosphorylation. The results provide evidence that p72(Syk)/FcgammaRII association is not restricted to immunological activation.

Topics: Blood Platelets; Blotting, Western; Electrophoresis, Polyacrylamide Gel; Enzyme Precursors; Humans; Intracellular Signaling Peptides and Proteins; Phosphorylation; Platelet Activation; Platelet Aggregation Inhibitors; Precipitin Tests; Protein-Tyrosine Kinases; Receptors, IgG; Signal Transduction; Stilbenes; Syk Kinase; Thrombin; Tyrosine

Syk protein-tyrosine kinase (PTK) has been implicated in a variety of hematopoietic cell responses including immunoreceptor signaling. However, so far, there has been no evidence of the expression of Syk or Syk-related PTK in non-hematopoietic tissues. In this study, we have purified from blood cell-depleted rat liver a 72-kDa cytoplasmic PTK which shows cross-reactivity with anti-Syk antibody. Partial amino acid sequence analysis revealed that this 72-kDa PTK is identical to Syk. Immunohistochemical and RT-PCR analyses demonstrated that Syk is expressed in human hepatocytes and two rat liver-derived cell lines, JTC-27 and RLC-16. Furthermore, Syk is significantly tyrosine-phosphorylated in response to angiotensin II in JTC-27 cells, and angiotensin II-induced MAP kinase activation is blocked by the treatment of cells with a Syk-selective inhibitor, piceatannol. These results suggest that Syk plays an important role in signaling events of hepatocytes, such as signaling steps leading to MAP kinase activation by G-protein-coupled receptors. This is the first report of the expression of Syk in non-hematopoietic tissue.

Topics: Amino Acid Sequence; Angiotensin II; Animals; Cells, Cultured; Cytosol; Enzyme Inhibitors; Enzyme Precursors; GTP-Binding Proteins; Humans; Intracellular Signaling Peptides and Proteins; Liver; Mitogen-Activated Protein Kinases; Molecular Sequence Data; Protein-Tyrosine Kinases; Rats; Signal Transduction; Stilbenes; Syk Kinase

The aim of the present study was to investigate the role of tyrosine phosphorylation pathways in fMLP-induced exocytosis of the different secretory compartments (primary and secondary granules, as well as secretory vesicles) of neutrophils. Genistein, a broad specificity tyrosine kinase inhibitor, blocked the exocytosis of primary and secondary granules, but had only a marginal effect on the release of secretory vesicles. Genistein also inhibited the phosphorylation of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinases (MAPK), raising the possibility that inhibition of ERK and/or p38 MAPK might be responsible for the effect of the drug on the degranulation response. Indeed, SB203580, an inhibitor of p38 MAPK, decreased the release of primary and secondary granules, but not that of secretory vesicles. However, blocking the ERK pathway with PD98059 had no effect on any of the exocytic responses tested. PP1, an inhibitor of Src family kinases, also attenuated the release of primary and secondary granules, and neutrophils from mice deficient in the Src family kinases Hck, Fgr, and Lyn were also defective in secondary granule release. Furthermore, activation of p38 MAPK was blocked by both PP1 and the hck-/-fgr-/-lyn-/- mutation. Taken together, our data indicate that fMLP-induced degranulation of primary and secondary granules of neutrophils is mediated by p38 MAPK activated via Src family tyrosine kinases. Although piceatannol, a reportedly selective inhibitor of Syk, also prevented degranulation and activation of p38 MAPK, no fMLP-induced phosphorylation of Syk could be observed, raising doubts about the specificity of the inhibitor.

Topics: Adjuvants, Immunologic; Animals; Calcium-Calmodulin-Dependent Protein Kinases; Cell Degranulation; Cytochalasin B; Cytoplasmic Granules; Enzyme Activation; Enzyme Inhibitors; Exocytosis; Genistein; Humans; MAP Kinase Signaling System; Mice; Mice, Inbred C57BL; Mice, Knockout; Mitogen-Activated Protein Kinases; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Protein-Tyrosine Kinases; src-Family Kinases; Stilbenes

Genistein, tyrphostin and piceatannol, which are specific inhibitors of protein tyrosine kinase, were screened for their effects on the motility of intact and demembranated hamster spermatozoa. Of the three inhibitors only piceatannol inhibited the motility of intact spermatozoa. None of the inhibitors had any inhibitory effect on the reactivation of motility of demembranated hamster spermatozoa. Taken together these results indicated that a protein tyrosine kinase associated with the membrane of hamster spermatozoa was probably involved in sustenance of hamster sperm motility. Therefore in the present study a membrane-associated protein tyrosine kinase was purified from a detergent-soluble extract of plasma membranes of mature hamster spermatozoa. The purification involved cation exchange chromatography on fast protein liquid chromatography (FPLC) followed by affinity chromatography either on an antiphosphotyrosine antibody agarose or poly glu-tyr agarose column. The pure protein tyrosine kinase had an apparent molecular mass of 45 kDa. The enzyme was not inhibited by genistein or herbimycin but was inhibited by piceatannol. This is the first report on the purification of a sperm plasma membrane-associated protein tyrosine kinase, an enzyme which has also been implicated in hamster sperm motility.

Topics: Animals; Cell Membrane; Cricetinae; Enzyme Inhibitors; Genistein; Male; Mesocricetus; Protein-Tyrosine Kinases; Sperm Motility; Spermatozoa; Stilbenes; Tyrphostins

Interferon-alpha (IFNalpha) can activate several members of the signal transducers and activator of transcription (STAT) transcription factor family, a process that requires the tyrosine kinases Jak1 and Tyk2. Here we provide evidence that IFNalpha-mediated activation of various STAT proteins is regulated by distinct mechanisms. Piceatannol, previously reported as a Syk/ZAP70-specific kinase inhibitor, selectively inhibits the tyrosine phosphorylation of STAT3 and STAT5, but not of STAT1 and STAT2. This inhibition is paralleled by the loss of Jak1 and IFNAR1 tyrosine phosphorylation in response to IFNalpha, whereas Tyk2 and IFNAR2 tyrosine phosphorylation is unaffected. Last, the IFNalpha-induced serine phosphorylation of STAT1 and STAT3 is not inhibited by piceatannol but is sensitive to the Src kinase-specific inhibitor PP2. Thus, our results not only demonstrate that the IFNalpha/beta receptor utilizes distinct mechanisms to trigger the tyrosine phosphorylation of specific STAT proteins, but they also indicate a diverging pathway that leads to the serine phosphorylation of STAT1 and STAT3.

Topics: Cell Line; DNA-Binding Proteins; Humans; Interferon-alpha; Janus Kinase 1; Jurkat Cells; Membrane Proteins; Milk Proteins; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases; Phosphorylation; Platelet Aggregation Inhibitors; Protein-Tyrosine Kinases; Receptor, Interferon alpha-beta; Receptors, Interferon; Ribonucleases; Serine; Signal Transduction; STAT1 Transcription Factor; STAT2 Transcription Factor; STAT3 Transcription Factor; STAT5 Transcription Factor; Stilbenes; Time Factors; Trans-Activators; Tyrosine

Phosphorylation of the band 3 anion exchange protein by the tyrosine kinases p72syk and p56lyn is thought to play a role in the pathway that regulates swelling-activated taurine efflux from the skate red blood cell. In this study, the protein tyrosine kinase (PTK) inhibitors piceatannol and tyrphostin A23 both inhibited taurine efflux and the activities of the tyrosine kinases p72syk and p56lyn in the skate erythrocyte. However, the PTK inhibitors genistein and tyrphostin A46 had only small effects on taurine efflux and PTK activities. In general, a strong correlation between the extent of inhibition of taurine efflux and of tyrosine kinase activity was observed. PTK inhibitors showed a similar pattern of inhibition of band 3 phosphorylation, with the greatest inhibition observed in cells treated with piceatannol. The protein kinase C inhibitors staurosporine and bisindolylmaleimide tested alone or in combination with piceatannol had little or no significant effect on swelling-activated taurine efflux. Overall the results support the hypothesis that phosphorylation of the skate band 3 protein by p72syk and p56lyn contributes to the regulation of volume-activated taurine efflux in skate red cells, and suggest that protein kinase C may not be involved in this regulation.

Topics: Animals; Anion Exchange Protein 1, Erythrocyte; Cell Size; Enzyme Inhibitors; Enzyme Precursors; Erythrocytes; Hypotonic Solutions; Intracellular Signaling Peptides and Proteins; Mitogen-Activated Protein Kinases; Phosphorylation; Protein Kinase C; Protein-Tyrosine Kinases; Proto-Oncogene Proteins pp60(c-src); Skates, Fish; src-Family Kinases; Stilbenes; Syk Kinase; Taurine

Signals transmitted by class II major histocompatibility complex are important regarding cell function related to antigen presentation. We examined effects of DR-mediated signaling on Ig production from B cells. Cross-linking HLA-DR molecules on B cells by solid-phase anti-HLA-DR monoclonal antibodies, led to an increased production of IgM, without proliferation or apoptosis. This event was accompanied by an enhanced expression of both membrane- and secretory-type IgM heavy chain mRNA. When peptide-pulsed B cells were co-incubated with an HLA-DR-restricted T cell clone treated by the protein synthesis inhibitor emetine, peptide-induced de novo expression of lymphokines and cell-surface molecules on T cells can be neglected. CD40-CD154 interaction was not involved in IgM enhancement, in such a system. The protein-tyrosine kinase inhibitors and the Syk inhibitor piceatannol, but not the Src inhibitor PP2 had a marked inhibitory effect on IgM secretion. Furthermore, ligation of HLA-DR on B cells using the F(ab')2 fragment of anti-DR monoclonal antibody, enhanced Syk activity. Our data suggest that HLA-DR on B cells not only present antigenic peptides to T cells, but also up-regulate IgM production, in association with Syk activation and without the involvement of Src kinases, hence the possible physiological relevance of Src-independent Syk activation.

Topics: Animals; Annexin A5; Apoptosis; B-Lymphocytes; CD40 Antigens; CD40 Ligand; Cell Division; Cross-Linking Reagents; Electrophoresis, Polyacrylamide Gel; Emetine; Enzyme Activation; Enzyme Inhibitors; Enzyme Precursors; Enzyme-Linked Immunosorbent Assay; HLA-DR Antigens; Humans; Immunoblotting; Immunoglobulin Fab Fragments; Immunoglobulin Heavy Chains; Immunoglobulin M; Intracellular Signaling Peptides and Proteins; Leukocytes, Mononuclear; Lymphokines; Mice; Phosphorylation; Protein Synthesis Inhibitors; Protein-Tyrosine Kinases; RNA, Messenger; Signal Transduction; Stilbenes; Syk Kinase; T-Lymphocytes; Time Factors; Up-Regulation

Agonists induce inside-out alphaIIbbeta3 signaling resulting in fibrinogen binding and platelet aggregation. These in turn trigger outside-in signaling resulting in further platelet stimulation. Because the Syk tyrosine kinase is activated during both phases of integrin signaling, we evaluated its role in alphaIIbbeta3 function in murine platelets rendered null for Syk by gene targeting and in human platelets incubated with piceatannol, a tyrosine kinase inhibitor reportedly selective for Syk. Both Syk null murine platelets and piceatannol-treated human platelets exhibited a partial, but statistically significant defect in activation of alphaIIbbeta3 by adenine diphosphate (ADP) +/- epinephrine as assessed by fibrinogen binding. Syk null platelets adhered normally to immobilized fibrinogen, and mice with these platelets exhibited normal tail bleeding times. In contrast, piceatannol treatment of human platelets completely inhibited platelet adhesion to immobilized fibrinogen. The discrepancy in extent of integrin dysfunction between murine and human platelet models may be due to lack of specificity of piceatannol, because this compound inhibited the activity of Src and FAK as well as Syk and also reduced tyrosine phosphorylation of multiple platelet proteins. These results provide genetic evidence that Syk plays a role in alphaIIbbeta3 signaling in platelets and pharmacological evidence that, although piceatannol also inhibits alphaIIbbeta3 signaling, it does so by inhibtion of multiple protein tyrosine kinases.

Topics: Animals; Bleeding Time; Blood Platelets; Enzyme Precursors; Fibrinogen; Genotype; Humans; In Vitro Techniques; Intracellular Signaling Peptides and Proteins; Liver; Mice; Mice, Knockout; Platelet Adhesiveness; Platelet Aggregation Inhibitors; Platelet Glycoprotein GPIIb-IIIa Complex; Protein-Tyrosine Kinases; Signal Transduction; Stilbenes; Syk Kinase

The Antarctic psychrotrophic bacterium Pseudomonas syringae contains a 66-kDa cytoplasmic protein which was found to by phosphorylated on a tyrosine residue [Ray, M.K. et al. (1994) FEMS Microbiol. Lett. 122, pp. 49-54]. To investigate the nature of the cytoplasmic protein tyrosine kinase and its role in the bacterial physiology, we carried out some biochemical studies of the enzyme in vitro in the presence of exogenous peptide substrates and expression studies in vivo at low and high temperature during various phases of growth. The results suggest that the protein tyrosine kinase associated with the cytoplasmic fraction of the bacterium has certain similarities and dissimilarities with the known eukaryotic tyrosine kinases. The protein tyrosine kinase could phosphorylate exogenous substrate corresponding to the N-terminal peptide of p34cdc2 kinase but could not do so on poly(Glu:Tyr). The enzyme could not be inhibited by genistein, staurosporine and dimethyl aminopurine, but could be inhibited by piceatannol which is a known competitive inhibitor of the peptide binding site of mammalian protein tyrosine kinases. The enzyme activity in the cytoplasm is uniquely inhibited by sodium orthovanadate (IC50 = 20 microM) which is a known protein tyrosine phosphatase inhibitor. The expression studies show that the enzyme is produced more at a higher temperature (22 degrees C) of growth than at lower temperature (4 degrees C) and during the stationary phase of growth of P. syringae.

Topics: Amino Acid Sequence; Antarctic Regions; Culture Media; Cytosol; Molecular Sequence Data; Protein-Tyrosine Kinases; Pseudomonas; Stilbenes; Temperature; Vanadates

Piceatannol is a stilbene phytochemical from the seeds of Euphorbia lagascae, previously identified as an antileukemic principle. Piceatannol is considered an inhibitor of several tyrosine kinases. We recently reported that resveratrol, another stilbene phytoalexin from grape seeds, was an inhibitor of ATP synthase. Here, we demonstrated that piceatannol potently inhibited the rat brain mitochondrial F0F1-ATPase activity in both solubilized and submitochondrial preparations (IC50 of 8-9 microM), while having relatively small effect on the Na(+), K(+)-ATPase activity of porcine cerebral cortex (no effect up to 7 microM). Piceatannol inhibited the ATPase activity of the purified rat liver F1 with IC50 of about 4 microM, while resveratrol was slightly less active (IC50 of about 14 microM). Our results indicate that piceatannol and resveratrol inhibit the F-type ATPase by targeting the F1 sector, which is located to the inner membrane of mitochondria and plasma membrane of normal endothelial cells and several cancer cell lines. This mechanism could potentially contribute to the multiple effects of these chemopreventive phytochemicals.

Topics: Animals; Antineoplastic Agents, Phytogenic; Brain; Cerebral Cortex; Enzyme Inhibitors; Female; In Vitro Techniques; Mitochondria; Mitochondria, Liver; Proton-Translocating ATPases; Rats; Rats, Sprague-Dawley; Resveratrol; Sodium-Potassium-Exchanging ATPase; Stilbenes; Swine

We examined the structure-activity relationships of isocoumarins, phthalides and stilbenes isolated from Hydrangeae Dulcis Folium and related compounds for the inhibition of histamine release in rat peritoneal mast cells. The activities of isocoumarins such as thunberginols A and B were more potent than those of dihydroisocoumarins such as hydrangenol and thunberginol G. The double bond at the 3-position seemed to be essential to potentiate the activity. The hydroxyl groups at the 8-, 3'- and 4'-positions of isocoumarin were essential for the activity, while the hydroxyl group at the 6-position was scarcely needed. Since the activities of benzylidenephthalides such as thunberginol F were more potent than those of hydramacrophyllols A and B, the presence of a double bond at the 3-position was needed to increase the activity. Moreover, the hydroxyl group at the 8-position was essential for the activity. On the time course study, thunberginols A, B and F completely inhibited histamine release by pretreatment at 100 microM for 1 to 15 min, whereas DSCG inhibited histamine release only following 1-min pretreatment at 1000 microM. These results suggested that the mechanisms of the inhibitory effect of thunberginols are different from that of DSCG.

Topics: Animals; Antigen-Antibody Reactions; Benzofurans; Benzopyrans; Bibenzyls; Calcimycin; Coumarins; Histamine Release; Immunoglobulin E; Inhibitory Concentration 50; Ionophores; Isocoumarins; Male; Mast Cells; p-Methoxy-N-methylphenethylamine; Peritoneum; Phenols; Phthalic Acids; Plant Leaves; Plants, Medicinal; Rats; Rats, Wistar; Stilbenes; Structure-Activity Relationship

We previously showed that LFA-1-dependent in vitro invasion and in vivo migration of a T cell hybridoma was blocked in cells overexpressing a truncated dominant-negative zeta-associated protein (ZAP)-70. The truncated ZAP-70 also blocked LFA-1-dependent chemotaxis through ICAM-1-coated filters induced by 1 ng/ml stromal cell-derived factor-1, but not LFA-1-independent chemotaxis induced by 100 ng/ml stromal cell-derived factor-1. This suggested that LFA-1 engagement triggers a signal that amplifies a weak chemokine signal and that dominant-negative ZAP-70 blocks this LFA-1 signal. Here we show that cross-linking of part of the LFA-1 molecules with Abs causes activation of free LFA-1 molecules (not occupied by the Ab) on the same cell, which then bind to ICAM-2 on other cells. This causes cell aggregation that was also blocked by dominant-negative ZAP-70. Thus, an LFA-1 signal involving ZAP-70 activates other LFA-1 molecules, suggesting that the chemokine signal can be amplified by multiple cycles of LFA-1 activation. The chemokine and the LFA-1 signal were both blocked by a phospholipase C inhibitor and a calpain inhibitor, suggesting that one of the amplified signals is the phospholipase C-dependent activation of calpain. Finally, we show that both Src-homology 2 domains are required for inhibition of invasion, chemotaxis, and aggregation by the truncated ZAP-70, suggesting that ZAP-70 interacts with a phosphorylated immunoreceptor tyrosine-based activation motif (ITAM) sequence. Remarkably, this is not an ITAM in the TCR/CD3 complex because this is not expressed by this T cell hybridoma.

Topics: Animals; Antibodies, Monoclonal; Antigens, CD; Binding Sites, Antibody; Calpain; Cell Adhesion; Cell Adhesion Molecules; Cell Aggregation; Cell Movement; Dose-Response Relationship, Immunologic; Enzyme Inhibitors; Hybridomas; Immunoglobulin Fab Fragments; Isoenzymes; Lymphocyte Function-Associated Antigen-1; Mice; Peptide Fragments; Phospholipase C gamma; Protein-Tyrosine Kinases; Rats; Signal Transduction; Stilbenes; T-Lymphocytes; Type C Phospholipases; ZAP-70 Protein-Tyrosine Kinase

We investigated the requirement for Syk activation to initiate downstream signaling events during polymorphonuclear leukocyte (PMN) phagocytosis of Ab-coated erythrocytes (EIgG). When PMN were challenged with EIgG, Syk phosphorylation increased in a time-dependent manner, paralleling the response of PMN phagocytosis. Pretreatment of PMN with piceatannol, a Syk-selective inhibitor, blocked EIgG phagocytosis and Syk phosphorylation. We found that piceatannol inhibited protein kinase Cdelta (PKCdelta) and Raf-1 translocation from cytosol to plasma membrane by >90%. Extracellular signal-regulated protein kinase-1 and -2 (ERK1 and ERK2) phosphorylation was similarly blocked. We also investigated phosphatidylinositide 3-kinase (PI 3-kinase) activity and Syk phosphorylation using piceatannol, wortmannin, and LY294002, inhibitors of PI 3-kinase. The phosphorylation of Syk preceded the activation of PI 3-kinase. Both wortmannin and piceatannol inhibited PI 3-kinase, but only piceatannol inhibited Syk. In contrast to piceatannol, wortmannin did not inhibit PKCdelta and Raf-1 translocation. To elucidate signaling downstream of Syk activation, we assessed whether the cell-permeable diacylglycerol analogue didecanoylglycerol could normalize PMN phagocytosis, PKCdelta and Raf-1 translocation, and ERK1 and ERK2 phosphorylation inhibited by piceatannol. The addition of didecanoylglycerol to the Syk-inhibited phagocytosing PMN normalized all three without a concomitant effect on PI 3-kinase activity and Syk phosphorylation. We conclude that Syk activation following Fcgamma receptor engagement initiates downstream signaling events leading to mitogen-activated protein kinase activation independent of PI 3-kinase activation.

Topics: Androstadienes; Animals; Biological Transport; Cell Membrane; Cell Migration Inhibition; Diglycerides; Enzyme Activation; Enzyme Inhibitors; Enzyme Precursors; Erythrocytes; Humans; Immunoglobulin G; Intracellular Signaling Peptides and Proteins; Isoenzymes; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases; Neutrophils; Opsonin Proteins; Phagocytosis; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Phosphotyrosine; Protein Kinase C; Protein Kinase C-delta; Protein-Tyrosine Kinases; Receptors, IgG; Sheep; Signal Transduction; Stilbenes; Syk Kinase; Wortmannin

This report describes the effect of piceatannol (3,4,3',5'-tetrahydroxy trans stilbene), a plant secondary natural product, on protein tyrosine kinase (PTK) activity in different stages of P. falciparum grown in vitro. Piceatannol inhibited PTK activity in trophozoites and schizonts suggesting that PTK may be important in the initial asexual maturation of the parasite. Inhibition of PTK activity by piceatannol may thus provide new insights into more specific tools for chemotherapeutic interventions for P. falciparum.

Topics: Animals; Antimalarials; Enzyme Inhibitors; Plasmodium falciparum; Protein-Tyrosine Kinases; Stilbenes

Treatment of A431 cell membranes with trypsin or Streptomyces griseus proteinase results in degradation of the EGF-R and the concomitant generation of an active kinase with a molecular mass of 42 kDa (42 kDa kinase). To investigate the biochemical properties of the 42 kDa kinase, the EGF-R was immunoaffinity-purified from the A431 cell membranes and the kinase proteolytically generated. The proteolysis of EGF-R changes both the Vmax and the Michaelis constants of substrates. These substrates determine the extent of the changes of the parameters. The 42 kDa kinase is less responsive to polyions as regulators of kinase activity and is less efficiently inhibited by genistein and tyrphostin. The experiments described here point to a role of the extracatalytic domains in determining the substrate specificity and regulation of kinase activity.

Topics: Binding Sites; ErbB Receptors; Genistein; Humans; Kinetics; Phosphorylation; Polylysine; Protamines; Spermidine; Stilbenes; Substrate Specificity; Trypsin

To investigate the role of tyrosine kinases (TK) in IgE-mediated signal transduction in human lung mast cells (HLMC) and basophils.. Peripheral blood basophils (n > or = 4) and human lung mast cells (n > or = 6).. Cells were preincubated with TK inhibitor for 15 min at 37 degrees C, before the addition of anti-IgE.. Histamine release (HR) was assayed using a fluorimetric technique. Results were compared using nonparametric statistics.. Piceatannol and ST638 significantly (p < or = 0.05) inhibited anti-IgE induced HR from HLMCs and basophils whilst lavendustin C had no effect in either cell type. Herbimycin A also significantly (p < or = 0.05) inhibited anti-IgE induced HR from both cell types, an effect which was dose dependent but did require a 16 h preincubation with drug.. In summary, HLMCs and basophils exhibit distinct inhibitory profiles in the presence of various inhibitors of TK.

Topics: Basophils; Benzoquinones; Cell Count; Cinnamates; Enzyme Inhibitors; Histamine Release; Humans; Immunoglobulin E; Lactams, Macrocyclic; Lung; Mast Cells; Phenols; Platelet Aggregation Inhibitors; Protein-Tyrosine Kinases; Quinones; Rifabutin; Signal Transduction; Stilbenes; Sulfides

The protein tyrosine kinase (PTK) inhibitor piceatannol is also an inhibitor of the rat liver cyclic AMP-dependent protein kinase (PKA) catalytic subunit (cAK), rat brain Ca(2+)- and phospholipid-dependent protein kinase C (PKC), avian gizzard Ca(2+)-calmodulin-dependent myosin light chain kinae (MLCK), and of wheat embryo Ca(2+)-dependent protein kinase (CDPK) (IC50 values 3, 8, 12, and 19 microM, respectively). However, a number of piceatannol-related compounds with fewer or no phenolic hydroxy substituents are inactive or very poor inhibitors of these serine/threonine protein kinases. Similarly, the PTK inhibitor ellagic acid is a potent inhibitor of cAK and of PKC (IC50 values 2 and 8 microM, respectively), whereas the non-phenolic perylene is ineffective as a protein kinase inhibitor. Ellagic acid is a competitive inhibitor of both cAK and of PKC but piceatannol inhibits these enzymes in a fashion that is competitive and non-competitive, respectively. Interaction with calmodulin may contribute to the inhibition of MLCK and CDPK by piceatannol.

Topics: Animals; Brain; Ellagic Acid; Enzyme Inhibitors; Protein Serine-Threonine Kinases; Rats; Stilbenes

Chemoattractant-stimulated polymorphonuclear leukocytes (PMNs) that are adherent to extracellular matrix proteins exhibit a massive, sustained respiratory burst that requires cell spreading. However, the signaling pathways culminating in PMN spreading are not well characterized. Studies showing that protein tyrosine phosphorylation increases with PMN spreading suggest that phosphorylation is critical for this process. In the present study, we observed increased tyrosine phosphorylation of both focal adhesion kinase and Syk in FMLP-activated PMNs that had been plated onto fibrinogen; an increase in Syk activity, but not focal adhesion kinase activity, was apparent. The time course of Syk phosphorylation correlated with the initiation of cell spreading and H2O2 release. Pretreatment of PMNs with piceatannol, a Syk-selective inhibitor, blocked Syk activity, cell spreading, and H2O2 release, indicating that Syk activity was required for the activation of adherent PMNs. Paxillin is a cytoskeletally associated protein that is also tyrosine phosphorylated during PMN spreading and H2O2 release. Paxillin phosphorylation is kinetically slower than Syk phosphorylation and is inhibited with piceatannol, suggesting that paxillin is a substrate for Syk. An analysis of Syk immunoprecipitates indicated that Syk and paxillin associate during PMN spreading. This interaction is not mediated by the src kinases Lyn and Fgr, since neither kinase coprecipitated with Syk. Syk from FMLP-activated, adherent PMNs phosphorylated paxillin-glutathione S-transferase, suggesting that paxillin is a substrate for Syk in vivo. These results indicate that PMN spreading and H2O2 release require a Syk-dependent signaling pathway leading to paxillin phosphorylation.

Topics: Cell Adhesion Molecules; Cytoskeletal Proteins; Enzyme Activation; Enzyme Precursors; Focal Adhesion Kinase 1; Focal Adhesion Protein-Tyrosine Kinases; Humans; Hydrogen Peroxide; Intracellular Signaling Peptides and Proteins; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Paxillin; Phosphoproteins; Phosphorylation; Protein-Tyrosine Kinases; Stilbenes; Syk Kinase; Tyrosine

The senile plaques of Alzheimer's disease are foci of local inflammatory responses, as evidenced by the presence of acute phase proteins and oxidative damage. Fibrillar forms of beta-amyloid (Abeta), which are the primary constituents of senile plaques, have been shown to activate tyrosine kinase-dependent signal transduction cascades, resulting in inflammatory responses in microglia. However, the downstream signaling pathways mediating Abeta-induced inflammatory events are not well characterized. We report that exposure of primary rat microglia and human THP1 monocytes to fibrillar Abeta results in the tyrosine kinase-dependent activation of two parallel signal transduction cascades involving members of the mitogen-activated protein kinase (MAPK) superfamily. Abeta stimulated the rapid, transient activation of extracellular signal-regulated kinase 1 (ERK1) and ERK2 in microglia and ERK2 in THP1 monocytes. A second superfamily member, p38 MAPK, was also activated with similar kinetics. Scavenger receptor and receptor for advanced glycated end products (RAGE) ligands failed to activate ERK and p38 MAPK in the absence of significant increases in protein tyrosine phosphorylation, demonstrating that scavenger receptors and RAGE are not linked to these pathways. Importantly, the stress-activated protein kinases (SAPKs) were not significantly activated in response to Abeta. Downstream effectors of the MAPK signal transduction cascades include MAPKAP kinases, such as RSK1 and RSK2, as well as transcription factors. Exposure of microglia and THP1 monocytes to Abeta resulted in the activation of RSK1 and RSK2 and phosphorylation of cAMP response element-binding protein at Ser133, providing a mechanism for Abeta-induced changes in gene expression.

Topics: Amyloid beta-Peptides; Animals; Calcium-Calmodulin-Dependent Protein Kinases; Cyclic AMP Response Element-Binding Protein; Enzyme Activation; Humans; Microglia; Mitogen-Activated Protein Kinases; Monocytes; p38 Mitogen-Activated Protein Kinases; Peptide Fragments; Phosphorylation; Protein Kinases; Rats; Ribosomal Protein S6 Kinases, 90-kDa; Stilbenes; Tyrosine

In human blood basophils, cross-linking the high-affinity IgE receptor Fc epsilonRI with multivalent antigen activates a signaling pathway leading to Ca2+ mobilization, actin polymerization, shape changes, secretion, and cytokine production.. The role of tyrosine kinases in human Fc epsilonRI signaling was explored by using human basophils isolated by Percoll gradient centrifugation followed by negative and/or positive selection with antibody-coated magnetic beads. Fc epsilonRI cross-linking of more than 95% pure basophil preparations activates the protein-tyrosine kinases Lyn and Syk, previously linked to Fc epsilonRI-coupled rodent mast cell activation, as well as Zap-70, previously implicated in T-cell receptor signaling, and causes the tyrosine phosphorylation of multiple proteins. The presence of Lyn, Syk, and Zap-70 in basophils was confirmed by Western blotting in lysates of highly purified basophils and independently by confocal fluorescence microscopy in cells labeled simultaneously with kinase-specific antibodies and with the basophil-specific antibody 2D7. Comparable amounts of Lyn and Syk were found in basophils and B cells, whereas T cells appear to have greater amounts of Zap-70 than basophils. The tyrosine kinase inhibitor piceatannol spares IgE-mediated Lyn activation but inhibits IgE-induced Syk and Zap-70 activation as well as overall protein tyrosine phosphorylation and secretion. Overall protein-tyrosine phosphorylation increases steadily over a range of anti-IgE concentrations that are low to optimal for secretion. However, tyrosine phosphorylation continues to increase at high anti-IgE concentrations that elicit very little secretion (the characteristic high-dose inhibition of secretion).. Our data demonstrate the association of anti-IgE-stimulated, protein-tyrosine phosphorylation by a cascade of tyrosine kinases, including Zap-70 as well as Lyn and Syk, with the initiation of Fc epsilonRI-mediated signaling in human basophils.

Topics: Basophil Degranulation Test; Basophils; Blotting, Western; Enzyme Activation; Enzyme Inhibitors; Fluorescent Antibody Technique, Indirect; Histamine Release; Humans; Phosphorylation; Protein-Tyrosine Kinases; Receptor Protein-Tyrosine Kinases; Receptors, IgE; src-Family Kinases; Stilbenes; ZAP-70 Protein-Tyrosine Kinase

The ZAP-70 tyrosine kinase is essential for T cell activation by the T cell receptor. We show that ZAP-70 is also required for migration of T cells that is dependent on the integrin LFA-1. Invasion of TAM2D2 T cell hybridoma cells into fibroblast monolayers, which is LFA-1-dependent, was blocked by overexpression of dominant-negative ZAP-70 and by piceatannol but not by herbimycin A. The Syk inhibitor piceatannol blocks the Syk homologue ZAP-70, which is expressed by TAM2D2 cells, with the same dose dependence as the inhibition of invasion. Dominant-negative ZAP-70 completely inhibited the extensive metastasis formation of TAM2D2 cells to multiple organs upon i.v. injection into mice. Migration of TAM2D2 cells through filters coated with the LFA-1 ligand ICAM-1, induced by 1 ng/ml of the chemokine SDF-1, was blocked by anti-LFA-1 mAb and also abrogated by dominant-negative ZAP-70 and piceatannol. In contrast, migration induced by 100 ng/ml SDF-1 was independent of both LFA-1 and ZAP-70. LFA-1 cross-linking induced tyrosine phosphorylation, which was blocked by dominant-negative ZAP-70 and piceatannol. We conclude that LFA-1 engagement triggers ZAP-70 activity that is essential for LFA-1-dependent migration.

Topics: Animals; Benzoquinones; Cell Movement; Chemokine CXCL12; Chemokines, CXC; Fibroblasts; Gene Expression; Humans; Hybridomas; Integrins; Intercellular Adhesion Molecule-1; Lactams, Macrocyclic; Lymphocyte Function-Associated Antigen-1; Mice; Neoplasm Metastasis; Phosphotyrosine; Protein-Tyrosine Kinases; Quinones; Rats; Rifabutin; Stilbenes; T-Lymphocytes; Virulence Factors, Bordetella; ZAP-70 Protein-Tyrosine Kinase

To study the chemical constituents in the root of Rheum wittrochii.. Chromatography and spectroscopic analysis to isolate and elucidate the chemical constituents in the plant.. Six compounds, namely 3, 5-dihydroxy-4'-methoxystilbene; 3, 5, 4'-tridroxystilbene; piceatannol; desoxyrhaponticin; piceatannol-4'-O-beta-D-glucopyranoside; 2, 5-dimethyl-7-hydroxychromone, have been isolated from ethyl ether and ethyl acetate fractions.. These compounds were isolated from the title plant for the first time.

Topics: Drugs, Chinese Herbal; Glucosides; Molecular Structure; Rheum; Stilbenes

Convulxin, a powerful platelet activator, was isolated from Crotalus durissus terrificus venom, and 20 amino acid N-terminal sequences of both subunits were determined. These indicated that convulxin belongs to the heterodimeric C-type lectin family. Neither antibodies against GPIb nor echicetin had any effect on convulxin-induced platelet aggregation showing that, in contrast to other venom C-type lectins acting on platelets, GPIb is not involved in convulxin-induced platelet activation. In addition, partially reduced/denatured convulxin only affects collagen-induced platelet aggregation. The mechanism of convulxin-induced platelet activation was examined by platelet aggregation, detection of time-dependent tyrosine phosphorylation of platelet proteins, and binding studies with 125I-convulxin. Convulxin induces signal transduction in part like collagen, involving the time-dependent tyrosine phosphorylation of Fc receptor gamma chain, phospholipase Cgamma2, p72(SYK), c-Cbl, and p36-38. However, unlike collagen, pp125(FAK) and some other bands are not tyrosine-phosphorylated. Convulxin binds to a glycosylated 62-kDa membrane component in platelet lysate and to p62/GPVI immunoprecipitated by human anti-p62/GPVI antibodies. Convulxin subunits inhibit both aggregation and tyrosine phosphorylation in response to collagen. Piceatannol, a tyrosine kinase inhibitor with some specificity for p72(SYK), showed differential effects on collagen and convulxin-stimulated signaling. These results suggest that convulxin uses the p62/GPVI but not the alpha2beta1 part of the collagen signaling pathways to activate platelets. Occupation and clustering of p62/GPVI may activate Src family kinases phosphorylating Fc receptor gamma chain and, by a mechanism previously described in T- and B-cells, activate p72(SYK) that is critical for downstream activation of platelets.

Topics: Amino Acid Sequence; Animals; Carrier Proteins; Chromatography, High Pressure Liquid; Collagen; Crotalid Venoms; Crotalus; Humans; Integrins; Lectins, C-Type; Molecular Sequence Data; Phosphorylation; Platelet Activation; Platelet Aggregation; Platelet Aggregation Inhibitors; Platelet Glycoprotein GPIb-IX Complex; Platelet Membrane Glycoproteins; Protein Binding; Protein Denaturation; Receptors, Collagen; Signal Transduction; Stilbenes; Tyrosine

The interaction of cells with the extracellular matrix can alter cell responses and is regulated by integrins on the cell surface. We used monoclonal antibodies to the VLA-4 integrins CD29 and CD49d followed by an F(ab')2 fragment of rabbit anti-mouse immunoglobulin G1 to crosslink integrins on the surface of human lung mast cells and basophils. Crosslinking either CD29 or CD49d caused a significant histamine release (HR) from the basophils of most asthmatic donors (10 of 14 for CD49d and 7 of 10 for CD29) (HR = 21 +/- 5%, n = 10, P < 0.005 for CD29 and HR = 19 +/- 4%, n = 14, P < 0.01 for CD49d) yet failed to initiate HR from the basophils of non-atopic and atopic donors (HR was 1 +/- 0.5% for CD29 and 1 +/- 0.5% for CD49d, n = 10, P = NS). Crosslinking either CD29 or CD49d also failed to initiate histamine release from human lung mast cells (HR was 1 +/- 1% for CD29 and 2 +/- 1% for CD49d). The basophils of asthmatic donors responded to 100 and 30 micrograms/ml tissue fibronectin (HR = 12 +/- 2% and 10 +/- 3% for 100 and 30 micrograms/ml fibronectin, respectively, n = 18, P < 0.05), whereas basophils of nonasthmatic patients again failed to degranulate (HR was 0 +/- 0.4% and 1 +/- 0.6%, respectively, n = 11, P = NS). In contrast to the basophil, crosslinking of either CD29 or CD49d failed to initiate histamine release in human lung mast cells (HR = 1 +/- 1% for CD29 and 2 +/- 1%, n = 15). Human lung mast cells were also unresponsive to tissue fibronectin (100 and 30 micrograms/ml) (HR = 1 +/- 1%, n = 5). The tyrosine kinase inhibitor, genistein, significantly reduced CD29- and CD49d-induced HR (inhibition = 83 +/- 7% for CD29 and 77 +/- 6% for CD49d, n > or = 5, P < 0.05). A second tyrosine kinase inhibitor, piceatannol, also significantly reduced both CD29- and CD49d-induced HR (inhibition was 62 +/- 19% for CD29 and 56 +/- 14% for CD49d, n = 7, P < or = 0.05). Integrin crosslinking also affected the response to a second, immunoglobulin E (IgE)-dependent stimulus. Both CD29 and CD49d clustering significantly inhibited anti-IgE-induced histamine release from the human basophil. Inhibition was 30 +/- 5%, n = 18, P < or = 0.001 for CD29 versus 40 +/- 6% for CD49d. In summary, we have shown that crosslinking the beta 1 integrins using either monoclonal antibodies or tissue fibronectin can initiate mediator release from the basophils of asthmatic patients by a mechanism which appears to be tyrosine kinase-mediated. In addition, clustering of integrins modul

Topics: Antibodies, Monoclonal; Antigens, CD; Basophils; Cell Degranulation; Cross-Linking Reagents; Enzyme Inhibitors; Fibronectins; Genistein; Histamine Release; Humans; Immunoglobulin E; Integrin alpha4; Integrin beta1; Integrins; Isoflavones; Lung; Mast Cells; Protein-Tyrosine Kinases; Stilbenes

Coronary arterioles demonstrate flow-dependent vasodilation that is mediated by endothelial release of nitric oxide. The signaling mechanisms for this response remain unknown. Because tyrosine kinases are an enzyme family linked to many signaling pathways, including some for mechanosensitive transduction, we hypothesized that tyrosine kinase activation is a critical step in flow-induced vasodilation. To test this hypothesis, coronary arterioles were isolated, cannulated with micropipettes, and perfused by two independent reservoir systems. Intraluminal pressure was set at 60 cmH2O, and flow was generated by changing the heights of the reservoirs in equal and opposite directions, thus establishing a pressure difference across the arteriole without altering intraluminal pressure. Vasodilatory responses to intraluminal flow and substance P (1 x 10(-12) to 1 x 10(-7) M) were evaluated before and after intraluminal application of the tyrosine kinase inhibitors genistein (5 microM) and piceatannol (10 microM). Exposure to these inhibitors did not alter spontaneous tone. Substance P caused dose-dependent vasodilation that was not affected by genistein or piceatannol. Increases in intraluminal flow (generated by pressure differences ranging from 4 to 60 cmH2O) elicited graded increases in diameter. Both genistein and piceatannol inhibited the vasodilatory responses to flow. Treatment with daidzein, an inactive analogue of genistein, had no effect on either the flow-induced responses or substance P-induced vasodilation. To further confirm that tyrosine kinase activation is involved in flow-induced vasodilation, vessels were exposed to flow in the absence or presence of genistein and subsequently stained with a fluorescein isothiocyanate-labeled phosphotyrosine antibody. Exposure to flow significantly increased fluorescence of endothelial cells. Genistein treatment reversed the flow-induced increase in tyrosine phosphorylation. These results indicate that endothelium-dependent, flow-induced vasodilation in isolated porcine coronary arterioles is accompanied by an increase in tyrosine kinase activity. We conclude that endothelium-dependent, nitroxidergic, flow-induced vasodilation is mediated, at least in part, by a signaling pathway involving a tyrosine kinase.

Topics: Animals; Arterioles; Coronary Vessels; Female; Genistein; In Vitro Techniques; Isoflavones; Male; Phosphorylation; Protein-Tyrosine Kinases; Regional Blood Flow; Signal Transduction; Stilbenes; Substance P; Swine; Vasodilation

Platelet activation induced by anti-CD9 mAb, which depends upon Fc gammaRII, has been considered to be similar to that induced by Fc gammaRII cross-linking. In this work, we present several lines of evidence to suggest that the mode of platelet activation induced by anti-CD9 mAb is distinct from that induced by Fc gammaRII cross-linking. Ca2+ release from intracellular Ca2+ stores induced by anti-CD9 mAb depended almost totally upon thromboxane A2 production and released ADP, whereas that induced by Fc gammaRII was affected only minimally by these factors. Fc gammaRII cross-linking induced Ca2+ channel opening, which is dependent upon the depletion of intracellular Ca2+ stores. In contrast, anti-CD9 mAb appeared to directly open Ca2+ channels, irrespective of intracellular Ca2+ stores (Kuroda et al., 1995. J. Immunol. 155: 4427). The Ca2+ requirement for the Ca2+ channels opened by Fc gammaRII cross-linking was also distinct from that induced by anti-CD9 mAb. The early phase of Fc gammaRII tyrosine phosphorylation was dependent upon thromboxane A2 production with anti-CD9 mAb-induced activation, whereas that of Fc gammaRII cross-linking was not. p72(syk) and p53/56(lyn) appeared to associate with Fc gammaRII in platelet activation induced by Fc gammaRII cross-linking, whereas there was little, if any, association between Fc gammaRII and these tyrosine kinases in anti-CD9 mAb-induced activation. Piceatannol, a selective inhibitor of p72(syk), enhanced Fc gammaRII tyrosine phosphorylation induced by Fc gammaRII cross-linking, whereas it attenuated the process in anti-CD9 mAb-induced platelet activation. It is suggested that the regulatory mechanism of Fc gammaRII tyrosine phosphorylation differs between these two modes of platelet activation.

Topics: Antibodies, Monoclonal; Antigens, CD; Calcium; Cells, Cultured; Cross-Linking Reagents; Enzyme Precursors; Humans; Intracellular Signaling Peptides and Proteins; Membrane Glycoproteins; Phosphoproteins; Phosphotyrosine; Platelet Activation; Protein-Tyrosine Kinases; Receptor Aggregation; Receptors, IgG; Signal Transduction; Stilbenes; Syk Kinase; Tetraspanin 29

A range of selective tyrosine kinase inhibitors, piceatannol, methyl-2,5-dihydroxycinnamate (MDC), genistein, psi-tectorigenin and lavendustin A, all reduced luteinizing hormone-releasing hormone (LHRH)-induced luteinizing hormone (LH) and follicle-stimulating hormone (FSH) release from pro-oestrous rat hemipituitaries incubated in vitro. In general, both 'initial' release and the augmented release resulting from LHRH self-priming, were reduced in parallel in a concentration-dependent fashion. The effects of piceatannol were independent of the steroidal status of the pituitary tissue. Both piceatannol and MDC greatly reduced LH release by ionomycin and a protein kinase C (PKC) activator, phorbol 12,13-dibutyrate (PDBu), suggesting that the tyrosine kinase(s)-dependent step is in the later stages of the stimulus-secretion pathway activated by the LHRH receptor. These data were supported by immunoblots for phosphotyrosine showing that in the gonadotrope-derived alpha T3-1 cell line, treatment with LHRH caused piceatannol-sensitive increases in specific tyrosine phosphorylation of several proteins (major bands at 65-75 and 120-130 kDa). Treatment of cells with PDBu mimicked the tyrosine phosphorylations evoked by LHRH whereas the PKC inhibitor, GF109203X, partially reduced both LHRH- and PDBu-induced tyrosine phosphorylations. Direct effects of MDC and piceatannol on PKC were assessed in an in vitro PKC assay; piceatannol, but not MDC, inhibited PKC activity but at considerably higher concentrations than required for inhibition of LHRH-induced gonadotropin secretion. These data support a role for tyrosine kinase activation in LHRH-induced secretion.

Topics: Animals; Cinnamates; Female; Follicle Stimulating Hormone; Genistein; Gonadotropin-Releasing Hormone; In Vitro Techniques; Ionomycin; Isoflavones; Luteinizing Hormone; Phenols; Phorbol 12,13-Dibutyrate; Pituitary Gland, Anterior; Proestrus; Protein-Tyrosine Kinases; Rats; Stilbenes

In RBL-2H3 rat tumor mast cells, antigens that cross-link the high affinity cell surface IgE receptor, Fc epsilon R1, activate at least two receptor-associated protein-tyrosine kinases, Lyn and Syk, and cause the tyrosine phosphorylation of the receptor beta and gamma subunits, PLC gamma 1, Vav, and other proteins. Cross-linking antigens also induce increased phosphatidylinositol turnover, Ca2+ mobilization, secretion, actin polymerization, spreading, and membrane ruffling. We have used the protein-tyrosine kinase inhibitor, piceatannol (3,4,3',5'-tetrahydroxy-trans-stilbene), to explore the coupling of specific kinases to cellular responses. Piceatannol preferentially inhibits the activity of Syk as compared with Lyn when added to in vitro assays with isolated enzymes. Treatment of RBL-2H3 cells with piceatannol strongly inhibits the antigen-stimulated activation of Syk measured in anti-Syk and anti-phosphotyrosine immune complex kinase assays at concentrations that have no effect on receptor subunit phosphorylation and maintain or increase the activity of Lyn in anti-phosphotyrosine immune complex kinase assays. In cells metabolically labeled with [32P]orthophosphate, piceatannol inhibits the antigen-stimulated tyrosine phosphorylation of Syk and most other proteins. However, receptor subunit phosphorylation is unchanged. Selective inhibition of Syk in this manner blocks receptor-mediated down-stream cellular responses (inositol 1,4,5-trisphosphate production, secretion, ruffling, and spreading) while having only minor effects when these responses are induced with drugs that bypass the receptor complex. These results reveal receptor-mediated Lyn activation as a relatively piceatannol-insensitive event that may contribute to receptor subunit phosphorylation and Syk activation but does not per se elicit cellular responses. Receptor-mediated Syk activation on the other hand is highly sensitive to piceatannol, is essential to Fc epsilon R1-mediated cellular responses, and, based on the increased phosphorylation of Lyn in piceatannol-treated cells, may be involved in terminating Lyn activity.

Topics: Animals; Cell Line; Enzyme Precursors; Intracellular Signaling Peptides and Proteins; Mast Cells; Mice; Phosphorylation; Precipitin Tests; Protein-Tyrosine Kinases; Receptors, IgE; Signal Transduction; src-Family Kinases; Stilbenes; Syk Kinase

Topics: Diosgenin; Drugs, Chinese Herbal; Sitosterols; Stilbenes

A series of hydroxylated trans-stilbenes related to the antileukemic natural product trans-3,3',4,5'-tetrahydroxystilbene (piceatannol) (1) has been prepared and tested for inhibition of the lymphoid cell lineage-specific protein-tyrosine kinase p56lck, which plays an important role in lymphocyte proliferation and immune function. A number of the analogues displayed enhanced enzyme inhibitory activity relative to the natural product. Reduction of the double bond bridging the two aromatic rings and benzylation of the phenolic hydroxyl groups was found to decrease activity significantly. The most potent compounds in the series proved to be trans-3,3',5,5'-tetrahydroxystilbene, trans-3,3',5-trihydroxystilbene, and trans-3,4,4'-trihydroxystilbene.

Topics: Hydroxylation; Lymphocyte Specific Protein Tyrosine Kinase p56(lck); Lymphocytes; Molecular Structure; Phenols; Protein-Tyrosine Kinases; Stilbenes; Structure-Activity Relationship

The effect of naturally occurring hydroxystilbene, 3,3',4,5-tetrahydroxystilbene (piceatanol), and its derivatives on gastric H+, K(+)-ATPase was studied. Piceatanol inhibited H+, K(+)-ATPase in a dose-dependent manner. The 50% inhibition value was 4.3 x 10(-6) M. It was found from the kinetic study that the inhibition of the enzyme by piceatanol was competitive with respect to ATP and was noncompetitive with respect to K+. Piceatanol also effectively inhibited gastric acid secretion. However, methylation of phenolic hydroxy groups of piceatanol resulted in a complete loss of inhibition of the enzyme and acid secretion, suggesting the role of phenolic hydroxy groups in the inhibition. The study on hydroxystilbene derivatives also showed that phenolic hydroxy groups are important in the interaction with H+, K(+)-ATPase and that stilbenes with neighbouring hydroxy groups are the most effective inhibitors.

Topics: Adenosine Triphosphate; Animals; Binding, Competitive; Dogs; Dose-Response Relationship, Drug; Gastric Acid; Gastric Mucosa; Kinetics; Potassium; Proton Pump Inhibitors; Sodium-Potassium-Exchanging ATPase; Stilbenes; Structure-Activity Relationship; Swine

We examined the inhibitory activities of 3,3'-dihydroxy-alpha,beta-diethylstilbene (DDS) and 3,3',4,5'-tetrahydroxystilbene (THS) on microtubule assembly in vitro and their effects on chromosome number and cellular microtubule networks in Chinese hamster V79 cells. DDS showed half the inhibitory activity of diethylstilbestrol (DES) on microtubule assembly in vitro, while THS had none of the inhibitory activity. DDS induced tetraploid at 30 microM, whereas THS was found to be inactive. Furthermore, DDS disturbed cellular microtubule networks at 100 microM. We also examined the effects of DES, DDS and THS on cellular actin networks in mouse BALB 3T3 cells. DES induced a change of actin stress fiber distribution and THS had similar activity, while DDS showed no activity.

Topics: Actins; Aneuploidy; Animals; Antineoplastic Agents; Cells, Cultured; Chromosomes; Cricetinae; Diethylstilbestrol; Glucans; Mice; Mice, Inbred Strains; Microtubules; Stilbenes

3,3',4,5'-Tetrahydroxystilbene (I), a constituent of Cassia garrettiana, strongly inhibited the anti-IgE-induced histamine release from human basophils in vitro at concentrations of 3 to 30 microM. Considering that disodium cromoglycate showed no significant inhibitory activity in this assay method, the strong effect of I should be emphasized.

Topics: Basophils; Cassia; Histamine Release; Humans; Immunoglobulin E; In Vitro Techniques; Plants, Medicinal; Stilbenes

3,3',4,5'-Tetrahydroxystilbene (I) and 3,3',4,5'-tetrahydroxybibenzyl (II), isolated from the heartwood of Cassia garrettiana Craib (Leguminosae), showed inhibitory effects on antigen-induced histamine release from rat peritoneal mast cells in vitro. The inhibitory effect of I (IC50 = 30.2 microM) was much stronger than that of II (greater than 100 microM). Compound II, as well as I (IC50 = 7.3 microM) reported previously, also inhibited the histamine release from human peripheral basophils induced by anti-immunoglobulin E (IgE) in vitro, and its IC50-value was 68.0 microM. These results suggest that the trans-olefin structure in the molecule may be necessary for I to have an inhibitory effect on histamine release. Considering that disodium cromoglycate did not show any significant inhibitory effect on anti-IgE-induced histamine release from human basophils, the strong inhibitory effects of I in both tests are of considerable interest.

Topics: Animals; Antigens; Basophils; Bibenzyls; Cassia; Histamine Antagonists; Histamine Release; Humans; In Vitro Techniques; Male; Mast Cells; Plants, Medicinal; Rats; Rats, Inbred Strains; Stilbenes

Piceatannol (3,4,3'5'-tetrahydroxy-trans-stilbene), a plant secondary natural product that had previously been identified as an antileukemic principle, has been shown to be an inhibitor of protein-tyrosine kinase activity. Piceatannol inhibits the purified thymocyte protein-tyrosine kinase, p40, by competing for the peptide or protein substrate binding site (Ki = 15 microM). Piceatannol also inhibits the activity of the p56lck protein-tyrosine kinase measured either in LSTRA cell membranes or in intact cells. In contrast, piceatannol does not inhibit the activity of the cAMP-dependent protein kinase.

Topics: Amino Acid Sequence; Animals; Antineoplastic Agents, Phytogenic; Cattle; Cell Membrane; Cells, Cultured; Kinetics; Molecular Sequence Data; Protein-Tyrosine Kinases; Stilbenes; Substrate Specificity; Thymus Gland

Topics: Animals; Anti-Infective Agents; Antifungal Agents; Fishes; Lethal Dose 50; Male; Mice; Plants, Medicinal; Stilbenes