benzofurans and usnic-acid

Lichens are among the most widely distributed plants on earth and have the longest growth cycle. Usnic acid is an abundant characteristic secondary metabolite of lichens and the earliest lichen compound used commercially. It has diverse pharmacological activities, such as anti-inflammatory, antibacterial, antiviral, anticancer, antioxidant, and photoprotective effects, and promotes wound healing. It is widely used in dietary supplements, daily chemical products (fodder, dyes, food, perfumery, and cosmetics), and medicine. However, some studies have found that usnic acid can cause allergic dermatitis and drug-induced liver injury. In this paper, the bioactivity, toxicity, in vivo and in vitro metabolism, and pharmacokinetics of usnic acid were summarized. The aims were to develop and utilize usnic acid and provide reference for its future research.

Topics: Anti-Bacterial Agents; Anti-Inflammatory Agents; Benzofurans; Lichens

Usnic acid is the best-studied lichen metabolite, presenting several biological activities, such as antibacterial, immunostimulating, antiviral, antifungal, anti-inflammatory, and antiparasitic agents; despite these relevant properties, it is a hydrophobic and toxic molecule. In this context, scientific research has driven the development of innovative alternatives, considering usnic acid as a source of raw material in obtaining new molecules, allowing structural modifications (syntheses) from it. The purpose is to optimize biological activities and toxicity, with less concentration and/or response time. This work presents a literature review with an analogy of the hydrophobic molecule of usnic acid with its hydrophilic derivative of potassium usnate, emphasizing the elucidation and structural characteristics, biological activities, and toxicological aspects of both molecules, and the advantages of using the promising derivative hydrophilic in different in vitro and in vivo assays when compared to usnic acid.

Topics: Analgesics; Animals; Anti-Inflammatory Agents; Antineoplastic Agents; Antiparasitic Agents; Benzofurans; Hydrophobic and Hydrophilic Interactions; Lichens; Potassium

Lichens are symbiotic organisms which are composed fungi and algae and/or cyanobacteria. They produce a variety of characteristic secondary metabolites. Such substances have various biological properties including antimicrobial, antiviral, and antitumor activities. Angiogenesis, the growth of new vessels from pre-existing vessels, contributes to numerous diseases including cancer, arthritis, atherosclerosis, infectious, and immune disorders. Antiangiogenic therapy is a promising approach for the treatment of such diseases by inhibiting the new vessel formation. Technological advances have led to the development of various antiangiogenic agents and have made possible antiangiogenic therapy in many diseases associated with angiogenesis. Some lichens and their metabolites are used in the drug industry, but many have not yet been tested for their antiangiogenic effects. The cytotoxic and angiogenic capacities of lichen-derived small molecules have been demonstrated in vivo and in vitro experiments. Therefore, some of them may be used as antiangiogenic agents in the future. The secondary compounds of lichen whose antiangiogenic effect has been studied in the literature are usnic acid, barbatolic acid, vulpinic acid, olivetoric acid, emodin, secalonic acid D, and parietin. In this article, we review the antiangiogenic effects and cellular targets of these lichen-derived metabolites.

Topics: Angiogenesis Inhibitors; Anti-Infective Agents; Benzofurans; Biological Products; Cyanobacteria; Emodin; Fungi; Furans; Humans; Lichens; Phenylacetates; Salicylates; Xanthones

Increasing prevalence of herbal and dietary supplement-induced hepatotoxicity has been reported worldwide. Usnic acid (UA) is a well-known hepatotoxin derived from lichens. Since 2000, more than 20 incident reports have been received by the US Food and Drug Administration after intake of UA containing dietary supplement resulting in severe complications. Scientists and clinicians have been studying the cause, prevention and treatment of UA-induced hepatotoxicity. It is now known that UA decouples oxidative phosphorylation, induces adenosine triphosphate (ATP) depletion, decreases glutathione (GSH), and induces oxidative stress markedly leading to lipid peroxidation and organelle stress. In addition, experimental rat liver tissues have shown massive vacuolization associated with cellular swellings. Additionally, various signaling pathways, such as c-JNK N-terminal kinase (JNK), store-operated calcium entry, nuclear erythroid 2-related factor 2 (Nrf2), and protein kinase B/mammalian target of rapamycin (Akt/mTOR) pathways are stimulated by UA causing beneficial or harmful effects. Nevertheless, there are controversial issues, such as UA-induced inflammatory or anti-inflammatory responses, cytochrome P450 detoxifying UA into non-toxic or transforming UA into reactive metabolites, and unknown mechanism of the formation of vacuolization and membrane pore. This article focused on the previous and latest comprehensive putative mechanistic findings of UA-induced hepatotoxicity and cell death. New insights on controversial issues and future perspectives are also discussed and summarized.

Topics: Animals; Autophagy; Benzofurans; Cell Death; Chemical and Drug Induced Liver Injury; Cytochrome P-450 Enzyme System; Humans; Inflammation; Liver; Mitochondria; Oxidative Phosphorylation; Oxidative Stress

Usnic acid (UA) is a secondary lichen metabolite extensively studied for the broad variety of biological features. The most interesting property of UA is its antimicrobial activity against Gram-positive bacteria growing either in planktonic or in biofilm mode. In this chapter, the most relevant studies assessing usnic acid activity against microbial biofilms have been summarized and the potential role of UA in the management of biofilm-based wound infections has been critically discussed. Additionally, an overview of the main strategies adopted so far to reduce drug toxicity and increase bioavailability is given in the perspective of a safe use of UA in the clinical management of infected wounds.

Topics: Anti-Bacterial Agents; Benzofurans; Biofilms; Humans; Lichens; Wound Infection

The growth rate inhibition of dermatophytes by compounds extracted by acetone, ethanol, methanol and water derived from representatives of several lichen genera (e.g. Caloplaca, Everniastrum, Heterodermia, Hypotrachyna, Platismatia and Ramalina) were compared on the basis of a worldwide review of published research. The examined dermatophytes included Epidermophyton floccosum, Microsporum audouinii, M. canis, M. gypseum, M. nanum, Trichophyton longifusus, T. mentagrophytes, T. rubrum, T. tonsurans and T. violaceum. The influence of selected secondary lichen compounds, for example, usnic acid, on the growth rates of these dermatophytes was also reviewed. The measurement of inhibition by lichen compounds was performed by several methods, but mostly those employing disc diffusion, broth dilution and agar dilution. The fungicidal activity of water-extracted compounds from Heterodermia leucomela and Hypotrachyna cirrhata and of methanol-extracted compounds from Evernia divaricata and Ramalina pollinaria, as well as protolichesterinic and 2-hydroxy-4-methoxy-3,6-dimethylbenzoic acids, are distinguished.

Topics: Antifungal Agents; Arthrodermataceae; Benzofurans; Epidermophyton; Lichens; Microsporum; Trichophyton

Usnic acid (UA) is a lichen-derived secondary metabolite with a unique dibenzofuran skeleton and is commonly found in lichenized fungi of the genera Usnea and Cladonia. Usnic acid has been incorporated for years in cosmetics, perfumery, and traditional medicines. It has a wide range of bioactivities, including antimicrobial, antiviral, anticancer, anti-inflammatory properties.. This review covers patents on therapeutic activities of UA and its synthetic derivatives published during the period 2000-2017.. UA demonstrates excellent anticancer and antimicrobial properties. However, its application was withdrawn due to acute liver toxicity reported with chronic consumption. The broad spectrum of its biological activity indicates high the variability of UA's binding preferences. The main idea to be addressed in the future should include the synthesis of UA derivatives because these might possess increased bioactivity, bioavailability and decreased toxicity. It is noteworthy that UA derivatives possessed better antibacterial, antitubercular, and anticancer activity than the parent compound . Most importantly, UA and its analogs (to a greater extent than UA) can be useful in cancer drug treatment. They have the potential for joint application with other anticancer drugs in order to overcome drug resistance.

Topics: Animals; Anti-Infective Agents; Anti-Inflammatory Agents; Antineoplastic Agents; Benzofurans; Drug Design; Humans; Patents as Topic

Usnic acid and its derivatives, a group of organic molecules with great importance, are characteristic to lichens, possessing pharmacological activities such as anti-virus, anti-bacteria, anti-humor, anti-inflammatory, analgesic, and anaesthetic effects. Many of them have been widely used as medicine, but also bring side effects such as dermatitis and liver damages. In the past decades, great efforts by isolation, organic synthesis, and structure modification methods were put on discovery of UA derivatives with higher biological activities or less side effects. This paper describes herein the most progress on natural sources, isolation and structure elucidation, structural characteristics, synthesis and modification results, pharmacological activities and toxicities of UA and its derivatives, hopefully to provide valuable reference for further research.

Topics: Benzofurans; Biological Products; Lichens

Since its first isolation in 1844, usnic acid [2,6-diacetyl-7,9-dihydroxy-8,9b-dimethyl-1,3(2H,9bH)-dibenzo-furandione] has become the most extensively studied lichen metabolite and one of the few that are commercially available. Lichens belonging to usnic acid-containing genera have been used as crude drugs throughout the world. There are indications of usnic acid being a potentially interesting candidate for such activities as anti-inflammatory, analgesic, healing, antioxidant, antimicrobial, antiprotozoal, antiviral, larvicidal and UV protection. However, some studies reported the liver toxicity and contact allergy. Thus, further studies are needed to establish the efficacy and safety of usnic acid.

Topics: Animals; Anti-Infective Agents; Anti-Inflammatory Agents; Antineoplastic Agents; Antioxidants; Benzofurans; Humans; Lichens; Molecular Structure

Lichens are a form of symbiont between a fungus and an alga or cyanobacterium, which contains a wide variety of organic compounds with certain secondary metabolite classes typical of these organisms. The Ramalina genus has approximately 246 species distributed around the World, of which in this review approximately 118 species with published chemical or biological activity studies of extracts or isolated compounds were cited. From the 153 mentioned compounds, only 27 passed were tested for biological activity, being usnic acid the most studied compound and the one showing the best results in almost all in vitro tests performed, although other compounds also presented excellent results as antimicrobial, antitumor and anti-inflammatory agents, among others. Extracts of several species also presented significant results in performed biological tests, demonstrating the potential that these organisms have, in particular, the gender Ramalina, to produce bioactive molecules that can be used as a model for the production of pharmaceuticals.

Topics: Animals; Benzofurans; Depsides; Humans; Lichens

Chronic diseases such as cancer, diabetes, neurodegenerative and cardiovascular diseases are characterized by an enhanced state of oxidative stress, which may result from the overproduction of reactive species and/or a decrease in antioxidant defenses. The search for new chemical entities with antioxidant profile is still thus an emerging field on ongoing interest. Due to the lack of reviews concerning the antioxidant activity of lichen-derived natural compounds, we performed a review of the antioxidant potential and mechanisms of action of natural compounds isolated from lichens. The search terms "lichens", "antioxidants" and "antioxidant response elements" were used to retrieve articles in LILACS, PubMed and Web of Science published until February 2014. From a total of 319 articles surveyed, 32 met the established inclusion and exclusion criteria. It was observed that the most common isolated compound studied was usnic acid, cited in 14 out of the 32 articles. The most often described antioxidant assays for the study of in vitro antioxidant activity were mainly DPPH, LPO and SOD. The most suggested mechanisms of action were scavenging of reactive species, enzymatic activation and inhibition of iNOS. Thus, compounds isolated from lichens are possible candidates for the management of oxidative stress, and may be useful in the treatment of chronic diseases.

Topics: Antioxidant Response Elements; Antioxidants; Benzofurans; Biphenyl Compounds; Free Radical Scavengers; Humans; Lichens; Neoplasms; Oxidation-Reduction; Oxidative Stress; Picrates

Intense current interest in supramolecular chemistry is devoted to the construction of molecular assemblies displaying controlled molecular motion associated to recognition. On this ground, molecular clips and tweezers have focused an increasing attention. This tutorial review points out the recent advances in the construction of always more sophisticated molecular clips and tweezers, illustrating their remarkably broad structural variety and focusing on their binding ability towards neutral guests. A particular attention is brought to recent findings in dynamic molecular tweezers whose recognition ability can be regulated by external stimuli. Porphyrin-based systems will not be covered here as this very active field has been recently reviewed.

Topics: Acridines; Alkynes; Anthracenes; Benzofurans; Fullerenes; Imidazoles; Models, Chemical; Molecular Conformation; Porphyrins; Rotaxanes

Globally, people are struggling with obesity. Many effective, nonconventional methods of weight reduction, such as herbal and natural dietary supplements, are increasingly being sought. Fat burners are believed to raise metabolism, burn more calories and hasten fat loss. Despite patient perceptions that herbal remedies are free of adverse effects, some supplements are associated with severe hepatotoxicity. The present report describes a young healthy woman who presented with fulminant hepatic failure requiring emergent liver transplantation caused by a dietary supplement and fat burner containing usnic acid, green tea and guggul tree extracts. Thorough investigation, including histopathological examination, revealed no other cause of hepatotoxicity. The present case adds to the increasing number of reports of hepatotoxicity associated with dietary supplements containing usnic acid, and highlights that herbal extracts from green tea or guggul tree may not be free of adverse effects. Until these products are more closely regulated and their advertising better scrutinized, physicians and patients should become more familiar with herbal products that are commonly used as weight loss supplements and recognize those that are potentially harmful.

Topics: Adipose Tissue; Adult; Benzofurans; Camellia sinensis; Commiphora; Dietary Supplements; Hepatic Encephalopathy; Humans; Hypolipidemic Agents; Liver Failure, Acute; Liver Transplantation; Monitoring, Physiologic; Obesity; Phytotherapy; Plant Extracts; Plant Gums; Plant Preparations; Tea; Treatment Outcome; Weight Loss

Since its first isolation in 1844, usnic acid [2,6-diacetyl-7,9-dihydroxy-8,9b-dimethyl-1,3(2H,9bH)-dibenzo-furandione] has become the most extensively studied lichen metabolite and one of the few that is commercially available. Usnic acid is uniquely found in lichens, and is especially abundant in genera such as Alectoria, Cladonia, Usnea, Lecanora, Ramalina and Evernia. Many lichens and extracts containing usnic acid have been utilized for medicinal, perfumery, cosmetic as well as ecological applications. Usnic acid as a pure substance has been formulated in creams, toothpaste, mouthwash, deodorants and sunscreen products, in some cases as an active principle, in others as a preservative. In addition to antimicrobial activity against human and plant pathogens, usnic acid has been shown to exhibit antiviral, antiprotozoal, antiproliferative, anti-inflammatory and analgesic activity. Ecological effects, such as antigrowth, antiherbivore and anti-insect properties, have also been demonstrated. A difference in biological activity has in some cases been observed between the two enantiomeric forms of usnic acid. Recently health food supplements containing usnic acid have been promoted for use in weight reduction, with little scientific support. The emphasis of the current review is on the chemistry and biological activity of usnic acid and its derivatives in addition to rational and ecologically acceptable methods for provision of this natural compound on a large scale.

Topics: Analgesics; Animals; Anti-Infective Agents; Antineoplastic Agents; Benzofurans; Humans; Lichens

Lichens are a world-widespread consortium of fungal and photosynthetic partners. Usnic acid is one of the most common and abundant lichen metabolites, well known as an antibiotic, but also endowed with several other interesting properties. This review summarises the most relevant studies on usnic acid, focusing on a number of biological activities in different fields. On the basis of the existing literature, usnic acid seems to be an exclusive lichen product. No synthetic derivatives more effective than the natural form are known. Both the (+) and (-) enantiomers of usnic acid are effective against a large variety of Gram-positive (G+) bacterial strains, including strains from clinical isolates, irrespective of their resistant phenotype. Of particular relevance is the inhibition of growth of multi-resistant strains of Streptococcus aureus, enterococci and mycobacteria. The (+)-usnic acid enantiomer appears to be selective against Streptococcus mutans without inducing perturbing side effects on the oral saprophyte flora. On the other hand, the (-)-usnic acid enantiomer is a selective natural herbicide because of its blocking action against a specific key plant enzyme. Other recognised characteristics of usnic acid are ultraviolet absorption and preserving properties. The toxicology, the in vitro anti-inflammatory effects and the mechanism of action of usnic acid need to be investigated in greater detail in order to reach clinical trials and to allow further applications. Furthermore, more research is needed to make possible intensive lichen culture, in order to produce large quantities of lichen substances for pharmaceutical, cosmetic and agricultural purposes. Some biological aspects, i.e. the possible biological roles of usnic acid, are discussed.

Topics: Anti-Bacterial Agents; Benzofurans; Gram-Negative Bacteria; Herbicides; Humans; Lichens; Streptococcus; Tinea Pedis

To evaluate the efficacy and safety of intravaginal administration of a zinc sulphate and usnic acid compound as adjuvant therapy of Human Papillomavirus (HPV) genital infection, after radiosurgical treatment (RS).. One hundred patients affected by HPV genital infection were enrolled in the study from October 1996 to July 1998. Patients were classified according to colposcopic and cytologic criteria and treated with RS. Patients were randomized into three groups: the first group did not follow any therapy after RS (control group), (n = 50); the second group was pharmacologically treated with intravaginal administration of a usnic acid and zinc sulphate compound (Zeta N, Bergamon Italia) before and after RS (n = 25), the third group was pharmacologically treated only after RS (n = 25). The last two groups were considered together for the statistical analysis. Patients were reevaluated after one, two, three and six months from electrocoagulation. The safety of treatment was also investigated.. One month after RS. HPV lesions disappeared in 93% of the patients in the control group and in 100% of patients treated with usnic acid and zinc sulphate. After one month, reepithelization was complete in 65% of cases treated with usnic acid and zinc sulphate and in only 28% of the control group (p = 0.001). Two months later reepithelization was 94% in the patients pharmacologically treated compared to 76% of the control group (p = 0.06). Treatment prior to RS resulted in a reduction of the overall area of lesions in 88% of cases. Three months after RS, there was a significant reduction of recurrence in the group treated with usnic acid and zinc sulphate (p = 0.01). This reduction was still significant at six months (p = 0.005).. Usnic acid and zinc sulphate adjuvant treatment improved time of reepithelization and reduce the recurrence with few side effects and a good compliance.

Topics: Adult; Anti-Infective Agents; Astringents; Benzofurans; Chemotherapy, Adjuvant; Colposcopy; Female; Genital Diseases, Female; Humans; Papillomaviridae; Papillomavirus Infections; Postoperative Period; Radiosurgery; Zinc Sulfate

Natural products continue to be an inspiration for new drugs to treat debilitating diseases such as cancer. Usnic acid is a secondary metabolite isolated predominately from lichen species and has been shown to exhibit antiproliferative properties, however its application is limited by poor drug-like properties and low specificity. We report our work on investigating the reactivity of usnic acid for incorporating heterocyclic rings and the divergent reactivity that can be obtained by simply altering the reaction solvent and temperature. The synthesised derivatives were then tested against HeLa cancer cells for their antiproliferative properties. A number of promising compounds were obtained including 4, 5 and 9 that showed an IC

Topics: Benzofurans; HeLa Cells; Humans; Lichens; Neoplasms

Topics: Benzofurans; Biological Products; Crystallization; Glycoside Hydrolase Inhibitors; Hypoglycemic Agents; Magnetic Resonance Spectroscopy; Spectroscopy, Fourier Transform Infrared; Usnea

Disorganization and breakdown of extracellular matrix proteins like fibronectin, collagen, and elastin are key characteristics of skin aging due to the increased activation of important proteolytic enzymes like elastases and collagenase enzymes. Also, inhibition of their enzymatic activities by natural molecules might be a promising factor to prevent extrinsic skin aging. All chemicals were obtained from Sigma-Aldrich unless otherwise stated. The assay employed was based on spectrophotometric methods reported in the literature. The collagenase and elastase inhibition assays of some phenolic compounds were performed according to the previous studies. These compounds showed excellent to good inhibitory activities of vulpinic acid against studied these enzymes with IC50 values of 195.36 µM for collagenase and 25.24 µM for elastase. The molecular docking calculations were conducted to investigate the chemical and biological activity of vulpinic acid and usnic acid against collagenase and elastase. The results indicated that these two compounds can interact with the essential residues of the enzymes and affect their activities. The calculations of binding free energies were also performed to obtain more details about the characteristics and free energies of the ligand-enzyme complexes. Additionally, both compounds exhibited the most potent inhibition in the three lung cancer cells, with an IC50 value of 21-68 µM, indicating that vulpinic acid is more potent than Doxorubicin, which exhibited an IC50 value of 21-29 µM.

Topics: Antineoplastic Agents; Benzofurans; Cell Line, Tumor; Collagenases; Dose-Response Relationship, Drug; Extracellular Matrix Proteins; Furans; Geroscience; Humans; Lung Neoplasms; Models, Molecular; Pancreatic Elastase; Phenylacetates; Skin Aging

Derivatives of usnic acid (UA), a secondary metabolite from lichens, were synthesized to improve its anticancer activity and selectivity. Recently we reported the synthesis and activity of an UA isoxazole derivative, named

Topics: Animals; Apoptosis; Benzofurans; Breast Neoplasms; Cell Death; Cell Line, Tumor; Endoplasmic Reticulum Stress; Female; Humans; Isoxazoles; Mice; Mice, Nude

Topics: Amides; Apoptosis; Benzofurans; Carcinoma, Squamous Cell; Cell Line, Tumor; DNA; Flow Cytometry; Humans; Spectroscopy, Fourier Transform Infrared

Usnic acid is an antibiotic metabolite produced by a wide variety of lichenized fungal lineages. The enantiomers of usnic acid have been shown to display contrasting bioactivities, and hence it is important to determine their spatial distribution, amounts and enantiomeric ratios in lichens to understand their roles in nature and grasp their pharmaceutical potential. The overall aim of the study was to characterise the spatial distribution of the predominant usnic acid enantiomer in lichens by combining spatial imaging and chiral chromatography. Specifically, separation and quantification of usnic acid enantiomers in four common lichens in Iceland was performed using a validated chiral chromatographic method. Molecular dynamics simulation was carried out to rationalize the chiral separation mechanism. Spatial distribution of usnic acid in the lichen thallus cross-sections were analysed using Desorption Electrospray Ionization-Imaging Mass Spectrometry (DESI-IMS) and fluorescence microscopy. DESI-IMS confirmed usnic acid as a cortical compound, and revealed that usnic acid can be more concentrated around the algal vicinity. Fluorescence microscopy complemented DESI-IMS by providing more detailed distribution information. By combining results from spatial imaging and chiral separation, we were able to visualize the distribution of the predominant usnic acid enantiomer in lichen cross-sections: (+)-usnic acid in Cladonia arbuscula and Ramalina siliquosa, and (-)-usnic acid in Alectoria ochroleuca and Flavocetraria nivalis. This study provides an analytical foundation for future environmental and functional studies of usnic acid enantiomers in lichens.

Topics: Anti-Bacterial Agents; Benzofurans; Iceland; Lichens

In this study, the cytotoxic activity of acetone extracts of Cladonia mitis was assessed with respect to the content of usnic acid, a secondary metabolite commonly present in this species. Following quantitative HPLC analysis of the extracts, usnic acid was isolated by preparative chromatography. The study of cytotoxic activity was performed using the MTT test on three melanoma cell lines - HTB140, A375 and WM793. The selectivity of action was also assessed by comparing the effect towards normal human keratinocytes HaCaT. The results showed a dose-dependent cytotoxic activity of the extracts tested and usnic acid itself, but no relationship was found between the content of usnic acid and the activity of the extracts. Furthermore, the extracts showed varied, but rather low anti-tyrosinase activity. Other in vitro and in vivo studies are necessary to demonstrate that C. mitis extracts may be useful in the adjuvant external treatment of skin melanoma.

Topics: Acetone; Antineoplastic Agents; Ascomycota; Benzofurans; Humans; Lichens; Melanoma

An extracellular matrix-mimicking, biodegradable tissue-engineered skin substitute with improved antibacterial, antibiofilm, and wound healing capabilities is essential in skin tissue regeneration applications. The purpose of this study was to develop a novel biodegradable composite nanofibrous poly(ε-caprolactone) (PCL)/decellularized extracellular matrix (dECM) scaffolds loaded with usnic acid (UA); (PEU), where UA is employed as an antibacterial agent as well as a wound-healing accelerator. The architecture and fiber structure of the scaffolds were examined using scanning electron microscopy, and the results revealed that the average diameters decreased as the dECM content increased. The chemical composition, changes in the crystalline structure, homogeneity, and thermal stability of the nanofiber scaffolds with different material compositions were determined using Fourier-transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis, respectively. The composite nanofibrous scaffolds exhibited strong antibacterial activity against various bacterial species, such as Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans, and Cutibactrium acnes, and fungal pathogens (such as Candida albicans). Additionally, the composite nanofibrous scaffolds exhibited biofilm inhibition properties against Klebsiella pneumoniae and Pseudomonas aeruginosa. An evaluation of the appearance of in vivo full-thickness excisional wounds treated with the composite nanofiber scaffolds, as well as a histological analysis of the wounds 21 days after surgery, revealed that treatment with nanofibrous PEU scaffolds enhanced wound healing. This study reveals that the proposed composite nanofibrous PEU scaffold has substantial potential for treating infectious full-thickness wounds.

Topics: Anti-Bacterial Agents; Benzofurans; Decellularized Extracellular Matrix; Humans; Nanofibers; Polyesters; Tissue Scaffolds; Wound Healing; Wound Infection

(+)-Usnic acid is a secondary metabolite of lichens belonging to the Usnea genus. Usnea lichens and purified usnic acids have been used historically in traditional herbal medicine as bactericidal and antimicrobial agents. (+)-Usnic acid exhibits membrane proton uncoupling activity, which not only forms the mechanistic basis of its bactericidal action, but also has provided a rationale for its use as a fat-burning, weight-loss agent. Purified (+)-usnic acid has been marketed in the United States for this purpose either alone or in combination with other chemical agents. Use of some of these fat-burning products that contain (+)-usnic acid has resulted in serious liver damage. This study investigated the potential toxicity of (+)-usnic acid in male and female F344/N Nctr rats and B6C3F1/Nctr mice that were exposed via feed for 3 months. F344/N Nctr rats were administered 0, 30, 60, 120, 360, or 720 ppm in feed, while B6C3F1/Nctr mice were administered 0, 15, 30, 60, 180, or 360 ppm in feed. (Abstract Abridged).

Topics: Animals; Anti-Obesity Agents; Benzofurans; Female; Male; Mice; Mice, Inbred Strains; Protons; Rats; Rats, Inbred F344; Usnea

Usnea lichens and purified usnic acids have been used historically in traditional herbal medicine as bactericidal and antimicrobial agents. Usnea lichens contain 1%-3% (+/-)-usnic acid and extracts of these lichens are currently marketed in the United States as herbal antimicrobial agents. (+/-)-Usnic acid exhibits membrane proton uncoupling activity, which not only forms the mechanistic basis of its bactericidal action, but also has provided a rationale for its use as a fat burning, weight-loss agent. Purified (+)-usnic acid has been marketed in the United States for this purpose either alone or in combination with other chemical agents. Use of some of these fat burning products that contain (+)-usnic acid has resulted in serious liver damage. This study investigated the potential toxicity of ground Usnea lichens containing (+/-)-usnic acid in male and female Fischer 344/N Nctr rats and B6C3F1/Nctr mice that were exposed via feed for 3 months. F344/N Nctr rats were administered 0, 30, 60, 120, 360, or 720 ppm in feed, while B6C3F1/Nctr mice were administered 0, 15, 30, 60, 180, or 360 ppm in feed. (Abstract Abridged).

Topics: Animals; Anti-Obesity Agents; Benzofurans; Female; Lichens; Male; Mice; Mice, Inbred Strains; Protons; Rats; Rats, Inbred F344; Usnea

Aldose reductase (AR) and sorbitol dehydrogenase (SDH) are important enzymes of the polyol pathway. In the current study, inhibitory effects of vulpinic acid (VA) carnosic acid (CA) and usnic acid (UA) on purified AR and SDH enzymes were determined. These enzymes inhibition could be essential to prevent diabetic complications. AR and SDH enzymes were purified from sheep kidney. Then, VA, CA and UA were tested in various concentrations against these enzymes activity

Topics: Animals; Benzofurans; L-Iditol 2-Dehydrogenase; Molecular Docking Simulation; Polymers; Sheep

Topics: Acrylates; Benzofurans; Fibroblasts; Humans; Keratinocytes; Melanocytes; Radiation-Protective Agents; Skin; Ultraviolet Rays

In the present study, quantitative analysis of usnic acid and the selected elements (Ag, Ca, Cd, Cr, Cu, Mg, Mn, Ni, Pb, Zn) in samples of Cladonia mitis thalli collected along a North-Central Europe transect, was performed. Additionally, we analysed geographical and environmental factors that could potentially influence the levels of the analytes. With the constructed partial least square (PLS) chemometric model we aimed to establish the relationships between the analysed factors. Our study is the first to provide comparative quantitative data on usnic acid in C. mitis. We proved this lichen species is a rich source of usnic acid (4.52 ± 0.54-21.58 ± 2.23 mg/g dry wt). Significant differences in usnic acid content between samples collected in the open and forest areas were noted, with the predominance of the former (mean 17.4 ± 2.8 and 8.8 ± 2.3 mg/g dry wt, respectively). Our results supported the hypothesis on the relationship between usnic acid and selected heavy metals content in lichens, as the positive correlation of the compound was noted with Pb. Our PLS model indicated also a positive correlation between usnic acid and Cr content, which was reported for the first time.

Topics: Ascomycota; Benzofurans; Lichens; Metals, Heavy

The present study describes the use of fucoidan, a negative sulfated polysaccharide, as a coating material for the development of liposomes targeted to macrophages infected with

Topics: Anti-Infective Agents; Benzofurans; Liposomes; Macrophages; Mycobacterium tuberculosis; Polysaccharides

Topics: 3,4-Dihydroxyphenylacetic Acid; Benzofurans; Biomass; Caffeic Acids; Chromatography, High Pressure Liquid; Cinnamates; Depsides; Eryngium; Flavonoids; Hydroxybenzoates; Plant Growth Regulators; Plant Shoots; Quercetin; Rosmarinic Acid

In the food industry, the increasing antimicrobial resistance of food-borne pathogens to conventional sanitizers poses the risk of food contamination and a decrease in product quality and safety. Therefore, we explored alternative antimicrobials

Topics: Acetylcysteine; Anti-Bacterial Agents; Anti-Infective Agents; Benzofurans; Biofilms; Cell Line; Escherichia coli; Food Contamination; Food Microbiology; Foodborne Diseases; Glycolipids; Humans; Listeria monocytogenes; Microbial Sensitivity Tests; Salmonella enterica; Staphylococcus aureus

Topics: Benzofurans; Caco-2 Cells; Cell Cycle; Cytostatic Agents; Humans

Usnic Acid (UA), also known as lichenol, has been reported to have inhibitory effects on a variety of cancer cells, but its specific mechanism remained to be elucidated. Tumor chemotherapy drugs, especially DNA damage chemotherapeutic drugs, target Chromosomal DNA, but their spontaneous and acquired drug resistance are also an urgent problem to be solved. Therefore, drug combination research has become the focus of researchers.. Here, we evaluated the tumor-suppressing molecular mechanism of UA in colorectal cancer cells RKO from the perspective of the ATM-mediated DNA damage signaling pathway through H2O2 simulating DNA damage chemotherapeutic drugs. CCK8 cell proliferation assay was used to determine the inhibition of RKO cells by hydrogen peroxide and UA alone or in combination, and wound healing assay was applied to determine the effect of the drug on cell migration.. Transfected cells with miRNA18a-5p mimics and inhibitors, MDC and DCFH-DA staining for the measurement of autophagy and ROS, cell cycle and apoptosis were detected by flow cytometry, expressions of microRNA and mRNA were determined by fluorescence quantitative PCR, and protein by Western blot.. We found that UA can upregulate ATM via miR-18a to activate the DNA damage signaling pathway and inhibit the proliferation and migration of RKO cells in a concentration-dependent manner.. At the same time, DNA damage responses, including cell cycle, autophagy, apoptosis and ROS levels, are also regulated by UA. Therefore, UA combined with DNA damage chemotherapeutic drugs may be an effective treatment for cancer.

Topics: Apoptosis; Ataxia Telangiectasia Mutated Proteins; Autophagy; Benzofurans; Cell Cycle; Cell Line, Tumor; Cell Movement; Cell Proliferation; Colorectal Neoplasms; DNA Damage; Drug Therapy, Combination; Humans; Hydrogen Peroxide; MicroRNAs; Signal Transduction; Up-Regulation; Wound Healing

Topics: Acetylcholinesterase; Alzheimer Disease; Amyloid beta-Peptides; Animals; Anti-Inflammatory Agents; Antioxidants; Behavior, Animal; Benzofurans; Cerebral Cortex; Cognitive Dysfunction; Disease Models, Animal; Female; Hippocampus; Inflammation; Injections, Intraventricular; Interleukin-1beta; Mice; Molecular Docking Simulation; Nootropic Agents; Peptide Fragments

Lichens are specific symbiotic organisms harboring various microorganisms in addition to the two classic partners (algae or cyanobacterium and fungus). Although lichens produce many antibiotic compounds such as (+)-usnic acid, their associated microorganisms possess the ability to colonize an environment where antibiosis exists. Here, we have studied the behavior of several lichen-associated bacterial strains in the presence of (+)-usnic acid, a known antibiotic lichen compound. The effect of this compound was firstly evaluated on the growth and metabolism of three bacteria, thus showing its ability to inhibit Gram-positive bacteria. This inhibition was not thwarted with the usnic acid producer strain Streptomyces cyaneofuscatus. The biotransformation of this lichen metabolite was also studied. An ethanolamine derivative of (+)-usnic acid with low antibiotic activity was highlighted with chemical profiling, using HPLC-UV combined with low resolution mass spectrometry. These findings highlight the way in which some strains develop resistance mechanisms. A methylated derivative of (+)-usnic acid was annotated using the molecular networking method, thus showing the interest of this computer-based approach in biotransformation studies.

Topics: Anti-Bacterial Agents; Benzofurans; Lichens; Streptomyces

Oakmoss and treemoss absolutes are the major natural extracts of concern as potential sources of skin sensitizers in cosmetics and personal care products (PCP). Two single constituents, atranol and chloroatranol, have been identified as primary culprits in both lichens, and industrial self-regulation has been proposed to limit their contents to less than 100 ppm. Nonetheless, evidence points to the presence of additional candidate skin sensitizers in these multicomponent extracts. These observations, along with a lack of data from non-animal alternative methods and the chemical variability of commercial absolutes, prompted further investigation of oakmoss absolute along with altranol-like compounds in these extracts. The major chemical constituents of a commercial sample were identified by two independent analytical techniques, GC-MS and HPLC-DAD-MS. The crude oakmoss extract and pure compounds were assayed with two in chemico methods (HTS-DCYA and DPRA) to gauge their chemical reactivity. Activation of inflammatory responses in vitro was also investigated by KeratinoSens™ and human cell line activation tests (h-CLAT). Based on weight of evidence, orcinol, ethyl orsellinate, and usnic acid were classified as candidate sensitizers, along with both atranols and oakmoss extract.

Topics: Animal Testing Alternatives; Benzaldehydes; Benzofurans; Cell Line; Haptens; Humans; Resins, Plant; Resorcinols; Terpenes

Despite the progress in chronic wound treatment, antibacterial cutaneous scaffold with high efficiency in wound healing is still the hot spot in the field. In present study, a functionalized silk fibroin (SF) cutaneous scaffold incorporated with natural medicine usnic acid (UA) is investigated, in which UA is used as an antibacterial and wound-healing reagent. Via electrospinning, UA-SF mixture is fabricated into UA-SF composite scaffold (USCS), which is composed of uniform nanofibers with average diameters of around 360 ± 10 nm. The interwoven nanofibers form mesh structure providing sufficient moisture permeability for scaffold. With methanol treatment, USCS presents improved mechanical properties and stability to protease XIV. In the presence of USCS, the growth rate of both Gram-positive and Gram-negative bacteria, including Staphylococcus aureus, Streptococci pyogenes, Escherichia coli, and Pseudomonas aeruginosa, is significantly inhibited in plate culture and suspension assays. In a cutaneous excisional mouse wound model, USCS presents a significant increase of wound closure rate, compared with pure SF scaffold and commercial dressing, Tegaderm Hydrocolloid

Topics: Animals; Anti-Bacterial Agents; Bacteria; Benzofurans; Biocompatible Materials; Fibroins; Keratin-10; Male; Mice; Microbial Sensitivity Tests; NIH 3T3 Cells; Skin; Spectroscopy, Fourier Transform Infrared; Stress, Mechanical; Tensile Strength; Tissue Scaffolds; Vascular Endothelial Growth Factor A; Wound Healing

The principal etiological agent of human dental caries, Streptococcus mutans is a multi-virulent pathogen that can transform commensal oral microbial community to plaque biofilms. Major virulence factors that are associated with the cariogenicity of S. mutans include adhesion, acidogenicity and acidurity. All these pathogenic traits coordinate and alter the dental plaque ecology which provide room for interaction with other similar acidogenic and aciduric bacteria. This cariogenic flora increases the possibility of enamel demineralization which headway to caries development. The present study was aimed at evaluating the antimicrobial and antiinfective potential of a lichen secondary metabolite usnic acid (UA) against S. mutans. Minimum inhibitory concentration (MIC), Minimum bactericidal concentration (MBC) and growth kinetics were evaluated to determine the antimicrobial potential of UA against S. mutans. UA at 5 µg mL

Topics: Bacterial Proteins; Benzofurans; Dental Caries; Down-Regulation; Gene Expression Regulation, Bacterial; Glucose; Humans; Oxidative Stress; Signal Transduction; Streptococcus mutans

Usnic acid (UA) is one of the well-known lichen metabolites that induces liver injury. It is mainly extracted from Usnea longissima and U. diffracta in China or from other lichens in other countries. U. longissima has been used as traditional Chinese medicine for treatment of cough, pain, indigestion, wound healing and infection. More than 20 incidences with hepatitis and liver failure have been reported by the US Food and Drug Administration since 2000. UA is an uncoupler of oxidative phosphorylation causing glutathione and ATP depletion. Previous histological studies observed extensive cell and organelle swellings accompanied with hydrotropic vacuolization of hepatocytes.. This study was to investigate the mechanism of UA-induced liver toxicity in normal human L02 liver cells and ICR mice using various techniques, such as immunoblotting and siRNA transfection.. Assays were performed to evaluate the oxidative stress and levels of GSH, MDA and SOD. Double flouresencence staining was used for the detection of apoptotic cell death. The protein expressions, such as glutathione S transferase, glutathione reductase, glutathione peroxidase 4, catalase, c-Jun N-terminal protein kinase, caspases, gastamin-D and porimin were detected by Western blotting. Comparisons between transfected and non-transfected cells were applied for the elucidation of the role of porimin in UA-induced hepatotoxicity. Histopathological examination of mice liver tissue, serum total bilirubin and hepatic enzymes of alanine aminotransferase and aspatate aminotransferase were also studied.. The protein expressions of glutathione reductase, glutathione S transferase and glutathione peroxidase-4 were increased significantly in normal human L02 liver cells. Catalase expression was diminished in dose-dependent manner. Moreover, (+)-UA did not induce the activation of caspase-3, caspase-1 or gasdermin-D. No evidence showed the occurrence of pyroptosis. However, the porimin expressions were increased significantly. In addition, (+)-UA caused no cytotoxicity in the porimin silencing L02 cells.. In conclusion, (+)-UA induces oncotic L02 cell death via increasing protein porimin and the formation of irreversible membrane pores. This may be the potential research area for future investigation in different aspects especially bioactivity and toxicology.

Topics: Animals; Anti-Infective Agents; Benzofurans; Caspase Inhibitors; Caspases; Cell Death; Cell Line; Cell Survival; Chemical and Drug Induced Liver Injury; Gene Knockdown Techniques; Glutathione; Hepatocytes; Humans; Intracellular Signaling Peptides and Proteins; Ischemia; JNK Mitogen-Activated Protein Kinases; Liver; Mice, Inbred ICR; Necrosis; Oxidative Stress; Phosphate-Binding Proteins; Receptors, Cell Surface

This study investigated a set of new potential antidiabetes agents. Derivatives of usnic acid were designed and synthesized. These analogs and nineteen benzylidene analogs from a previous study were evaluated for enzyme inhibition of α-glucosidase. Analogs synthesized using the Dakin oxidative method displayed stronger activity than the pristine usnic acid (IC

Topics: alpha-Glucosidases; Benzofurans; Glycoside Hydrolase Inhibitors; Humans; Molecular Docking Simulation; Molecular Structure

Naturally occurring phytochemicals of different origin and structure, arctigenin, bergenin, usnic acid and xanthohumol, were shown to affect Nrf2 pathway in the context of various diseases, but their effect on this pathway in cancer cells was not extensively investigated. This study aimed to evaluate the effect of these compounds on Nrf2 expression and activation in hypopharyngeal FaDu squamous cell carcinoma cells. FaDu cells were treated with 2 or 10 μM arctigenin, bergenin, (+)-usnic acid or xanthohumol for 24 h. While arctigenin, bergenin, and xanthohumol did not affect either Nrf2 expression or activation, (+)-usnic acid treatment increased its transcript level and increased the nuclear/cytosol Nrf2 protein ratio-the measure of Nrf2 pathway activation. Consequently, (+)-usnic acid enhanced the transcription and translation of Nrf2 target genes: NQO1, SOD, and to a lesser extent, GSTP. The treatment of FaDu cells with (+)-usnic acid decreased both GSK-3β transcript and protein level, indicating its possible involvement in Nrf2 activation. All the tested compounds decreased Bax mRNA but did not change the level of Bax protein. (+)-Usnic acid tended to increase the percentage of early apoptotic cells and LC3 protein, autophagy marker. Significant induction of p53 also was observed after treatment with (+)-usnic acid. In summary, the results of this study indicate that low concentrations of (+)-usnic acid activate Nrf2 transcription factor, most probably as a result of ROS accumulation, but do not lead to FaDu hypopharyngeal carcinoma cells death.

Topics: Antioxidant Response Elements; Benzofurans; Cell Line, Tumor; Humans; Hypopharyngeal Neoplasms; Neoplasm Proteins; NF-E2-Related Factor 2; Signal Transduction

The programmed cell death 1 (PD-1)/programmed death ligand 1 (PD-L1) pathway is abnormally expressed in cervical cancer cells. Moreover, PD-1/PD-L1 blockade reduces the apoptosis and exhaustion of T cells and inhibits the development of malignant tumors. Usnic acid is a dibenzofuran compound originating from Usnea diffracta Vain and has anti-inflammatory, antifungal, and anticancer activities. However, the molecular mechanism of its antitumor effects has not been fully elucidated. In this work, we first observed that usnic acid decreased the expression of PD-L1 in HeLa cells and enhanced the cytotoxicity of co-cultured T cells toward tumor cells. Usnic acid inhibited PD-L1 protein synthesis by reducing STAT3 and RAS pathways cooperatively. It was subsequently shown that usnic acid induced MiT/TFE nuclear translocation through the suppression of mTOR signaling pathways, and promoted the biogenesis of lysosomes and the translocation of PD-L1 to the lysosomes for proteolysis. Furthermore, usnic acid inhibited cell proliferation, angiogenesis, migration, and invasion, respectively, by downregulating PD-L1, thereby inhibiting tumor growth. Taken together, our results show that usnic acid is an effective inhibitor of PD-L1 and our study provide novel insights into the mechanism of its anticancer targeted therapy.

Topics: B7-H1 Antigen; Benzofurans; Cell Line, Tumor; Cell Proliferation; HeLa Cells; Humans; Parmeliaceae; T-Lymphocytes

Alzheimer's disease perpetually demands enormous research on the development of effective treatment strategies. The present study aims to define the role of Oxyresveratrol (OXY) alone and in combination with Alkoxy glycerols (AKG) to reduce Tau protein level and improve the climbing behaviour of Drosophila fly models expressed with human-Tau protein. Oxyresveratrol, a polyphenolic stilbene, possesses a wide range of biological activities like antioxidant, anti-inflammatory, and neuroprotective effects. Nevertheless, chemical instability and low solubility of OXY in aqueous solutions reduce its bioavailability and hinder it from exerting neuroprotective activities. An inclusion complex of OXY with β- cyclodextrin (CD) (OXY-CD complex) was employed in the study for increased dissolution rate and oral availability of OXY. Fish oils and their derivatives have a plethora of applications in in vivo biological activities. Herein, we also remark on the role of AKG in reducing Tau protein level in flies by enhancing OXY-CD activity. Dietary supplementation of OXY-CD together with AKG improved the learning and memory abilities during the climbing assay in Tau flies. The study highlights OXY-CD and AKG as neuroprotective agents and put forward a plausible approach towards the increased permeability of pharmacological agents across the blood-brain barrier (BBB) for the central nervous system elicited by AKG.

Topics: Alzheimer Disease; Animals; Animals, Genetically Modified; Behavior, Animal; Benzofurans; Drosophila melanogaster; Glycerol; Humans; Learning; Memory; Neuroprotective Agents; Plant Extracts; Stilbenes; tau Proteins

To gain insight into the mechanisms of ionophoric activity of usnic acid (UA), we examined the UA-induced generation of potentials on a planar bilayer lipid membrane (BLM) in the presence of concentration gradients of hydrogen and magnesium or calcium ions under open-circuit conditions. Remarkably, the BLM potential generated by UA at the proton concentration gradient of 1 pH unit was approximately twice the Nernst equilibrium level. With a concentration gradient of magnesium or calcium ions, the BLM potential generated by UA had the opposite sign. The observed anomalies in the membrane potentials were consistent with a theory developed by Markin and Sokolov (Bioelectrochem. Bioenerg. 1990) for the case of ionophore-mediated coupled fluxes of several ions across a membrane.

Topics: Benzofurans; Calcium; Cations, Divalent; Ionophores; Lipid Bilayers; Magnesium; Membrane Potentials

Usnic acid (UA) is a secondary metabolite of lichens that exhibits a wide range of biological activities. Previously, we found that UA derivatives are effective inhibitors of tyrosyl-DNA phosphodiesterase 1 (TDP1). It can remove covalent complex DNA-topoisomerase 1 (TOP1) stabilized by the TOP1 inhibitor topotecan, neutralizing the effect of the drugs. TDP1 removes damage at the 3' end of DNA caused by other anticancer agents. Thus, TDP1 is a promising therapeutic target for the development of drug combinations with topotecan, as well as other drugs for cancer treatment. Ten new UA enamino derivatives with variation in the terpene fragment and substituent of the UA backbone were synthesized and tested as TDP1 inhibitors. Four compounds,

Topics: Benzofurans; HEK293 Cells; Humans; Monoterpenes; Phosphodiesterase Inhibitors; Phosphoric Diester Hydrolases

Tyrosyl-DNA phosphodiesterase 1 (Tdp1) is a repair enzyme for 3'-end DNA lesions, predominantly stalled DNA-topoisomerase 1 (Top1) cleavage complexes. Tdp1 is a promising target for anticancer therapy based on DNA damage caused by Top1 poisoning. Earlier, we have reported about usnic acid enamine derivatives that are Tdp1 inhibitors sensitizing tumor cells to the action of Top1 poison (Zakharenko in J Nat Prod 79:2961-2967, 2016). In the present work, we showed a sensitizing effect of an enamine derivative of usnic acid (when administered intragastrically) on Lewis lung carcinoma in mice in combination with topotecan (TPT, Top1 poison used in the clinic). In the presence of the usnic acid derivative, both the volume of the primary tumor and the number of metastases significantly diminished. The absence of acute toxicity of this compound was demonstrated, as was the importance of the method of its administration for the manifestation of the sensitizing properties.

Topics: Animals; Benzofurans; Carcinoma, Lewis Lung; Female; Male; Mice; Mice, Inbred Strains; Neoplasm Metastasis; Neoplasm Transplantation; Phosphodiesterase Inhibitors; Phosphoric Diester Hydrolases; Topotecan

Potassium usnate (KU), a water-soluble form of usnic acid, shows anticancer activity. However, the underlying mechanisms have not been fully elucidated.. We aimed to identify the pathways involved in anticancer effects of KU in human gastric cancer (GC) and colorectal cancer (CRC) cells using RNA-sequencing (RNA-seq) based transcriptome analysis.. We analyzed the cytotoxic effects of KU to identify the common molecular events in GC and CRC cells upon KU exposure using unbiased approaches.. Cell viability assays and western blot experiments were used to examine apoptotic changes, cell cycle arrest, and endoplasmic reticulum (ER) stress-induced cellular responses in KU-treated cells. Total RNA from KU-treated human GC and CRC cells was prepared for RNA-seq analysis. Gene ontology term and gene set enrichment analyses were used to identify the key mediators of the cytotoxic effects of KU. The expression of ER stress-induced apoptotic markers was evaluated using quantitative reverse-transcription PCR and western blot analysis. Chromatin immunoprecipitation assays for ATF3 and H3K27ac, and ATF3 knockdown were employed to verify the underlying molecular mechanisms. The inhibitory effect of KU on tumor growth in vivo was validated with metastatic tumor nodule formations in a mouse liver model.. KU exerted cytotoxicity in human GC and CRC cells through the activation of the ER stress-induced apoptotic pathway. KU stimulated ATF3 expression, an important mediator of molecular events of apoptosis. ATF3 binds to the promoter region of ATF3, CHOP, GADD34, GADD45A, DR5, and PUMA genes and subsequently promoted apoptotic events. Knockdown of ATF3 significantly reduced the expression of ATF3 target genes and the cytotoxic effects of KU. The intraperitoneal injection of KU induced ATF3 and the apoptosis of implanted colon cancer cells, resulting in reduced metastatic tumor growth in the mouse livers.. KU exerts cytotoxic effects in human GC and CRC cells by triggering ER stress-induced apoptosis via an ATF3 dependent pathway.

Topics: Activating Transcription Factor 3; Animals; Apoptosis; Benzofurans; Cell Line, Tumor; Colonic Neoplasms; Endoplasmic Reticulum Stress; Gene Expression Profiling; Humans; Mice; Potassium; Stomach Neoplasms

A series of usnic acid benzylidene derivatives (groups

Topics: Antineoplastic Agents; Benzofurans; Benzylidene Compounds; Carbon-13 Magnetic Resonance Spectroscopy; Cell Death; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; HEK293 Cells; Humans; K562 Cells; Proton Magnetic Resonance Spectroscopy; Structure-Activity Relationship

Currently, the control of schistosomiasis is based on a single drug, praziquantel, which is effective against all species of Schistosoma but only in the adult stage, presenting a schistosomicidal deficit at the other developmental stages of the parasites. Recently our research group has demonstrated that the potassium salt of usnic acid (PS-UA) presented schistosomicidal property against couples of adult worms of S. mansoni. Thus, the present study seeks to report for the first time the in vitro activity of PS-UA against different developmental stages of S. mansoni (schistosomules and young worms). As schistosomicide parameters, we evaluated motility, mortality, cell viability of the worms and tegument changes by scanning electron microscopy (SEM). After 3 h exposure, PS-UA was lethal to schistosomules at concentrations of 100 and 50 μM, whereas for concentrations 25 and 12.5 μM, 38 and 18% of mortality and 62 and 24% changes in motility, respectively, were reached. Yet for schistosomules, concentration of 25 μM caused 90 and 100% of death after 6 and 12 h, respectively. In the concentration of 12.5 μM at intervals of 12 and 24 h mortality was 68 and 100%, respectively. For young worms, after 3 h of exposure at concentrations of 200 and 100 μM caused 57 and 27% mortality, respectively. After 12 and 24 h, these concentrations caused mortality of 90 and 100% and 47 and 60% respectively. After 24 h, concentrations of 50 and 25 μM caused 80 and 30% change in motility, respectively. However, at the 12.5 μM concentration no change was observed. In addition, PS-UA reduced the cellular viability of young worms by 50.98% and 85.87% at concentrations of 100 and 200 μM, respectively. In both stages of worms and at different exposure intervals, PS-UA caused alterations such as: dorsoventral contraction, peeling, swelling, blisters, erosion, exposure of subtegumental tissue and disintegration of tegument. According to the results, changes in motility and mortality caused by PS-UA against schistosomules and young worms were concentration and time-dependents, also PS-UA even at low concentration, was able to cause profound ultrastructural changes in the integument of the worms. PS-UA is a promising candidate as prophylactic agent in the control of schistosomiasis mansoni.

Topics: Animals; Benzofurans; Cell Survival; Microscopy, Electron, Scanning; Schistosoma mansoni

Breast cancer still remains to be one of the most threatening cancer types in women. Recent studies have allowed scientists to better investigate the potential use of natural compounds in the treatment of breast cancers. Usnic acid is a secondary metabolite extracted from lichen species and has many biological activities. The response of microRNAs regulated by drug molecules may provide useful diagnostic and prognostic biomarkers, as well as potential therapeutics for breast cancers. Although the aberrant expression of microRNAs was observed after drug treatment, the regulatory mechanisms remain partially known. Micro RNAs (miRNAs) play an important role in gene regulation at the post-transcriptional level.. In this study, we used quantitative Real-Time PCR (qRT-PCR) technology to demonstrate that usnic acid significantly changes the expression profile of miRNAs.. Eleven miRNAs were significantly and differentially expressed in breast cancer cells after treatment with usnic acid. Three miRNAs were up-regulated, while eight were down-regulated in usnic acid treated cells. Target prediction and GO analysis revealed many target genes and their related pathways that are potentially regulated by usnic acid regulated differentially expressed miRNAs. We found that usnic acid treatment caused significant changes in the expression of hsa-miR-5006-5p, hsa-miR-892c-3p, hsa-miR-4430, hsa-miR-5194, hsa-miR-3198, hsa-miR-3171, hsa-miR-933 and hsa-miR-185-3p in breast cancer cells.. Usnic acid response miRNAs might play important regulatory roles in the tumorigenesis and development of breast cancer, and they could serve as prognostic predictors for breast cancer patients.

Topics: Antineoplastic Agents; Benzofurans; Breast Neoplasms; Cell Proliferation; Computational Biology; Dose-Response Relationship, Drug; Down-Regulation; Drug Screening Assays, Antitumor; Humans; MCF-7 Cells; MicroRNAs; Molecular Structure; Real-Time Polymerase Chain Reaction; Structure-Activity Relationship; Tumor Cells, Cultured

Here, we report enhanced the in vitro effect of potassium usnate on coupled adult Schistosoma mansoni worms at different time intervals and concentrations. The evaluated schistosomicidal parameters were the following: motility, mortality, fecundity and integumentary changes, as viewed in photomicrographs. Potassium usnate was able to cause 100 and 50% mortality at 100 and 50 μM concentrations, respectively, after 24 h of exposure, while 25 and 12.5 μM concentrations caused changes in motility at 48 and 72 h, and lethality at 96 and 120 h respectively. Eggs were not detected at any of the concentrations analyzed. Photomicrographs revealed morphological tegument alterations within all periods of observation, such as swelling, blisters, dorsoventral contraction, short and curved worms. In conclusion, our results indicate that potassium usnate represents a possible candidate for a new drug in the control of schistosomiasis.

Topics: Analysis of Variance; Animals; Anthelmintics; Benzofurans; Dose-Response Relationship, Drug; Female; Fertility; Male; Mice; Movement; Photomicrography; Schistosoma mansoni; Schistosomiasis mansoni; Time Factors

We performed comparative profiling of four specialized metabolites in the lichen Evernia prunastri, collected at three different geographic locations, California and Maine, USA, and Yoshkar Ola, Mari El, Russia. Among the compounds produced at high concentrations that were identified in all three specimens, evernic acid, usnic acid, lecanoric acid and chloroatranorin, evernic acid was the most abundant. Two depsidones, salazinic acid and physodic acid, were detected in the Yoshkar-Ola collection only. The crystalline structure of evernic acid (2-hydroxy-4-[(2-hydroxy-4-methoxy-6-methylbenzoyl)oxy]-6-methylbenzoate) (hmb) revealed two crystallographically and conformationally distinct hmb anions, along with two monovalent sodium atoms. One hmb moiety contained an exotetradentate binding mode to sodium, whereas the other exhibited an exohexadentate binding mode to sodium. Embedded edge-sharing {Na

Topics: Benzofurans; Hydroxybenzoates; Lichens; Models, Molecular; Salicylates

Usnic acid, a dibenzofuran derivative found in many lichen species, is reported to have anticancer activity against human gastric cancer. We investigated the molecular alterations associated with anticancer effects of usnic acid against human gastric adenocarcinoma AGS and gastric carcinoma SNU-1 cells. Usnic acid (10-25 μM) treatment to these cells caused a significant increase in mitochondrial membrane depolarization and apoptotic cells. Apoptosis induction was accompanied by an increase in the ratio of Bax:Bcl-2 expression and cleaved-PARP. Usnic acid increased the comet tail length and tail DNA in alkaline comet assay indicating DNA double-strand breaks which was also evidenced by an increase in γH2A.X (Ser139) phosphorylation. The expression of DNA damage response proteins including DNA-PKcs, pATM (Ser1981), Chk-2 and p53 were increased. Further, N-acetyl cysteine, a known reactive oxygen species (ROS) scavenger, reversed the effects of usnic acid on expression of DNA damage response proteins and γH2A.X (Ser139) phosphorylation. This reversal was also observed in comet assay in a time and dose-dependent manner suggesting that usnic acid-induced DNA damage was caused by ROS. In addition, the non-toxic concentrations (1-10 μM) of usnic acid inhibited colony forming potential of AGS cells indicating its anti-proliferation activity. More importantly, the concentration of usnic acid that caused significant death in gastric cancer cells, did not show any considerable toxicity to normal human embryonic kidney HEK293 cells, human keratinocyte HaCaT cells and mouse primary gastric cells. Collectively, these results for the first time demonstrated the selective apoptotic effect of usnic acid (10-25 μM) through ROS generation and DNA damage on human gastric cancer cells accompanied with upregulation of γH2A.X (Ser139) phosphorylation, DNA-PKcs and p53.

Topics: Animals; Apoptosis; Benzofurans; Cell Line; Cell Line, Tumor; DNA Damage; DNA-Activated Protein Kinase; DNA-Binding Proteins; Female; HEK293 Cells; Histones; Humans; Mice; Mice, Inbred C57BL; Phosphorylation; Reactive Oxygen Species; Stomach Neoplasms; Up-Regulation

(+)-Usnic acid, a product of secondary metabolism in lichens, has displayed a broad range of biological properties such as antitumor, antimicrobial, antiviral, anti-inflammatory, and insecticidal activities. Interested by these pharmacological activities and to tap into its potential, we herein present the synthesis and biological evaluation of new usnic acid enaminone-conjugated 1,2,3-triazoles

Topics: Anti-Bacterial Agents; Antitubercular Agents; Bacillus subtilis; Benzofurans; Lichens; Microbial Sensitivity Tests; Molecular Structure; Mycobacterium tuberculosis; Triazoles

Accumulation of tau protein aggregation plays a crucial role in neurodegenerative diseases, such as Alzheimer's disease (AD). Uncontrollable neuroinflammation and tau pathology form a vicious circle that further aggravates AD progression. Herein, we reported the synthesis of usnic acid derivatives and evaluation of their inhibitory activities against tau-aggregation and neuroinflammation. The inhibitory activity of the derivatives against the self-fibrillation of the hexapeptide AcPHF6 was initially screened by ThT fluorescence assay. Using circular dichroism and transmission electron microscopy, compound 30 showed the most potent inhibitory activity against AcPHF6 self-fibrillation. Compound 30 was further confirmed to inhibit the aggregation of full-length 2N4R tau protein by a heparin-induced mechanism. In addition, we investigated the anti-inflammatory activity of compound 30, and showed that compared with sodium usnate, it reduced NO release in LPS-stimulated mouse microglia BV2 cells. More importantly, 30 showed significant protective effects against okadaic acid-induced memory impairment in rats. Thus, 30 was a novel tau-aggregation and neuroinflammation inhibitor that represented a potential therapeutic candidate for AD.

Topics: Alzheimer Disease; Animals; Benzofurans; Cell Line, Tumor; Disease Models, Animal; Dose-Response Relationship, Drug; Humans; Inflammation; Lipopolysaccharides; Male; Maze Learning; Mice; Models, Molecular; Molecular Structure; Nitric Oxide; Protein Aggregates; Rats; Rats, Sprague-Dawley; Structure-Activity Relationship; tau Proteins

Neuroinflammation is often associated with astrocyte and microglial activations particularly in Parkinson's disease (PD) and other brain damage such as Alzheimer's disease. Therefore, the modulation of glial activation offers a possible target for treating PD-associated pathologies. Here, we evaluated the neuroprotective effects of usnic acid, a naturally occurring dibenzofuran derivative found in several lichen species in an acute mouse model of PD. Male mice were administered with vehicle or usnic acid (5 or 25 mg/kg) for 10 consecutive days, and then on day 11, MPTP (20 mg/kg, i.p.) was administered four times (with 2hrs intervals between injections) to induce PD pathologies. It was found that MPTP-induced motor dysfunction and neuronal loss were ameliorated in the usnic acid-treated mice versus vehicle-treated controls. Further study revealed that usnic acid effectively inhibited MPP

Topics: Animals; Anti-Inflammatory Agents; Benzofurans; Brain; Disease Models, Animal; Dopaminergic Neurons; Encephalitis; Male; Mice, Inbred C57BL; Neuroglia; Neuroprotective Agents; Nitric Oxide Synthase Type II; Parkinsonian Disorders; Rotarod Performance Test

Lung squamous cell carcinoma (LUSC) has a poor prognosis, in part due to poor therapeutic response and limited therapeutic alternatives. Lichens are symbiotic organisms, producing a variety of substances with multiple biological activities. (+)-Usnic acid, an important biologically active metabolite of lichens, has been shown to have high anti-cancer activity at low doses. However, there have been no reports regarding the effect of (+)-usnic acid on LUSC cells. This study found that (+)-usnic acid reduced viability and induced apoptosis in LUSC cells by reactive oxygen species (ROS) accumulation. (+)-Usnic acid induced mitochondria-derived ROS production via inhibition of complex I and complex III of the mitochondrial respiratory chain (MRC). Interestingly, the elimination of mitochondrial ROS by Mito-TEMPOL only partially reversed the effect of (+)-usnic acid on cellular ROS production. Further study showed that (+)-usnic acid also induced ROS production via reducing Nrf2 stability through disruption of the PI3K/Akt pathway. The in vitro and in vivo xenograft studies showed that combined treatment of (+)-usnic acid and paclitaxel synergistically suppressed LUSC cells. In conclusion, this study indicates that (+)-usnic acid induces apoptosis of LUSC cells through ROS accumulation, probably via disrupting the mitochondrial respiratory chain (MRC) and the PI3K/Akt/Nrf2 pathway. Therefore, although clinical use of (+)-usnic acid will be limited due to toxicity issues, derivatives thereof may turn out as promising anticancer candidates for adjuvant treatment of LUSC.

Topics: Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Benzofurans; Carcinoma, Squamous Cell; Cell Line, Tumor; Electron Transport Chain Complex Proteins; Humans; Lung Neoplasms; Mice; Mitochondria; NF-E2-Related Factor 2; Paclitaxel; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Reactive Oxygen Species; Signal Transduction; Transplantation, Heterologous

Topics: Benzofurans; Cell Line; Cell Survival; Hepatocytes; Humans; Melanocytes; Monophenol Monooxygenase; Photolysis; Ultraviolet Rays

Usnic acid (UA), a secondary lichen metabolite, has long been popular as one of natural fat-burning dietary supplements. Similar to 2,4-dinitrophenol, the weight-loss effect of UA is assumed to be associated with its protonophoric uncoupling activity. Recently, we have shown that the ability of UA to shuttle protons across both mitochondrial and artificial membranes is strongly modulated by the presence of calcium ions in the medium. Here, by using fluorescent probes, we studied the calcium-transporting capacity of usnic acid in a variety of membrane systems comprising liposomes, isolated rat liver mitochondria, erythrocytes and rat basophilic leukemia cell culture (RBL-2H3). At concentrations of tens of micromoles, UA appeared to be able to carry calcium ions across membranes in all the systems studied. Similar to the calcium ionophore A23187, UA caused degranulation of RBL-2H3 cells. Therefore, UA, being a protonophoric uncoupler of oxidative phosphorylation, at higher concentrations manifests itself as a calcium ionophore, which could be relevant to its overdose toxicity in humans and also its phytotoxicity.

Topics: 2,4-Dinitrophenol; Animals; Benzofurans; Calcimycin; Calcium Ionophores; Cell Line, Tumor; Erythrocytes; Humans; Ion Transport; Lichens; Mitochondria; Oxidative Phosphorylation; Protons; Rats

Breast cancer is the most common cancer types among women. Recent researches have focused on determining the efficiency of alternative molecules and miRNAs in breast cancer treatment. The aim of this study was to determine the effect of usnic acid response-miR-185-5p on proliferation in the breast cancer cell and to determine its relationship with apoptosis pathway.. The cell proliferation and cell apoptosis rate were significantly increased following the ectopic expression of miR-185-5p in BT-474 cells. Furthermore, the results of cell cycle assay performed by flow cytometry revealed that the transfection with miR-185-5p induced G1/S phase arrest. The apoptosis-related genes expression analysis was performed by qRT-PCR and the direct target of miR-185-5p in BT-474 cells was identified by western blot and luciferase reporter assay.. Our data showed that miR-185-5p can cause significant changes in apoptosis-related genes expression levels, suggesting that cell proliferation was suppressed by miR-185-5p via inducing apoptosis in breast cancer cells. According to western blot results, miR-185-5p lead to decrease BCL2 protein level in BT-474 cells and direct target of miR-185-5p was identified as BCL by luciferase reporter assay.. This study revealed that miR-185-5p may be an effective agent in the treatment of breast cancer.

Topics: Apoptosis; Benzofurans; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Down-Regulation; Female; Gene Expression Regulation, Neoplastic; Humans; MicroRNAs; Proto-Oncogene Proteins c-bcl-2; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Transfection

Polymer-drug conjugates have received considerable attention over the last decades due to their potential for improving the clinical outcomes for a range of diseases. It is of importance to develop methods for their preparation that have simple synthesis and purification requirements but maintain high therapeutic efficacy and utilize macromolecules that can be cleared via natural excretory pathways upon breakdown. Herein, the combination of ring-opening polymerization (ROP) and reversible addition-fragmentation chain-transfer (RAFT) polymerization is described for the straightforward synthesis of amphiphilic, stimuli-responsive, biodegradable, and highly functionalizable hyperbranched polymers. These unimolecular nanoparticles demonstrate a versatile platform for the synthesis of polymer-drug conjugates owing to the inclusion of a Boc-protected polycarbonate moiety in either a block or random copolymer formation. A proof-of-concept study on the complexation of the poorly water-soluble antimicrobial drug usnic acid results in polymer-drug complexes with powerful antimicrobial properties against gram-positive bacteria. Therefore, this work highlights the potential of amphiphilic and biodegradable hyperbranched polymers for antimicrobial applications.

Topics: Anti-Infective Agents; Benzofurans; Polymerization; Polymers

(+)-Usnic acid (UA) is a natural substance that displays pharmacological activity, but it is barely soluble in water, so it was included in liposomes in order to study its properties. First, the effects of phospholipid structure and loading methodology on UA entrapment efficacy were evaluated. Then, the physicochemical and biological properties (UA delivery efficacy to Staphylococcus aureus bacterial cells) of different liposome formulations containing structurally related amphiphiles derived from L-prolinol were fully investigated. Entrapment efficiency of UA with passive loading by incubation was 80-100 molar percentage, which is related to lipophilicity of the drug and to the packing and fluidity of the bilayer. Some of the investigated formulations show the potential of UA in delivery systems (minimum inhibitory concentration of liposomal UA: 8 μg/mL) and even subtle variations of the molecular structure of lipids can significantly affect the liposomes' physicochemical properties and efficiency of drug release.

Topics: Anti-Infective Agents; Benzofurans; Dimyristoylphosphatidylcholine; Drug Liberation; Liposomes; Microbial Sensitivity Tests; Staphylococcus aureus; Thermodynamics

The present study aimed to prepare usnic acid (UA)-loaded chitosan (CS) nanoparticles (UA-CS NPs) and evaluate its antibacterial activity against biofilm-forming pathogenic bacteria. UA-CS NPs were prepared through simple ionic gelification of UA with CS, and further characterized using Fourier transform infrared spectroscopy, X-ray diffraction, and field-emission transmission electron microscopy. The UA-CS NPs presented a loading capacity (LC) of 5.2%, encapsulation efficiency (EE) of 24%, and a spherical shape and rough surface. The maximum release of UA was higher in pH 1.2 buffer solution as compared to that in pH 6.8 and 7.4 buffer solution. The average size and zeta potential of the UA-CS NPs was 311.5 ± 49.9 nm in diameter and +27.3 ± 0.8 mV, respectively. The newly prepared UA-CS NPs exhibited antibacterial activity against persister cells obtained from the stationary phase in batch culture, mature biofilms, and antibiotic-induced gram-positive and gram-negative pathogenic bacteria. Exposure of sub-inhibitory concentrations of UA-CS NPs to the bacterial cells resulted in a change in morphology. The present study suggests an alternative method for the application of UA into nanoparticles. Furthermore, the anti-persister activity of UA-CS NPs may be another possible strategy for the treatment of infections caused by biofilm-forming pathogenic bacteria.

Topics: Animals; Anti-Bacterial Agents; Benzofurans; Biofilms; Chitosan; Gram-Negative Bacteria; Gram-Positive Bacteria; Humans; Nanoparticles

We analyzed cytotoxicity of water-soluble potassium salts of (+)- and (-) usnic acid (UA) for ciliates P. caudatum. The median lethal concentrations for (+)- and (-) enantiomers did not significantly differ and were 7.5±0.5 and 6.7±0.4, respectively. In a concentration of 8 μM, (+)-UA and (-)-UA salts increased the content of TBA-reactive products, which indicates the formation of oxidative stress under the action of high UA concentrations. In the presence of (+)-UA and (-)-UA salts in a concentration range from 2 to 8 μM, the number of food vacuoles in ciliates decreased, which attested to a decrease in phagocytosis activity. The concentrations of UA enantiomers >0.5 μM affected macronucleus morphology (shape and size). The cytotoxic activity of (+)-UA and (-)-UA salts against P. caudatum did not differ.

Topics: Animals; Benzofurans; Dose-Response Relationship, Drug; Molecular Conformation; Oxidative Stress; Paramecium caudatum; Potassium; Salts; Structure-Activity Relationship; Toxicity Tests

The metabolomic profiles of rat primary hepatocytes following treatment with rotenone, FCCP, or (+)-usnic acid were determined using liquid chromatography-mass spectrometry/mass spectrometry and gas chromatography-mass spectrometry. Significant and similar changes in the levels of 283 biochemical metabolites were associated with the three treatments compared with solvent control samples. Overall, the three treatments generated similar global biochemical profiles, with some minor differences associated with rotenone treatment. All three treatments resulted in a shift in energy metabolism as demonstrated by decreased glycogen stores and glycolysis. A reduced antioxidant response was detected in cells following all treatments. In addition, bile acid biosynthesis decreased as a potential consequence of increased oxidative stress by all three treatments. Conversely, rotenone treatment induced a number of changes after 1 hr, which were not detected in FCCP- or (+)-usnic acid-treated samples; these changes were not sustained over time and included increased NAD+ salvage and lysine degradation. In conclusion, these biochemical profiles could provide new insights into the mechanism(s) of mitochondrial toxicity.

Topics: Animals; Benzofurans; Bile Acids and Salts; Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; Cells, Cultured; Chromatography, Liquid; Energy Metabolism; Gas Chromatography-Mass Spectrometry; Glycogen; Glycolysis; Hepatocytes; Metabolomics; Mitochondria, Liver; Oxidative Stress; Rats, Inbred F344; Rotenone

This study aims to determine whether usnic acid (UA) could induce the expression of apoptosis-related genes in apoptosis pathway. The current study has enabled us to better understand the target of UA in the treatment of breast cancer. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Based on the previous study and the results of this study, UA had the most antiproliferative effect on SK-BR-3 breast cancer cell line. We examined differential expression of 88 apoptosis-related genes by quantitative real-time polymerase chain reaction using the apoptosis primary library panel in SK-BR-3 breast cancer cell. We observed a difference in the significant differential expression of 74 apoptosis-related genes in breast cancer after SK-BR-3 cells applied to UA (7.21 µM) for 48 h. The expression level of 56 of these 74 differentiated apoptosis-related genes increased (

Topics: Antineoplastic Agents; Apoptosis; Benzofurans; Breast Neoplasms; Caspase 3; Caspase 9; Cell Line; Cell Proliferation; Cell Survival; Epithelial Cells; Gene Expression Regulation, Neoplastic; Humans; Proto-Oncogene Proteins c-bcl-2

To evaluate the safety and potential healing efficacy of the topical ocular administration of a gelatin membrane containing usnic acid/liposomes (UALs) for corneal cicatrization. UALs have shown healing activity in animal models of dermal burn lesions. We evaluated the safety of topical ocular administration of UAL and its potential healing efficacy as an ophthalmic treatment on chemical lesions in rabbit eyes.. The Draize test was used to check for ocular toxicity and the score was zero at each observation, indicating the ocular safety of a gelatin membrane containing usnic acid/liposome. Its potential healing efficacy as an ophthalmic treatment on chemical lesions in rabbit eyes was also assessed.. After epithelial removal and treatment with UAL, there was a 49.4 % reduction in injury under in vivo conditions compared with a 36.6 % reduction in the control, a gelatin membrane containing liposome without usnic acid. Histological analysis of ocular surface chemical injury-tissue sections after treatment with UAL supported these observations. The corneal expression of VEGF and TGF-β1increased by 70 % and 50 % respectively following treatment with UAL gelatin membrane.. These results indicate the potential therapeutic application of UAL gelatin membranes as an ophthalmic treatment that may be used for corneal cicatrization.

Topics: Administration, Ophthalmic; Animals; Benzofurans; Chickens; Cicatrix; Cornea; Drug Delivery Systems; Female; Gelatin; Liposomes; Neovascularization, Physiologic; Ophthalmic Solutions; Wound Healing

Hybrid molecules created from different pharmacophores of natural and synthetic equivalents are successfully used in pharmaceutical practice. One promising target for anticancer therapy is tyrosyl-DNA phosphodiesterase 1 (Tdp1) because it can repair DNA lesions caused by DNA-topoisomerase 1 (Top1) inhibitors, resulting in drug resistance. In this study, new hybrid compounds were synthesized by combining the pharmacophoric moiety of a set of natural compounds with inhibitory properties against Tdp1, particularly, phenolic usnic acid and a set of different monoterpenoid fragments. These fragments were connected through a hydrazinothiazole linker. The inhibitory properties of the new compounds mainly depended on the structure of the terpenoid moieties. The two most potent compounds,

Topics: Benzofurans; Crystallography, X-Ray; HeLa Cells; Humans; Hydrogen Bonding; Models, Molecular; Molecular Structure; Monoterpenes; Phosphodiesterase Inhibitors; Phosphoric Diester Hydrolases; Spectrum Analysis; Structure-Activity Relationship

Ischemia-reperfusion (I/R) injury causes oxidative stress, leading to severe cardiac dysfunction. Thus, biologically active compounds with antioxidant properties may be viewed as a promising therapeutic strategy against oxidative-related cardiac disorders. Usnic acid (UA), a natural antioxidant, was complexed with β-cyclodextrin (βCD) to improve its bioavailability. Wistar male rats were orally treated with the free form of UA (50 mg/kg) or the inclusion complex UA/βCD (50 mg/kg) for seven consecutive days. Afterward, hearts were subjected to I/R injury, and the cardiac contractility, rhythmicity, infarct size, and antioxidant enzyme activities were evaluated. Here, we show that neither UA nor UA/βCD treatments developed signs of toxicity. After I/R injury, animals treated with UA/βCD showed improved post-ischemic cardiac functional recovery while the release of cell injury biomarkers decreased. Following reduced cardiac damage, a lower incidence of ventricular arrhythmias and smaller myocardial infarct size were associated with reduced lipid peroxidation, along with preserved activity of antioxidant enzymes compared to untreated rats. Surprisingly, uncomplexed UA did not protect hearts against IR injury. Altogether, our results indicate that the inclusion complex UA/βCD is a critical determining factor responsible for the cardioprotection action of UA, suggesting the involvement of an antioxidant-dependent mechanisms. Moreover, our findings support that UA/βCD is a structurally engineered compound with active cardioprotective properties.

Topics: Animals; Benzofurans; beta-Cyclodextrins; Cardiotonic Agents; Male; Myocardial Reperfusion Injury; Rats, Wistar; Spectroscopy, Fourier Transform Infrared; Thermogravimetry

Lichen-forming fungi are known to produce a large number of secondary metabolites. Some metabolites are deposited in the cortical layer of the lichen thallus where they exert important ecological functions, such as UV filtering. The fact that closely related lineages of lichen-forming fungi can differ in cortical chemistry suggests that natural product biosynthesis in lichens can evolve independent from phylogenetic constraints. Usnic acid is one of the major cortical pigments in lichens. Here we used a comparative genomic approach on 46 lichen-forming fungal species of the Lecanoromycetes to elucidate the biosynthetic gene content and evolution of the gene cluster putatively responsible for the biosynthesis of usnic acid. Whole-genome sequences were gathered from taxa belonging to different orders and families of Lecanoromycetes, where Parmeliaceae is the most well-represented taxon, and analyzed with a variety of genomic tools. The highest number of biosynthetic gene clusters was found in Evernia prunastri, Pannoparmelia angustata, and Parmotrema austrosinense, respectively, and lowest in Canoparmelia nairobiensis, Bulbothrix sensibilis, and Hypotrachyna scytodes. We found that all studied species producing usnic acid contain the putative usnic acid biosynthetic gene cluster, whereas the cluster was absent in all genomes of species lacking usnic acid. The absence of the gene cluster was supported by an additional unsuccessful search for ß-ketoacylsynthase, the most conserved domain of the gene cluster, in the genomes of species lacking usnic acid. The domain architecture of this PKS cluster-homologous to the already known usnic acid PKS cluster (MPAS) and CYT450 (MPAO)-varies within the studied species, whereas the gene arrangement is highly similar in closely related taxa. We hypothesize that the ancestor of these lichen-forming fungi contained the putative usnic acid producing PKS cluster and that the gene cluster was lost repeatedly during the evolution of these groups. Our study provides insight into the genomic adaptations to the evolutionary success of these lichen-forming fungal species and sets a baseline for further exploration of biosynthetic gene content and its evolutionary significance.

Topics: Benzofurans; Evolution, Molecular; Gene Rearrangement; Genome, Fungal; Lichens; Multigene Family; Parmeliaceae; Phylogeny; Polyketide Synthases

Topics: Anti-Bacterial Agents; Benzofurans; Escherichia coli; Parmeliaceae; Salmonella typhi; Staphylococcus aureus

Topics: Acetone; Anti-Bacterial Agents; Anti-Infective Agents; Aspergillus; Benzofurans; Candida albicans; Heterocyclic Compounds, 3-Ring; Lichens; Microbial Sensitivity Tests; Molecular Structure; Parmeliaceae; Secondary Metabolism; Staphylococcus aureus

The purpose of this study was to develop and validate a specific and sensitive liquid chromatography tandem mass-spectrometry method for quantification of usnic acid concentration in the lichen, Cladonia uncialis, suitable for detection of relatively small fluctuations of usnic acid concentration in response to environmental changes.. The resulting method was fully validated according to international guidelines and demonstrated good selectivity and sensitivity with minor levels of a matrix effect and high accuracy.

Topics: Benzofurans; Biological Assay; Chromatography, Liquid; Lichens; Reference Standards; Tandem Mass Spectrometry

Tyrosyl-DNA phosphodiesterase 1 (Tdp1) is a promising therapeutic target in cancer therapy. Combination chemotherapy using Tdp1 inhibitors as a component can potentially improve therapeutic response to many chemotherapeutic regimes. A new set of usnic acid derivatives with hydrazonothiazole pharmacophore moieties were synthesized and evaluated as Tdp1 inhibitors. Most of these compounds were found to be potent inhibitors with IC

Topics: Benzofurans; Cell Survival; Dose-Response Relationship, Drug; Humans; Models, Molecular; Molecular Conformation; Molecular Structure; Phosphodiesterase Inhibitors; Phosphoric Diester Hydrolases; Protein Binding; Structure-Activity Relationship; Thiazoles

Usnic acid (UA) is a multifunctional bioactive lichen secondary metabolite with potential anti-cancer properties. Although the promising therapeutic effects of UA have been investigated in different cancer cell lines, the mechanism driving UA-induced cell death has yet to be elucidated. As the type of cell death (apoptosis or autophagy) induced by UA may vary depending on the cancer cell type, we first studied the cytotoxic effects of UA in HEPG2 (HBV(-)) and SNU-449(HBV(+)) hepatocellular carcinoma (HCC) cell lines. HCC cell viability was considerably reduced in a dose-dependent manner at 12, 24, and 48 h after treatment with UA ( p < 0.05). However, SNU-449 cells were more sensitive to UA than HEPG2 cells. UA also induced apoptotic cell death in HCC cells with cell cycle arrest at G0/G1 and G2/M phase depending on the genetic profile of each cell type. On the other hand, we observed acidic vesicular organelles in HCC cells after 36 h of UA treatment. Taken together, these findings suggest that UA stimulates apoptosis and autophagy in HEPG2 and SNU-449 cells without damaging normal control cells. Thus, UA might be a potential therapeutic compound for HCC treatment. However, there is a need for further studies investigating the death-promoting or preventing roles for autophagy and the molecular signaling mechanisms induced by UA treatment.

Topics: Antineoplastic Agents; Apoptosis; Autophagy; Benzofurans; Carcinoma, Hepatocellular; Cell Cycle Checkpoints; Cell Line, Tumor; Humans; Liver Neoplasms

Usnic acid, a lichen secondary metabolite produced by a whole number of lichens, has attracted the interest of researchers owing to its broad range of biological activity, including antiviral, antibiotic, anticancer properties, and it possessing a certain toxicity. The synthesis of new usnic acid derivatives and the investigation of their biological activity may lead to the discovery of compounds with better pharmacological and toxicity profiles. In this context, a series of new usnic acid derivatives comprising a terpenoid moiety were synthesized, and their ability to inhibit the catalytic activity of the human DNA repair enzyme tyrosyl-DNA phosphodiesterase 1 was investigated. The most potent compounds (15A, 15B, 15G: , and 16A, 16B, 16G: ) had IC

Topics: Benzofurans; Cell Line, Tumor; Escherichia coli; HEK293 Cells; Humans; MCF-7 Cells; Microorganisms, Genetically-Modified; Molecular Docking Simulation; Phosphodiesterase Inhibitors; Phosphoric Diester Hydrolases

Breast Cancer (BC) is the most common type of cancer diagnosed in women. A common treatment strategy for BC is still not available because of its molecular heterogeneity and resistance is developed in most of the patients through the course of treatment. Therefore, alternative medicine resources as being novel treatment options are needed to be used for the treatment of BC. Usnic Acid (UA) that is one of the secondary metabolites of lichens used for different purposes in the field of medicine and its anti-proliferative effect has been shown in certain cancer types, suggesting its potential use for the treatment.. Anti-proliferative effect of UA in BC cells (MDA-MB-231, MCF-7, BT-474) was identified through MTT analysis. Microarray analysis was performed in cells treated with the effective concentration of UA and UA-responsive miRNAs were detected. Their targets and the pathways that they involve were determined using a miRNA target prediction tool.. Microarray experiments showed that 67 miRNAs were specifically responsive to UA in MDA-MB-231 cells while 15 and 8 were specific to BT-474 and MCF-7 cells, respectively. The miRNA targets were mostly found to play role in Hedgehog signaling pathway. TGF-Beta, MAPK and apoptosis pathways were also the prominent ones according to the miRNA enrichment analysis.. The current study is important as being the first study in the literature which aimed to explore the UA related miRNAs, their targets and molecular pathways that may have roles in the BC. The results of pathway enrichment analysis and anti-proliferative effects of UA support the idea that UA might be used as a potential alternative therapeutic agent for BC treatment.

Topics: Antineoplastic Agents; Benzofurans; Breast Neoplasms; Cell Proliferation; Cell Survival; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Female; Humans; MicroRNAs; Molecular Docking Simulation; Molecular Structure; Oligonucleotide Array Sequence Analysis; Structure-Activity Relationship; Tumor Cells, Cultured

We report for the first time the in vitro effect of Potassium Salt, derived from Usnic Acid (PS-UA), isolated from the lichen Cladonia substellata Vanio, on couples of Schistosoma mansoni. As schistosomicide parameters, we evaluated mortality, motility, cell viability of the worms and tegument changes by scanning electron microscopy (SEM). Exposure to a concentration of 100 μM caused 75% mortality after 3 h. After 6 h, changes in motility in concentrations of 50 and 25 μM are evidenced. After 12 h and 24h, the concentrations of 50 and 100 μM caused 6.25% and 87.5% and 50% and 100% mortality, respectively. PS-UA reduced the cell viability of the worms by 27.36% and 52.82% at concentrations 50 and 100 μM, respectively. Through SEM we observed progressive dose-and time-dependent, alterations such as swelling, blisters, dorsoventral contraction, erosion until disintegration of the tubercles in the tegument of male and female. PS-UA did not alter the viability of human peripheral blood mononuclear cells and showed high selectivity indices (IC

Topics: Animals; Anthelmintics; Benzofurans; Cell Survival; Dose-Response Relationship, Drug; Female; Leukocytes, Mononuclear; Lichens; Male; Microscopy, Electron, Scanning; Schistosoma mansoni

The intention of present research work is to formulate usnic acid (UA) loaded heparin modified gellan gum (HAG) nanoparticles (NPs). HAG copolymer based conjugation was synthesized and characterized by

Topics: A549 Cells; Adipates; Animals; Antineoplastic Agents; Apoptosis; Benzofurans; Cell Cycle; Drug Carriers; Drug Liberation; Erythrocytes; Hematologic Tests; Hemolysis; Heparin; Humans; Male; Nanoparticles; Polysaccharides, Bacterial; Rats

Topics: Animals; Benzofurans; Bile; Chromatography, High Pressure Liquid; Male; Molecular Structure; Plasma; Rats; Rats, Sprague-Dawley; Spectrometry, Mass, Electrospray Ionization; Urine

Topics: Anti-Bacterial Agents; Benzofurans; Biofilms; Chemistry Techniques, Synthetic; Copper; Drug Resistance, Multiple, Bacterial; Metal Nanoparticles; Microbial Sensitivity Tests; Silver; Thymol

Usnic acid (UA), an old antibiotic and one of the first described mitochondrial uncouplers, has demonstrated many beneficial activities, such as antimicrobial, antiviral, antitumour and anti-inflammatory properties. Here, we performed a thorough investigation of effects of usnic acid and its analogues on artificial planar bilayer lipid membrane (BLM), rat liver mitochondria and bacteria. Surprisingly enough, all of the three hydroxyl groups of UA appeared to be involved in its proton-shuttling activity on BLM. We ascribed this fact to an ability of UA to form complexes with calcium ions, aiding it in cycling protons across the membrane. Actually, the addition of calcium ions markedly stimulated the UA-induced electrical current across BLM. By using the calcium ionophore A23187, we proved the involvement of calcium ions in the UA uncoupling action on isolated rat liver mitochondria. The calcium-chelating property of UA was demonstrated here by the method of extracting metal ions into a hydrophobic phase. Modification of any of the hydroxyl groups in UA dramatically reduced not only the UA-induced current across BLM and the UA-mediated calcium extraction, but also the uncoupling activity of UA in mitochondria and the inhibiting effect of UA on the growth of Bacillus subtilis. The ability of UA to cause dissipation of membrane potential in isolated liver mitochondria and bacterial cells was shown here for the first time. In view of the data obtained, the protonophoric activity of UA is considered to make a significant contribution to its antibacterial action.

Topics: Animals; Anti-Bacterial Agents; Bacillus subtilis; Benzofurans; Calcimycin; Calcium; Ion Transport; Lipid Bilayers; Membrane Potential, Mitochondrial; Mitochondria, Liver; Rats

Usnic acid, which is the most widespread and well-studied secondary lichen compound, has antibacterial and cytotoxic effects. Usnic acid is present in lichens as the (+)- and (-)-enantiomers, which have different biological activities. We used a DNA-comet assay to determine the genotoxic effect of (+)- and (-)-usnic acid in the liver and kidney cells of mice. The genotoxic effect of usnic acid was only observed 1 h after oral administration. Usnic acid doses of 100 and 50 mg/kg resulted in DNA damage in the liver and kidney cells. The genotoxic effect of usnic acid is associated with oxidative stress in cells. There were no significant differences in the effects of (+)- and (-)-enantiomers.

Topics: Animals; Anti-Infective Agents; Benzofurans; DNA Damage; Kidney; Lichens; Liver; Male; Mice; Oxidative Stress; Stereoisomerism

Natural products are produced via primary and secondary metabolism in different organisms. The compounds obtained via secondary metabolism are not essential for the survival of the organism, but they can have a different value for humans.. The objective of this study was to examine inhibitory effects of Usnic Acid (UA), a well-known lichen secondary metabolite, and Carnosic Acid (CA), the primary antioxidant compound of Rosmarinus officinalis L., on purified Human Paraoxonase, (PON1), Glutathione Reductase (GR) and Glutathione S-Transferase (GST). These enzymes have antioxidant properties and a protective effect on the oxidation of free radicals. Hence, deficiencies of such enzymes inside cells can result in a buildup of toxic substances and cause some metabolic disorders.. UA and CA were tested in various concentrations against human GST, PON1, and GR activity in vitro and they reduced human GST, PON1, and GR activity.. UA Ki constants were calculated as 0.012±0.0019, 0.107±0.06 and 0.21±0.1 mM for GST, PON1, and GR enzymes. CA Ki constants were determined as 0.028±0.009, 0.094±0.03 and 0.79±0.33 mM, for GST, PON1, and GR enzymes. UA and CA showed competitive inhibition for GR and GST enzymes, while they exhibited non-competitive inhibition for PON1.. These findings indicate that UA and CA could be useful in drug development studies.

Topics: Abietanes; Antioxidants; Aryldialkylphosphatase; Benzofurans; Enzyme Inhibitors; Glutathione Reductase; Glutathione Transferase; Humans; Oxidation-Reduction; Rosmarinus

Usnic acid (UA) is a lichenic secondary metabolite useful for the treatment of burn wounds thanks to its antimicrobial activity, particularly toward strains responsible for their infections. However, the poor solubility is the main factor limiting the activity and thus its use in health care products. Adhesive polymeric films were designed to improve UA use by enhancing its bioavailability in the wounded tissues. Three different NaCMC hydrogel films, NaCMC 2% alone (F1), mixed to PVP K90 0.1% (F2) or to Carbopol 971 P 0.1% (F3), were prepared by casting method. Ex vivo experiments performed on pig skin samples showed their suitable adhesion capacity. in vitro release test, performed using the extraction cell, showed that film F2 provides the highest UA concentrations. Differential scanning calorimetry and X-ray analyses performed on the three films highlighted that UA is present in a more soluble form in F2. The in vitro antibacterial activity studies demonstrated that F2 is the most effective film against UA sensitive bacteria S. Epidermidis, E. Faecalis, B. Cereus and S. Pyogenes. In vitro cytotoxicity assays on human keratinocytes and fibroblasts showed that cells viability is not compromised.

Topics: Animals; Anti-Bacterial Agents; Bacillus cereus; Benzofurans; Burns; Cell Survival; Enterococcus faecalis; Humans; Keratinocytes; Polymers; Staphylococcus epidermidis; Streptococcus pyogenes; Swine; Wound Healing

The aim of this study was to investigate the combined effects of usnic acid (UA) and Tamoxifen (Tam) or Enzalutamide (Enz) on hormone receptor-positive breast and prostate cancer (BC and PC), respectively. The antiproliferative and apoptotic effects of Tam or Enz alone and in combination with UA on MCF7 and LNCaP cancer cells were detected. The results of the WST-1 assay indicated that UA was a promising anticancer compound that significantly enhanced the effectiveness of hormone therapy drugs compared with each drug alone (combination index < 1). In addition, the combination of UA with Tam or Enz remarkably induced more cell cycle arrest at the G0/G1 phase and apoptosis than only drug-treated cells (P < 0.01). Consequently, our findings suggest that the combination of UA with Tam or Enz may be a potential therapeutic approach for the treatment of BC and PC and further studies are required to exploit the potential mechanisms of synergistic effects.

Topics: Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Benzofurans; Breast Neoplasms; Cell Line, Tumor; Drug Synergism; Female; Humans; Male; Prostatic Neoplasms; Receptors, Cell Surface

Leishmaniasis is a neglected disease caused by a trypanosomatid protozoan of the genus. The amino acid sequence of a conserved hypothetical protein [Leishmania mexicana MHOM/GT/2001/U1103] has been deposited in GenBank (CBZ28005.1).

Topics: 4-Hydroxyphenylpyruvate Dioxygenase; Benzofurans; Cyclohexanones; Enzyme Inhibitors; Leishmania; Nitrobenzoates; Tocopherols

Sorafenib (SOR) is an orally administered molecular targeted agent in the systemic chemotherapy of hepatocellular carcinoma (HCC). However, the partial response of SOR is limited due to its adverse side effect and high heterogeneity and resistant phenotype of HCC. In the current study, we investigated synergistic effects of SOR and usnic acid (UA) on HCC cell lines including HepG2 and SNU-449, and a normal cell line, HUVEC.. The antiproliferative and apoptotic effects of combination therapy and SOR alone were analysed by WST-1 and Annexin V analysis, respectively. Furthermore, cell cycle, gene expression analysis of SOR-targeted kinases and acridine orange-ethidium bromide staining were also performed in combined treatments.. Our results demonstrated that SOR and UA combination indicated a strong synergism in HCC cell lines and reduced SOR toxicity in HUVEC cells. Additionally, the combination treatment SOR and UA significantly induced much more apoptotic cell death and G0/G1 arrest through downregulation of SOR-targeted kinases.. Consequently, SOR and UA combination could be a new therapeutic strategy for HCC treatment.

Topics: Annexin A5; Antineoplastic Agents; Apoptosis; Benzofurans; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Proliferation; Drug Synergism; Drug Therapy, Combination; Hep G2 Cells; Humans; Liver Neoplasms; Protein-Tyrosine Kinases; Sorafenib

Multidrug-resistant Staphylococcus aureus infections place a huge burden on the healthcare sector and the wider community. An increasing rate of infections caused by methicillin-resistant Staphylococcus aureus (MRSA) has necessitated the development of alternative agents. We previously reported that usnic acid (UA) has activity against MRSA; here, we report the effect of UA in combination with norfloxacin on the drug resistance of MRSA clinical isolates. We observed that the combination of UA-norfloxacin significantly reduces the bacterial burden in mouse models infected with S. aureus, without causing any detectable associated toxicity. Proteomic analysis indicated that UA-norfloxacin induces oxidative stress within cells, which leads to membrane damage and inhibits metabolic activity and biosynthesis of peptidoglycan and fatty acids. Collectively, this study provides evidence that UA in combination with norfloxacin may be a potential candidate for development into a resistance-modifying agent for the treatment of invasive MRSA infections.

Topics: Animals; Anti-Bacterial Agents; Benzofurans; Drug Resistance; Drug Synergism; Fatty Acids; Male; Methicillin-Resistant Staphylococcus aureus; Mice; Microbial Sensitivity Tests; Norfloxacin; Peptidoglycan; Staphylococcal Infections; Staphylococcus aureus

Topics: Animals; Anticarcinogenic Agents; Benzofurans; CHO Cells; Colonic Neoplasms; Cricetinae; Cricetulus; Genomic Instability; Mutagenicity Tests; Precancerous Conditions

Specialised metabolites in lichens are generally considered repellent compounds by consumers. Nevertheless, if the only food available is lichens rich in specialised metabolites, lichenophages must implement strategies to overcome the toxicity of these metabolites. Thus, the balance between phagostimulant nutrients and deterrent metabolites could play a key role in feeding preferences. To further understand lichen-gastropod interactions, we studied the feeding behaviour and consumption in Notodiscus hookeri, the land snail native to sub-Antarctic islands. The lichen Usnea taylorii was used because of its simple chemistry, its richness in usnic acid (specialised metabolite) and arabitol (primary metabolite) and its presence in snail habitats. Choice tests in arenas with intact lichens versus acetone-rinsed lichens were carried out to study the influence of specialised metabolites on snail behaviour and feeding preference. Simultaneously, usnic acid and arabitol were quantified and located within the lichen thallus using HPLC-DAD-MS and in situ imaging by mass spectrometry to assess whether their spatial distribution explained preferential snail grazing. No-choice feeding experiments, with the pure metabolites embedded in an artificial diet, defined a gradual gustatory response, from strong repellence (usnic acid) to high appetence (D-arabitol). This case study demonstrates that the nutritional activity of N. hookeri is governed by the chemical quality of the food and primarily by nutrient availability (arabitol), despite the presence of deterrent metabolite (usnic acid).

Topics: Animals; Benzofurans; Chromatography, High Pressure Liquid; Mass Spectrometry; Snails; Sugar Alcohols; Usnea

Topics: Analgesics; Animals; Behavior, Animal; Benzofurans; Disease Models, Animal; Drinking Behavior; Feeding Behavior; Female; Mice; Molecular Conformation; Organ Specificity; Toxicity Tests, Acute

Topics: Adaptor Proteins, Signal Transducing; Antineoplastic Agents; Apoptosis; Benzofurans; Binding Sites; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Drug Evaluation, Preclinical; Gene Expression Regulation, Neoplastic; Humans; Leukemia; Molecular Docking Simulation; Phosphorylation; Protein Kinase Inhibitors; Protein Structure, Tertiary; Proto-Oncogene Proteins c-pim-1; Signal Transduction; Stereoisomerism

Because of the increased incidence of infections caused by resistant pathogens, due to the intensive use of antibiotics, there is an urgent need to develop new therapeutic strategies against bacteria, possibly based on non conventional drugs. (+)-Usnic acid is a natural compound that exerts a potent antibacterial activity, however its clinical application is hampered by its scarce solubility in water. Usnic acid was included, by both passive and active loading techniques, in liposomes containing structurally related glucosylated amphiphiles. Liposome formulations were characterized from the physicochemical point of view and their activity against biofilm associated Staphylococcus epidermidis was also evaluated. The inclusion of usnic acid in glucosylated cationic liposomes promotes its penetration in biofilm matrix with a consequent increase of its antimicrobial activity. The effect of both cationic charge and sugar residue seems to be synergistic.

Topics: Anti-Bacterial Agents; Bacterial Infections; Benzofurans; Biofilms; Drug Delivery Systems; Glycosylation; Liposomes; Microbial Sensitivity Tests; Molecular Structure; Particle Size; Staphylococcus epidermidis; Surface Properties

Mycousfurans (

Topics: Anti-Bacterial Agents; Ascomycota; Benzofurans; Furans; Geologic Sediments; Heterocyclic Compounds, 3-Ring; Microbial Sensitivity Tests; Micrococcaceae; Molecular Structure; Staphylococcus aureus

Six series of (+)-usnic acid derivatives were synthesized. The IC

Topics: Animals; Antiprotozoal Agents; Benzofurans; Drug Evaluation, Preclinical; Female; HeLa Cells; Humans; Mice; Molecular Structure; Toxoplasma; Toxoplasmosis

The search for compounds that interact synergistically with entomopathogenic fungi is aimed at enhancing the efficacy and stability of biological products against pest insects, for example, against the Colorado potato beetle (CPB). We hypothesized that fluorine-containing derivatives of usnic acid (FUA) might be candidates for the development of multicomponent bio-insecticides. The aim of this study was to analyze the co-influence of FUA and Beauveria bassiana on the survival and immune-physiological reactions of CPB larvae.. Synergy between FUA and B. bassiana was observed after treatment of second, third and fourth larvae instars under laboratory conditions. Furthermore, synergy was observed in field trials in continental climate conditions in southeastern Kazakhstan. In a field experiment, the median lethal time was shortened three-fold, and cumulative mortality for 15 days increased by 36% in the combined treatment compared with a fungal infection alone. FUA treatment delayed larval development, decreased the total hemocyte count, and increased both the phenoloxidase activity in integuments and the detoxification enzyme rate in hemolymph. A combined treatment with fungus and FUA led to increases in the aforementioned changes.. Toxicosis caused by FUA provides a stable synergistic effect between FUA and B. bassiana. The combination can be promising for the development of highly efficient products against CPB. © 2017 Society of Chemical Industry.

Topics: Animal Shells; Animals; Beauveria; Benzofurans; Coleoptera; Fluorine; Hemolymph; Immunity, Innate; Insect Control; Insecticides; Larva; Longevity; Pest Control, Biological

Topics: Animals; Anisoles; Benzofurans; Chromatography, High Pressure Liquid; Female; Hydroxybenzoates; Linear Models; Male; Mass Spectrometry; Phthalic Acids; Rats; Reproducibility of Results; Sensitivity and Specificity

Wound healing is the process of repairing and remodeling damaged tissue. This is a public health problem that can influence the survival rate and quality of life of injured people. This attracts the attention of the medical community because it has high health care costs and there is presently a lack of successful therapy. Thus, the application of natural ingredients and medicinal plants has become a focus of research. The purpose of this study is to investigate the effectiveness of topically-applied sodium usnic acid on macroscopic and microscopic changes under dermal injury. These effects were measured using wound contraction experiments, histological analysis, and immunohistochemistry analysis, and gentamicin was used as a positive control medicine. Our results revealed that wound healing rates were higher and re-epithelialized times were shorter with topical application of sodium usnic acid, as compared to the negative control group. Histological results showed treatment with sodium usnic acid caused a reduction in inflammatory cells and an increase in fibroblast proliferation, granulation tissue, vascular regeneration. Sodium usnic acid treatment also resulted in earlier complete re-epithelialization, formation of well-organized bands of collagen, and epidermal keratinization. Furthermore, the levels of VEGF were significantly higher at day 1 post-wounding in those treated with sodium usnic acid. In conclusion, our results indicate that the topical use of sodium usnic acid could promote skin wound healing, and this mechanism might be related to anti-inflammatory effects at the wound site.

Topics: Administration, Topical; Animals; Anti-Infective Agents; Benzofurans; Male; Rats; Rats, Wistar; Skin; Sodium; Treatment Outcome; Wound Healing

To prepare a new nanosystem of usnic acid (UA) with higher solid content and higher bioavailability.. Usnic acid nanocrystal suspensions were prepared by the wet milling method, and then the particle size distributions and zeta potential were determined with the Nano ZS90 laser diffraction particle size analyzer. The particles morphology of UA-NCS were observed by scanning electron microscopy method. In addition, solubility and dissolution of UA-NCS in water and phosphate buffer solution were determined in vitro, analyzed by the HPLC method, and then the cellular uptake and pharmacokinetic were carried out on the Caco-2 cells and rats, analyzed by the UPLC-MS/MS method.. Particle size distributions and zeta potential of the UA nanocrystal suspension were 268.7 ± 4.0 nm and -23.1 ± 0.7 mV, respectively. About the dissolution rate of UA, nanosuspension were significantly faster and higher than common suspension in water and phosphate buffer. And in cellular uptake experiments, the ratio of the maximum amount of drug in unit protein of UA nanosuspension to common suspension was 2.8 times. In rats, oral absorption of nanocrystal UA were superior to the ordinary groups, with the 348% of the maximum concentration and 181% of the AUC after the same dosage administration.. The wet-milling technique was suitable for the preparation of UA nanocrystal suspension, and a new nanosystem of UA with higher solid content and higher bioavailability was achieved.

Topics: Animals; Benzofurans; Biological Availability; Caco-2 Cells; Humans; Mass Spectrometry; Microscopy, Electron, Scanning; Nanoparticles; Particle Size; Rats; Solubility; Suspensions

This study reports the molluscicidal activity of usnic acid isolated from Cladonia substellata Vanio (lichen) on embryos at various stages of development and in adult mollusks of Biomphalaria glabrata. The toxicity of usnic acid was also evaluated through Artemia salina larvae mortality. Usnic acid was extracted with diethyl ether, isolated, purified, and its structure confirmed by analyzing the spectra of proton nuclear magnetic resonance. LC

Topics: Animals; Artemia; Benzofurans; Biomphalaria; Embryo, Nonmammalian; Larva; Lichens; Molluscacides

The effect of usnic acid enantiomers on the genotoxic effects of dioxidine and methyl methanesulfonate was studied in vitro in human peripheral blood lymphocytes by the DNA comet method. We found that usnic acid enantiomers in a concentration range of 0.01-1.00 μM demonstrated pronounced antigenotoxic activity and reduced DNA damage induced by genotoxicants by 37-70%. In the same concentration range, the test enantiomers reduced the level of atypical DNA comets (hedgehogs) induced by genotoxicants by 23-61%. The test compounds did not modulate the effects of genotoxicants in a concentration of 10 μM and potentiated them in a concentration of 100 μM. The modifying activity of usnic acid did not depend on spatial configuration and on the used model genotoxicant.

Topics: Benzofurans; Comet Assay; DNA Fragmentation; Hormesis; Humans; Leukocytes, Mononuclear; Lichens; Methyl Methanesulfonate; Mutagens; Protective Agents; Quinoxalines; Stereoisomerism

BACKGROUND Usnic acid (UA), a secondary metabolite, is mainly derived from certain lichen species. Growing evidence suggests that UA has antitumor, anti-oxidative, anti-inflammatory, and other activities in a variety of cancer cells. However, the antitumor effect of UA in gastric cancer cells (GC) is unclear. The aim of this investigation was to assess the antitumor effect of UA in GC cells in vitro and in vivo, and to explore the underlying mechanisms. MATERIAL AND METHODS Cell proliferation was measured by CCK8 assay, the arrest of cell cycle was assessed by flow cytometry, and cellular apoptosis was observed via Hoechst 33258 staining assay. Expression levels of apoptosis-related proteins (activated caspase-3 and PARP, Bax, Bcl2) and autophagy-associated proteins (LC3-II and p62) were verified through Western blot analysis. H&E staining and immunohistochemistry were carried out in the subcutaneously implanted BGC823 tumor model in a nude mouse experiment. RESULTS In vitro, we demonstrated that UA was significantly effective in inducing morphological changes, inhibiting the cell proliferation dose- and time-dependently, arresting the cell cycle phase, promoting cancer cellular apoptosis, and inducing autophagy activity. In vivo, compared to mice treated with 5-FU alone, UA treatment was significantly more effective in suppressing the tumor growth without affecting body weight, and in regulating the amount of Bax and Bcl2 in tumor tissues. CONCLUSIONS UA induces cell cycle arrest and autophagy and exerts anti-proliferative and apoptotic effects by modulating expression of apoptosis-related proteins in stomach neoplasm cells, and has a better antitumor effect compared to 5-Fu in the xenograft model.

Topics: Animals; Apoptosis; Autophagy; Benzofurans; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Cell Shape; Female; Mice; Mice, Inbred BALB C; Mice, Nude; Stomach Neoplasms

This work presents investigations of biologically active metabolites of Usnea barbata lichen. Extraction conditions for usnic acid and other biologically active phytocomponents using various solvent systems were chosen. Modern analytical techniques were used to study composition of the obtained extracts; usnic acid and phenolic compound contents were estimated. Antioxidant activity and antimicrobial properties of lichen dry extract against bacteria Bacillus subtilis and Pseudomonas fluorescens were studied.

Topics: Anti-Bacterial Agents; Antioxidants; Bacillus subtilis; Benzofurans; Biological Factors; Microbial Sensitivity Tests; Phenols; Pseudomonas fluorescens; Solvents; Usnea

The improved bactericidal activity of new composites for wound dressing prototypes represents an important strategy for development of more efficient devices that make use of synergistic interaction between components. The doping level of polyaniline represents a critical parameter for its corresponding biologic activity. In this work, it is explored the doping effect of usnic acid on undoped polyaniline, that introduces important advantages namely, improved bactericidal activity of polyaniline and the anti-biofilm properties of lichen derivative. The deposition of the resulting material on polyurethane foam potentializes its applicability as wound dressing, characterizing a new platform for application against Escherichia coli and Staphylococcus aureus.

Topics: Aniline Compounds; Anti-Bacterial Agents; Bandages; Benzofurans; Biofilms; Disk Diffusion Antimicrobial Tests; Drug Carriers; Escherichia coli; Microscopy, Electron, Scanning; Polyurethanes; Staphylococcus aureus

New drugs are needed to treat infections with antimicrobial-resistant

Topics: Anti-Bacterial Agents; Anti-Infective Agents; Benzofurans; Drug Interactions; Ethidium; Microbial Sensitivity Tests; Mycobacterium abscessus

Usnic acid is a lichen compound which is extensively studied due to its cytotoxic, antiproliferative, antimicrobial, antiviral, antiprotozoal, and anti-inflammatory activities. Despite a broad spectrum of biological properties, usnic acid is a hepatotoxic agent, thus its potential use as a drug is limited. Certain hepatotoxic drugs may act by generating reactive metabolites that damage the liver. The aim of the study was to predict the biotransformation of usnic acid enantiomers to reactive products using a trapping assay with glutathione in human, rat, and mice liver microsomes. Our results indicate that each enantiomer forms two reactive metabolites; in turn, these metabolites form adducts with glutathione, which may partially explain the toxicity of usnic acid. In silico analysis indicated structural alerts for the generation of reactive metabolites in usnic acid formula. This study proposes a novel mode of the hepatic toxicity of usnic acid enantiomers; it also provides some useful suggestions for designing safer usnic acid derivatives.

Topics: Animals; Benzofurans; Biotransformation; Chromatography, Liquid; Glutathione; Humans; Liver; Mice; Microsomes, Liver; Rats; Stereoisomerism; Tandem Mass Spectrometry

Usnic acid is a unique polyketide produced by lichens. To characterize usnic acid biosynthesis, the transcriptome of the usnic-acid-producing lichen-forming fungus Nephromopsis pallescens was sequenced using Illumina NextSeq technology. Seven complete non-reducing polyketide synthase genes and nine highly-reducing polyketide synthase genes were obtained through transcriptome analysis. Gene expression results obtained by qPCR and usnic acid detection with LCMS-IT-TOF showed that Nppks7 is probably involved in usnic acid biosynthesis in N. pallescens. Nppks7 is a non-reducing polyketide synthase with a MeT domain that also possesses beta-ketoacyl-ACP synthase, acyl transferase, product template, acyl carrier protein, C-methyltransferase, and Claisen cyclase domains. Phylogenetic analysis shows that Nppks7and other polyketide synthases from lichens form a unique monophyletic clade. Taken together, our data indicate that Nppks7 is a novel PKS in N. pallescens that is likely involved in usnic acid biosynthesis.

Topics: Amino Acid Sequence; Base Sequence; Benzofurans; Lichens; Parmeliaceae; Phylogeny; Polyketide Synthases; Sequence Analysis, DNA

Tyrosyl-DNA phosphodiesterase 1 (Tdp1) is a repair enzyme for stalled DNA-topoisomerase 1 (Top 1) cleavage complexes and other 3'-end DNA lesions. Tdp1 is a promising target for anticancer therapy, since it can repair DNA lesions caused by Top1 inhibitors leading to drug resistance. Hence, Tdp1 inhibition should result in synergistic effect with Top1 inhibitors. Twenty nine derivatives of (+)-usnic acid were tested for in vitro Tdp1 inhibitory activity using a fluorescent-based assay. Excellent activity was obtained, with derivative 6m demonstrating the lowest IC

Topics: Allosteric Regulation; Antineoplastic Agents; Benzofurans; Binding Sites; Cell Survival; DNA; Furans; HEK293 Cells; Humans; Molecular Docking Simulation; Phosphodiesterase Inhibitors; Phosphoric Diester Hydrolases; Protein Structure, Tertiary; Recombinant Proteins; Structure-Activity Relationship; Substrate Specificity

Topics: Antineoplastic Agents; Apoptosis; Benzofurans; Breast Neoplasms; Cell Line; Cell Line, Tumor; Cell Proliferation; Female; G1 Phase; Humans; Inhibitory Concentration 50; Male; Neoplasms, Hormone-Dependent; Prostatic Neoplasms; Resting Phase, Cell Cycle

The endophytic fungus Mycosphaerella sp. (UFMGCB2032) was isolated from the healthy leaves of Eugenia bimarginata, a plant from the Brazilian savanna. Two novel usnic acid derivatives, mycousfuranine (1) and mycousnicdiol (2), were isolated from the ethyl acetate extract, and their structure was elucidated by NMR and MS analyses. Compounds 1 and 2 exhibited moderate antifungal activities against Cryptococcus neoformans and Cryptococcus gattii, each with minimum inhibitory concentration values of 50.0 μg/mL and 250.0 μg/mL, respectively.

Topics: Antifungal Agents; Ascomycota; Benzofurans; Cryptococcus; Eugenia

Hypertrophic scarring is a common condition in the Chinese population; however, there are currently no satisfactory drugs to treat the disorder. Previous studies showed that angiogenesis plays an important role in the early phase of hypertrophic scarring and inhibition of angiogenesis has been reported as an effective strategy for anti-hypertrophic scar therapy. A recent study showed that usnic acid (UA), an active compound found mainly in lichens, inhibited tumor angiogenesis both in vivo and in vitro. To investigate the therapeutic effects of UA on hypertrophic scarring and to explore the possible mechanism involved, a rabbit ear hypertrophic scar model was established. Scars were treated once a week for four weeks with UA, DMSO or triamcinolone acetonide acetate. Histological evaluation of hematoxylin and eosin staining indicated that UA significantly inhibited hypertrophic scar formation, with obvious reductions in scar height and coloration. The scar elevation index (SEI) was also evidently reduced. Masson's trichrome staining showed that UA significantly ameliorated accumulation of collagen tissue. Immunohistochemical analysis of CD31 expression showed that UA significantly inhibited scar angiogenesis. In vitro, UA inhibited endothelial cell migration and tube formation as well as the proliferation of both human umbilical vein endothelial cells and scar fibroblast cells. These results provide the first evidence of the therapeutic effectiveness of UA in hypertrophic scar formation in an animal model via a mechanism that involves suppression of scar angiogenesis.

Topics: Animals; Benzofurans; Cell Line; Cicatrix; Disease Models, Animal; Female; Human Umbilical Vein Endothelial Cells; Humans; Male; Neovascularization, Pathologic; Platelet Endothelial Cell Adhesion Molecule-1; Rabbits

Usnic acid (UA), a lichen secondary substance, has considerable anticancer activity in vitro, whereas its effect in vivo is limited. Here, potassium usnate (KU) was prepared by the salinization of UA to enhance its water solubility. KU showed increased bioavailability compared with UA in the tumor, liver, and plasma of a CT26 syngeneic mouse tumor xenograft model after oral administration, as determined by LC-MS/MS analysis. KU exhibited potent anticancer effects on colorectal cancer cells and inhibited liver metastasis in an orthotopic murine colorectal cancer model. KU treatment downregulated the epithelial-mesenchymal markers Twist, Snail, and Slug and the metastasis-related genes CAPN1, CDC42, CFL1, IGF1, WASF1, and WASL in cells and tumor tissues. The present results suggest the potential application of the water-soluble form of UA, KU, in anticancer therapy.

Topics: Administration, Oral; Animals; Antineoplastic Agents; Benzofurans; Biological Availability; Cell Line, Tumor; Cell Movement; Cell Proliferation; Colorectal Neoplasms; Disease Models, Animal; Drug Screening Assays, Antitumor; Epithelial-Mesenchymal Transition; Gene Expression Regulation, Neoplastic; Humans; Male; Mice; Neoplasm Invasiveness; Potassium; Selenic Acid; Treatment Outcome

New therapeutics are urgently needed to fight tuberculosis and mycobacteria-related diseases that are a major health hazard especially in poor countries. Natural products have been the source of important antitubercular drugs in the past and still need to receive attention as a potent reservoir of chemical structures. Fifteen known and two new (+)-usnic acid (a benzofurandione formerly isolated from lichens) enamines and hydrazones are here described and tested against sensitive and multidrug-resistant strains of mycobacteria. Among several (+)-usnic acid conjugates, PS14 and PS18 showed potent activity against both susceptible and resistant Mycobacterium tuberculosis strains (MIC values of 1-32 and 2-32 mg/L, respectively) comparable with MIC of other antitubercular drugs already in use for tuberculosis treatment.

Topics: Anti-Bacterial Agents; Benzofurans; Cell Line; Cell Survival; Drug Design; Drug Resistance, Bacterial; Humans; Microbial Sensitivity Tests; Molecular Structure; Mycobacterium; Mycobacterium tuberculosis

Studies about toxicological potential of usnic acid are limited. This way, the vast majority of data available in the literature are related only to biological activities. This is the first study that aimed to evaluate the oral toxicity of usnic acid during the period of organogenesis. Females rats were distributed in the control groups, treated I and II, at doses of 15 and 25 mg/kg, administered by gavage during the 6° to 15° days of pregnancy. After 20 days the fetuses were removed and analyzed. A reduction in weight gain during pregnancy, increased resorption, reduction in the number of viable fetuses, and their body weight were observed. Morphological changes in the litter were visualized as exposure of the eye and atrophy of the limbs at the dose of 25 mg/kg. Histological analysis of the liver of the fetus showed reduction in the number of megakaryocytes between experimental groups and increase in the number of hepatocytes in a dose of 25 mg/kg. The experimental model used in this study reveals teratogenic effect of usnic acid in the period of organogenesis. Since this achievement, the importance of evaluating the toxic effects of natural substances is imperative, in order to elucidate the care in their indication as drug.

Topics: Animals; Ascomycota; Benzofurans; Body Weight; Female; Fetal Development; Fetus; Male; Organ Size; Organogenesis; Pregnancy; Rats; Teratogenesis

Lichens species produce unique secondary metabolites that attract increasing pharmacological interest, including their redox modulatory activities. Current work evaluated for the first time the in vitro cytoprotective properties, based on the antioxidant activities, of the Parmeliaceae lichens Evernia prunastri and Usnea ghattensis and the mechanism of action of their major phenolic constituents: the evernic and usnic acids, respectively. In two models of central nervous system-like cells (U373-MG and SH-SY5Y cell lines), exogenous H

Topics: Antioxidants; Apoptosis; Benzofurans; Caspase 3; Cell Line, Tumor; Central Nervous System; Humans; Hydrogen Peroxide; Hydroxybenzoates; Lichens; Oxidation-Reduction; Oxidative Stress; Protective Agents

Two-week administration of (+)-usnic acid (UA) induces mitochondrial swelling of cardiomyocytes, and toxicogenomic analysis of the heart revealed upregulation of oxidative stress, amino acid limitation, and endoplasmic reticulum stress-related genes in rats. To analyze the pathogenesis, UA was orally administrated to rats for 1, 4, 7, and 14 days, and sequential histopathological, genomic, and metabolomic analyses were performed on the heart, liver, and plasma. As a result, mitochondrial swelling of cardiomyocytes was observed on day 15 preceded by genomic upregulation on days 5 and 8. Of the focused gene groups, amino acid limitation-related genes represented by Mthfd2 showed numerically higher values or upregulation from day 5, which was sustained through the experimental period. On the contrary, oxidative stress-related genes were upregulated temporally on day 5. In metabolomic analysis, amino acids such as taurocholate and their metabolites fluctuated in concert with the upregulation of amino acid limitation-related genes in the heart, liver, and plasma. Moreover, accumulations of bile acids were manifested in all the tested tissues, while no histopathological change was seen in the liver. Increased bile acids might have an indirect effect on the myocardium; however, more detailed analysis is required. In conclusion, amino acid limitation was suggested as the pivotal toxic trigger of UA-induced cardiotoxicity.

Topics: Alanine Transaminase; Amino Acids; Animals; Aspartate Aminotransferases; Benzofurans; Bile Acids and Salts; Cardiotoxicity; Creatine Kinase; Endoplasmic Reticulum Stress; Female; Heart; L-Lactate Dehydrogenase; Liver; Metabolomics; Methylenetetrahydrofolate Dehydrogenase (NADP); Myocytes, Cardiac; Oxidative Stress; Rats; Rats, Inbred F344; Up-Regulation

The extreme resiliency of lichens to UV radiations makes them an interesting model to find new photoprotective agents acting as UV-blockers and antioxidant. In this research, using a new in vitro method designed to overcome the shortage of material associated to many studies dealing with natural products, we show that the three major compounds isolated from the lichen

Topics: Antioxidants; Benzofurans; Furans; Humans; Keratinocytes; Lichens; Phenylacetates; Plant Extracts; Radiation-Protective Agents; Ultraviolet Rays

Many common herbs and spices are claimed to have blood sugar lowering properties that make them useful for people with or at high risk of diabetes. The main of compounds of kiwifruit (Actinidia deliciosa), rhubarb (Rheum ribes), membrane inner of egg shell, wool of sheep, human fingernail (unguis), hyaluronic acid produced by the Bifidobacterium, and usnic acid of Aspicilia lichen were extracted by different methods. All compounds of the extract were divided into five groups. We used variables such as pH, different compounds, concentration, number of injections, and blood glucose monitoring in different situations. Our study, extracts changed to nanoform. The extract compounds and nanoparticles were analyzed by gas chromatography mass spectroscopy, Fourier transform infrared spectroscopy, hydrogen-1 nuclear magnetic resonance, and scanning electron microscope. The average size of the nanoparticles was found to be 55 nm. Five groups of nanoparticles were injected into rats, and they reduced their blood glucose levels significantly (statistical significance was declared at p < 0.05). The synthesized hyaluronic acid helped to treat diabetes in rats. Copyright © 2017 John Wiley & Sons, Ltd.

Topics: Animals; Ascomycota; Benzofurans; Bifidobacterium; Biological Products; Blood Glucose; Diabetes Mellitus, Experimental; Fruit; Humans; Hyaluronic Acid; Nanoparticles; Rats; Sheep; Spectroscopy, Fourier Transform Infrared

Plasmodium falciparum is sensitive to oxidative stress in vitro and in vivo, and many drugs such as artemisinin, chloroquine and cercosporin interfere in the parasite's redox system. To minimize the damage caused by reactive radicals, antioxidant enzymes and their substrates found in parasites and in erythrocytes must be functionally active. It was shown that P. falciparum synthesizes vitamin E and that usnic acid acts as an inhibitor of its biosynthesis. Vitamin E is a potent antioxidant that protects polyunsaturated fatty acids from lipid peroxidation, and this activity can be measured by detecting its oxidized product and by evaluating reactive oxygen species (ROS) levels.. Here, we demonstrated that ROS levels increased in P. falciparum when vitamin E biosynthesis was inhibited by usnic acid treatment and decreased to basal levels if exogenous vitamin E was added. Furthermore, we used metabolic labelling to demonstrate that vitamin E biosynthesized by the parasite acts as an antioxidant since we could detect its radiolabeled oxidized product. The treatment with chloroquine or cercosporin of the parasites increased the ratio between α-tocopherolquinone and α-tocopherol.. Our findings demonstrate that vitamin E produced endogenously by P. falciparum is active as an antioxidant, probably protecting the parasite from the radicals generated by drugs.

Topics: Animals; Antimalarials; Benzofurans; Chloroquine; Erythrocytes; Humans; Malaria, Falciparum; Microscopy, Fluorescence; Oxidative Stress; Perylene; Plasmodium falciparum; Protozoan Proteins; Reactive Oxygen Species; Vitamin E

Many usnic acid-containing dietary supplements have been marketed as weight loss agents, although severe hepatotoxicity and acute liver failure have been associated with their overuse. Our previous mechanistic studies revealed that autophagy, disturbance of calcium homeostasis, and ER stress are involved in usnic acid-induced toxicity. In this study, we investigated the role of oxidative stress and the Nrf2 signaling pathway in usnic acid-induced toxicity in HepG2 cells. We found that a 24-h treatment with usnic acid caused DNA damage and S-phase cell cycle arrest in a concentration-dependent manner. Usnic acid also triggered oxidative stress as demonstrated by increased reactive oxygen species generation and glutathione depletion. Short-term treatment (6 h) with usnic acid significantly increased the protein level for Nrf2 (nuclear factor erythroid 2-related factor 2), promoted Nrf2 translocation to the nucleus, up-regulated antioxidant response element (ARE)-luciferase reporter activity, and induced the expression of Nrf2-regulated targets, including glutathione reductase, glutathione S-transferase, and NAD(P)H quinone oxidoreductase-1 (NQO1). Furthermore, knockdown of Nrf2 with shRNA potentiated usnic acid-induced DNA damage and cytotoxicity. Taken together, our results show that usnic acid causes cell cycle dysregulation, DNA damage, and oxidative stress and that the Nrf2 signaling pathway is activated in usnic acid-induced cytotoxicity.

Topics: Antioxidant Response Elements; Benzofurans; DNA Damage; Dose-Response Relationship, Drug; Gene Expression Regulation; Glutathione; Hep G2 Cells; Humans; NF-E2-Related Factor 2; Reactive Oxygen Species; S Phase Cell Cycle Checkpoints; Signal Transduction

Lichen secondary metabolites can function as allelochemicals and affect the development and growth of neighboring bryophytes, fungi, vascular plants, microorganisms, and even other lichens. Lichen overgrowth on bryophytes is frequently observed in nature even though mosses grow faster than lichens, but there is still little information on the interactions between lichens and bryophytes.In the present study, we used extracts from six lichen thalli containing secondary metabolites like usnic acid, protocetraric acid, atranorin, lecanoric acid, nortistic acid, and thamnolic acid. To observe the influence of these metabolites on bryophytes, the moss Physcomitrella patens was cultivated for 5 weeks under laboratory conditions and treated with lichen extracts. Toxicity of natural mixtures of secondary metabolites was tested at three selected doses (0.001, 0.01, and 0.1 %). When the mixture contained substantial amounts of usnic acid, we observed growth inhibition of protonemata and reduced development of gametophores. Significant differences in cell lengths and widths were also noticed. Furthermore, usnic acid had a strong effect on cell division in protonemata suggesting a strong impact on the early stages of bryophyte development by allelochemicals contained in the lichen secondary metabolites.Biological activities of lichen secondary metabolites were confirmed in several studies such as antiviral, antibacterial, antitumor, antiherbivore, antioxidant, antipyretic, and analgetic action or photoprotection. This work aimed to expand the knowledge on allelopathic effects on bryophyte growth.

Topics: Allelopathy; Benzofurans; Bryopsida; Cell Division; Cell Size; Germ Cells, Plant; Heterocyclic Compounds, 3-Ring; Hydroxybenzoates; Lichens; Plant Extracts; Salicylates; Secondary Metabolism

Angiogenesis plays a major role in the normal embryonic development and in diseases such as cancer. Drugs that control angiogenesis are an alternative way to tackle this disease. The polyphenols usnic acid (3), genistein (5), and daidzein (6) were tested for antiangiogenic and unwanted effects in zebrafish embryos whose blood vessel system resembles that of mammals. The established tyrosine kinase inhibitors axitinib (1) and tyrphostin AG490 (2) were included for comparison. All compounds except 6 caused distinct antiangiogenic effects such as a concentration-dependent reduction of intersegmental vessels, dorsal longitudinal anastomotic vessels, subintestinal veins and secondary sprouts. As side effects, pericardial oedema and the impairment of blood flow were observed. Usnic acid (3), genistein (5) and Cu(II)-genisteinate (7) gave rise to a curvature of the spine. Compounds 5 and 7 also induced cell death in the head of the embryos at higher doses. All effects were more pronounced when the compounds had been applied at an early stage (24 hpf) rather than at 48 hpf. The copper complexes 4 and 7 showed a stronger antiangiogenic effect than the free ligands 3 and 5. The genistein complex 7 was antiangiogenic at doses so low that side effects were tolerable, and thus it may be a potential anticancer drug candidate.

Topics: Angiogenesis Inhibitors; Animals; Axitinib; Benzofurans; Cell Line, Tumor; Cell Movement; Cell Survival; Coordination Complexes; Copper; Embryo, Nonmammalian; Embryonic Development; Genistein; Humans; Imidazoles; Indazoles; Matrix Metalloproteinases; Microscopy, Fluorescence; Neovascularization, Physiologic; Zebrafish

Continuous lifetime exposure to certain natural and man-made chemicals is a major cause of cancers in humans; therefore, evaluating the carcinogenic risks of chemicals remains important. Currently, substantial progress has been made in identification of genotoxic carcinogens; in contrast, predicting the carcinogenic potential of nongenotoxic compounds is a challenge due to many different modes of action that may lead to tumorigenesis. In the present study, we investigated the effects of the nongenotoxic liver carcinogen methapyrilene and the nongenotoxic noncarcinogen usnic acid, at doses that do not exhibit organ cytotoxicity, on epigenomic alterations in the livers and kidneys of Fischer 344 (F344) rats. We demonstrate that a repeat-dose oral treatment of male F344 rats with methapyrilene for 6 weeks caused target organ-specific epigenetic alterations in the livers. In contrast, only very slight epigenetic changes were found in the livers of F344 rats treated with hepatotoxicant, but noncarcinogen, usnic acid. The methapyrilene-induced epigenetic changes consisted of changes in histone lysine acetylation and methylation, with the greatest increase occurring in global and gene-specific histone H3 lysine 9 (H3K9) deacetylation. Importantly, the results of the present study show an association between gene-specific histone H3K9 deacetylation and a reduced expression of critical cancer-related genes, including prospero homeobox 1 (Prox1), HNF1 homebox A (Hnf1a), and peroxisome proliferator activated receptor alpha (Ppara), which provides a mechanistic link between methapyrilene-induced epigenetic aberrations and liver carcinogenesis.

Topics: Acetylation; Administration, Oral; Animals; Benzofurans; Carcinogens; Chromatin Assembly and Disassembly; Dose-Response Relationship, Drug; Epigenesis, Genetic; Hepatocyte Nuclear Factor 1-alpha; Histones; Homeodomain Proteins; Kidney; Liver; Lysine; Male; Methapyrilene; Methylation; Organ Specificity; PPAR alpha; Protein Processing, Post-Translational; Random Allocation; Rats, Inbred F344; Tumor Suppressor Proteins

The aim of this work was to determine the chemical composition of the ether, ethyl acetate and dichloromethane extracts of Ramalina capitata by GC-FID and GC-MS for the first time. The main identified components in the ether, ethyl acetate and dichloromethane extracts were everninic acid (24.7, 33.7 and 22.2%), orcinol (25.8, 16.7 and 11.9%), orcinol monomethyl ether (11.6, 7.6 and 4.8%), 3-methylorsellinic acid (10.2, 7.1 and 9.0%) and usnic acid (4.4, 8.2 and 25.8%), respectively. Considerable amount (10.4%) of 2-hydroxy-4-methoxy-3,5,6-trimethylbenzoic acid was detected in ethyl acetate extract. Additionally, palmitic acid, linoleic acid, oleic acid and stearic acid and their esters were observed in the dichloromethane and ethyl acetate extracts in the range of 4.1-0.1%, while their amount was below 0.05% in the ether extract. According to the results reported here R. capitata predominantly biosynthesises derivatives of orcinol and, in much lesser extent, derivatives of β-orcinol.

Topics: Ascomycota; Benzofurans; Chromatography, Gas; Flame Ionization; Gas Chromatography-Mass Spectrometry; Methanol; Resorcinols; Solvents

Lichens are an interesting source of potential anti-tumor compounds, among which usnic acid and atranorin seem to be the most promising, but their impact on invasive potential of tumor cells has not yet been comprehensively addressed. The aim of the study was focused on the impact of the two lichen metabolites, on the viability (by Trypan blue test and fluoresceine diacetate and ethidium bromide assay), proliferation (cell counting in a Bürker's chamber), apoptosis (flow cytometry analysis and Western blot) and motile activity (cell movement recording and image analysis) and actin cytoskeleton organization (immunofluorescent staining) of melanoma HTB-140, prostate cancers DU-145 and PC-3, normal human skin fibroblasts and prostate epithelial PNT2 cells, with special emphasis to their selectivity and versatility.. Both compounds exerted strong inhibitory effects on cancer cell proliferation, migration and actin cytoskeleton organization, while their effect on apoptosis process was less relevant. The impact of usnic acid on the examined cancer cells was found more efficient in comparison to atranorin. Also, selective effect of both agents on tumor cells was observed.. The ability of usnic acid and atranorin to inhibit cancer cells motility may have future implications for development of new therapeutic strategies targeted at the interference with the metastatic cascade.

Topics: Actins; Antineoplastic Agents; Apoptosis; Benzofurans; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cell Survival; Cells, Cultured; Cytostatic Agents; Fibroblasts; Humans; Hydroxybenzoates; Male; Melanoma; Prostatic Neoplasms

(+)-Usnic acid ((R)-2,6-diacetyl-7,9-dihydroxy-8,9b-dimethyl-1,3(2H,9bH)-dibenzo-furandione), a dibenzofuran isolated from the lichen Usnea longissima, has been chemically transformed to synthesize a series of sixteen novel triazole analogs by click chemistry approach. The synthesized compounds were tested for their anti-inflammatory potential against the cytokines TNF-[Formula: see text] and IL-1[Formula: see text] in U937 cell lines. The bromo enamines (2a, 2b), azido enamines (3a, 3b) and triazole analogs (4f, 4g, 4h, 5f, 5g and 5h) exhibited promising anti-inflammatory activity against TNF-[Formula: see text] with [Formula: see text] values ranging from 1.40 to 5.70 [Formula: see text]M. Most significantly, the [Formula: see text] values of compounds 5f (1.40 [Formula: see text]M) and 5h (1.88 [Formula: see text]M) are the lowest among the compounds tested and found close to that of standard prednisolone. Hence, these two compounds can be considered as lead molecules for further fine tuning to make highly potent anti-inflammatory therapeutic agents.

Topics: Anti-Inflammatory Agents; Benzofurans; Click Chemistry; Humans; Interleukin-1beta; Triazoles; Tumor Necrosis Factor-alpha; U937 Cells; Usnea

(+)-Usnic acid (1) is a common bioactive lichen-derived secondary metabolite with a characteristic dibenzofuran scaffold. It displayed low micromolar antiproliferative activity levels and, notably, induced autophagy in a panel of diverse breast cancer cell lines, suggesting the mechanistic (formerly "mammalian") target of rapamycin (mTOR) as a potential macromolecular target. The cellular autophagic markers were significantly upregulated due to the inhibition of mTOR downstream effectors. Additionally, 1 showed an optimal binding pose at the mTOR kinase pocket aided by multiple interactions to critical amino acids. Rationally designed benzylidene analogues of 1 displayed excellent fitting into a targeted deep hydrophobic pocket at the core of the kinase cleft, through stacking with the phenolic side chain of the Tyr2225 residue. Several potent analogues were generated, including 52, that exhibited potent (nM concentrations) antiproliferative, antimigratory, and anti-invasive activities against cells from multiple breast cancer clonal lines, without affecting the nontumorigenic MCF-10A mammary epithelial cells. Analogue 52 also exhibited potent mTOR inhibition and autophagy induction. Furthermore, 52 showed potent in vivo antitumor activity in two athymic nude mice breast cancer xenograft models. Collectively, usnic acid and analogues are potential lead mTOR inhibitors appropriate for future use to control breast malignancies.

Topics: Animals; Apoptosis; Autophagy; Benzofurans; Benzylidene Compounds; Breast Neoplasms; Cell Proliferation; Crystallography, X-Ray; Disease Models, Animal; Female; Humans; Lichens; Mice; Mice, Nude; Models, Molecular; Molecular Conformation; Molecular Structure; Protein Kinase Inhibitors; Sirolimus; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays

Usnic acid (UA) can be found in certain lichen species. Growing evidence suggests that UA possesses antitumoral, antioxidative and anti-inflammatory activities. Bleomycin (BLM) is widely used in the treatment of malignant ascites, however, it unexpectedly causes pulmonary fibrosis (PF). Researches show that excessive inflammatory response and oxidative stress in lung tissue is conspicuous causes of BLM-induced PF. Here we investigated mechanism underlying the effect-enhancing and toxicity-reducing activity of UA on H22-bearing mice treated with BLM. UA combined with BLM was significantly more effective than BLM alone in inhibiting the tumor growth, arresting the cell cycle at G0/G1 phase, and promoting the cleaved caspase-3 and cleaved caspase-8 activities to induce cancer cellular apoptosis. The mechanism may be associated with the transcriptional regulation of p53/p21/Cyclin pathway. Furthermore, UA effectively moderated the histopathological changes, reduced the content of MDA, HYP, TNF-α, IL-1β, IL-6 and TGF-β1, and increased the level of SOD when combined with BLM in lung tissues of H22-bearing mice, which was believed to be related to the inhibition on the protein level of p-Smad2/3 and enhancement of Smad7 expression. These findings suggested that UA might be a potential effect-enhancing and toxicity-reducing candidate for BLM in the treatment of malignant ascites.

Topics: Adjuvants, Pharmaceutic; Animals; Antineoplastic Agents; Apoptosis; Ascites; Benzofurans; Bleomycin; Carcinoma, Hepatocellular; Cell Cycle Checkpoints; Cell Line, Tumor; Drug-Related Side Effects and Adverse Reactions; Humans; Lichens; Liver Neoplasms; Male; Mice; Mice, Inbred Strains; Neoplasms, Experimental; Pulmonary Fibrosis; Smad Proteins

Lichen secondary metabolites (LSMs) are regarded with interest for valuable biological properties, but chemical variability among/within lichen taxa has been only fragmentarily characterized by advanced analytical techniques. Knowledge of variability at a local geographic scale has been particularly neglected, while it should address the collection of chemically homogeneous materials to test and exploit LSMs. Here we evaluated the chemical variability of 48 Xanthoparmelia specimens from two rock outcrops in Western Italian Alps, representative of nine morphotypes and sixteen rDNA ITS haplotypes. Qualitative and quantitative analyses were performed by HPLC-DAD-ESI-MS

Topics: Benzofurans; Chromatography, High Pressure Liquid; DNA, Ribosomal; Europe; Haplotypes; Italy; Lichens; Parmeliaceae; Secondary Metabolism; Tandem Mass Spectrometry

Rappiidic acid, a new o-orsellinic acid derivative, was isolated from the lichen Cladonia rappii. Its capability to scavenge reactive oxygen species (ROS) and reactive nitrogen species (RNS) was investigated and compared with resveratrol and (+)-usnic acid. Usnic acid at 100 μM was the most efficient ROS scavenger, exhibiting activity 3-fold higher than that of resveratrol. At the same concentration, rappidic acid scavenged 23.1% of ROS formed, demonstrating that this compound is twice as active as resveratrol. Both compounds were shown to be poor RNS scavengers.

Topics: Benzofurans; Brazil; Free Radical Scavengers; Lichens; Molecular Structure; Resorcinols; Resveratrol

Lichens are symbiotic organisms composed of fungi and algae and are very common in Turkey. Lichen secondary metabolites are mainly phenolic compounds produced by fungal partner of lichen symbiosis. Usnic acid (UA) is one of the most common lichen metabolites, and it was reported that to be effective for a wide range of pharmacological purposes including antiviral, antitumor, and antiprotozoal. However, there are limited data on the genotoxic and antioxidant effects of UA in cultured human peripheral blood cells. Therefore, the aim of this thesis study was to investigate the genetic and oxidative effects of UA in cultured human blood cells (n = 5). The UA was added into culture tubes at various concentrations (0-200 μg/ml). Chromosomal aberrations (CA) and micronuclei (MN) tests were performed for genotoxic damage influences estimation. In addition, biochemical parameters (total antioxidant capacity (TAC) and total oxidative status (TOS)) were examined to determine oxidative effects. In our in vitro test systems, it was observed that UA had no mutagenic effects on human lymphocytes. Furthermore, our results indicated that low concentrations (1 and 5 μg/ml) of UA caused increases of TAC levels in cultured human blood cells. And, the TOS levels were not changed (p > 0.05) when all the concentrations (except for 200 μg/ml) of UA were applied. In conclusion, UA can be a new resource of therapeutics as recognized in this study with their nonmutagenic and antioxidant features.

Topics: Adult; Benzofurans; Cells, Cultured; Chromosome Aberrations; DNA Damage; Humans; Lichens; Lymphocytes; Micronucleus Tests; Oxidative Stress; Turkey; Young Adult

The major bioactive constituents of Usnea longissima Ach. are organic acids. However, few recent literatures involve the preparative separation of these organic acids. In the present study, pH zone-refining counter-current chromatography is used to separate organic acids from crude sample of U. longissima Ach. The crude extract was separated with the two-phase solvent system Pet-EtAc-MeOH-H2O (5:5:3:7, v/v) with 10mM TFA in organic stationary phase and different concentration of the eluter in aqueous mobile phase for the screening of the most suitable separation conditions. From the crude extract (1.2g), 74.0mg of orsellinic acid at 92.7% purity, 55.5mg of 4-O-methylorsellinic acid at 97.7% purity, 353.5mg of evernic acid at 93.8% purity, 102.0mg of barbatic acid at 94.8% purity, 19.4 mg of diffractaic acid at 92.2% purity, and 44.9 mg of usnic acid at 95.7% purity were obtained using the selected conditions in which the concentration of TFA in stationary phase was 10mM and the concentration of NaOH in mobile phase was 10-20mM. The purities of the separated organic acids were measured by HPLC. And the data of electrospray ionization-liquid chromatography/mass spectrometry (ESI-LC/MS), (1)H NMR, and (13)C NMR were used for confirming chemical structures.

Topics: Anisoles; Benzofurans; Chromatography, High Pressure Liquid; Countercurrent Distribution; Hydrogen-Ion Concentration; Hydroxybenzoates; Phthalic Acids; Resorcinols; Spectrometry, Mass, Electrospray Ionization; Usnea

There is a worldwide ongoing investigation for novel natural constituents with cytotoxic and antioxidant properties. The aim of this study was to investigate chemical profile and stated biological activities of the supercritical CO2 extract (SCE) of old man's beard compared to the extracts obtained using the conventional techniques (Soxhlet extracts and macerate). The most abundant compound identified was usnic acid, which content was inversely proportional to the polarity of the solvent used and was the highest in the SCE, which was the sample revealing the highest cytotoxic activity in tested tumor cell lines (B16 mouse melanoma and C6 rat glioma), with lower IC50 values compared to pure usnic acid. Further investigations suggested both SCE and usnic acid to induce apoptosis and/or autophagy in B16 and C6, indicating higher cytotoxicity of SCE to be related to the higher degree of ROS production. A good correlation of usnic acid content in the extracts and their antioxidant capacity was established, extricating SCE as the most active one. Presented results support further investigations of SCE of old man's beard as a prospective therapeutic agent with potential relevance in the treatment of cancer and/or in oxidative stress-mediated conditions.

Topics: Animals; Antineoplastic Agents, Phytogenic; Antioxidants; Apoptosis; Autophagy; Benzofurans; Biphenyl Compounds; Carbon Dioxide; Cell Cycle; Cell Line, Tumor; Chromatography, Supercritical Fluid; Mice; Oxidation-Reduction; Picrates; Rats; Usnea

Lichens are symbiotic organisms that produce various unique chemicals that can be used for pharmaceutical purposes. With the aim of screening new anti-cancer agents that inhibit cancer cell motility, we tested the inhibitory activity of seven lichen species collected from the Romanian Carpathian Mountains against migration and invasion of human lung cancer cells and further investigated the molecular mechanisms underlying their anti-metastatic activity. Among them, Alectoria samentosa, Flavocetraria nivalis, Alectoria ochroleuca, and Usnea florida showed significant inhibitory activity against motility of human lung cancer cells. HPLC results showed that usnic acid is the main compound in these lichens, and (+)-usnic acid showed similar inhibitory activity that crude extract have. Mechanistically, β-catenin-mediated TOPFLASH activity and KITENIN-mediated AP-1 activity were decreased by (+)-usnic acid treatment in a dose-dependent manner. The quantitative real-time PCR data showed that (+)-usnic acid decreased the mRNA level of CD44, Cyclin D1 and c-myc, which are the downstream target genes of both β-catenin/LEF and c-jun/AP-1. Also, Rac1 and RhoA activities were decreased by treatment with (+)-usnic acid. Interestingly, higher inhibitory activity for cell invasion was observed when cells were treated with (+)-usnic acid and cetuximab. These results implied that (+)-usnic acid might have potential activity in inhibition of cancer cell metastasis, and (+)-usnic acid could be used for anti-cancer therapy with a distinct mechanisms of action.

Topics: Antineoplastic Agents; Benzofurans; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cell Movement; Chromatography, High Pressure Liquid; Chromatography, Liquid; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; HEK293 Cells; Humans; Inhibitory Concentration 50; Lichens; Lung Neoplasms; Mass Spectrometry; Neoplasm Invasiveness; Neoplasm Metastasis; Real-Time Polymerase Chain Reaction; Romania

The aim of this study was to develop, characterize and assess the biological activity of a new regenerative 3D matrix with antimicrobial properties, based on collagen (COLL), hydroxyapatite (HAp), β-cyclodextrin (β-CD) and usnic acid (UA). The prepared 3D matrix was characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Microscopy (FT-IRM), Transmission Electron Microscopy (TEM), and X-ray Diffraction (XRD). In vitro qualitative and quantitative analyses performed on cultured diploid cells demonstrated that the 3D matrix is biocompatible, allowing the normal development and growth of MG-63 osteoblast-like cells and exhibited an antimicrobial effect, especially on the Staphylococcus aureus strain, explained by the particular higher inhibitory activity of usnic acid (UA) against Gram positive bacterial strains. Our data strongly recommend the obtained 3D matrix to be used as a successful alternative for the fabrication of three dimensional (3D) anti-infective regeneration matrix for bone tissue engineering.

Topics: Anti-Infective Agents; Benzofurans; Biocompatible Materials; Cell Line; Cell Survival; Collagen; Durapatite; Humans; Materials Testing; Microbial Sensitivity Tests; Microscopy, Electron, Transmission; Spectroscopy, Fourier Transform Infrared; Tissue Engineering; Tissue Scaffolds; X-Ray Diffraction

To identify the biosynthetic gene cluster responsible for the biosynthesis of the polyketide usnic acid we carried out the de novo genome sequencing of the fungal partner of Cladonia uncialis. This was followed by comprehensive in silico annotation of polyketide synthase (PKS) genes. The biosynthesis of usnic acid requires a non-reducing PKS possessing a carbon methylation (CMeT) domain, a terminal Claisen cyclase (CLC) domain, and an accompanying oxidative enzyme that dimerizes methylphloracetophenone to usnic acid. Of the 32 candidate PKS genes identified in the mycobiont genome, only one was identified as consistent with these biosynthetic requirements. This gene cluster contains two genes encoding a non-reducing PKS and a cytochrome p450, which have been respectively named methylphloracetophenone synthase (MPAS) and methylphloracetophenone oxidase (MPAO). Both mpas and mpao were demonstrated to be transcriptionally active by reverse transcriptase-PCR of the mRNA in a lichen sample that was observed by HPLC to produce usnic acid. Phylogenetic analysis of the bioinformatically identified ketosynthase (KS) and CLC domains of MPAS demonstrated that mpas grouped within a unique clade and that mpas could be used as a phylogenetic probe to identify other MPAS genes.

Topics: Ascomycota; Benzofurans; Biosynthetic Pathways; Chromatography, High Pressure Liquid; Gene Expression Profiling; Genome, Fungal; Ligases; Multigene Family; Oxidoreductases; Phylogeny; Reverse Transcriptase Polymerase Chain Reaction; Sequence Analysis, DNA; Sequence Homology, Amino Acid

Toxoplasma gondii pathogen is a threat to human health that results in economic burden. Unfortunately, there are very few high-efficiency and low-toxicity drugs for toxoplasmosis in the clinic. (+)-Usnic acid derived from lichen species has been reported to have anti-inflammatory, antibacterial, anti-parasitology, and even anti-cancer activities. Herein, the systematic effect of (+)-usnic acid and (+)-usnic acid-liposome on toxoplasma were studied in vitro and in vivo. The viability of toxoplasma tachyzoite was assayed with trypan blue and Giemsa staining; while the invasive capability of tachyzoite to cardiofibroblasts was detected using Giemsa staining. The survival time of mice and the changes in tachyzoite ultrastructure were studied in vivo. The results showed that (+)-usnic acid inhibited the viability of tachyzoite; pretreatment with (+)-usnic acid significantly decreased the invasion of tachyzoite to cardiofibroblasts in vitro; (+)-usnic acid and (+)-usnic acid-liposome extensively prolonged the survival time of mice about 90.9% and 117%, respectively; and improved the ultrastructural changes of tachyzoite, especially in dense granules, rhoptries, endoplasmic reticulum, mitochondria and other membrane organelles. In summary, these results demonstrate that (+)-usnic acid and (+)-usnic acid-liposome with low toxicity have an inhibitory effect on the viability of toxoplasma tachyzoite, and mainly destructed membrane organelles which are connected with the virulence of toxoplasma. These findings provide the basis for further study and development of usnic acid as a potential agent for treating toxoplasmosis.

Topics: Animals; Antiprotozoal Agents; Benzofurans; Cells, Cultured; Female; Fibroblasts; Liposomes; Male; Mice; Microscopy, Electron, Transmission; Myocytes, Cardiac; Random Allocation; Rats; Rats, Sprague-Dawley; Toxoplasma; Toxoplasmosis, Animal; Usnea

A screening using a dengue replicon virus-cell-based assay was performed on 3563 ethyl acetate (EtOAc) extracts from different parts of 1500 plants. The screening led to the selection of species from the genus Diospyros (Ebenaceae), among which 25 species distributed in tropical areas showed significant inhibitory activity on dengue virus replication. A metabolic analysis was conducted from the UPLC-HRMS profiles of 33 biologically active and inactive plant extracts, and their metabolic proximity is presented in the form of a dendrogram. The results of the study showed that chemical similarity is not related to plant species or organ. Overall, metabolomic profiling allowed us to define large groups of extracts, comprising both active and inactive ones. Closely related profiles from active extracts might indicate that the common major components of these extracts were responsible for the antiviral activity, while the comparison of chemically similar active and inactive extracts, will permit to find compounds of interest. Eventually, the phytochemical investigation of Diospyros glans bark EtOAc extract afforded usnic acid and 7 known ursane- and lupane-type triterpenoids, among which 5 were found significantly active against dengue virus replication. The inhibitory potency of these compounds was also evaluated on a DENV-NS5 RNA-dependant RNA polymerase assay.

Topics: Animals; Antiviral Agents; Benzofurans; Chlorocebus aethiops; COS Cells; Dengue Virus; Diospyros; Metabolome; Plant Bark; Plant Extracts; Triterpenes; Virus Replication

Mycobacterium tuberculosis (Mtb) has acquired resistance and consequently the antibiotic therapeutic options available against this microorganism are limited. In this scenario, the use of usnic acid (UA), a natural compound, encapsulated into liposomes is proposed as a new approach in multidrug-resistant tuberculosis (MDR-TB) therapy. Thus the aim of this study was to evaluate the effect of the encapsulation of UA into liposomes, as well as its combination with antituberculous agents such as rifampicin (RIF) and isoniazid (INH) against MDR-TB clinical isolates. The in vitro antimycobacterial activity of UA-loaded liposomes (UA-Lipo) against MDR-TB was assessed by the microdilution method. The in vitro interaction of UA with antituberculous agents was carried out using checkerboard method. Minimal inhibitory concentration values were 31.25 and 0.98 µg/mL for UA and UA-Lipo, respectively. The results exhibited a synergistic interaction between RIF and UA [fractional inhibitory concentration index (FICI) = 0.31] or UA-Lipo (FICI = 0.28). Regarding INH, the combination of UA or UA-Lipo revealed no marked effect (FICI = 1.30-2.50). The UA-Lipo may be used as a dosage form to improve the antimycobacterial activity of RIF, a first-line drug for the treatment of infections caused by Mtb.

Topics: Antibiotics, Antitubercular; Benzofurans; Capsules; Drug Resistance, Multiple, Bacterial; Drug Synergism; Humans; Isoniazid; Liposomes; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Rifampin

Usnic acid has been progressively reported in the literature as one of the most important lichen metabolites characterized by a rich diversity of applications such as antifungal, antimicrobial, antiprotozoal and antiviral agent. Particularly, antimicrobial activity of usnic acid can be improved by encapsulation of active molecules in enteric electrospun fibers, allowing the controlled release of active molecule at specific pH. Few relevant patents to the topic have been reviewed and cited.. Bactericidal activity of usnic acid-loaded electrospun fibers of Eudragit L-100 and polyvinylpyrrolidone was examined against Staphylococcus aureus using inhibition hales methodology.. The controlled release of active material at high pH is established after 10 minutes of interaction with media and results in reasonable activity against S. aureus, as detected by inhibition hales.. The strong biological activity of usnic acid-loaded electrospun fibers provides a promising application for corresponding material as a bactericidal agent for wound healing treatment.

Topics: Anti-Bacterial Agents; Benzofurans; Patents as Topic; Polymethacrylic Acids; Staphylococcus aureus

Eight usnic acid derivatives, that is, usenamines A-F (1-6), usone (7), and isousone (8), together with the known (+)-usnic acid (9), were isolated from the lichen Usnea longissima. Their structures were elucidated using 1D and 2D NMR and MS data, and the absolute configurations of compounds 1 and 2 were defined by single-crystal X-ray diffraction analyses. Compounds 1, 2, and 8 showed inhibitory effects on the growth of human hepatoma HepG2 cells with IC50 values of 6.0-53.3 μM compared with methotrexate as the positive control, which had an IC50 value of 15.8 μM. Furthermore, 1 induced apoptosis of HepG2 cells in a dose-dependent manner at concentrations of 0-15.0 μM. The isolated compounds were also evaluated for their antifungal and antibacterial activities, with 7 and 8 exhibiting weak inhibitory effects on fungal Trichophyton rubrum spp. with an MIC value of 41.0 μM.

Topics: Anti-Bacterial Agents; Antifungal Agents; Antineoplastic Agents; Apoptosis; Benzofurans; Candida; Dose-Response Relationship, Drug; Drugs, Chinese Herbal; Hep G2 Cells; Humans; Methotrexate; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Trichophyton; Usnea

The antimicrobial activity and possible synergistic effects of extracts and compounds isolated from Usnea steineri were evaluated against four resistant bacterial species. A phytochemical study of the acetone extract of U. steineri resulted in the isolation and characterization of difractaic acid and (+)-usnic acid as the main compounds. The acetone extract showed strong activity (less than 10 µg/mL) against resistant strains of Staphylococcus epidermidis and Enterococcus faecalis, and (+)-usnic acid exhibited strong activity against S. epidermidis (MIC 3.12 µg/mL), S. aureus and S. haemnolyticus (MIC 12.5 µg/mL). Combinations of penicillin and tetracycline with (+)-usnic acid did not show any synergistic antimicrobial effects. Difractaic acid was inactive. Our results showed that the acetone extract of U. steineri possesses significant in vitro antimicrobial activity, which is likely related to the presence of (+)-usnic acid.

Topics: Anti-Bacterial Agents; Benzofurans; Depsides; Drug Resistance, Multiple, Bacterial; Microbial Sensitivity Tests; Usnea

Topics: Antineoplastic Agents; Benzofurans; Humans

The main of this study was to evaluate the mutagenic and carcinogenic potential of (+) - usnic acid (UA), using Somatic Mutation and Recombination Test (SMART) and the test for detecting epithelial tumor clones (wts) in Drosophila melanogaster. Larvae from 72 ± 4 h from Drosophila were fed with UA (5.0, 10.0 or 20.0 mM); urethane (10.0 mM) (positive control); and solvent (Milli-Q water, 1% Tween-80 and 3% ethanol) (negative control). ST cross produced increase in total mutant spots in the individuals treated with 5.0, 10.0 or 20.0 mM of UA. HB cross produced spot frequencies in the concentration of 5.0 mM that were higher than the frequency for the same concentration in the ST cross. In the highest concentrations the result was negative, which means that the difference observed can be attributed, in part, to the high levels of P450, suggesting that increasing the metabolic capacity maximized the toxic effect of these doses. In the evaluation of carcinogenesis using the wts test, the results obtained for the same concentrations of UA show a positive result for the presence of tumors when compared to the negative control. We conclude that UA has recombinogenic, mutagenic and carcinogenic effects on somatic cells in D. melanogaster.

Topics: Animals; Anti-Infective Agents; Benzofurans; Carcinogenesis; Carcinogens; Drosophila melanogaster; Larva; Mutagenesis; Mutagens; Recombination, Genetic; Wings, Animal

To evaluate the antibacterial and antibiofilm mechanisms of usnic acid (USN) against methicillin-resistant Staphylococcus aureus from cystic fibrosis patients.. The effects exerted by USN at subinhibitory concentrations on S. aureus Sa3 strain was evaluated by proteomic, real-time PCR and electron microscopy analyses.. Proteomic analysis showed that USN caused damage in peptidoglycan synthesis, as confirmed by microscopy. Real-time PCR analysis showed that antibiofilm activity of USN is mainly due to impaired adhesion to the host matrix binding proteins, and decreasing lipase and thermonuclease expression. Our data show that USN exerts anti-staphylococcal effects through multitarget inhibitory effects, thus confirming the rationale for considering it 'lead compound' for the treatment of cystic fibrosis infections.

Topics: Adhesins, Bacterial; Anti-Bacterial Agents; Bacterial Proteins; Benzofurans; Biofilms; Carrier Proteins; Cell Membrane; Cell Survival; Colony Count, Microbial; Cystic Fibrosis; DNA, Bacterial; Down-Regulation; Lipase; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Microbial Viability; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Peptidoglycan; Propidium; Protein Interaction Maps; Proteomics; Real-Time Polymerase Chain Reaction; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Staphylococcal Infections; Time Factors; Virulence

Natural products from lichens are widely investigated for their biological properties, yet their potential as central nervous system (CNS) therapeutic agents is less explored.. The present study investigated the neuroactive properties of selected lichen compounds (atranorin, perlatolic acid, physodic acid and usnic acid), for their neurotrophic, neurogenic and acetylcholine esterase (AChE) activities.. Neurotrophic activity (neurite outgrowth) was determined using murine neuroblastoma Neuro2A cells. A MTT assay was performed to assess the cytotoxicity of compounds at optimum neurotrophic activity. Neuro2A cells treated with neurotrophic lichen compounds were used for RT-PCR to evaluate the induction of genes that code for the neurotrophic markers BDNF and NGF. Immunoblotting was used to assess acetyl H3 and H4 levels, the epigenetic markers associated with neurotrophic and/or neurogenic activity. The neurogenic property of the compounds was determined using murine hippocampal primary cultures. AChE inhibition activity was performed using a modified Ellman's esterase method.. Lichen compounds atranorin, perlatolic acid, physodic acid and (+)-usnic acid showed neurotrophic activity in a preliminary cell-based screening based on Neuro2A neurite outgrowth. Except for usnic acid, no cytotoxic effects were observed for the two depsides (atranorin and perlatolic acid) and the alkyl depsidone (physodic acid). Perlatolic acid appears to be promising, as it also exhibited AChE inhibition activity and potent proneurogenic activity. The neurotrophic lichen compounds (atranorin, perlatolic acid, physodic acid) modulated the gene expression of BDNF and NGF. In addition, perlatolic acid showed increased protein levels of acetyl H3 and H4 in Neuro2A cells.. These lichen depsides and depsidones showed neuroactive properties in vitro (Neuro2A cells) and ex vivo (primary neural stem or progenitor cells), suggesting their potential to treat CNS disorders.

Topics: Acetylcholinesterase; Animals; Benzoates; Benzofurans; Biological Products; Brain-Derived Neurotrophic Factor; Cell Line; Central Nervous System; Central Nervous System Diseases; Cholinesterase Inhibitors; Depsides; Dibenzoxepins; Gene Expression; Hydroxybenzoates; Lactones; Lichens; Mice; Nerve Growth Factor; Neural Stem Cells; Neurogenesis

Tyrosyl-DNA phosphodiesterase 1 (TDP1) is a repair enzyme for stalled DNA-topoisomerase 1 (Top1) cleavage complexes and other 3'-end DNA lesions. TDP1 is a perspective target for anticancer therapy based on Top1-poison-mediated DNA damage. Several novel usnic acid derivatives with an enamine moiety have been synthesized and tested as inhibitors of TDP1. The enamines of usnic acid showed IC

Topics: Benzofurans; Camptothecin; DNA Topoisomerases, Type I; Humans; MCF-7 Cells; Models, Molecular; Molecular Structure; Phosphodiesterase Inhibitors; Phosphoric Diester Hydrolases

The evolution of drug resistance is a recurrent problem that has plagued efforts to treat and control malaria. Recent emergence of artemisinin resistance in Southeast Asia underscores the need to develop novel antimalarials and identify new targetable pathways in Plasmodium parasites. Transmission-blocking approaches, which typically target gametocytes in the host bloodstream or parasite stages in the mosquito gut, are recognized collectively as a strategy that when used in combination with antimalarials that target erythrocytic stages will not only cure malaria but will also prevent subsequent transmission. We tested four derivatives of (+)-usnic acid, a metabolite isolated from lichens, for transmission-blocking activity against Plasmodium falciparum using the standard membrane feeding assay. For two of the derivatives, BT37 and BT122, we observed a consistent dose-response relationship between concentration in the blood meal and oocyst intensity in the midgut. To explore their mechanism of action, we used the murine model Plasmodium berghei and found that both derivatives prevent ookinete maturation. Using fluorescence microscopy, we demonstrated that in the presence of each compound zygote vitality was severely affected, and those that did survive failed to elongate and mature into ookinetes. The observed phenotypes were similar to those described for mutants of specific kinases (NEK2/NEK4) and of inner membrane complex 1 (IMC1) proteins, which are all vital to the zygote-to-ookinete transition. We discuss the implications of our findings and our high-throughput screening approach to identifying next generation, transmission-blocking antimalarials based on the scaffolds of these (+)-usnic acid derivatives.

Topics: Animals; Anopheles; Antimalarials; Benzofurans; Cell Line; Drug Discovery; Female; Insect Vectors; Malaria; Mice; Plasmodium berghei; Plasmodium falciparum; Rats; Zygote

(+)-Usnic acid (UA) has been known to be a strong uncoupler, and mitochondrial and endoplasmic reticulum (ER)-related stresses are suggested to be involved in the mechanism of hepatotoxicity. However, it has not been clarified whether UA causes toxicity in other mitochondria-rich organs such as the heart. We elucidated whether UA induces cardiotoxicity and its mechanism. UA was orally administered to rats for 14 days, and laboratory and histopathological examinations were performed in conjunction with toxicogenomic analysis. As a result, there was no alteration in blood chemistry, whereas cytoplasmic rarefaction of myocardium was observed microscopically. This finding corresponded to the swollen mitochondria observed ultrastructurally. Immunohistochemically, expression of prohibitin, indicating mitochondrial imbalance, increased in the sarcoplasmic area. Toxicogenomic analysis highlighted the upregulation of gene groups consisting of oxidative stress, ER stress, and amino acid limitation. Interestingly, the number of upregulated genes was larger in the amino acid limitation-related gene group than that in other groups, implying that amino acid limitation might be one of the sources of oxidative stress, not only mitochondria and ER-originated stresses. In conclusion, the heart was manifested to be one of the target organs of UA. Mitochondrial imbalance with complex stresses may be involved in the toxic mechanism.

Topics: Amino Acids; Animals; Anti-Infective Agents; Benzofurans; Endoplasmic Reticulum Stress; Female; Gene Expression; Heart Diseases; Microarray Analysis; Myocardium; Oxidative Stress; Rats; Rats, Inbred F344; RNA

Cancer is the second leading cause of human deaths in the USA. Despite continuous efforts to treat cancer over the past 50 years, human mortality rates have not decreased significantly. Natural products, such as lichens, have been good sources of anticancer drugs. This study reports the cytotoxic activity of crude extracts of 17 lichen species against Burkitt's lymphoma (Raji) cells. Out of the 17 lichen species, extracts from 14 species showed cytotoxicity against Raji cells. On the basis of IC50 values, we selected Xanthoparmelia chlorochroa and Tuckermannopsis ciliaris to study the mechanism of cell death. Viability of normal lymphocytes was not affected by the extracts of X. chlorochroa and T. ciliaris. We found that extracts from both lichens decreased proliferation, accumulated cells at the G0 /G1 stage, and caused apoptosis in a dose-dependent manner. Both lichen extracts also caused upregulation of p53. The T. ciliaris extract upregulated the expression of TK1 but X. chlorochroa did not. We also found that usnic, salazinic, constictic, and norstictic acids were present in the extract of X. chlorochroa, whereas protolichesterinic acid in T. ciliaris extracts. Our data demonstrate that lichen extracts merit further research as a potential source of anticancer drugs.

Topics: 4-Butyrolactone; Antineoplastic Agents; Apoptosis; Benzofurans; Cell Line, Tumor; Cell Survival; Humans; Inhibitory Concentration 50; Lactones; Lichens; Lymphocytes; Molecular Structure; Salicylates; Thymidine Kinase; Tumor Suppressor Protein p53; United States

Group A Streptococci (GAS) are involved in a number of life threatening diseases and biofilm formation by these pathogens are considered as an important virulence determinant as it mediates antibiotic resistance among them. In the present study, we have explored the ability of (+)-usnic acid, a lichen secondary metabolite, as an antibiofilm agent against four serotypes of Streptococcus pyogenes causing pharyngitis. Usnic acid inhibited the biofilms of M serotypes M56, st38, M89 efficiently and the biofilm of M74 to a lesser extent. Confocal imaging of the treated samples showed that usnic acid reduced the biomass of the biofilms when compared to that of the control. Fourier Transfer Infrared (FT-IR) spectroscopy indicated that usnic acid reduced the cellular components (proteins and fatty acids) of the biofilms. Interestingly, the FT-IR spectrum further revealed that usnic acid probably acted upon the fatty acids of the biofilms as evident from the disappearance of a peak at 2,455-2,100 cm(-1) when compared to the control only in serotypes M56, st38 and M89 but not in M74. The present study shows, for the first time, that usnic acid can act as an effective antibiofilm agent against GAS.

Topics: Anti-Bacterial Agents; Benzofurans; Biofilms; Biomass; Cytosol; Fatty Acids; Humans; Lichens; Microscopy, Confocal; Pharyngitis; Secondary Metabolism; Spectroscopy, Fourier Transform Infrared; Streptococcal Infections; Streptococcus pyogenes

Topics: Benzofurans; Cytochromes c; Depsides; Gramicidin; Insulin, Regular, Pork; Lichens; Myoglobin; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Stereoisomerism; Yohimbine

Heptane (Hep), diethyl ether (Et2O), acetone (Me2CO) and methanolic (MeOH) extracts, as well as (-)-usnic acid and squamatic acid, were obtained from thallus of Cladonia uncialis (Cladoniaceae). The antimicrobial activities of these extracts, (-)-usnic acid and squamatic acid, were tested against reference strains: Staphylococcus aureus, Escherichia coli and Candida albicans. In addition, Me2CO extract was analysed against 10 strains of Methicillin-resistant S. aureus (MRSA) isolated from patients. All extracts exerted antibacterial activity against the reference strain S. aureus, comparably to chloramphenicol [minimum inhibitory concentration (MIC) = 5.0 μg/mL]. The Me2CO extract exhibited the strongest activity against S. aureus (MIC = 0.5 μg/mL), higher than (-)-usnic acid, whereas squamatic acid proved inactive. The Me2CO extract showed potent antimicrobial activity against MRSA (MIC 2.5-7.5 μg/mL). Also no activity of C. uncialis extracts against E. coli and C. albicans was observed.

Topics: Anti-Infective Agents; Ascomycota; Benzofurans; Candida albicans; Escherichia coli; Lichens; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Staphylococcus aureus

Leishmaniasis is considered by the World Health Organization as one of the infectious parasitic diseases endemic of great relevance and a global public health problem. Pentavalent antimonials used for treatment of this disease are limited and new phytochemicals emerge as an alternative to existing treatments, due to the low toxicity and cost reduction. Usnic acid is uniquely found in lichens and is especially abundant in genera such as Alectoria, Cladonia, Evernia, Lecanora, Ramalina, and Usnea. Usnic acid has been shown to exhibit antiviral, antiprotozoal, antiproliferative, anti-inflammatory, and analgesic activity. The aim of this study was to evaluate the antileishmanial activity of usnic acid on Leishmania infantum chagasi promastigotes and the occurrence of drug-induced ultrastructural damage in the parasite. Usnic acid was effective against the promastigote forms (IC50=18.30±2.00 µg/mL). Structural and ultrastructural aspects of parasite were analyzed. Morphological alterations were observed as blebs in cell membrane and shapes given off, increasing the number of cytoplasmic vacuoles, and cellular and mitochondrial swelling, with loss of cell polarity. We concluded that the usnic acid presented antileishmanial activity against promastigote forms of Leishmania infantum chagasi and structural and ultrastructural analysis reinforces its cytotoxicity. Further, in vitro studies are warranted to further evaluate this potential.

Topics: Animals; Benzofurans; In Vitro Techniques; Leishmania infantum

The use of usnic acid as a weight loss agent is a safety concern due to reports of acute liver failure in humans. Previously we demonstrated that usnic acid induces apoptosis and cytotoxicity in hepatic HepG2 cells. We also demonstrated that usnic acid induces autophagy as a survival mechanism against its cytotoxicity. In this study, we investigated and characterized further molecular mechanisms underlying the toxicity of usnic acid in HepG2 cells. We found that usnic acid causes endoplasmic reticulum (ER) stress demonstrated by the increased expression of typical ER stress markers, including CHOP, ATF-4, p-eIF2α, and spliced XBP1. Usnic acid inhibited the secretion of Gaussia luciferase measured by an ER stress reporter assay. An ER stress inhibitor 4-phenylbutyrate attenuated usnic acid-induced apoptosis. Moreover, usnic acid significantly increased the cytosolic free Ca(2+) concentration. Usnic acid increased the expression of calcium release-activated calcium channel protein 1 (CRAM1 or ORAI1) and stromal interaction molecule 1, two key components of store-operated calcium entry (SOCE), which is the major Ca(2+) influx pathway in non-excitable cells, this finding was also confirmed in primary rat hepatocytes. Furthermore, knockdown of ORAI1 prevented ER stress and ATP depletion in response to usnic acid. In contrast, overexpression of ORAI1 increased ER stress and ATP depletion caused by usnic acid. Taken together, our results suggest that usnic acid disturbs calcium homeostasis, induces ER stress, and that usnic acid-induced cellular damage occurs at least partially via activation of the Ca(2+) channel of SOCE.

Topics: Benzofurans; Calcium; Endoplasmic Reticulum; Hep G2 Cells; Humans; Stress, Physiological

The application of magnetic nanoparticles (MNPs) in medicine is considered much promising especially because they can be handled and directed to specific body sites by external magnetic fields. MNPs have been investigated in magnetic resonance imaging, hyperthermia and drug targeting. In this study, properly functionalized core/shell MNPs with antimicrobial properties were developed to be used for the prevention and treatment of medical device-related infections. Particularly, surface-engineered manganese iron oxide MNPs, produced by a micro-emulsion method, were coated with two different polymers and loaded with usnic acid (UA), a dibenzofuran natural extract possessing antimicrobial activity. Between the two polymer coatings, the one based on an intrinsically antimicrobial cationic polyacrylamide (pAcDED) resulted to be able to provide MNPs with proper magnetic properties and basic groups for UA loading. Thanks to the establishment of acid-base interactions, pAcDED-coated MNPs were able to load and release significant drug amounts resulting in good antimicrobial properties versus Staphylococcus epidermidis (MIC = 0.1 mg/mL). The use of pAcDED having intrinsic antimicrobial activity as MNP coating in combination with UA likely contributed to obtain an enhanced antimicrobial effect. The developed drug-loaded MNPs could be injected in the patient soon after device implantation to prevent biofilm formation, or, later, in presence of signs of infection to treat the biofilm grown on the device surfaces.

Topics: Anti-Infective Agents; Benzofurans; Magnetics; Magnetite Nanoparticles; Staphylococcus epidermidis

A new series of Fe80-x-yCrxMoyP13C7 (x = 10, y = 10; x = 20, y = 5; x = 2 0, y = 10, all in at.%) bulk metallic glasses (BMGs) with the maximum diameter of 6mm have been developed for biomedical implant application by the combination method of fluxing treatment and J-quenching technique. The corrosion performance of the present Fe-based BMGs is investigated in both Hank's solution (pH = 7.4) and artificial saliva solution (pH = 6.3) at 37 °C by electrochemical measurements. The result indicates that the corrosion resistance of the present Fe-based BMGs in the above two simulated body solutions is much better than that of biomedical 316 L stainless steel (316 L SS), and approaching that of Ti6Al4V biomedical alloy (TC4). The concentrations of Fe, Ni and Cr ions released into the Hank's solution and artificial saliva solution from the present Fe-based BMGs after potentiodynamic polarization are significant lower than that released from 316 L SS. The biocompatibility of the present Fe-based BMGs is evaluated through the in vitro test of NIH3T3 cells culture in the present Fe-based BMG extraction media for 1, 3 and 5 days. The result indicates that the present Fe-based BMGs exhibit no cytotoxicity to NIH3T3 cells. And the test result of the cell adhesion and growth on the surface of the samples indicates that the present Fe-based BMGs exhibit the better cell viability compared with 316 L SS and TC4 biomedical alloys. The present Fe-based BMGs, especially Fe55Cr20Mo5P13C7 BMG, exhibit good glass formation ability, the high corrosion resistance and excellent biocompatibility, suggesting their promising potential as biomaterials.

Topics: Benzofurans; Biocompatible Materials; Materials Testing; Microscopy, Electron, Transmission; Nanocomposites; Staphylococcus epidermidis

The anti-proliferative activities of the lichen substances (-)-usnic acid and vulpinic acid on the viability of HepG2 hepatocarcinoma cells, NS20Y neuroblastoma cells and HUVEC endothelial cells were studied by the MTT assay. The anti-angiogenic potential of the substances was determined by the endothelial tube formation assay. Both lichen substances exhibited strong anti-angiogenic activity and were more cytotoxic to the cancer cell lines than to the normal cell line, but vulpinic acid has more potential as an anti-angiogenic substance because of its low cytotoxicity and stronger anti-angiogenic activity on the HUVEC cell line.

Topics: Angiogenesis Inhibitors; Antineoplastic Agents, Phytogenic; Benzofurans; Cell Line, Tumor; Furans; Human Umbilical Vein Endothelial Cells; Humans; Lichens; Phenylacetates

Usnic acid (UA) has been associated with chronic diseases through its antioxidant action. Its main target is the cell membrane; however, its effect on that of human erythrocytes has been scarcely investigated. To gain insight into the molecular mechanisms of the interaction between UA and cell membranes human erythrocytes and molecular models of its membrane have been utilized. Dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE) were chosen as representative of phospholipid classes located in the outer and inner monolayers of the erythrocyte membrane, respectively. Results by X-ray diffraction showed that UA produced structural perturbations on DMPC and DMPE bilayers. DSC studies have indicated that thermotropic behavior of DMPE was most strongly distorted by UA than DMPC, whereas the latter is mainly affected on the pretransition. Scanning electron (SEM) and defocusing microscopy (DM) showed that UA induced alterations to erythrocytes from the normal discoid shape to echinocytes. These results imply that UA molecules were located in the outer monolayer of the erythrocyte membrane. Results of its antioxidant properties showed that UA neutralized the oxidative capacity of HClO on DMPC and DMPE bilayers; SEM, DM and hemolysis assays demonstrated the protective effect of UA against the deleterious oxidant effects of HClO upon human erythrocytes.

Topics: Antioxidants; Benzofurans; Cell Shape; Cells, Cultured; Dimyristoylphosphatidylcholine; Dose-Response Relationship, Drug; Erythrocyte Membrane; Erythrocytes; Hemolysis; Humans; Hypochlorous Acid; Lipid Bilayers; Microscopy; Microscopy, Electron, Scanning; Models, Molecular; Molecular Structure; Phosphatidylethanolamines; X-Ray Diffraction

Biofilms are often the cause of chronic human infections and contaminate industrial or medical equipment. The traditional approach has been to use increasing concentrations of antibiotics, but microorganisms rapidly develop multiresistance to them. Therefore, we investigated the use of natural substances as an alternative solution. The quantification of the biofilms based on the colonized areas was measured using a Cellavista automatic microscope equipped with image analysis software. Using the Cellavista device brings new possibilities for qualification and quantification of sessile cells. In our study, this feature was documented by exploring the antifungal/anti-biofilm activity of amphotericin B, baicalein, chitosan and usnic acid against yeast biofilm formation. The influence of these substances on the formation and eradication of opportunistic pathogenic yeasts Candida parapsilosis and Candida krusei biofilms was studied in 96-well polystyrene microtiter plates. While amphotericin B was not very efficient, the use of baicalein and chitosan, even in minimum inhibitory concentrations, was found to rapidly decrease the colonized areas in the wells. The usnic acid did not display any significant antibiofilm properties even at concentration 300μgml(-1). Our results propose that Cellavista is a promising tool for the study of yeast biofilm formation and the effects of antimicrobial agents.

Topics: Amphotericin B; Anti-Infective Agents; Benzofurans; Biofilms; Candida; Chitosan; Flavanones; Humans; Image Processing, Computer-Assisted; Microbial Sensitivity Tests; Microscopy

Biofilm formation and the yeast to hyphal switch are considered to be important virulence factors of Candida albicans. The present study reports about the potential of usnic acid, a lichen secondary metabolite inhibiting these virulent factors. Usnic acid, at its biofilm inhibitory concentration (BIC) largely reduced the viability of the metabolically active cells in matured C. albicans biofilms, exhibited significant biofilm inhibition (65%) and prevented the property of adhesion. Light microscopic images revealed that usnic acid effectively inhibited the yeast to hyphal switch and confocal microscopy showed that usnic acid greatly reduced the thickness of matured biofilms. Furthermore, usnic acid was able to reduce various sugars present in the exopolysaccharide layer (EPS) which was also confirmed by FT-IR analysis. Taken together, the present study showcases usnic acid as a potent anti-virulent compound against C. albicans and opens up a new avenue for bioprospecting lichen secondary metabolites as anti-virulent compounds.

Topics: Antifungal Agents; Benzofurans; Biofilms; Candida albicans; Hyphae; Lichens; Microscopy, Confocal; Spectroscopy, Fourier Transform Infrared; Virulence

Influenza is a disease of significant morbidity and mortality, the number of anti-influenza drugs is small; many of them stimulate the appearance of resistant strains. In this work, we demonstrate activity of some usnic acid (UA) derivatives against influenza virus in vitro and in vivo.. Organic synthesis was used to prepare compounds. Antiviral activity of the compounds in vitro was evaluated by their ability to decrease the virus titer on Madin-Darby Canine Kidney cells. In vivo activity was evaluated by decrease of mortality and index of protection.. Compounds were tested against a broad spectrum of influenza virus strains and showed activity against all used strains. One compound, [5] (valine enamine of UA), also significantly reduced lethality of infected animals and does not give rise to the appearance of resistant strains. Additional studies showed that hepatotoxicity of compound [5] is reduced comparatively to UA.. Our results suggest that valine enamine of UA could be a potential candidate for the development of a new anti-influenza therapy.

Topics: Animals; Antiviral Agents; Benzofurans; Cell Survival; Dogs; Dose-Response Relationship, Drug; Female; Hepatocytes; Madin Darby Canine Kidney Cells; Mice; Mice, Inbred Strains; Microbial Sensitivity Tests; Orthomyxoviridae; Orthomyxoviridae Infections; Structure-Activity Relationship

(+)-Usnic acid (UA) is consumed as a dietary supplement to promote weight loss; however, dietary supplements containing UA have been associated with clinical cases of severe liver injury. UA has been shown to be hepatotoxic in rats and is extensively metabolized by hepatic cytochrome P450s (CYPs); therefore, we examined if UA metabolism results in the formation of cytotoxic metabolites or if metabolism is a detoxification process in primary rat hepatocytes. When CYP activity was suppressed by the non-isoenzyme-selective inhibitor SKF-525A (20 μM), or the CYP1A inhibitor alpha-naphthoflavone (10 μM), or the CYP3A inhibitor ketoconazole (25 μM), the cytotoxicity of UA at 3~6 μM after 3~20 h of exposure was significantly increased as measured by lactate dehydrogenase (LDH) leakage. At 2 h after UA exposure, an earlier time point prior to LDH release, these CYP inhibitors potentiated UA-induced inhibition of cellular respiration as determined by the Clark type oxygen electrode. Cellular adenosine triphosphate (ATP) depletion by UA was also exacerbated by these CYP inhibitors. The CYP2B/2C inhibitor, ticlopidine at 20 μM, showed no effects in parallel experiments. These data demonstrate that UA is bio-transformed to less toxic metabolites in rat primary hepatocytes, probably mainly by CYP1A and 3A, but not 2B/2C. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Topics: Animals; Benzoflavones; Benzofurans; Cells, Cultured; Chemical and Drug Induced Liver Injury; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Dietary Supplements; Enzyme Inhibitors; Hepatocytes; Ketoconazole; Liver; Male; Mitochondria; Proadifen; Rats; Rats, Sprague-Dawley; Ticlopidine

The aims of this study were the development, characterization and bioevaluation of a novel biocompatible, resorbable and bio-active wound dressing prototype, based on anionic polymers (sodium alginate--AlgNa, carboximethylcellulose--CMC) and magnetic nanoparticles loaded with usnic acid (Fe₃O₄@UA). The antimicrobial activity was tested against Staphylococcus aureus grown in biofilms. The biocompatibility testing model included an endothelial cell line from human umbilical vein and human foetal progenitor cells derived from the amniotic fluid, that express a wide spectrum of surface molecules involved in different vascular functions and inflammatory response, and may be used as skin regenerative support. The obtained results demonstrated that CMC/Fe₃O₄@UA and AlgNa/Fe₃O₄@UA are exhibiting structural and functional properties that recommend them for further applications in the biomedical field. They could be used alone or coated with different bio-active compounds, such as Fe₃O₄@UA, for the development of novel, multifunctional porous materials used in tissues regeneration, as antimicrobial substances releasing devices, providing also a mechanical support for the eukaryotic cells adhesion, and exhibiting the advantage of low cytotoxicity on human progenitor cells. The great antimicrobial properties exhibited by the newly synthesized nano-bioactive coatings are recommending them as successful candidates for improving the implanted devices surfaces used in regenerative medicine.

Topics: Alginates; Anti-Infective Agents; Bandages; Benzofurans; Biofilms; Carboxymethylcellulose Sodium; Cell Line; Cells, Cultured; Fetal Stem Cells; Glucuronic Acid; Hexuronic Acids; Humans; Magnetite Nanoparticles; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Spectroscopy, Fourier Transform Infrared; Staphylococcus aureus; X-Ray Diffraction

A series of lichen secondary metabolites (parietin, atranorin, usnic and gyrophoric acid) and their interactions with calf thymus DNA were investigated using molecular biophysics and biochemical methods. The binding constants K were estimated to range from 4.3×10(5) to 2.4×10(7)M(-1) and the percentage of hypochromism was found to be 16-34% (from spectral titration). The results of spectral measurement indicate that the compounds act as effective DNA-interacting agents. Electrophoretic separation studies prove that from all the metabolites tested in this study, only gyrophoric acid exhibited an inhibitory effect on Topo I (25μM).

Topics: Animals; Benzoates; Benzofurans; Cattle; Circular Dichroism; DNA; Emodin; Humans; Hydroxybenzoates; Intercalating Agents; Kinetics; Lichens; Nucleic Acid Conformation; Spectrophotometry, Ultraviolet; Topoisomerase I Inhibitors; Topoisomerase II Inhibitors

Reindeer (Rangifer tarandus tarandus) may include large proportions of lichens in their winter diet. These dietary lichens are rich in phenolic secondary compounds, the most well-known being the antimicrobial usnic acid. Previous studies have shown that reindeer host rumen bacteria resistant to usnic acid and that usnic acid is quickly detoxified in their rumen. In the present study, reindeer (n = 3) were sampled before, during, and after usnic acid supplementation to determine the effect on their rumen microbial ecology. Ad libitum intake of usnic acid averaged up to 278 mg/kg body mass. Population densities of rumen bacteria and methanogenic archaea determined by real-time PCR, ranged from 1.36 × 10(9) to 11.8 × 10(9) and 9.0 × 10(5) to 1.35 × 10(8) cells/g wet weight, respectively, and the two populations did not change significantly during usnic acid supplementation (repeated measures ANOVA) or vary significantly between the rumen liquid and particle fraction (paired t test). Rumen bacterial community structure determined by denaturing gradient gel electrophoresis did not change in response to intake of usnic acid. Firmicutes (38.7 %) and Bacteriodetes (27.4 %) were prevalent among the 16S rRNA gene sequences (n = 62) from the DGGE gels, but representatives of the phyla Verrucomicrobia (14.5 %) and Proteobacteria (1.6 %) were also detected. Rapid detoxification of the usnic acid or resistance to usnic acid may explain why the diversity of the dominant bacterial populations and the bacterial density in the reindeer rumen does not change during usnic acid supplementation.

Topics: Animals; Anti-Infective Agents; Archaea; Bacteria; Benzofurans; Biota; Denaturing Gradient Gel Electrophoresis; Dietary Supplements; Molecular Sequence Data; Reindeer; Rumen; Sequence Analysis, DNA

Usnic acid, a compound produced by various lichen species, has been demonstrated previously to inhibit growth of different bacteria and fungi; however, mechanism of its antimicrobial activity remained unknown. In this report, we demonstrate that usnic acid causes rapid and strong inhibition of RNA and DNA synthesis in Gram-positive bacteria, represented by Bacillus subtilis and Staphylococcus aureus, while it does not inhibit production of macromolecules (DNA, RNA, and proteins) in Escherichia coli, which is resistant to even high doses of this compound. However, we also observed slight inhibition of RNA synthesis in a Gram-negative bacterium, Vibrio harveyi. Inhibition of protein synthesis in B. subtilis and S. aureus was delayed, which suggest indirect action (possibly through impairment of transcription) of usnic acid on translation. Interestingly, DNA synthesis was halted rapidly in B. subtilis and S. aureus, suggesting interference of usnic acid with elongation of DNA replication. We propose that inhibition of RNA synthesis may be a general mechanism of antibacterial action of usnic acid, with additional direct mechanisms, such as impairment of DNA replication in B. subtilis and S. aureus.

Topics: Anti-Bacterial Agents; Benzofurans; DNA; Gram-Positive Bacteria; Lichens; Microbial Sensitivity Tests; RNA

Novel multifunctional hydroxyphenylimino ligands (L1, L2 and L3) were synthesized by the condensation of 2-aminophenol, 3-aminophenol and 4-aminophenol with usnic acid, a lichen metabolite. The synthesized ligands and their Cu(II), Co(II), Ni(II) and Mn(II) complexes were characterized using FT-IR, UV-Vis, (1)H-NMR, (13)C-NMR, 1D- and 2D NMR (DEPT, COSY, HMQC and HMBC), LC-MS and TGA. In addition, the metal complexes of the novel ligands were prepared with high yields using Cu(II), Co(II), Ni(II) and Mn(II) salts and were characterized using the FT-MIR/FAR, UV-Vis, elemental analysis, ICP-OES and TG/DTA techniques. The ligands and their complexes were tested against ten important pathogen microorganisms using the disc diffusion method and the metal complexes of the ligands were more active against all of the microorganisms tested with a broad spectrum than the ligands exhibiting 11–32 mm inhibition zones. On the other hand, a broad spectrum of the strongest antimicrobial activity was determined for the Mn(II) and Cu(II) complexes of the hydroxyphenylimino ligand with usnic acid (L3). In addition, the antimutagenic activities of all of the ligands and their metal complexes were determined using the Ames-Salmonella and E. coli WP2 microbial assay systems and they showed varied and strong antimutagenic effects. In general, it has been found that the Co and Mn complexes of the ligands possess potent antimutagenic activity. In view of these results, it can be concluded that some metal complexes can be used as antimicrobial and anticancer agents.

Topics: Aminophenols; Anti-Infective Agents; Antimutagenic Agents; Bacteria; Benzofurans; Coordination Complexes; Ligands; Metals, Heavy; Mutagens; Usnea; Yeasts

Usnic acid is a secondary metabolite found in several species of lichens, organisms resulting from the symbiosis between fungi and algae. This compound has been extensively studied because of its pharmacological properties. Despite its potential medicinal importance, it exhibits a high degree of toxicity. The confinement of the usnic acid within liposomes has been investigated as a possibility to reduce its toxicity. In this work, we characterize the interaction of usnic acid in its neutral and anionic states (usniate) with DPPC and DOPC by means of molecular dynamics simulations. A lamellar to nonlamellar transition is observed for both membranes upon contact with usniate within 100 ns time scale. The transition suggests the formation of a liposome-like structure encapsulating the metabolyte. Furthermore, such process occurs at a significantly shorter time frame for DOPC.

Topics: 1,2-Dipalmitoylphosphatidylcholine; Anions; Benzofurans; Hydrogen Bonding; Liposomes; Molecular Dynamics Simulation; Phosphatidylcholines

A strain of the lichen mycobiont of Ramalina celastri, isolated from ascospores, was cultured axenically on two solid media containing high amounts of the carbon source: sucrose in MY10 and mannitol in BMRM. Usnic acid, the major cortical lichen metabolite, was produced by the colonies grown on MY10, with a very high yield (7.9%) in comparison with that in the lichen thallus. Mycelia grown on BMRM did not produce the lichen secondary metabolite and rendered triacylglycerides (8.5%) instead. Analysis by GC-MS of the fatty acid methyl esters revealed the presence of oleic, palmitic and stearic acids as the main triacylglyceride constituents. The present results highlight the impact of the culture conditions on the lichen mycobiont secondary metabolism and confirm that MY10 is a useful medium to obtain usnic acid from mycobionts in the laboratory.

Topics: Benzofurans; Lichens; Symbiosis; Triglycerides

Due to their persistence and resistance to the current therapeutic approaches, Staphylococcus aureus biofilm-associated infections represent a major cause of morbidity and mortality in the hospital environment. Since (+)-usnic acid (UA), a secondary lichen metabolite, possesses antimicrobial activity against Gram-positive cocci, including S. aureus, the aim of this study was to load magnetic polylactic-co-glycolic acid-polyvinyl alcohol (PLGA-PVA) microspheres with UA, then to obtain thin coatings using matrix-assisted pulsed laser evaporation and to quantitatively assess the capacity of the bio-nano-active modified surface to control biofilm formation by S. aureus, using a culture-based assay. The UA-loaded microspheres inhibited both the initial attachment of S. aureus to the coated surfaces, as well as the development of mature biofilms. In vitro bioevalution tests performed on the fabricated thin films revealed great biocompatibility, which may endorse them as competitive candidates for the development of improved non-toxic surfaces resistant to S. aureus colonization and as scaffolds for stem cell cultivation and tissue engineering.

Topics: Benzofurans; Biocompatible Materials; Biofilms; Drug Carriers; Drug Delivery Systems; Drug Resistance, Bacterial; Lactic Acid; Microspheres; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Staphylococcus aureus

Lichens are resilient organisms, known for their unique profiles of secondary metabolites and for exhibiting antioxidative, antibacterial, and cytotoxic effects. Analyzing the cytotoxic potential of Lobaria scrobiculata, a bioassay-guided fractionation strategy yielded seven known metabolites, with two of these compounds, 2 and 3, exhibiting cytotoxicity against HL-60 cells. In order to verify the potential impact of degradation on observed bioactivity, a purity and stability evaluation was conducted. The consistency of results obtained by the water-soluble tetrazolium salt-1 assay and trypan blue cytotoxicity assay was evaluated for selected compounds.

Topics: Anti-Bacterial Agents; Antineoplastic Agents, Phytogenic; Benzofurans; Drug Screening Assays, Antitumor; France; HL-60 Cells; Humans; Lichens; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Phenols; Trypan Blue

Usnic acid, a major active compound in lichens, was first isolated in 1884. Since then, usnic acid and its sodium salt (sodium usnic acid) have been used in medicine, perfumery, cosmetics, and other industries due to its extensive biological activities. However, its acaricidal activity has not been studied. In this paper, we investigated the acaricidal activity of usnic acid and sodium usnic acid against Psoroptes cuniculi in vitro. After evaluating the acaricidal activity and toxicity of usnic acid and sodium usnic acid in vitro, the results showed that at doses of 250, 125, and 62.5 mg/ml, usnic acid and sodium usnic acid can kill mites with 91.67, 85.00, and 55.00% and 100, 100, and 60.00% mortality after treatment 24 h. The LT50 values were 4.208, 8.249, and 16.950 h and 3.712, 7.339, and 15.773 h for usnic acid and sodium usnic acid, respectively. Sodium usnic acid has a higher acaricidal activity than usnic acid, which may be related to the difference in their structures.

Topics: Acaricides; Animals; Benzofurans; Dose-Response Relationship, Drug; Heterocyclic Compounds, 3-Ring; Molecular Structure; Psoroptidae

Three lichen secondary metabolites atranorin (1), evernic acid (2), and usnic acid (3), were evaluated for their in vitro clastogenic and antiproliferative effects on human lymphocytes using the cytochalasin-B blocked micronucleus (CBMN) assay at concentrations of 2 microg/mL, 4 microg/mL and 6 microg/mL of final culture solution. The frequency of micronucleus (MN) was scored in binucleated cells, and cytokinesis-block proliferation index (CBPI) was calculated. Among the tested compounds, 3 exhibited the most prominent effect decreasing the frequency of MN in the range of 42.5% - 48.9%, that is about double of the positive control amifostin WR-2721 that reduces MN frequency for 22.0%. The effect of evernic acid was approximately equal to action of amifostin (23.2% -32.9%). Atranorin at concentrations of 2 microg/mL and 4 microg/mL decreasing the frequency of MN only for 11.1% and 1.8%, while in concentration of 6 microg/mL increases the frequency of MN for 9.6 %. The comparable CBPI values of the investigated compounds and control suggested that they did not show a statistically significant inhibitory effect on lymphocyte cell proliferation at applied concentrations.

Topics: Benzofurans; Cell Proliferation; Humans; Hydroxybenzoates; Lymphocytes; Molecular Structure

The use of controlled drug delivery systems could give a significant contribution to the improvement of therapies against biofilm-based infections. The aim of this study was to develop polymer microparticles, based on carboxylated poly(L-lactide)s, to be employed as carriers for usnic acid (UA), a poorly soluble drug possessing antiviral, antiproliferative and wide spectrum antimicrobial activity. Thanks to polymer surfactant-like structure, 2.4 μm-in-size microparticles were obtained by a surfactant-free oil-in-water emulsion/evaporation method. UA was encapsulated into these microparticles with a high loading efficiency (80%). The drug release kinetics was found to be temperature dependent (the released dose increasing with temperature) and showed bimodal release behavior. By polarized optical microscopy observations and the application of kinetics models, the initial burst effect was attributed to the delivery of the drug amorphous fraction while the slower release occurring for longer times to the crystalline one, both entrapped in the polymer amorphous phase. UA-loaded microparticles were able to promote the killing of a 24h-old Staphylococcus epidermidis biofilm more efficaciously than free UA.

Topics: Anti-Bacterial Agents; Benzofurans; Biofilms; Calorimetry, Differential Scanning; Carboxylic Acids; Microscopy, Electron, Scanning; Polyesters; Staphylococcus epidermidis

Bioassay-guided fractionation of an extract of the lichen Cladonia incrassata against Staphylococcus aureus led to a novel compound, 1,5-dihydroxy-2,4,6-trichloro-7-methylxanthone (1), along with six known compounds: (-)-usnic acid (2), didymic acid (3), condidymic acid (4), squamatic acid (5), thamnolic acid (6), and prasinic acid (7). Didymic, condidymic, and prasinic acids were isolated for the first time from C. incrassata. Didymic, condidymic, and (-)-usnic acids were active against S. aureus (a minimum inhibitory concentration of 7.5 µg/mL).

Topics: Anti-Bacterial Agents; Aspergillus; Benzofurans; Candida albicans; Halogenation; Lichens; Microbial Sensitivity Tests; Molecular Structure; Staphylococcus aureus; Xanthenes; Xanthones

Usnic acid is a dibenzofuran derivative found in several lichen species, which has been shown to possess several activities, including antiviral, antibiotic, antitumoral, antipyretic, analgesic, antioxidative and anti-inflammatory activities. However, there were few reports on the effects of usnic acid on LPS-induced acute lung injury (ALI). The aim of our study was to explore the effect and possible mechanism of usnic acid on LPS-induced lung injury. In the present study, we found that pretreatment with usnic acid significantly improved survival rate, pulmonary edema. In the meantime, protein content and the number of inflammatory cells in bronchoalveolar lavage fluid (BALF) significantly decreased, and the levels of MPO, MDA, and H2O2 in lung tissue were markedly suppressed after treatment with usnic acid. Meanwhile, the activities of SOD and GSH in lung tissue significantly increased after treatment with usnic acid. Additionally, to evaluate the anti-inflammatory activity of usnic acid, the expression of pro-inflammatory cytokines including tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and anti-inflammatory cytokine IL-10, and chemokines interleukin-8 (IL-8) and macrophage inflammatory protein-2 (MIP-2) in BALF were studied. The results in the present study indicated that usnic acid attenuated the expression of TNF-α, IL-6, IL-8 and MIP-2. Meanwhile, the improved level of IL-10 in BALF was observed. In conclusion, these data showed that the protective effect of usnic acid on LPS-induced ALI in mice might relate to the suppression of excessive inflammatory responses and oxidative stress in lung tissue. Thus, it was suggested that usnic acid might be a potential therapeutic agent for ALI.

Topics: Acute Lung Injury; Animals; Anti-Inflammatory Agents; Antioxidants; Benzofurans; Bronchoalveolar Lavage Fluid; Cell Count; Cytokines; Glutathione; Hydrogen Peroxide; Lipopolysaccharides; Lung; Male; Mice; Oxidative Stress; Peroxidase; Superoxide Dismutase

The use of usnic acid and usnic acid-containing products is associated with acute liver failure; however, mechanistic studies of hepatotoxicity caused by usnic acid are limited. In this study, we investigated and characterized the possible mechanisms, especially the role of autophagy in usnic acid's toxicity in human HepG2 cells. Usnic acid caused apoptosis as demonstrated by an increased caspase-3/7 activity and an increased subdiploid nucleus formation. Usnic acid-induced autophagy as demonstrated by the conversion of LC3B-I to LC3B-II, degradation of P62, and an increased number of puncta. Inhibition of autophagy by treating cells with autophagy inhibitors (3-methyladenine or chloroquine) or by small interfering RNA against Atg7 aggravated usnic acid-induced apoptosis and decreased cell viability, indicating that autophagy plays a protective role against usnic acid-induced toxicity. Moreover, usnic acid activated the MAPK signaling pathway. Usnic acid-elicited apoptosis was enhanced and autophagy was decreased when JNK was suppressed by a specific inhibitor. Additionally, inhibition of autophagy decreased the activity of JNK. Taken together, our results suggest that usnic acid perturbs various interrelated signaling pathways and that autophagy induction is a defensive mechanism against usnic acid-induced cytotoxicity.

Topics: Apoptosis; Autophagy; Benzofurans; Caspase 3; Caspase 7; Cell Culture Techniques; Cell Cycle; Cell Survival; Hep G2 Cells; Humans; Liver; MAP Kinase Kinase 4; MAP Kinase Signaling System

In the present study, we investigated the effects of usnic acid (UA) on the endoplasmic reticulum (ER) stress processes in rat cardiomyocytes.. Gene expression of pro-inflammatory cytokines and activation of ER stress signaling were analyzed. Besides, levels of phosphorylated AMPK were measured to evaluate the mechanisms of UA. Finally, small interfering RNA (siRNA) oligos targeting AMPK subunits were used to determine the roles of AMPK in rat cardiomyocytes treated with UA.. We found that UA treatment significantly reduced ER stress activation and expression of pro-inflammatory cytokines, via an AMPK signaling-dependent manner.. UA might be useful to reduce the occurrence of adverse cardiovascular events.

Topics: AMP-Activated Protein Kinases; Animals; Benzofurans; Cells, Cultured; Endoplasmic Reticulum Stress; Enzyme Activation; Gene Expression; Myocytes, Cardiac; Phosphorylation; Rats; Signal Transduction

Lichens are symbiotic organisms which produce distinct secondary metabolic products. In the present study, we tested the cytotoxic activity of 17 lichen species against several human cancer cells and further investigated the molecular mechanisms underlying their anti-cancer activity. We found that among 17 lichens species, F. cucullata exhibited the most potent cytotoxicity in several human cancer cells. High performance liquid chromatography analysis revealed that the acetone extract of F. cucullata contains usnic acid, salazinic acid, Squamatic acid, Baeomycesic acid, d-protolichesterinic acid, and lichesterinic acid as subcomponents. MTT assay showed that cancer cell lines were more vulnerable to the cytotoxic effects of the extract than non-cancer cell lines. Furthermore, among the identified subcomponents, usnic acid treatment had a similar cytotoxic effect on cancer cell lines but with lower potency than the extract. At a lethal dose, treatment with the extract or with usnic acid greatly increased the apoptotic cell population and specifically activated the apoptotic signaling pathway; however, using sub-lethal doses, extract and usnic acid treatment decreased cancer cell motility and inhibited in vitro and in vivo tumorigenic potentials. In these cells, we observed significantly reduced levels of epithelial-mesenchymal transition (EMT) markers and phosphor-Akt, while phosphor-c-Jun and phosphor-ERK1/2 levels were only marginally affected. Overall, the anti-cancer activity of the extract is more potent than that of usnic acid alone. Taken together, F. cucullata and its subcomponent, usnic acid together with additional component, exert anti-cancer effects on human cancer cells through the induction of apoptosis and the inhibition of EMT.

Topics: Animals; Annexin A5; Antineoplastic Agents; Apoptosis; Benzofurans; Carcinogenesis; Cell Adhesion; Cell Line, Tumor; Cell Movement; Cell Nucleus; Cell Proliferation; G1 Phase; Humans; Lichens; Mice, Inbred BALB C; Mice, Nude; Phosphorylation; Proto-Oncogene Proteins c-akt; Secondary Metabolism

In Brazil, the snail Biomphalaria glabrata is the most important vector of schistosomiasis due to its wide geographical distribution, high infection rate and efficient disease transmission. Among the methods of schistosomiasis control, the World Health Organization recommends the use of synthetic molluscicides, such as niclosamide. However, different substances of natural origin have been tested as alternatives for the control or eradication of mollusks. The literature describes the antitumor, antimicrobial and antiviral properties of usnic acid as well as other important activities of common interest between medicine and the environment. However, usnic acid has a low degree of water solubility, which can be a limiting factor for its use, especially in aquatic environments, since the organic solvents commonly used to solubilize this substance can have toxic effects on aquatic biota. Thus, the aim of the present study was to test the potassium salt of usnic acid (potassium usnate) with regard to molluscicidal activity and toxicity to brine shrimp (Artemia salina). To obtain potassium usnate, usnic acid was extracted with diethyl ether isolated and purified from the lichen Cladonia substellata. Biological assays were performed with embryos and adult snails of B. glabrata exposed for 24 h to the usnate solution solubilized in dechlorinated water at 2.5; 5 and 10 µg/ml for embryos, 0.5; 0.9; 1;5 and 10 µg/ml for mollusks and 0.5; 1; 5; 10 µg/ml for A. salina. The lowest lethal concentration for the embryos and adult snails was 10 and 1 µg/ml, respectively. No toxicity to A. salina was found. The results show that modified usnic acid has increased solubility (100%) without losing its biological activity and may be a viable alternative for the control of B. glabrata.

Topics: Animals; Benzofurans; Biomphalaria; Molluscacides; Schistosoma mansoni; Schistosomiasis

Influenza virus is serious human pathogen leading to high morbidity and mortality all over the world. Due to high rate of mutation, it is able to fast development of drug resistance that makes necessary to search novel antivirals with broad range and alternative targets. In the present study we describe synthesis and anti-viral activity of novel derivatives of usnic acid (2,6-diacetyl-7,9-dihydroxy-8,9b-dimethyl-1,3(2H,9bH)-dibenzo-furandione). It is shown that anti-viral activity of usnic acid can be increased by side moieties introduction. The modification with chalcones appeared to be the most effective. Our study revealed that (-)-usnic acid exhibited higher antiviral activity than its (+)-enantiomer, but in the pairs of enantiomer derivatives such as enamines, pyrazoles and chalcones, the (+)-enantiomers were more potent inhibitors of the virus. For other groups of compounds the inhibiting activities of the enantiomers were comparable. Further optimization of the structure could therefore result in development of novel anti-influenza compound with alternative target and mechanism of virus-inhibiting action.

Topics: Animals; Antiviral Agents; Benzofurans; Cell Survival; Dogs; Humans; Influenza A virus; Madin Darby Canine Kidney Cells; Stereoisomerism; Structure-Activity Relationship; Virus Replication

Three lichen extracts and ten lichenic compounds have been screened for their photoprotective activities. The determination of their Sun Protection Factor (SPF) and Protection Factor-UVA (PF-UVA) values was done in vitro. Among them, a Lasallia pustulata extract and gyrophoric acid exhibited SPF values over 5, which is better than Homosalate (SPF≈4). Their photoprotective properties are only slightly modified after a 2-hours period of irradiation. Salazinic acid and L. pustulata presented characteristics of a UVA booster like the butyl-methoxydibenzoylmethane (Avobenzone) (PF-UVA≈2 vs. 2.8 for Avobenzone). Salazinic acid was a better anion superoxide scavenger than ascorbic acid and none of them exhibited a photosensitizing cytotoxicity by exposing them on HaCaT cells to UVA radiations (photo-irritancy factor PIF<5).

Topics: Antioxidants; Ascomycota; Benzoates; Benzofurans; Cell Line; Fumarates; Humans; Lactones; Salicylates; Sun Protection Factor; Ultraviolet Rays; Usnea

Usnic acid is a naturally occurring dibenzofuran derivative found in several lichen species. The compound has been marketed as an ingredient of food supplements for weight reduction. There is evidence that the compound acts as an uncoupler of mitochondrial oxidative phosphorylation and it is also clear that consumption of the drug can lead to severe hepatotoxicity depending on the doses. Based on these and other ideas the objective of the present work was to investigate the possible effects of usnic acid on liver metabolism. Livers of male Wistar rats were perfused in a non-recirculating system. Usnic acid stimulated oxygen consumption at low concentrations, diminished the cellular ATP levels, increased the cytosolic but diminished the mitochondrial NADH/NAD(+) ratio, strongly inhibited gluconeogenesis from three different substrates (IC(50) between 1.33 and 3.61 μM), stimulated glycolysis, fructolysis, glycogenolysis and ammoniagenesis and inhibited ureogenesis. The (14)CO(2) production from [1-(14)C]octanoate and [1-(14)C]oleate was increased by usnic acid, but ketogenesis from octanoate was diminished and that from oleate was not affected. It may be concluded that the effects of usnic acid up to 2.5 μM reflect predominantly its activity as an uncoupler. At higher concentrations, however, several other effects may become significant, including inhibition of mitochondrial electron flow and inhibition of medium-chain fatty acid oxidation. In metabolic terms, toxicity of usnic acid can be predicted to be especially dangerous in the fasted state due to the combination of several deleterius events such as diminished hepatic glucose and ketone bodies output to the brain and increased ammonia production.

Topics: Adenine Nucleotides; Alanine; Animals; Anti-Obesity Agents; Benzofurans; Fatty Acids; Fructose; Glucose; Glycogen; Glycolysis; Lactic Acid; Liver; Male; Rats; Rats, Wistar

Wound healing is a significant concern in many pathologies (post-surgeries, burns, scars) and the search for new chemical entities is advisable. The lichen compound (+)-usnic acid (1) has found application in dermatological and cosmetic preparations, due to its bacteriostatic and antioxidant activities. The compound has also been shown to stimulate the wound closure of keratinocyte monolayers at subtoxic doses. Here we describe the design and synthesis of usnic acid enamines (compounds 2-11), obtained through nucleophilic attack of amino acids or decarboxyamino acids at the acyl carbonyl of the enolized 1,3 diketone. The wound repair properties of these derivatives were evaluated using in vitro and in vivo assays. Compounds 8 and 9 combine low cytotoxicity with high wound healing performance, suggesting their possible use in wound healing-promoting or antiage skin preparations.

Topics: Animals; Anti-Infective Agents; Antioxidants; Benzofurans; Cell Line; Cell Survival; Humans; Keratinocytes; Lichens; Male; Mice; Rats; Rats, Sprague-Dawley; Wound Healing

Usnic acid is one of the most common and abundant metabolites found in various lichen genera, which are important sources of biologically active compounds. The aim of this study was to evaluate the genotoxic and antigenotoxic potential of (+)-usnic acid (UA) by the micronucleus and comet assays in V79 cell cultures and Swiss mice. For assessment of genotoxicity, V79 cells were treated with 15, 30, 60, and 120μg/mL UA, established based on clonogenic efficiency cytotoxic assay. Swiss mice were treated with UA doses of 25, 50, 100, and 200mg/kg body weight. The same concentrations of UA were combined with methyl methanesulfonate (MMS) for evaluation of antigenotoxicity. The in vitro results demonstrated that UA induced DNA damage at concentrations of 60 and 120μg/mL in the comet assay. However, no genotoxic effect was observed in the micronucleus test using V79 cells at the concentrations tested. No genotoxic effects were observed for the different UA treatments in in vivo test system. Combined administration of UA and MMS significantly reduced the frequencies of micronuclei and DNA damage in vitro and in vivo when compared to treatment with MMS alone. Although the mechanisms underlying the protective effect of UA are not completely understood, the antioxidant activity of this metabolite may explain its protective effect against MMS-induced genotoxicity.

Topics: Animals; Antimutagenic Agents; Antioxidants; Benzofurans; Bone Marrow; Cell Line; Comet Assay; Dose-Response Relationship, Drug; Male; Methyl Methanesulfonate; Mice; Micronucleus Tests

Usnic acid, a potent antimicrobial and anticancer agent, poorly soluble in water, was complexed to novel antimicrobial polyacrylamides by establishment of strong acidic-base interactions. Thermal and spectroscopic analysis evidenced a molecular dispersion of the drug in the polymers and a complete drug/polymer miscibility for all the tested compositions. The polymer/drug complexes promptly dissolved in water and possessed a greater antimicrobial activity against Staphylococcus epidermidis than both the free drug and the polymer alone. The best results were obtained with the complex based on the lowest molecular weight polymer and containing a low drug content. Such a complex showed a larger inhibition zone of bacterial growth and a lower minimum inhibitory concentration (MIC) with respect to usnic acid alone. This improved killing effect is presumably due to the reduced size of the complexes that allows an efficient cellular uptake of the antimicrobial complexes. The killing effect extent seems to be not significantly dependent on usnic acid content in the samples.

Topics: Acrylic Resins; Anti-Infective Agents; Benzofurans; Solubility; Staphylococcus epidermidis

Acetone-extractable carbon based secondary compounds (CBSCs) were quantified in two epiphytic lichens to study possible effects of external factors (season and aspect) on secondary chemistry and to relate defense investments to biomass growth and changes in specific thallus mass (STM). At the end of four separate annual cycles starting in each of the four seasons, the cyanolichen Lobaria scrobiculata and the cephalolichen Lobaria pulmonaria (green algae as the primary photobiont and with localized Nostoc in internal cephalodia) were monitored in their natural forest habitats and after being transplanted at three contrasting aspects in open sites. Season strongly influenced most CBSCs. Medullary CBSCs in both species were twice as high in summer as in winter. Aspect hardly affected major CBSCs, whereas transplantation from forest to clear-cut slightly reduced these compounds. No major CBSCs in any species showed a trade-off with growth rate. Dry matter- as well as thallus area-based medullary CBSC contents increased with STM. The cortical usnic acid strongly increased with growth rate and followed spatial, but not seasonal variations in light exposure. Maximal CBSC levels during seasons with most herbivores is consistent with the hypothesis inferring that herbivory is a major selective force for CBSCs. Lack of trade-off between growth and defence investments suggests that these two processes do not compete for photosynthates.

Topics: Benzofurans; Biomass; Carbon; Chlorophyta; Cyanobacteria; Ecosystem; Lichens; Light; Seasons; Trees

Usnic acid (UA) is a secondary metabolite abundantly found in lichens. Some studies have shown the anticancer potential of UA; however, its efficacy and associated mechanisms are yet to be fully explored. Herein, we assessed the anticancer potency and associated molecular alterations by UA in human lung carcinoma A549 cells. UA treatment (25-100 μM) for 24 and 48 h decreased total cell number by 39-67% (P < 0.01) and 68-89% (P < 0.001), respectively, and enhanced cell death by up to twofold and eightfold (P < 0.001), respectively. UA (1-10 μM) also significantly (P < 0.001) suppressed colony formation of A549 cells. The cell growth inhibition was associated with cell cycle arrest at G0/ G1 phase. UA decreased the expression of cyclin-dependent kinase (CDK)4, CDK6, and cyclin D1 and increased the expression of CDK inhibitor (CDKI) p21/cip1 protein. While examining the cell death associated molecular changes, we observed that UA induces mitochondrial membrane depolarization and led to more than twofold increase (P < 0.01) in apoptotic cells. The apoptotic effect of UA was accompanied by enhanced poly(ADP-ribose) polymerase cleavage. This study shows that UA inhibits cell growth involving G0/G1 phase cell cycle arrest and induces cell death via mitochondrial membrane depolarization and induction of apoptosis in human lung carcinoma cells.

Topics: Antineoplastic Agents; Apoptosis; Benzofurans; Cell Cycle Checkpoints; Cell Line, Tumor; Cyclin D1; Cyclin-Dependent Kinase 4; Cyclin-Dependent Kinase 6; Cyclin-Dependent Kinase Inhibitor p21; G1 Phase; Gene Expression Regulation; Humans; Lichens; Lung Neoplasms; Poly(ADP-ribose) Polymerases

To investigate the chemical constituents of the lichen plants Parmelia tinctorum and Parmelia nimandairana collected from Meng Mountain in Shandong province.. Various chromatographic techniques were used to isolate and purify the constituents and their structures were elucidated by means of spectral evidence and physiochemical properties.. Four compounds were isolated from Parmelia tinctorum and identified as: lecanoric acid (I), evernic acid (II), ethyl orsellinate (III) and 3,5-dihydroxytoluene (IV). Two compounds were isolated from Parmelia nimandairana and identified as: usnic acid (V) and salazinic acid (VI).. Compounds V and VI are isolated from Parmelia nimandairana for the first time.

Topics: Benzofurans; China; Chromatography, High Pressure Liquid; Hydroxybenzoates; Lactones; Lichens; Molecular Structure; Resorcinols; Salicylates; Solvents

The purpose of this study was to investigate the effects of six lichen metabolites (diffractaic acid, lobaric acid, usnic acid, vicanicin, variolaric acid, protolichesterinic acid) on proliferation, viability and reactive oxygen species (ROS) level towards three human cancer cell lines, MCF-7 (breast adenocarcinoma), HeLa (cervix adenocarcinoma) and HCT-116 (colon carcinoma). Cells were treated with different concentrations (2.5-100 μM) of these compounds for 48 h. In this comparative study, our lichen metabolites showed various cytotoxic effects in a concentration-dependent manner, and usnic acid was the most potent cytotoxic agent, while variolaric acid did not inhibit the proliferation of any of the three cell lines used. All tested lichen compounds did not exhibit free radical scavenging activity using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The lichen metabolites did not significantly increase the intracellular ROS level and did not prevent oxidative injury induced by t-butylhydroperoxide in HeLa cells. To better clarify the mechanism(s) of cytotoxic effect induced by protolichesterinic acid in HeLa cells, we investigated apoptotic markers such as condensation and fragmentation of nuclear chromatin and activation of caspase-3, 8 and 9. Our results revealed that the antiproliferative activity of 40 μM protolichesterinic acid in HeLa cells is related to its ability to induce programmed cell death involving caspase-3, 8 and 9 activation.

Topics: 4-Butyrolactone; Anisoles; Antioxidants; Apoptosis; Benzofurans; Caspases; Cell Line, Tumor; Cell Proliferation; Cell Survival; Depsides; Free Radical Scavengers; Humans; Hydroxybenzoates; Lactones; Lichens; Oxidative Stress; Reactive Oxygen Species; Salicylates

Au naturel! (+)-Usnic acid (green) is a weak antimalarial agent, however, in conjugation with known antimalarial scaffolds and drugs, such as dihydroartemisinin (blue), potent activity against the blood-stage parasite can be seen both in vitro and in vivo. The compound shown exhibits an IC(50) value of 1.4 nM against Plasmodium falciparum in vitro and proved nearly as efficacious as artesunate in a mouse model of infection.

Topics: Animals; Antimalarials; Artemisinins; Benzofurans; Biological Products; Cell Line; Drug Discovery; Female; Malaria, Falciparum; Mice; Parasitic Sensitivity Tests; Plasmodium falciparum; Rats

Three secondary metabolites of lichens - usnic acid, atranorin and fumarprotocetraric acid - were evaluated for their in vitro antibacterial and antibiofilm activities against three strains each of methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MRSA) from cystic fibrosis patients.. Antibacterial activity was assessed by broth microdilution, while antibiofilm activity was evaluated by spectrophotometry or viable count.. Usnic acid was significantly more active than atranorin against planktonic cells, while fumarprotocetraric acid exhibited no activity. Atranorin was the most effective in counteracting adhesion to polystyrene, although usnic acid was more active against MRSA. Usnic acid and atranorin showed comparable activity against biofilm formation, although atranorin was more active against MRSA. Usnic acid was significantly more active than atranorin against preformed biofilms.. Secondary metabolites of lichens may be considered to be 'lead compounds' for the development of novel molecules for the treatment of S. aureus infections in cystic fibrosis patients.

Topics: Anti-Bacterial Agents; Benzofurans; Biofilms; Biological Products; Colony Count, Microbial; Cystic Fibrosis; Fumarates; Humans; Hydroxybenzoates; Lichens; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Plant Extracts; Staphylococcal Infections

The larvicidal activity of some lichen metabolites, (+)-usnic acid, atranorin, 3-hydroxyphysodic acid and gyrophoric acid, against the second and third instar larvae of the mosquito Culiseta longiareolata were studied. All metabolites caused high larvicidal activities. When metabolites were compared on the basis of their LC(50) values, the order of increasing toxicity was as follows: gyrophoric acid (0.41 ppm) > (+)-usnic acid (0.48 ppm) > atranorin (0.52 ppm) > 3-hydroxyphysodic acid (0.97 ppm). However, when LC(90) values were compared, the order of toxicity was (+)-usnic acid (1.54 ppm) > gyrophoric acid (1.93 ppm) > 3-hydroxyphysodic acid (4.33 ppm) > atranorin (5.63 ppm). In conclusion, our results found that lichen secondary metabolites may have a promising role as potential larvicides.

Topics: Animals; Benzoates; Benzofurans; Culicidae; Dibenzoxepins; Hydroxybenzoates; Insecticides; Larva; Lethal Dose 50; Lichens; Molecular Structure

Usnic acid, a natural botanical product, is a constituent of some dietary supplements used for weight loss. It has been associated with clinical hepatotoxicity leading to liver failure in humans. The present study was undertaken for metabolism and toxicity evaluations of usnic acid in human hepatoblastoma HepG2 cells in culture. The cells were treated with the vehicle control and usnic acid at concentrations of 0-100 µm for 24 h at 37 °C in 5% CO2 . Following the treatment period, the cells were evaluated by biochemical and toxicogenomic endpoints of toxicity that included cytochrome P450 activity, cytotoxicity, oxidative stress, mitochondrial dysfunction and changes in pathway focused gene expression profiles. Usnic acid exposure resulted in increased P450 activity, cytotoxicity, oxidative stress and mitochondrial dysfunction in HepG2 cells. The pathway-focused gene expression analysis resulted in significantly altered expression of six genes out of a total of 84 genes examined. Of the six altered genes, three genes were up-regulated and three genes down-regulated. A marked up-regulation of one gene CCL21 associated with inflammation, one gene CCNC associated with proliferation and carcinogenesis and one gene UGT1A4 associated with metabolism as well as DNA damage and repair were observed in the usnic acid-treated cells compared with the vehicle control. Also a marked down-regulation of one gene CSF2 associated with inflammation and two genes (CYP7A1 and CYP2E1) associated with oxidative metabolic stress were observed in the usnic acid-treated cells compared with the control. The biomarkers used in this study demonstrate the toxicity of usnic acid in human hepatoblastoma HepG2 cells, suggesting an oxidative mechanism of action.

Topics: Anti-Infective Agents; Anti-Obesity Agents; Benzofurans; Biomarkers; Cell Survival; Cytochrome P-450 Enzyme System; Gene Expression; Hep G2 Cells; Hepatoblastoma; Hepatocytes; Humans; Liver Neoplasms; Membrane Potential, Mitochondrial; Mitochondria, Liver; Mitochondrial Diseases; Oxidative Stress

The activity of usnic acid against Candida orthopsilosis and Candida parapsilosis on planktonic and biofilm conditions was investigated by using a broth microdilution and microplate methods. Potent in vitro activities against different Candida species were obtained. The metabolic activity of sessile cells of C. parapsilosis complex was reduced by 80% at four times the 80% inhibitory concentration. The in vitro studies support further efforts to determine whether usnic acid can be used clinically to cure patients with Candida infections.

Topics: Antifungal Agents; Benzofurans; Biofilms; Candida; Candidiasis; Humans; Microbial Sensitivity Tests; Plankton

The development of miniaturized Raman instrumentation is in demand for applications relevant to forensic, pharmaceutical and art analyses, as well as geosciences, and planetary exploration. In this study we report on evaluation of a portable dispersive Raman spectrometer equipped with 1064 nm laser excitation. Selected samples from geological, geobiological and forensic areas of interest have been studied from which the advantages, disadvantages and the analytical potential of the instrument are assessed based on a comparison with bench instrumentation and other portable Raman spectrometers using 785 nm excitation. It is demonstrated that the instrument operating with 1064 nm excitation has potential for expanding the number and types of samples that can be measured by miniaturized Raman spectroscopy without interfering fluorescence background emission. It includes inorganic and organic minerals, biomolecules within living lichen and endolithic cyanobacteria as well as drugs of abuse and explosives.

Topics: Amber; Benzoates; Benzofurans; beta Carotene; Calcium Oxalate; Explosive Agents; Forensic Sciences; Fossils; Geology; Illicit Drugs; Mercury Compounds; Minerals; Polystyrenes; Spectrum Analysis, Raman

The in vitro antimicrobial activities of usnic acid were evaluated in combination with five therapeutically available antibiotics, using checkerboard microdilution assay against methicillin-resistant clinical isolates strains of Staphylococcus aureus. MIC₉₀, MIC₅₀, as well as MBC₉₀ and MBC₅₀, were evaluated. A synergistic action was observed in combination with gentamicin, while antagonism was observed with levofloxacin. The combination with erythromycin showed indifference, while variability was observed for clindamycin and oxacillin. Data from checkerboard assay were analysed and interpreted using the fractional inhibitory concentration index (FICI) and the response surface approach using the ΔE model. Discrepancies were found between both methods for some combinations. These could mainly be explained by the failure of FIC approach, being too much subjective and sensitive to experimental errors. These findings, beside confirm the well known antimicrobial activity of usnic acid, suggest, however, that this substance might be a good candidate for the individuation of novel templates for the development of new antimicrobial agents or combinations of drugs for chemotherapy.

Topics: Anti-Bacterial Agents; Benzofurans; Clindamycin; Culture Media; Drug Resistance, Multiple, Bacterial; Drug Synergism; Erythromycin; Gentamicins; Levofloxacin; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Models, Biological; Ofloxacin; Oxacillin

Usnic acid (UA) is the most common and abundant lichenic secondary metabolite with potential therapeutic application. Anti-inflammatory and antitumour properties have already been reported and UA-enriched extracts are widely used to treat several diseases in the folk medicine. First, we performed in silico evaluation of UA interactions with genes/proteins and important compounds for cellular redox balance and NO pathway. Then, we assessed UA redox properties against different reactive species (RS) generated in vitro, and evaluated its action on SH-SY5Y neuronal like cells upon hydrogen peroxide (H(2)O(2)), since no in vitro neurotoxicological data has been reported so far. Total reactive antioxidant potential index (TRAP) showed a significant antioxidant capacity of UA at the highest tested concentration; UA was also effective against hydroxyl radicals and reduced the formation of nitric oxide. In vitro, lipoperoxidation was enhanced by UA and changed the cellular viability at highest concentration of 20μg/mL for 1 and 4h, as well as 2 and 20μg/mL for 24h of treatment, according to MTT reduction assay. Moreover, UA did not display protective effects against H(2)O(2)-induced cell death in any case. Evaluation of intracellular RS production by the DCFH-based assay indicated that UA was able to induce changes in basal RS production at concentration of 20μg/mL for 1h and from 2ng/mL to 20μg/mL for 4 and 24h. In conclusion, UA could display variable redox-active properties, according to different system conditions and/or cellular environment. Moreover, our results suggest that potential neurotoxicological effects of UA should be further studied by additional approaches; for instance, in vivo and clinical studies.

Topics: Benzofurans; Cell Line, Tumor; Cell Survival; Humans; Hydrogen Peroxide; Hydroxyl Radical; Nitric Oxide; Oxidation-Reduction; Superoxide Dismutase; Thiobarbituric Acid Reactive Substances

Tumor growth depends on angiogenesis and inducing angiogenesis is one of the most important hallmarks in the cancer development. Treatment with small molecules that inhibit angiogenesis has been an effective strategy for anti-cancer therapy. Some anti-angiogenic factors are derived from traditional Chinese herbs. Usnic acid (UA), an active compound mainly found in lichens, has shown some biological and physiological activities. However, the role and mechanism of UA in tumor angiogenesis are still unknown. The aim of this study was to assess the effects of UA on tumor angiogenesis. In this study, we demonstrated that UA strongly inhibited in vivo angiogenesis in a chick embryo chorioallantoic membrane assay and vascular endothelial growth factor-induced mouse corneal angiogenesis model. In a mouse xenograft tumor model, UA suppressed Bcap-37 breast tumor growth and angiogenesis without affecting mice body weight. In an in vitro assay, UA not only significantly inhibited endothelial cell proliferation, migration and tube formation, but also induced morphological changes and apoptosis in endothelial cells. In addition, UA inhibited Bcap-37 tumor cell proliferation. Moreover, western blot analysis of cell signaling molecules indicated that UA blocked vascular endothelial growth factor receptor (VEGFR) 2 mediated Extracellular signal-regulated protein kinases 1 and 2(ERK1/2) and AKT/P70S6K signaling pathways in endothelial cells. These results provided the first evidence of the biological function and molecular mechanism of UA in tumor angiogenesis.

Topics: Animals; Apoptosis; Benzofurans; Blotting, Western; Breast Neoplasms; Cell Proliferation; Cells, Cultured; Chick Embryo; Female; Humans; Immunohistochemistry; MAP Kinase Signaling System; Mice; Neovascularization, Pathologic; Proto-Oncogene Proteins c-akt; Signal Transduction; Transplantation, Heterologous; Vascular Endothelial Growth Factor Receptor-2

The influence of a number of usnic acid derivatives on auto(polyADP-ribosyl)ation catalyzed by PARP1 and DNA synthesis catalyzed by DNA polymerase β was studied. The derivatives of usnic acid containing aromatic substituents were shown to be moderate inhibitors of PARP1. The presence of both usnic acid tricyclic structure and aromatic substituent at any position of the molecule is a key factor for the inhibitory action. In the case of DNA polymerase β, no relationship between the structure and inhibitory properties has been found with the only exception. Derivatives with modified ring A showed mild activation of DNA synthesis catalyzed by DNA polymerase β.

Topics: Animals; Benzofurans; Cell Line; Cell Survival; DNA; DNA Polymerase beta; Enzyme Inhibitors; Humans; Hydrophobic and Hydrophilic Interactions; Kinetics; Mice; Molecular Structure; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerase Inhibitors; Poly(ADP-ribose) Polymerases; Recombinant Proteins

Usnic acid, a lichen metabolite, is used as a dietary supplement for weight loss. However, clinical studies have shown that usnic acid causes hepatotoxicity. The present study aims to investigate the mechanism of usnic acid hepatotoxicity in vivo. Two-dimensional gel electrophoresis coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used to analyze the expression profiles of differentially regulated and expressed proteins in rat liver after usnic acid administration. The results reveal the differential expression of 10 proteins in usnic-acid-treated rats compared to the normal controls. These proteins are associated with oxidative stress, lipid metabolism, and several other molecular pathways. The endoplasmic reticulum and mitochondria may be the primary targets of usnic-acid-induced hepatotoxicity.

Topics: Animals; Benzofurans; Chemical and Drug Induced Liver Injury; Electrophoresis, Gel, Two-Dimensional; Endoplasmic Reticulum; Hepatocytes; Liver Diseases; Male; Mitochondria, Liver; Oxidative Stress; Proteins; Proteomics; Rats; Rats, Wistar; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Transcriptome

Lichens have been used for various purposes such as dyes, perfumes and remedies in folk medicine indicating the pharmaceutical potential of lichens.. Lichen growth in nature is very slow. To overcome this major drawback, we standardized the culture media to culture the lichen Usnea complanata (Müll.Arg.) Motyka (Parmeliaceae) for (1) in vitro synthesis of natural lichen substances, and (2) determination of antioxidative and cardiovascular-protective activity of usnic acid and psoromic acid.. Lichen U. complanata has been cultured in fermentor under submerged condition. Antioxidative and cardiovascular-protective activity of the extract and the purified lichen substances usnic and psoromic acid have been determined.. Except methanol, all other extracts exhibited antioxidative action in terms of free radical scavenging activity (FRSA) with a half-inhibiting concentration (IC₅₀) value of 22.86 to 25.0 µg/mL, nitric oxide radical scavenging activity (NORSA) 141.3 to 149.1 µg/mL and for lipid peroxidation inhibition (LPI) 125 to 157.9 µg/mL. Usnic acid or psoromic acid showed antioxidative action with IC₅₀ values ranging from 0.174 to 0.271 mg/mL. Methanol and ethyl acetate extract showed hydroxy-3-methyl-glutaryl-CoA reductase (HMGR) inhibition of 65.18 to 74.81%. Only 43.47% inhibition of angiotensin converting enzyme (ACE) was shown by methanol extract. Usnic acid showed noncompetitive type of HMGR inhibition and uncompetitive type of ACE inhibition. Psoromic acid exhibited competitive type of HMGR inhibition and mixed type of ACE inhibition.. U. complanata showed both cardiovascular-protective and antioxidant properties. The lichen species U. complanata may be a natural bioresource for possible pharmaceutical applications.

Topics: Angiotensin-Converting Enzyme Inhibitors; Antioxidants; Benzofurans; Benzoxepins; Biological Products; Bioreactors; Carboxylic Acids; Culture Media, Conditioned; Drug Discovery; Ethnopharmacology; Fermentation; Free Radical Scavengers; Hydroxymethylglutaryl-CoA Reductase Inhibitors; India; Kinetics; Lipid Peroxidation; Nitric Oxide; Osmolar Concentration; Solubility; Solvents; Usnea

Usnic acid (UA), a natural botanical product, is a constituent of some dietary supplements used for weight loss. It has been associated with clinical hepatotoxicity leading to liver failure in humans. The present study was undertaken to evaluate the interactive toxicity, if any, of UA with lipopolysaccarides (LPS), a potential contaminant of food, at low non-toxic concentrations. The human hepatoblastoma HepG2 cells were treated with the vehicle control and test agents, separately and in a binary mixture, for 24 h at 37°C in 5% CO2. After the treatment period, the cells were evaluated by the traditional biochemical endpoints of toxicity in combination with the toxicogenomic endpoints that included cytotoxicity, oxidative stress, mitochondrial injury and changes in pathway-focused gene expression profiles. Compared with the controls, low non-toxic concentrations of UA and LPS separately showed no effect on the cells as determined by the biochemical endpoints. However, the simultaneous mixed exposure of the cells to their binary mixture resulted in increased cytotoxicity, oxidative stress and mitochondrial injury. The pathway-focused gene expression analysis resulted in the altered expression of several genes out of 84 genes examined. Most altered gene expressions induced by the binary mixture of UA and LPS were different from those induced by the individual constituents. The genes affected by the mixture were not modulated by either UA or LPS. The results of the present study suggest that the interactions of low nontoxic concentrations of UA and LPS produce toxicity in HepG2 cells.

Topics: Anti-Obesity Agents; Benzofurans; Cell Survival; Dietary Supplements; Dose-Response Relationship, Drug; Drug Interactions; Drug Therapy, Combination; Gene Expression; Hep G2 Cells; Hepatocytes; Humans; Lipopolysaccharides; Mitochondria, Liver; Mitochondrial Diseases; Oxidative Stress; Transcriptome

The purpose of this investigation was to try to understand the antibacterial mechanism of L-(-)-usnic acid isolated for the first time from fruticose lichen Usnea subfloridana using clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentration (MIC) of L-(-)-usnic acid against the clinical isolates of MRSA and reference strain S. aureus MTCC-96 (SA-96) was in the range 25-50 μg/ml. Treatment of both reference and clinical strains (MRSA-ST 2071) with four-fold MIC concentrations (100-200 μg/ml) of L-(-)-usnic acid reduced the viability of cells without damaging the cell wall. However, the loss of 260 nm absorbing material and increase in propidium iodide uptake was observed in both of the strains. Similarly, a combined effect of L-(-)-usnic acid (25-50 μg/ml) and 7.5 % NaCl resulted in a reduced number of viable cells within 24 h in comparison to the control. These observations clearly indicate that L-(-)-usnic acid exerts its action by disruption of the bacterial membrane. Further, in vivo efficacy showed that L-(-)-usnic acid significantly (p < 0.001) lowered the microbial load of spleen at doses ranging from 1 to 5 mg/kg. Further, toxicity studies in infected mice at doses 20 times higher than the efficacious dose indicated L-(-)usnic acid to be safe. Paradoxically, L-(-)usnic acid exhibited changes in serum triglycerides, alkaline phosphatase (ALKP) and liver organ weight in the healthy mice administered with only 25 mg/kg body weight. The results obtained in this study showed that natural L-(-)-usnic acid exerts its antibacterial activity against MRSA by disruption of the cell membrane. Further, the natural L-(-)-usnic acid was found to be safe up to 100 mg/kg body weight, thereby, making it a probable candidate for treating S. aureus infections.

Topics: Animals; Anti-Bacterial Agents; Benzofurans; Cell Membrane; Colony Count, Microbial; Disease Models, Animal; Female; Humans; Methicillin-Resistant Staphylococcus aureus; Mice; Microbial Sensitivity Tests; Microbial Viability; Spleen; Staphylococcal Infections; Usnea

The aim of this study is to investigate chemical composition of acetone extracts of the lichens Parmelia caperata, P. saxatilis and P. sulcata and antioxidant, antimicrobial and anticancer activities of some their major metabolites. The phytochemical analysis of acetone extracts of three Parmelia lichens were determined by HPLC-UV method. The predominant phenolic compounds in these extracts were protocetraric and usnic acids (P. caperata) and depsidone salazinic acid (other two species). Besides these compounds, atranorin and chloroatranorin, were also detected in some of these extracts. Antioxidant activity of their isolated metabolites was evaluated by free radical scavenging, superoxide anion radical scavenging and reducing power. As a result of the study salazinic acid had stronger antioxidant activity than protocetraric acid. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. Both compounds were highly active with minimum inhibitory concentration values ranging from 0.015 to 1mg/ml. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method. Salazinic acid and protocetraric acid were found to be strong anticancer activity toward both cell lines with IC(50) values ranging from 35.67 to 60.18μg/ml. The present study shows that tested lichen compounds demonstrated a strong antioxidant, antimicrobial, and anticancer effects. That suggest that these lichens can be used as new sources of the natural antimicrobial agents, antioxidants and anticancer compounds.

Topics: Anti-Infective Agents; Antineoplastic Agents; Antioxidants; Benzofurans; Cell Line, Tumor; Drug Screening Assays, Antitumor; Heterocyclic Compounds, 3-Ring; Humans; Lactones; Lichens; Microbial Sensitivity Tests; Salicylates

Influenza is a widespread respiratory infection. Every year it causes epidemics, quickly spreading from country to country, or even pandemics, involving a significant part of the human population of the earth. Being a highly variable infection, influenza easy accumulates the resistance mutations to many antivirals. Usnic acid, a dibenzofuran originally isolated from lichens belongs to the secondary metabolites and has a broad spectrum of biological activity. In humans, it can act as an anti-inflammatory, antimitotic, antineoplasic, antibacterial, and antimycotic agent. In this work we studied for the first time the antiviral activity of usnic acid and its derivatives against the pandemic influenza virus A(H1N1)pdm09. A total of 26 compounds representing (+) and (-) isomers of usnic acid and their derivates were tested for cytotoxicity and anti-viral activity in MDCK cells by microtetrazolium test and virus yield assay, respectively. Based on the results obtained, 50% cytotoxic dose (CTD(50)) and 50% effective dose (ED(50)) and selectivity index (SI) were calculated for each compound. Eleven of them were found to have SI higher than 10 (highest value 37.3). Absolute configuration was shown to have critical significance for the anti-viral activity. With minor exceptions, in the pair of enantiomers, (-)-usnic acid was more active comparing to (+)-isomer, but its biological activity was reversed after the usnic acid was chemically modified. Based on the obtained results, derivatives of usnic acid should be considered as prospective compounds for further optimization as anti-influenza substances.

Topics: Animals; Anti-Inflammatory Agents; Antiviral Agents; Benzofurans; Cell Line; Cell Survival; Dogs; Humans; Influenza A Virus, H1N1 Subtype; Macrophages; Madin Darby Canine Kidney Cells; Mice; Nitric Oxide Synthase Type II; Stereoisomerism; Structure-Activity Relationship; Transcription Factor RelA; Tumor Necrosis Factor-alpha

The aim of this study was to investigate the chemical composition of acetone extracts of the lichens Toninia candida and Usnea barbata and in vitro antioxidant, antimicrobial, and anticancer activities of these extracts together with some of their major metabolites. The chemical composition of T. candida and U. barbata extracts was determined using HPLC-UV analysis. The major phenolic compounds in these extracts were norstictic acid (T. candida) and usnic acid (U. barbata). Antioxidant activity was evaluated by free radical scavenging, superoxide anion radical scavenging, reducing power and determination of total phenolic compounds. Results of the study proved that norstictic acid had the largest antioxidant activity. The total content of phenols in the extracts was determined as the pyrocatechol equivalent. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration using the broth microdilution method. The most active was usnic acid with minimum inhibitory concentration values ranging from 0.0008 to 0.5 mg/mL. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using the microculture tetrazolium test. Usnic acid was found to have the strongest anticancer activity towards both cell lines with IC(50) values of 12.72 and 15.66 μg/mL.

Topics: Anti-Infective Agents; Antioxidants; Ascomycota; Bacteria; Benzofurans; Biphenyl Compounds; Cell Cycle; Cell Line, Tumor; Cell Survival; Fungi; Humans; Inhibitory Concentration 50; Lactones; Lichens; Microbial Sensitivity Tests; Molecular Structure; Phenols; Picrates; Salicylates; Usnea

The lichen compound usnic acid (UA) is a lipophilic weak acid that acts as a proton shuttle and causes loss of mitochondrial inner membrane potential. In the current study we show that UA treatment induced the formation of autophagosomes in human cancer cells, but had minimal effects on normal human fibroblasts. However, autophagic flux was incomplete, degradation of autophagosomal content did not occur and acidification was defective. UA-treated cells showed reduced ATP levels and activation of AMP kinase as well as signs of cellular stress. UA is thus likely to trigger autophagosome formation both by energy depletion and stress conditions. Our findings indicate that the H(+)-shuttling effect of UA operates not only in mitochondria as previously shown, but also in lysosomes, and have implications for therapeutic manipulation of autophagy and pH-determined drug distribution.

Topics: Adenosine Triphosphate; Adenylate Kinase; Benzofurans; Drug Screening Assays, Antitumor; Enzyme Activation; Humans; Lichens; Lysosomes; Microtubule-Associated Proteins; Mitochondria; Neoplasms; Phagosomes; Protons; Signal Transduction; Vacuoles

One of the ways for searching for potentially new anti-cancer drugs is the testing of various naturally synthesized compounds. Lichens are a source of unique chemical agents of which some have already been proved to be effective against various cancer in vitro models. Our study reports on the sensitivity of up to nine human cancer cell lines (A2780, HeLa, MCF-7, SK-BR-3, HT-29, HCT-116 p53(+/+), HCT-116 p53(-/-), HL-60 and Jurkat) to the anti-proliferative/cytotoxic effects of four typical secondary metabolites of lichens (parietin, atranorin, usnic acid and gyrophoric acid). Variations in the dynamics of tumour cell line populations were evaluated by the MTT, clonogenic and viability assays, cell proliferation and detachment, cell cycle transition and apoptotic nuclear morphology, thereby confirming their concentration- and time-dependent cytotoxicity. However, in comparison with parietin and gyrophoric acid, the suppression of viability and cell proliferation by usnic acid or atranorin was found to be more efficient at equitoxic doses and correlated more strongly with an increased number of floating cells or a higher apoptotic index. Moreover, the analysis of cell cycle distribution also revealed an accumulation of cells in S-phase. This study has confirmed a differential sensitivity of cancer cell lines to lichen secondary metabolites.

Topics: Antineoplastic Agents; Apoptosis; Benzoates; Benzofurans; Cell Adhesion; Cell Line, Tumor; Cell Nucleus Shape; Cell Proliferation; Cell Survival; Drug Discovery; Drug Screening Assays, Antitumor; Emodin; Humans; Hydroxybenzoates; Lichens; Neoplasms; Osmolar Concentration; S Phase

The aim of this study was assess the effect of collagen-based films containing usnic acid as a wound dressing for dermal burn healing. Second-degree burn wounds were performed in forty-five Wistar rats, assigned into nine groups: COL-animals treated with collagen-based films; PHO-animals treated with collagen films containing empty liposomes; UAL-animals treated with collagen-based films containing usnic acid incorporated into liposomes. After 7, 14, and 21 days the animals were euthanized. On 7th day there was a moderate infiltration of neutrophils, in UAL, distributed throughout the burn wounds, whereas in COL and PHO, the severity of the reaction was slighter and still limited to the margins of the burn wounds. On the 14th day, the inflammatory reaction was less intense in UAL, with remarkable plasma cells infiltration. On the 21st day, there was reduction of the inflammation, which was predominantly composed of plasma cells in all groups, particularly in UAL. The use of the usnic acid provided more rapid substitution of type-III for type-I collagen on the 14th day, and improved the collagenization density on the 21st day. It was concluded that the use of reconstituted bovine type-I collagen-based films containing usnic acid improved burn healing process in rats.

Topics: Actins; Animals; Benzofurans; Biological Dressings; Burns; Collagen; Collagen Type I; Collagen Type III; Immunohistochemistry; Inflammation; Liposomes; Male; Myofibroblasts; Rats; Rats, Wistar; Wound Healing

The present study was conducted to evaluate the antibacterial activity of lichen-forming fungi (LFF) against Helicobacter pylori, and to optimize the culture conditions of LFF for maximum production of natural antibiotics against H. pylori. To accomplish this, a screening assay was first conducted among 19 species of LFF. The extract of Nephromopsis pallescens (KOLRI-040516) exhibited the strongest anti-ff. pylori activity. Bioautograghic TLC and HPLC analysis identified usnic acid as the main antibacterial substance produced by JV. pallescens. The growth of JV. pallescens and production of antibacterial substances produced by the fungus were then investigated under several culture conditions including the culture media, initial medium pHs, incubation temperatures, and the degree of aeration. The results indicated that culture in MY medium with an initial pH of 6.0, a temperature of 15°C and a low degree of aeration supported the largest usnic acid production of the fungus (16.4 ug usnic acid/g dry biomass). Especially, aeration was found to be an important factor that affect both growth and usnic acid production of N. pallescens.

Topics: Anti-Bacterial Agents; Ascomycota; Benzofurans; Chromatography, High Pressure Liquid; Chromatography, Thin Layer; Culture Media; Helicobacter pylori; Hydrogen-Ion Concentration; Microbial Sensitivity Tests; Temperature

The lichen metabolite usnic acid (UA) has been promoted as a dietary supplement for weight loss, although cases of hepatotoxicity have been reported. Here we evaluated UA-associated hepatotoxicity in vitro using isolated rat hepatocytes. We measured cell viability and ATP content to evaluate UA induced cytotoxicity and applied (13)C isotopomer distribution measuring techniques to gain a better understanding of glucose metabolism during cytotoxicity. The cells were exposed to 0, 1, 5 or 10 μM UA concentrations for 2, 6 or 24h. Aliquots of media were collected at the end of these time periods and the (13)C mass isotopomer distribution determined for CO(2), lactate, glucose and glutamate. The 1 μM UA exposure did not appear to cause significant change in cell viability compared to controls. However, the 5 and 10 μM UA concentrations significantly reduced cell viability as exposure time increased. Similar results were obtained for ATP depletion experiments. The 1 and 5 μM UA doses suggest increased oxidative phosphorylation. Conversely, oxidative phosphorylation and gluconeogenesis were dramatically inhibited by 10 μM UA. Augmented oxidative phosphorylation at the lower UA concentrations may be an adaptive response by the cells to compensate for diminished mitochondrial function.

Topics: Animals; Benzofurans; Carbon; Carbon Isotopes; Cell Survival; Cells, Cultured; Dose-Response Relationship, Drug; Glucose; Glutamic Acid; Hepatocytes; Lactic Acid; Lichens; Mitochondria, Liver; Rats; Rats, Sprague-Dawley

Three doses of (+)-usnic acid (100, 200, and 240 mg/kg per d) were administered orally to Wistar rats for 8 days, and metabonomic characterization of (+)-usnic acid-induced liver injury based on gas chromatography-mass spectrometry metabolic profiles was evaluated. Serum biochemical analysis and histopathological examinations were simultaneously performed. The liver/body weight ratio was significantly increased in (+)-usnic acid-treated groups, whereas serum alanine aminotransferase and total bilirubin were significantly elevated. In liver sections of 200 and 240 mg/kg dosage groups, widespread hydropic degeneration of hepatocytes was observed. Clusters in partial least squares discriminant analysis score plots showed control and (+)-usnic acid-treated groups had an obvious separation. (+)-Usnic acid exposure can lead to disturbances in energy metabolism, amino acid metabolism, lipid metabolism, and nucleotide metabolism, which may be attributable to (+)-usnic acid toxicological effects on the liver through oxidative stress. The significant changes in 22 metabolites in liver might be adopted as potential biomarkers.

Topics: Administration, Oral; Animals; Benzofurans; Biomarkers; Chemical and Drug Induced Liver Injury; Dose-Response Relationship, Drug; Energy Metabolism; Gas Chromatography-Mass Spectrometry; Hepatocytes; Lipid Metabolism; Liver; Male; Metabolome; Metabolomics; Oxidative Stress; Plasma; Rats; Rats, Wistar; Reproducibility of Results

Experiments were performed to test the null hypothesis that the addition of a natural occurring antibiotic would not alter mechanical properties of polymethylmethacrylate (PMMA). Compression and four-point bending tests were used to assess mechanical properties of zirconium dioxide bearing bone cement (Type Zr) and barium sulfate bearing bone cement (Type Ba), mixed with the antibiotic usnic acid ("usnic"), used to create a surface resistant to biofilm formation. Addition of usnic had a statistically significant effect on the material properties. Compressive and bending strengths decreased as usnic was added and Type Zr was stronger than Type Ba although material properties remained above recommended minima. With implications of liver toxicity with large doses of usnic taken as a dietary supplement, cytotoxicity tests using bone cement coupons were performed and showed very little or no toxicity in primary cultures of rabbit skin derived fibroblasts. A simple test of usnic's efficacy as a biofilm prophylaxis in PMMA was also conducted. Bone cement coupons with usnic were tested for their effectiveness against methicillin resistant Staphylococcus aureus. Diminished biofilm formation on usnic-containing coupons indicated that usnic can be an effective anti-microbial agent.

Topics: Animals; Anti-Bacterial Agents; Anti-Infective Agents; Barium Sulfate; Benzofurans; Biofilms; Bone Cements; Compressive Strength; Fibroblasts; Microscopy, Confocal; Polymethyl Methacrylate; Rabbits; Staphylococcus aureus; Stress, Mechanical; Surface Properties; Zirconium

The 2-C-methyl-D-erythritol-4-phosphate and shikimate pathways were found to be active in Plasmodium falciparum and both can result in vitamin E biosynthesis in plants and algae. This study biochemically confirmed vitamin E biosynthesis in the malaria parasite, which can be inhibited by usnic acid. Furthermore, we found evidence pointing to a role of this vitamin in infected erythrocytes. These findings not only contribute to current understanding of P. falciparum biology but also reveal a pathway that could serve as a chemotherapeutic target.

Topics: alpha-Tocopherol; Animals; Benzofurans; Erythrocytes; gamma-Tocopherol; Gas Chromatography-Mass Spectrometry; Life Cycle Stages; Lipid Peroxidation; Plasmodium falciparum; Schizonts; Vitamin E

Usnea undulata Stirton (Usneaaceae) is a fruticose lichen used locally in ethnoveterinary medicine to treat mammary infections in cattle while human beings use it for the treatment of wounds in Eastern Cape, South Africa. Bioactivity-guided fractionation of its extracts led to the isolation and characterization of a new depsidone, 2'-O-methylhypostictic acid (8), together with seven known compounds, i.e. methyl β-orsellinate, norstictic acid, menegazziaic acid, (+) usnic acid, hypoconstictic acid, salazinic acid, and galbinic acid. The structures of the compounds were elucidated on the basis of their spectral analysis including homo- and hetero-nuclear correlation NMR experiments (COSY, NOESY, HMQC, and HMBC) and mass spectra as well as by comparison with available data in the literature. The minimum inhibitory concentrations (MICs) values of the compounds against six bacteria were determined. Compound 8 showed inhibitory activity against Bacillus cereus, Bacillus subtilis, and Staphylococcus epidermidis with MICs of 31, 62.5, 62.5 μg/ml, respectively. (+) Usnic acid was most active against B. subtilis, B. cereus, Staphylococcus aureus, and Escherichia coli with MICs of 8, 8, 31, and 31 μg/ml, respectively, while other compounds exhibited moderate activity.

Topics: Animals; Anti-Bacterial Agents; Bacillus cereus; Bacillus subtilis; Benzofurans; Cattle; Depsides; Escherichia coli; Humans; Lactones; Microbial Sensitivity Tests; Salicylates; South Africa; Staphylococcus aureus; Usnea

Undesired biofilm development is a major concern in many areas, especially in the medical field. The purpose of the present study was to comparatively investigate the antibiofilm efficacy of usnic acid, in soluble versus nanofluid formulation, in order to highlight the potential use of Fe(3) O(4)/oleic acid (FeOA) nanofluid as potential controlled release vehicle of this antibiofilm agent. The (+) -UA loaded into nanofluid exhibited an improved antibiofilm effect on S. aureus biofilm formation, revealed by the drastic decrease of the viable cell counts as well as by confocal laser scanning microscopy images. Our results demonstrate that FeOA nanoparticles could be used as successful coating agents for obtaining antibiofilm pellicles on different medical devices, opening a new perspective for obtaining new antimicrobial and antibiofilm surfaces, based on hybrid functionalized nanostructured biomaterials.

Topics: Anti-Infective Agents; Benzofurans; Biocompatible Materials; Biofilms; Ferrosoferric Oxide; Microscopy, Confocal; Nanoconjugates; Nanoparticles; Oleic Acid; Oleic Acids; Staphylococcus aureus

This study compared the effects of three anti-mutagenic lichen extracts on colorectal oncogenesis in azoxymethane (AOM)-treated mice and determined whether the extracts also regulated the homeostatic response to genotoxic damage. C57BL/6J mice (n = 12 per group) were treated with the lichen extracts Antimutagen-He (AMH): AMH-C, AMH-D, or AMH-E dimethyl sulfoxide (DMSO, control) for 2 weeks. At the end of the treatment, mice were given a single AOM injection to induce DNA damage and killed 6 h later for measuring apoptosis and proliferation. Apoptotic and proliferation indexes in mice treated with AMH-C, AMH-D, and AMH-E were 0.61%, 1.41%, and 0.77%; and 30.62%, 21.93%, and 27.27%, respectively, which were significantly lower than those of control mice (5.88% and 38.69%) (p < 0.05). To examine the effects of lichen extracts on colorectal cancer, separate groups of mice (n = 25 per group) treated with AMH-C, AMH-D, AMH-E, or DMSO were given 4-weekly AOM injections to induce oncogenesis. Mice were killed 24 weeks after the last AOM injection for assessing colon tumor formation. Colonic tumor incidences were 47.3%, 13%, and 20%; the tumor volumes were 18.47, 2.75, and 10.78 mm(3), respectively, in mice treated with AMH-C (p < 0.05), AMH-D (p < 0.05), and AMH-E (p > 0.05), compared to 24% and 13.28 mm(3) in mice of control correspondingly. No lichen extract showed evident toxic effects on mice. No usnic acid was found in these lichen extracts. The regulation of acute apoptosis and cell proliferation in colonic epithelial cells and the anti-mutagenesis do not seem directly related to the cancer protective effect.

Topics: Adenocarcinoma; Animals; Antimutagenic Agents; Apoptosis; Azo Compounds; Benzofurans; Body Weight; Carcinogens; Cell Proliferation; Colon; Colonic Neoplasms; DNA Damage; Intestinal Mucosa; Lichens; Longevity; Male; Mice; Mice, Inbred C57BL; Plant Extracts

Reindeer (Rangifer tarandus) eat and utilize lichens as an important source of energy and nutrients in winter. Lichens synthesize and accumulate a wide variety of phenolic secondary compounds, such as usnic acid, as a defense against herbivores and to protect against damage by UV-light in solar radiation. We have examined where and to what extent these phenolic compounds are degraded in the digestive tract of the reindeer, with particular focus on usnic acid. Three male reindeer were given ad libitum access to a control diet containing no usnic acid for three weeks and then fed lichens ad libitum (primarily Cladonia stellaris) containing 9.1 mg/g DM usnic acid for 4 weeks. Usnic acid intake in reindeer on the lichen diet was 91-117 mg/kg BM/day. In spite of this, no trace of usnic acid or conjugates of usnic acid was found either in fresh rumen fluid, urine, or feces. This suggests that usnic acid is rapidly degraded by rumen microbes, and that it consequently is not absorbed by the animal. This apparent ability to detoxify lichen phenolic compounds may gain increased importance with future enhanced UV-B radiation expected to cause increased protective usnic acid/phenol production in lichens.

Topics: Animal Feed; Animals; Benzofurans; Cecum; Colon; Digestion; Ecosystem; Feces; Gastrointestinal Tract; Intestine, Small; Kidney; Lichens; Liver; Male; Norway; Reindeer; Rumen; Ultraviolet Rays

The lichen compound usnic acid is used for its antimicrobial activities in cosmetic products and is also a component of slimming agents. Its effect against cancer cells was first noted over 30 years ago. In this study possible mechanisms of this effect were investigated using two human cell lines, the breast cancer cell line T-47D and the pancreatic cancer cell line Capan-2. Pure (+)-usnic acid from CLADONIA ARBUSCULA and (-)-usnic acid from ALECTORIA OCHROLEUCA were shown to be equally effective inhibitors of DNA synthesis, with IC (50) 4.2 microg/mL and 4.0 microg/mL for (+) and (-)-usnic acid against T-47D, and 5.3 microg/mL and 5.0 microg/mL against Capan-2, respectively. Flow cytometric analysis confirmed the inhibited entry into the S-phase and showed reduction in cell size. Classical apoptosis, as assessed by TUNEL staining, was not observed. Necrosis, measured by LDH release, was seen only in Capan-2 after exposure for 48 hours. Staining with the mitochondrial dye JC-1 demonstrated dose-dependent loss of mitochondrial membrane potential following treatment with usnic acid in both cell lines. In conclusion, usnic acid had a marked inhibitory effect on growth and proliferation of two different human cancer cell lines and led to loss of mitochondrial membrane potential. Cell survival was little affected; late necrosis was seen in one of the cell lines. No difference was noted between the two enantiomers.

Topics: Antineoplastic Agents, Phytogenic; Benzimidazoles; Benzofurans; Breast Neoplasms; Carbocyanines; Cell Cycle; Cell Line, Tumor; Cell Proliferation; DNA; Dose-Response Relationship, Drug; Female; Flow Cytometry; Humans; Inhibitory Concentration 50; Lichens; Membrane Potential, Mitochondrial; Necrosis; Pancreatic Neoplasms; Phytotherapy; Plant Extracts

The phytotoxic effects of the lichen secondary metabolite-usnic acid on cultures of free living alga-Scenedesmus quadricauda (UTEX 76) and aposymbiotically grown lichen photobiont Trebouxia erici (UTEX 911) were assessed. We found a relatively strong inhibition effect of usnic acid on the growth of alga Scenedesmus, accompanied by an increase of cell size, an alteration of assimilation pigment composition, followed by strong degradation of chlorophyll a, a decrease of chlorophyll a fluorescence, and an increase of reactive oxygen species in the cells. The content of soluble proteins remained a stable parameter. Phytotoxicity of usnic acid on cultures of Trebouxia photobiont was significantly lower. Usnic acid in lichens may act as an allochemical that controls the division of photobiont cells, thereby regulating the balance between the photobiont and mycobiont forming thallus. Higher tolerance to usnic acid in Trebouxia cultures may be an adaptation resulting from the long term co-evolution of these algae with fungi that produce secondary metabolites.

Topics: Anti-Infective Agents; Benzofurans; Biological Evolution; Lichens; Scenedesmus; Symbiosis

Usnic acid, a lichen metabolite, is known to exert antimitotic and antiproliferative activities against normal and malignant human cells. Many chemotherapy agents exert their activities by blocking cell cycle progression, inducing cell death through apoptosis. Microtubules, protein structure involved in the segregation of chromosomes during mitosis, serve as chemotherapeutical targets due to their key role in cellular division as well as apoptosis. The aim of this work was to investigate whether usnic acid affects the formation and/or stabilisation of microtubules by visualising microtubules and determining mitotic indices after treatment. The breast cancer cell line MCF7 and the lung cancer cell line H1299 were treated with usnic acid 29 microM for 24 hours and two positive controls: vincristine (which prevents the formation of microtubules) or taxol (which stabilizes microtubules). Treatment of MCF7 and H1299 cells with usnic acid did not result in any morphological changes in microtubules or increase in the mitotic index. These results suggest that the antineoplastic activity of usnic acid is not related to alterations in the formation and/or stabilisation of microtubules.

Topics: Antimitotic Agents; Antineoplastic Agents; Benzofurans; Breast Neoplasms; Cell Line, Tumor; Female; Humans; Lung Neoplasms; Microtubules; Paclitaxel; Vincristine

A chromatographic method is described for the purification and characterization of secondary lichen substances with biological activity. A simple reversed-phase high-performance liquid chromatography method with gradient elution has been developed that allows the determination and isolation of salazinic, usnic and stictic acids from lichen samples in a single run and the quantification of every acid in the tested extracts. The antioxidant activity of both the isolated compounds and the respective lichen belonging to Xanthoparmelia genus was determined by the Oxygen Radical Absorbance Capacity (ORAC) assay; their effect as free radical scavengers, effect on cell survival by the 3(4,5-dimethyltiazol-2-yl)-2,5-diphenyltetrazolium reduction assay and 2',7'-dichlorofluorescin diacetate method were tested on U373 MG human astrocytome cell line. Both lichens extracts and all isolated compounds protected U373 MG cells from hydrogen peroxide-induced damage, suggesting that they could act as antioxidant agents in those neurodegenerative disorders associated with oxidative damage, such as Alzheimer's disease and Parkinson's disease.

Topics: Antioxidants; Benzofurans; Cell Line, Tumor; Cell Survival; Chromatography, Reverse-Phase; Drug Screening Assays, Antitumor; Free Radical Scavengers; Heterocyclic Compounds, 4 or More Rings; Humans; Lactones; Lichens; Oxepins; Plant Extracts; Salicylates

Cladonia clathrata Ahti & L. Xavier-Filho (Cladoniaceae) is a lichen; several Cladonia species extracts have been used for various remedies in folk medicine. In order to evaluate the actions of this lichen, studies were performed on antinociceptive, anti-inflammatory, and antioxidant activities. The hydroalcoholic extract (HE) of C. clathrata stems was used in the following experiments. Oral treatment with the HE of C. clathrata elicited inhibitory activity (p < 0.001) on acetic acid-induced abdominal writhes at 100 (47.2%), 200 (47.2%), and 400 mg/kg (86.4%), and reduced the formalin-induced nociception on both the neurogenic (400 mg/kg, p < 0.01) and inflammatory phases (200 and 400 mg/kg, p < 0.01). It was not associated with non-specific effects, such as muscle relaxation or sedation. The HE reduced the carrageenan-induced edema formation at 100, 200, and 400 mg/kg (p < 0.05) and inhibited neutrophil migration into the peritoneal cavity at 400 mg/kg (p < 0.001). The HE of C. clathrata reacted with the DPPH radical and reduced the same by 50.19%, and exhibited an IC(50) value of 69.25 +/- 0.65 mug/mL. The HE of C. clathrata stems shows antinociceptive and anti-inflammatory activities, with a moderate antioxidant potential.

Topics: Analgesics; Animals; Anti-Inflammatory Agents; Antioxidants; Ascomycota; Benzofurans; Biphenyl Compounds; Carrageenan; Drug Evaluation, Preclinical; Lichens; Mice; Motor Activity; Neutrophil Infiltration; Pain Measurement; Picrates; Rats; Rats, Wistar

Tuberculosis remains a serious public health problem, with nine million cases being reported annually. Treatment with antibiotics is the most effective mechanism to control this disease, although the increase in cases with resistant strains, co-infection with HIV, and the long duration of treatment has established the need to develop new drugs. Here we show the activity of usnic acid against susceptible and resistant Mycobacterium tuberculosis strains and against nontuberculous mycobacteria. Further, we did not identify any contribution of efflux in innate resistance to usnic acid.

Topics: Anti-Bacterial Agents; Benzofurans; Calcium Channel Blockers; Carbonyl Cyanide m-Chlorophenyl Hydrazone; Drug Evaluation, Preclinical; Drug Resistance, Bacterial; Ionophores; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Nontuberculous Mycobacteria; Tuberculosis, Multidrug-Resistant; Verapamil

Natural compounds which can behave as antioxidants and protect against UV-radiation may well have medical and cosmetic value. Usnic acid, which can be obtained from lichens offer such a potential. The latter is one of the best known and reviewed compounds present in lichens and exhibits many properties of value such as antibiotic, antitumor and UV-filter-effects. We report studies of the potential antioxidant and prooxidant activity of usnic acid extracted from Xanthoparmelia farinosa (Vainio) using a human lymphocyte cell line (Jurkat-cells) under UV-B-irradiation. Cell survival and cell metabolism were determined using different conditions such as usnic acid concentration and UVB dose. Compared to the controls the cells incubated with usnic acid in concentrations of 1 x 10(-8) and 1 x 10(-6) M showed a higher cell survival and a normal metabolism under low doses of UVB-light up to 0.1 J/cm(2). When both higher UVB doses (up to 14 J/cm(2)) and higher concentrations of usnic acid (1 x 10(-4) M) where used, the opposite effect was observed. It is concluded that these effects are due to bifunctional (a switch of) anti-oxidative-pro-oxidative behaviour of usnic acid under UV-B-irradiation.

Topics: Antioxidants; Apoptosis; Ascomycota; Benzofurans; Humans; Jurkat Cells; Lichens; Oxidants; Reactive Oxygen Species; Ultraviolet Rays

In this study, we demonstrate the first in situ detection of usnic acid (UA) in selected species of the lichen Cladonia, using FPA-FTIR imaging and Raman microscopy. Fruticose lichens present a variety of defensive mechanisms, one of which is the production of UA. This polyketide secondary metabolite, produced by certain lichenized fungi, has a protective function for the lichen that includes a strong absorption in the ultraviolet range. Upon confirming the distinct spectral signature of UA in lichen tissue, we mapped its distribution in Cladonia arbuscula, Cladonia uncialis and Cladonia sulphurina tissues. Spectroscopic images were obtained from cryosectioned lichen fragments embedded in media and from hand-sectioned fragments that were media-free. UA was present in the pycnidia, and younger walls of C. arbuscula and C. uncialis, the spore-producing region of a C. uncialis apothecium, and in both the younger and older soredia of C. sulphurina. The localization of UA in lichens is an important precursor to future work that includes the identification of the gene cluster responsible for its biosynthesis. Our results show that FTIR and Raman imaging can be an effective way to study the distribution of natural products in lichens with micron-scale precision.

Topics: Benzofurans; Lichens; Microscopy; Molecular Structure; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis, Raman

Lecanoric acid (1), orsellinic acid methyl ester (2), orcinol (3), and usnic acid (4) were isolated from the lichen Parmelia subrudecta, collected on Palma of the Canary Islands, Spain. Compounds 1, 2, 3, and 4 were purified by solvent extraction, silica gel column chromatography, and preparative high-performance liquid chromatography (HPLC) consecutively. The structures of the four compounds were elucidated by one- and two-dimensional nuclear magnetic resonance (NMR) experiments and mass spectrometric investigations. These compounds showed activity against important gram-positive and gram-negative pathogens like mycobacteria and multiresistant staphylococci. This activity is combined with antiproliferative activity and cytotoxicity.

Topics: Anti-Infective Agents; Antineoplastic Agents; Bacteria; Bacterial Infections; Benzofurans; Cell Line, Tumor; Cell Proliferation; Humans; Lichens; Magnetic Resonance Spectroscopy; Molecular Structure; Neoplasms; Resorcinols; Salicylates; Spectrometry, Mass, Electrospray Ionization

Many species of lichen-forming fungi contain yellow or orange extracellular pigments belonging to the dibenzofurans (usnic acid), anthraquinones (e.g. parietin) or pulvinic acid group. These pigments are all equally efficient light screens, leading us to question the potential ecological and evolutionary significance of diversity in yellow and orange lichen substances. Here the hypothesis is tested that the different pigments differ in metal-binding characteristics, which suggest that they may contribute to adaptation to sites differing in pH and metal availability.. UV spectroscopy was used to study the dissociation and the pH dependence of the metal-binding behaviour of seven isolated lichen substances in methanol. Metals applied were selected macro- and micro-nutrients (Cu(2+), Fe(2+), Fe(3+), Mg(2+), Mn(2+) and Zn(2+)).. All the pigments studied are strong to moderate acids with pK(a1) values between 2.8 and 4.5. Metal complexation is common in the lichen substances studied. Complexation takes place under acidic conditions with usnic acid, but under alkaline conditions with parietin and most compounds of the pulvinic acid group. The pulvinic acid derivative rhizocarpic acid forms metal complexes both in the acidic and the alkaline range.. Metal complexation by lichen substances could be a prerequisite for lichen substance-mediated control of metal uptake. Assuming such an effect at pH values where the affinity of the metal for the lichen substance is intermediate would explain the strong preference of lichens with usnic or rhizocarpic acids to acidic substrata. Moreover, it would explain the preference of lichens with parietin and some lichens with compounds of the pulvinic acid group either for nutrient-rich substrata at low pH or for calcareous substrata.

Topics: Anthraquinones; Benzofurans; Carboxylic Acids; Copper; Hydrogen-Ion Concentration; Iron; Lactones; Lichens; Magnesium; Manganese; Metals; Spectrophotometry, Ultraviolet; Zinc

Raman spectroscopy using 785 nm excitation was tested as a nondestructive method for determining the presence of the potential biomarker, usnic acid, in experimentally prepared mineral matrices. Investigated samples consisting of usnic acid mixed with powdered hydrothermal minerals, gypsum and calcite were studied. Various concentrations of usnic acid in the mineral matrix were studied to determine the detection limits of this biomarker. Usnic acid was mixed with gypsum (respectively, calcite) and covered by a UV-transparent crystal of gypsum (CaSO(4) x 2 H(2)O), thereby creating artificial inclusions similar to those which could be present in Martian minerals. A Raman usnic acid signal at the concentration level as low as 1 g kg(-1) was obtained in the powdered mineral matrix and 5 g kg(-1) when analyzed through the monocrystal. The number of registered usnic acid key Raman bands was dependent on the particular mineral matrix. If a similar concentration of usnic acid could persist in Martian samples, then Raman spectroscopy will be able to identify it. Obtained results will aid both in situ Raman analyses on Mars and on Earth.

Topics: Benzofurans; Calcium Carbonate; Calcium Sulfate; Crystallization; Exobiology; Extraterrestrial Environment; Mars; Minerals; Spectrum Analysis, Raman

A new chiral molecular tweezer was synthesized with (1R,2R)-1,2-diaminocyclohexane as spacer and two molecules of (+)-usnic acid as pincers. The ability of this molecular tweezer to bind 2,4,7-trinitrofluorenone was studied. A charge-transfer complex was formed in which TNF was sandwiched between the two usnic acid units with pi-pi-stacked aromatic interactions.

Topics: Benzofurans; Binding Sites; Crystallography, X-Ray; Cyclohexanes; Fluorenes; Heterocyclic Compounds, 4 or More Rings; Models, Molecular; Molecular Conformation; Molecular Structure; Stereoisomerism

The dibenzofuran usnic acid, a widespread cortical secondary metabolite produced by lichen-forming fungi, was shown to promote the intracellular uptake of Cu(2+) in two epiphytic lichens, Evernia mesomorpha and Ramalina menziesii, from acidic, nutrient-poor bark. Higher Cu(2+) uptake in the former, which produces the depside divaricatic acid in addition to usnic acid, suggests that this depside promotes Cu(2+) uptake. Since Cu(2+) is one of the rarest micronutrients, promotion of Cu(2+) uptake by lichen substances may be crucial for the studied lichens to survive in their nutrient-poor habitats. In contrast, study of the uptake of other metals in E. mesomorpha revealed that the intracellular uptake of Mn(2+), which regularly exceeds potentially toxic concentrations in leachates of acidic tree bark, was partially inhibited by the lichen substances produced by this species. Inhibition of Mn(2+) uptake by lichen substances previously has been demonstrated in lichens. The uptake of Fe(2+), Fe(3+), Mg(2+), and Zn(2+), which fail to reach toxic concentrations in acidic bark at unpolluted sites, although they are more common than Cu(2+), was not affected by lichen substances of E. mesomorpha.

Topics: Benzofurans; Biological Transport; Copper; Depsides; Lichens; Manganese

Five compounds representative of major structural classes of lichen polyketides, VIZ. (+)-usnic (1), salazinic (2), vulpinic (3), gyrophoric (4), and evernic acids (5), were investigated for their ability to affect cell proliferation or wound healing, two functional targets of relevance for research on cancer or tissue regeneration. The experiments were carried out on MM98 malignant mesothelioma cells, A431 vulvar carcinoma cells, and HaCaT keratinocytes. The NRU and CV cytotoxicity assays showed high toxicity for (+)-usnic acid, intermediate toxicity for vulpinic acid, and low toxicity for salazinic, gyrophoric and evernic acids. Scratch wounding experiments on HaCaT monolayers, in the presence of subtoxic doses of lichen compounds, showed strong wound closure effects by (+)-usnic and gyrophoric acid, an intermediate effect by vulpinic and salazinic acids, and no effect by evernic acid. A combination of (+)-usnic and gyrophoric acids gave a further increase in the wound closure rates. The results of a cell migration test correlated with the wound healing data. In conclusion, (+)-usnic acid might be a particularly interesting compound for the prevention of hyperproliferation syndromes, while (+)-usnic and gyrophoric acids qualify as interesting leads in the promotion of tissue regeneration.

Topics: Antineoplastic Agents, Phytogenic; Benzoates; Benzofurans; Cell Line, Tumor; Cell Proliferation; Female; Furans; Humans; Hydroxybenzoates; Keratinocytes; Lactones; Lichens; Neoplasms; Phenylacetates; Phytotherapy; Plant Extracts; Salicylates; Wound Healing

Usnic acid, a highly functionalized dibenzofuran, is a polyketide secondary metabolite produced by several species of lichens. Synthesis of usnic acid from commercially available starting material was accomplished in two steps. The synthesis involves the methylation of phloracetophenone followed by oxidation with horseradish peroxidase. This work will lay the foundation for further biosynthetic studies on usnic acid.

Topics: Anti-Infective Agents; Benzofurans; Chemistry, Organic; Horseradish Peroxidase; Lichens; Models, Chemical; Oxygen

Eradication of Helicobacter pylori is an important objective in overcoming gastric diseases. Many regimens are currently available but none of them could achieve 100% success in eradication. Medicinal lichen is used in the treatment of gastric ulcer in local folk medicine in Anatolia (Turkey). The present study was performed to assess the in vitro effects of usnic acid from Usnea dasypoga against clinical isolates and standard H. pylori strains and their minimum inhibitory concentrations (MICs). A total of 38 strains was assayed for anti-H. pylori activity. The agar dilution method was used for the determination of usnic acid and clarithromycin resistance.Six (16.2%) clinical isolates were resistant to usnic acid and five (13.5%) were resistant to clarithromycin. Dual susceptibility to usnic acid and clarithromycin rate was detected as very high (97.3%). Usnic acid has a strong and dose-dependent activity against H. pylori strains. The synergism between usnic acid and clarithromycin may be effective in the treatment of H. pylori infection.

Topics: Anti-Bacterial Agents; Benzofurans; Clarithromycin; Dose-Response Relationship, Drug; Drug Resistance, Bacterial; Helicobacter pylori; Humans; Microbial Sensitivity Tests; Usnea

Usnic acid is a lichen metabolite used as a weight-loss dietary supplement due to its uncoupling action on mitochondria. However, its use has been associated with severe liver disorders in some individuals. Animal studies conducted thus far evaluated the effects of usnic acid on mitochondria primarily by measuring the rate of oxygen consumption and/or ATP generation. To obtain further insight into usnic acid-mediated effects on mitochondria, we examined the expression levels of 542 genes associated with mitochondrial structure and functions in liver of B6C3F(1) female mice using a mitochondria-specific microarray. Beginning at 8 weeks of age, mice received usnic acid at 0, 60, 180, and 600 ppm in ground, irradiated 5LG6 diet for 14 days. Microarray analysis showed a significant effect of usnic acid on the expression of several genes only at the highest dose of 600 ppm. A prominent finding of the study was a significant induction of genes associated with complexes I through IV of the electron transport chain. Moreover, several genes involved in fatty acid oxidation, the Krebs cycle, apoptosis, and membrane transporters were over-expressed. Usnic acid is a lipophilic weak acid that can diffuse through mitochondrial membranes and cause a proton leak (uncoupling). The up-regulation of complexes I-IV may be a compensatory mechanism to maintain the proton gradient across the mitochondrial inner membrane. In addition, induction of fatty acid oxidation and the Krebs cycle may be an adaptive response to uncoupling of mitochondria.

Topics: Animals; Benzofurans; Energy Metabolism; Female; Gene Expression Profiling; Liver; Metabolic Networks and Pathways; Mice; Mitochondria; Oligonucleotide Array Sequence Analysis; Uncoupling Agents

The cellular uptake and antimycobacterial activity of usnic acid (UA) and usnic acid-loaded liposomes (UA-LIPOs) were assessed on J774 macrophages. The minimal inhibitory concentration (MIC) and the minimal bactericidal concentration (MBC) of UA and UA-LIPO against Mycobacterium tuberculosis were determined. Concentrations required to inhibit 50% of cell proliferation (IC(50)) were 22.5 (+/-0.60) and 12.5 (+/-0.26) microg/ml, for UA and UA-LIPO, respectively. The MICs of UA and UA-LIPO were 6.5 and 5.8 microg/mL, respectively. The MBC of UA-LIPO was twice as low (16 microg/mL) as that of UA (32 microg/mL). An improvement in the intracellular uptake of UA-LIPO was found (21.6 x 10(4) +/- 28.3 x 10(2) c.p.s), in comparison with UA (9.5 x 10(4) +/- 11.4 x 10(2) c.p.s). In addition, UA-LIPO remains much longer inside macrophages (30 hours). All data obtained from the encapsulation of usnic acid into liposomes as a drug delivery system (DDS) indicate a strong interaction between UA-liposomes and J774 macrophages, thereby facilitating UA penetration into cells. Considering such a process as ruling the Mycobacterium-transfection by magrophages, we could state that associating UA with this DDS leads to an improvement in its antimycobacterial activity.

Topics: Animals; Antitubercular Agents; Benzofurans; Cell Line; Cell Proliferation; Dose-Response Relationship, Drug; Liposomes; Macrophages; Mice; Mycobacterium tuberculosis; Tuberculosis

To observe the oral acute toxicity of of (+)-usnic acid in mice and assess its cytotoxicity in rat cardiac fibroblasts.. The mice with acute poisoning of (+)-usnic acid at different doses by oral administration were observed for toxic manifestations, and the LD(50) was determined. The survival time and survival rate of the mice receiving different doses of (+)-usnic acid were observed. Cultured rat cardiac fibroblasts were inoculated with different concentrations of (+)-usnic acid, and the cell growth inhibition rate was estimated and the IC(50) determined using MTT assay.. Higher dose of (+)-usnic acid resulted in more obvious symptoms of poisoning and shorter survival time of the mice. The LD(50) of (+)-usnic acid in mice by oral administration was 388 mg/kg. The manifestations of poisoning such as apathism, pilomotor, chill, dyspnea, torpidity and anorexia was observed. Rat cardiac fibroblasts incubated with (+)-usnic acid showed obvious growth inhibition, which was positively correlated to the dose of (+)-usnic acid, and high dose of (+)-usnic acid caused severe cell injuries. The IC(50) of (+)-usnic acid in rat cardiac fibroblasts was 322 microg/ml.. (+)-usnic acid is a natural compound of low toxicity in mice, and low to medium dose of (+)-usnic acid dose not produce obvious cytotoxicity.

Topics: Administration, Oral; Animals; Benzofurans; Fibroblasts; Lethal Dose 50; Mice; Myocardium; Rats; Stereoisomerism

Phytochemical investigation of the Australian lichen, Ramalina glaucescens resulted in the isolation of a new halogenated depside, 5-chlorosekikaic acid 5, together with (+)-usnic acid 1, sekikaic acid 2, atranorin 6 and parietin 7, the latter of which was isolated from the associated (co-occurring) lichen, X. parietina. Compound 5 is suspected to be an artifact of the isolation procedure. All structures were assigned using spectroscopic methods and mass spectrometry. In addition to the full characterization of 5, this report represents the first application of 2D NMR spectroscopy to complete the unequivocal chemical shift assignment for compounds 2 and 7. Compounds 1-2 and 5-7 all displayed varying degrees of antitumor activity (ranging from an IC50 of 15 microM to >44 microM) with compounds 1, 2 and 5 also displaying antibacterial properties. Of these, (+)-usnic acid 1 displayed the most significant antitumor and antibacterial activities.

Topics: Animals; Anti-Bacterial Agents; Antifungal Agents; Antineoplastic Agents; Australia; Bacteria; Benzofurans; Cell Line, Tumor; Chromatography, High Pressure Liquid; Drug Screening Assays, Antitumor; Fungi; Leukemia P388; Lichens; Magnetic Resonance Spectroscopy; Mice; Microbial Sensitivity Tests; Spectrometry, Mass, Electrospray Ionization

Protoplasts isolated from the mycobiont of a cultured lichen Usnea ghattensis were fused with protoplasts of the fungus Aspergillus nidulans in order to increase the growth rate of the cultured lichen mycobiont in vitro. The maximum protoplast yield (102 x 10(4)/g fresh cell mass) was reached in citrate buffer with 50 mmol/L 2-sulfanylethanol ('2-mercaptoethanol') containing 0.1 % Novozym after 1.5 h at pH 5 and

Topics: Aspergillus nidulans; Benzofurans; Biomass; Cell Fusion; Cells, Cultured; Protoplasts; Regeneration; Usnea

Nine usnic acid-amine conjugates were evaluated on murine and human cancer cell lines. The polyamine derivatives showed significant cytotoxicity in L1210 cells. Their activities appeared to be independent of the polyamine transport system (PTS). Indeed, their activities were similar in chinese hamster ovary (CHO) and in the PTS deficient CHO-MG cells. In addition, alpha-difluoromethylornithine, an ornithine decarboxylase inhibitor known to indirectly enhance the activity of the PTS and consequently increase the cytotoxicity of cytotoxic drugs entering cells via the PTS, had no effect on the activity of the polyamine derivatives. The more active derivative (1,8-diaminooctane derivative) displayed similar activities on all cancer cell lines studied and induced apoptosis.

Topics: Animals; Antineoplastic Agents; Apoptosis; Benzofurans; Carrier Proteins; Cell Line, Tumor; CHO Cells; Cricetinae; Cricetulus; Humans; Mice; Polyamines; Structure-Activity Relationship

The purpose of this study was to investigate the molecular mechanisms that are responsible for the antiinflammatory effect of usnic acid (UA). UA is one of the most common and abundant lichen metabolites. The present study examined the effects of UA on the tumor necrosis factor-alpha (TNF-alpha) and nitric oxide (NO) production induced by lipopolysaccharide (LPS) in RAW264.7 macrophages and the underlying molecular mechanisms. UA decreased the TNF-alpha level in LPS-stimulated RAW264.7 macrophages in dose-dependent manner, the IC(50) value was 12.8 microM. RT-PCR analysis indicated that it inhibited TNF-alpha mRNA expression. Furthermore, it inhibited NO production in LPS-activated RAW264.7 macrophages, the IC(50) value was 4.7 microM. Western blot analysis showed that UA attenuated LPS-induced synthesis of iNOS protein and nuclear translocation of NF-kappaB p65 in the macrophages, in parallel. UA also inhibited LPS-mediated I-kappaBalpha degradation. Taken together, this suggests that UA has an antiinflammatory effect by inhibiting TNF-alpha and iNOS expression, possibly through suppression of nuclear translocation of NF-kappaB p65 and I-kappaBalpha degradation.

Topics: Analysis of Variance; Animals; Anti-Inflammatory Agents; Benzofurans; Cell Line; Cell Survival; Down-Regulation; Gene Expression Regulation; Lipopolysaccharides; Macrophages; Mice; NF-kappa B; Nitric Oxide; Nitric Oxide Synthase Type II; Reverse Transcriptase Polymerase Chain Reaction; RNA; Tumor Necrosis Factor-alpha; Usnea

Chiral copper(II) and nickel(II) complexes were obtained after reaction of diacetate salts with a new chiral salen ligand derived from (+)-usnic acid.

Topics: Benzofurans; Copper; Ethylenediamines; Ligands; Nickel; Organometallic Compounds; Stereoisomerism

In order to determine the allelopathic nature of lichen acids produced by lichen mycobionts, we compared lichen photobionts with other photosynthetic organisms in terms of inhibition of photosynthetic electron transport around photosystem II (PSII) by representative lichen acids. Whereas at the thylakoid level we found no clear difference in tolerance against lichen acids between lichen photobionts and other species, at the cellular level lichen photobionts showed strong tolerance as compared with other species. These findings suggest the presence of a lichen acid-specific exclusion or detoxification mechanism in lichen photobiont cells.

Topics: Acids, Carbocyclic; Benzofurans; Cells, Cultured; Chlorophyll; Electron Transport; Fluorescence; Lichens; Photosynthesis; Photosystem II Protein Complex; Plant Cells; Plant Development; Plants

To explore the effect of usnic acid on Toxoplasma gondii tachyzoites in vitro.. There are four groups named as (+)-usnic acid group, acetylspiramycin group, DMSO group and normal saline group. Groups of (+)-usnic acid and acetylspiramycin were further divided into 4 subgroups with final concentration of 5, 10, 25, 50 microg/ml respectively. Normal saline group and DMSO group were respectively given equal volume normal saline and 1% DMSO. Each group have 15 parallel tubes with 1 ml (1 x 10(6)/ml) T. gondii tachyzoites aqueous suspension. At 1 h, 2h and 4 h after drug treatment, tachyzoites were counted by light microscope with 0.4% Trypan blue staining. Tachyzoites in aqueous suspension was collected, and washed 3 times by PBS solution. Normal mice were inoculated intraperitoneally and observed for three generations. The cultivated rat cardiofibroblasts were then infected in vitro with T. gondii tachyzoites. At the same time, rat cardiomyocytes invasion by T. gondii tachyzoites was investigated.. At 4 h treated by 10, 25 and 50 microg/ml (+)-usnic acid, 100% T. gondii tachyzoites were stained. Some tachyzoites were swelling, blunt or round in the two ends; and granules appeared in the cytoplasm, the nuclei were deep stained. The changes of tachyzoites in acetylspiramycin group were similar to (+)-usnic acid group, 100% T. gondii tachyzoites were stained in 50 microg/ml acetylspiramycin subgroup. In inoculation tests, mice died at 8th to 9th days in 5 microg/ml (+)-usnic acid subgroup and numerous tachyzoites were detected in ascites. However, most mice survived to be killed in the other (+)-usnic acid subgroups and the tachyzoites were not found in ascites. All mice in acetylespirmycin groups died at 6th to 8th days after inoculation and many tachyzoites or pseudocysts were observed in mice ascites. In infecting cell tests, the cultivated rat cardiofibroblasts were infected in vitro by the tachyzoites after treated with 5 microg/ml (+)-usnic acid for 4 h, and pseudocysts were formed in infected cells. It was negative in the other subgroups of (+)-usnic acid. But the cultivated rat cardiofibroblasts were infected to varying degree in acetylspiramycin groups, normal saline group and DMSO group.. (+)-Usnic acid has a remarkable effect on T. gondii tachyzoites.

Topics: Animals; Benzofurans; Cells, Cultured; In Vitro Techniques; Mice; Mice, Inbred Strains; Rats; Spiramycin; Toxoplasma; Toxoplasmosis, Animal

Phomodione, [(4aS(*),9bR(*))-2,6-diacetyl-7-hydroxy-4a,9-dimethoxy-8,9b-dimethyl-4a.9b-dihydrodibenzo[b,d]furan-1,3(2H,4H)-dione], an usnic acid derivative, was isolated from culture broth of a Phoma species, discovered as an endophyte on a Guinea plant (Saurauia scaberrinae). It was identified using NMR, X-ray crystallography, high resolution mass spectrometry, as well as infrared and Raman spectroscopy. In addition to phomodione, usnic acid and cercosporamide, known compounds with antibiotic activity, were also found in the culture medium. Phomodione exhibited a minimum inhibitory concentration of 1.6 microg/mL against Staphylococcus aureus using the disk diffusion assay, and was active against a representative oomycete, ascomycete and basidiomycete at between three and eight micro-grams per mL.

Topics: Actinidiaceae; Ascomycota; Basidiomycota; Benzofurans; Crystallography, X-Ray; Magnetic Resonance Spectroscopy; Mass Spectrometry; Microbial Sensitivity Tests; Microscopy, Electron, Scanning; Molecular Structure; Oomycetes; Staphylococcus

Based on results of a former study in 2005, this investigation aimed at quantifying UV- and cold temperature stress-induced changes within the secondary metabolite production of the cultured mycobiont of the lichen Heterodea muelleri (Hampe) Nyl. The chemical profiles of the mycobiont cultures and the lichen thallus were determined by high-performance liquid chromatography (HPLC) and thin layer chromatography (TLC) analyses. The voucher specimen of H. muelleri produced diffractaic acid as a major polyketide and barbatic acid as a satellite compound, whereas the untreated mycobiont did not contain any detectable secondary metabolites. While UV-C stress caused a general increase in substance formation, cold temperature stress resulted in a strong activation of barbatic acid biosynthesis. A further series of experiments focused on the effect of diffractaic and barbatic acids on the growth of the symbiotic photobiont Trebouxia jamesii; usnic acid was similarly tested. Pure substances were obtained from mycobiont cultures by performing preparative TLC. A determined quantity of algae was incubated on BBM plates that contained three different concentrations of the pure lichen metabolites. The growth of the photobionts was monitored over a period of 1 mo to evaluate the impact of each substance on the cultured algae. While diffractaic and usnic acid had no noticeable effect, barbatic acid strongly inhibited algal growth and resulted in cell death.

Topics: Anisoles; Ascomycota; Benzofurans; Chlorophyta; Hydroxybenzoates; Lichens; Phthalic Acids

Toxicity following ingestion of the vagrant, foliose lichen Xanthoparmelia chlorochroa was identified as the putative etiology in the death of an estimated 400-500 elk on the Red Rim-Daley Wildlife Habitat Management Area in Wyoming during the winter of 2004. A single, unsubstantiated report in 1939 attributed toxicity of X. chlorochroa in cattle and sheep to usnic acid, a common lichen secondary metabolite. To test the hypothesis that usnic acid is the proximate cause of death in animals poisoned by lichen, domestic sheep were dosed PO with (+)-usnic acid. Clinical signs in symptomatic ewes included lethargy, anorexia, and signs indicative of abdominal discomfort. Serum creatine kinase, aspartate aminotransferase, and lactate dehydrogenase activities were considerably elevated in symptomatic sheep. Similarly, only symptomatic ewes exhibited appreciable postmortem lesions consisting of severe degenerative appendicular skeletal myopathy. The median toxic dose (ED(50)) of (+)-usnic acid in domestic sheep was estimated to be between 485 and 647 mg/kg/day for 7 days.

Topics: Animals; Benzofurans; Female; Lichens; Muscle, Skeletal; Plant Poisoning; Sheep; Sheep Diseases

The quantitative determination of usnic acid (UA), perlatolic acid (PA), and atranorin (AT) in Alaska lichens by micellar electrokinetic chromatography (MEKC) is reported. The background electrolyte (BGE) included sodium docecyl sulfate (SDS), and beta-cyclodextrin (beta-CD) in a high-pH borate buffer. The presence of beta-CD in the buffer significantly decreases peak width, especially for UA, as it decreases migration time for both UA and PA. Linear calibration curves for UA, PA, and AT were established using an internal standard of benzoic acid (BA). Concentration limits of detection (cLODs) are 2.5, 2.2 and 2.0microg/mL (S/N 3) for UA, PA, and AT, respectively. Dry samples of lichen were extracted at room temperature with acetone for 24h in the presence of BA as internal standard. Recoveries of UA from spiked samples ranged from 92 to 98%. Amounts of UA and PA in the lichen samples ranged from 0.28 to 1.7% dry weight and 0.02 to 0.23%, respectively.

Topics: Benzoates; Benzofurans; Chromatography, Micellar Electrokinetic Capillary; Hydroxybenzoates; Lichens; Molecular Structure; Reproducibility of Results

The hypotheses were tested that, firstly, lichens producing the dibenzofuran usnic acid colonize substrates characterized by specific pH ranges, secondly, this preferred pH is in a range where soluble usnic acid and its corresponding anion occur in similar concentrations, and thirdly, usnic acid makes lichens vulnerable to acidity. Lichens with usnic acid prefer an ambient pH range between 3.5 and 5.5 with an optimum between 4.0 and 4.5. This optimum is close to the pK(a1) value of usnic acid of 4.4. Below this optimum pH, dissolved SO(2) reduces the chlorophyll fluorescence yield more in lichens with than without their natural content of usnic acid. This suggests that usnic acid influences the acidity tolerance of lichens. The putative mechanism of the limited acidity tolerance of usnic acid-containing lichens is the acidification of the cytosol by molecules of protonated usnic acid shuttling protons through the plasma membrane at an apoplastic pH

Topics: Air Pollutants; Benzofurans; Hydrogen-Ion Concentration; Lichens; Models, Biological; Species Specificity; Sulfur Dioxide

In this research, (-)-usnic acid and (+)-usnic acid, commonly encountered lichen secondary metabolites, were evaluated for their insecticidal effects against the larvae of Culex pipiens L. (Diptera: Culicidae) under laboratory conditions. Both compounds showed strong larvicidal activity and caused 100% mortality on third-fourth larval stages of the species at 24 h at the doses of 5 and 10 ppm. Bioassays with (-)- and (+)-usnic acids against larvae of C. pipiens revealed that the LC50 values were 0.8 and 0.9 ppm, respectively. The results suggest that lichen compounds could be useful in the search of new insecticides.

Topics: Animals; Benzofurans; Culex; Insecticides; Larva; Lethal Dose 50; Lichens; Molecular Structure; Survival Analysis

Usnic acid is a component of nutritional supplements promoted for weight loss that have been associated with liver-related adverse events including mild hepatic toxicity, chemical hepatitis, and liver failure requiring transplant. To determine if metabolism factors might have had a role in defining individual susceptibility to hepatotoxicity, in vitro metabolism studies were undertaken using human plasma, hepatocytes, and liver subcellular fractions. Usnic acid was metabolized to form three monohydroxylated metabolites and two regio-isomeric glucuronide conjugates of the parent drug. Oxidative metabolism was mainly by cytochrome P450 (CYP) 1A2 and glucuronidation was carried out by uridine diphosphate-glucuronosyltransferase (UGT) 1A1 and UGT1A3. In human hepatocytes, usnic acid at 20 microM was not an inducer of CYP1A2, CYP2B6, or CYP3A4 relative to positive controls omeprazole, phenobarbital, and rifampicin, respectively. Usnic acid was a relatively weak inhibitor of CYP2D6 and a potent inhibitor of CYP2C19 (the concentration eliciting 50% inhibition (IC(50)) = 9 nM) and CYP2C9 (IC(50) = 94 nM), with less potent inhibition of CYP2C8 (IC(50) = 1.9 microM) and CYP2C18 (IC(50) = 6.3 microM). Pre-incubation of microsomes with usnic acid did not afford any evidence of time-dependent inhibition of CYP2C19, although evidence of slight time-dependent inhibition of CYP2C9 (K(I) = 2.79 microM and K(inact) = 0.022 min(-1)) was obtained. In vitro data were used with SimCYP(R)to model potential drug interactions. Based on usnic acid doses in case reports of 450 mg to >1 g day(-1), these in vitro data indicate that usnic acid has significant potential to interact with other medications. Individual characteristics such as CYP1A induction status, co-administration of CYP1A2 inhibitors, UGT1A1 polymorphisms, and related hyperbilirubinaemias, or co-administration of low therapeutic index CYP2C substrates could work alone or in consort with other idiosyncrasy risk factors to increase the risk of adverse events and/or hepatotoxicity. Thus, usnic acid in nutritional supplements might be involved as both victim and/or perpetrator in clinically significant drug-drug interactions.

Topics: Benzofurans; Chemical and Drug Induced Liver Injury; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Dietary Supplements; Drug Interactions; Enzyme Induction; Enzyme Inhibitors; Humans; Inhibitory Concentration 50; Kinetics; Liver Diseases; Microsomes, Liver; Models, Molecular; Protein Binding; Risk Factors; Substrate Specificity

Usimines A-C ( 1- 3), three new usnic acid derivatives, have been isolated from a MeOH extract of the Antarctic lichen Stereocaulon alpinum by various chromatographic methods. The structures of 1- 3 were determined by analysis of their spectroscopic data (NMR, UV, MS) and by chemical methods. The known compound usnic acid ( 4) was also obtained. Compounds 1- 4 showed moderate inhibitory activity against therapeutically targeted protein tyrosine phosphatase 1B (PTP1B).

Topics: Antarctic Regions; Benzofurans; Humans; Lichens; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Protein Tyrosine Phosphatase, Non-Receptor Type 1

Reindeer are able to eat and utilize lichens as an important source of energy and nutrients. In the current study, the activities of antibiotic secondary metabolites including usnic, antranoric, fumarprotocetraric, and lobaric acid commonly found in lichens were tested against a collection of 26 anaerobic rumen bacterial isolates from reindeer (Rangifer tarandus tarandus) using the agar diffusion method. The isolates were identified based on their 16S ribosomal ribonucleic acid (rRNA) gene sequences. Usnic acid had a potent antimicrobial effect against 25 of the isolates, belonging to Clostridiales, Enterococci, and Streptococci. Isolates of Clostridia and Streptococci were also susceptible to atranoric and lobaric acid. However, one isolate (R3_91_1) was found to be resistant to usnic, antranoric, fumarprotocetraric, and lobaric acid. R3_91_1 was also seen invading and adhering to lichen particles when grown in a liquid anaerobic culture as demonstrated by transmission electron microscopy. This was a Gram-negative, nonmotile rod (0.2-0.7 x 2.0-3.5 microm) with a deoxyribonucleic acid G + C content of 47.0 mol% and main cellular fatty acids including 15:0 anteiso-dimethyl acetal (DMA), 16:0 iso-fatty acid methyl ester (FAME), 13:0 iso-3OH FAME, and 17:0 anteiso-FAME, not matching any of the presently known profiles in the MIDI database. Combined, the phenotypic and genotypic traits including the 16S rRNA gene sequence show that R3_91_1 is a novel species inside the order Clostridiales within the family Lachnospiraceae, for which we propose the name Eubacterium rangiferina. This is the first record of a rumen bacterium able to tolerate and grow in the presence of usnic acid, indicating that the rumen microorganisms in these animals have adapted mechanisms to deal with lichen secondary metabolites, well known for their antimicrobial and toxic effects.

Topics: Animals; Anti-Infective Agents; Benzofurans; Clostridium; DNA Primers; DNA, Bacterial; Drug Resistance, Bacterial; Eubacterium; Phylogeny; Reindeer; RNA, Ribosomal; Rumen; Salicylates

Vancomycin-resistant enterococci (VRE) and methicillin-resistant staphylococci, most notably methicillin-resistant Staphylococcus aureus (MRSA), are serious clinical problems. The antibiotic arsenal available against them is limited, and new mutants worsen the situation. We studied the activity of (+)-usnic acid, an old lichen-derived drug, and its sodium salt against clinical isolates of VRE and MRSA using the agar diffusion and minimal inhibitory concentration (MIC) methods. The acid and, especially, the sodium salt had potent antimicrobial activity against all clinical isolates of VRE and MRSA studied. The MIC values of the sodium salt against VRE strains ranged between 4 and 16 microg/ml (1-day test) and between 4 and 31 microg/ml (2-day test), being below 8 microg/ml for most strains. The salt had potent activity even against those strains that were not inhibited by ampicillin (125 microg/ml), and it never lost its activity after 24 h, in contrast to ampicillin. Thus, in spite of the fact that usnic acid can in some cases cause serious toxicity, it and its salts may be worth considering in clinical practice in cases where other therapies have failed or the microbe is resistant toward other agents.

Topics: Anti-Infective Agents; Benzofurans; Drug Resistance; Enterococcus; Lichens; Methicillin Resistance; Microbial Sensitivity Tests; Staphylococcus aureus; Vancomycin

According to classic text books on lichen biology, the phenolic secondary chemicals in lichens have antibiotic effects on soil microorganisms and mycorrhizal fungi in ecosystems. However, the experimental evidence for this under natural conditions is still relatively scarce. We examined some of the assumptions behind the concept of antimicrobial effects of lichen secondary substances: (1) the secondary substances of Cladonia stellaris, usnic and perlatolic acids, are leached out from the lichens by rainwater; (2) these substances inhibit the microbial activity of soil, and; (3) since they are extremely resistant to microbial decomposition, the soil underneath a continuous lichen mat is enriched in usnic and perlatolic acids. Our results did not support any of these assumptions. The evidence for the antimicrobial activity of lichen secondary substances seems to be weak in comparison to other suggested functions such as light filtering and herbivore protection. We suggest that it is time to re-evaluate the evidence for the antimicrobial ecological role of lichen secondary substances in natural systems.

Topics: Anti-Bacterial Agents; Benzoates; Benzofurans; Lichens; Rain; Soil; Soil Microbiology; Water

Injecting scolicidal agents into the intact hydatid cyst and packing the operative field with sponges soaked in scolicidal agents have been used to avoid dissemination of the parasite into the pleural cavity and bronchial system during surgery. The aim of this study was to determine the scolicidal property of different concentrations and exposure times of various agents on the protoscolexes. For this reason, usnic acid, betadine (%10 povidine iodine), savlosol (15% cetrimide-1.5% chlorhexidine), and desderman (96% ethanol and 2-biphenylol) and their various dilutions were used. Protoscolexes were obtained from lungs containing cysts of the naturally infected sheep and viability was determined by dye-uptake (0.1% Eosin). It was found that usnic acid did not completely kill the scolexes in 15 minutes. Betadine, savlosol, and desderman was strongly germicidal in 15 minutes. Savlosol was found to have a germicidal effect at the lowest concentration among the agents studied.

Topics: Animals; Anti-Infective Agents; Benzofurans; Cetrimonium; Cetrimonium Compounds; Chlorhexidine; Echinococcosis; Echinococcus; Humans; Lung; Povidone-Iodine

Usnea longissima, a medicinal lichen of Anatolia (Turkey), is used in the treatment of gastric ulcer in local folk medicine. In this paper, the gastroprotective effect of usnic acid (UA) isolated from Usnea longissima was investigated in the indomethacin-induced gastric ulcers in rats at doses of 25, 50, 100 and 200 mg/kg body weight. The gastric lesions were significantly reduced by all doses of UA as compared with the indomethacin (25 mg/kg body weight) treated group. In the stomach tissues of treated animals, the in vivo antioxidant levels were evaluated. The administration of indomethacin caused a significant decrease in the levels of superoxide dismutase (SOD), glutathione peroxidase (GPx) and reduced glutathione (GSH), and an increase in the lipid peroxidation (LPO) level (p < 0.05). The administration of all doses of UA reversed the trend, inducing a significant increase of SOD, GSH and GPx levels and a reduction in LPO level in tissues. However, catalase (CAT), glutathione reductase (GR) and myeloperoxidase (MPx) activities, increased by indomethacin, were found to be lower in the UA- and ranitidine-treated groups. The gastric mucosal constitutive NO synthase (cNOS) and inducible NO synthase (iNOS) activities were also investigated in tissues of UA- (100 mg/kg), ranitidine- (50 mg/kg) and indomethacin-treated rat groups. The administration of UA and ranitidine increased the cNOS activity and lowered the iNOS activity as compared with indomethacin-treated group. These results suggest that the gastroprotective effect of UA can be attributed to its reducing effect on the oxidative damage and neutrophil infiltration in tissues.

Topics: Animals; Antioxidants; Benzofurans; Cytoprotection; Gastric Mucosa; Glutathione Peroxidase; Indomethacin; Male; Neutrophil Infiltration; Nitric Oxide; Peroxidase; Rats; Rats, Wistar; Stomach Ulcer; Superoxide Dismutase

The investigation of the characteristics of mixed floating monolayers of phospholipids and usnic acid (UA), an active metabolite from lichens, can provide valuable information on how to prepare stable liposomes that could serve as carriers of UA for therapeutic proposes. The present paper is concerned with the thermodynamic analysis of the behavior of Langmuir monolayers formed by mixing different phospholipids (dibehenoylphosphatidylcholine, DBPC, dipalmitoylphosphatidylcholine, DPPC, and dioleoylphosphatidylcholine, DOPC) and UA at varied molar fractions. Relevant thermodynamic parameters such as excess areas, excess free energies and free energy of mixing were derived from the surface pressure data obtained from compression measurements performed in a Langmuir trough. For the largest lateral pressure examined (25 mN/m), negative values of the excess free energy were found only for the DOPC/UA monolayer, which should be the most stable of them. Based on the calculated values of the free energy of mixing, we note that the DBPC/UA and DPPC/UA systems present the best mixed character at low pressures and when the molar fraction of the UA is 0.5; at that relative concentration and at low values of the external pressure, the UA molecules can better mix and interact with the phospholipid molecules. The compression isotherms for mixed monolayers show no visible transitions, exhibiting a more organized phase that corresponds to a negative free energy of mixing. We have established that the most stable monolayers were those corresponding to DOPC/UA mixtures with a UA molar fraction of 0.75.

Topics: Benzofurans; Entropy; Membranes, Artificial; Phospholipids; Pressure; Surface Tension

Usnic acid is unambiguously confirmed by tandem mass spectrometry (MS/MS) in tumbleweed shield lichen, Xanthoparmelia chlorochroa. The lichen contains 2% usnic acid by liquid chromatography with UV quantification at 282 nm. The UV linear range for usnic acid quantification is from its 4 ng limit of detection to 2 microg injected. UV signal saturation is recognized by distortion of the usnic acid UV spectrum. Positive ion electrospray-tandem mass spectrometry offers no similar means to recognize quantification data recorded above the linear range of electrospray. Electrospray ionization capacity and matrix effects limit the reliability of tandem mass spectrometry quantification. The combination of UV quantification and MS confirmation provides a reliable analytical method for measuring usnic acid levels in plant material.

Topics: Acetone; Acetonitriles; Animals; Benzofurans; Chromatography, High Pressure Liquid; Deer; Lichens; Solubility; Spectrometry, Mass, Electrospray Ionization; Wyoming

Dietary supplements containing usnic acid are marketed for weight loss and have been associated with hepatotoxicity. The specific ingredient responsible for the hepatotoxicity is currently unknown. We describe 2 patients who developed severe hepatotoxicity within 3 months of taking a dietary supplement containing usnic acid. One patient developed fulminant hepatic failure requiring emergency liver transplantation; the other developed submassive hepatic necrosis but did not require transplantation. Thorough investigation, including histopathological examination of the liver, revealed no other cause of acute liver injury. Usnic acid hepatotoxicity should be considered as a possible etiologic factor in patients presenting with fulminant hepatic failure, especially if they have been taking dietary supplements for weight reduction.

Topics: Adult; Antitrichomonal Agents; Benzofurans; Dietary Supplements; Female; Follow-Up Studies; Humans; Liver Failure, Acute; Liver Transplantation; Male

To observe the influence of Usnic acid on the antibiotic-resistant plasmid in Staphylococcus aureus (Sa).. The antibiotic-resistant plasmid was abstracted from the clinical divided strain of Sa and plasmid elimination test was performed in vitro.. Plasmid elimination test showed that Usnic acid could eliminate the resistant plasmid in Sa effectively. At 24th and 48th hour after the treatment of Usnic acid, the elimination rate of resistant plasmid was 5.2% and 16.4% respectively.. Usnic acid can eliminate the antibiotic-resistant plasmid in Sa. It is possible to use Usnic acid to treat the infection of antibiotic-resistant Sa in clinic.

Topics: Anti-Bacterial Agents; Benzofurans; Drug Resistance, Bacterial; Electrophoresis, Agar Gel; R Factors; Staphylococcus aureus; Time Factors

The study was aimed to optimize the culture conditions for the production of usnic acid in the cultured cell aggregates composed of symbionts in lichen Usnea ghattensis in vitro. The cultured lichen tissue composed of symbionts appeared after about 2-3 weeks of inoculation in water-agar and malt-yeast extract (MYE) media and shown the production of usnic acid after 2-3 months of inoculation. However, the growth of symbionts was strongly affected by different culture conditions. The addition of excess carbon and nitrogen sources in the media has significantly enhanced the growth as well as usnic acid content. The cultured symbionts in MYE medium having 4% sucrose, 4% polyethyl glycol (PEG) gave 7.63 g dry biomass with 3.9 microg usnic acid/g dry biomass. In water-agar medium having 4% sucrose and 4% PEG gave 3.08 g dry biomass with 1.11 microg usnic acid/g dry biomass. The positive effects of medium on the growth of symbionts and the production of usnic acid are seemed to be due to nutritional factors.

Topics: Benzofurans; Culture Media; Polyethylene Glycols; Sucrose; Symbiosis; Time Factors; Usnea

Botanical ingredients used in personal care products are a significant and underreported cause of allergic contact dermatitis.. To evaluate allergic contact dermatitis from a widely-used botanical deodorant.. We conducted patch testing in four patients who were using the botanical deodorant and were referred to the contact dermatitis clinic; three patients had axillary dermatitis and one had dermatitis of the external ear.. All four patients had positive patch test reactions to lichen acid mix and D-usnic acid. Of the three patients who were patch tested to the botanical deodorant, all had positive reactions.. We did not test to the specific lichen used in the natural deodorant but rather used our own lichen acid mix and d-usnic acid in addition to testing to the actual product. One of the patients declined to be tested with the natural deodorant, but did test positive to the lichen acid mix and d-usnic acid.. Personal care products such as deodorants may represent a new route of exposure to lichen extract, a known allergen.

Topics: Adult; Antifungal Agents; Benzofurans; Deodorants; Dermatitis, Allergic Contact; Humans; Lichens; Male; Middle Aged; Plant Extracts

Despite the recognised antiproliferative and antitumour properties of usnic acid, its therapeutic application has yet to be introduced. In fact, the high hepatotoxicity and low water solubility of usnic acid have somewhat restricted its practical use in anticancer therapy. The aim of this study was therefore to investigate the antitumour activity of usnic acid encapsulated into nanocapsules prepared with lactic co-glycolic acid polymer. Usnic acid-loaded nanocapsules were obtained using the interfacial deposition of a preformed polymer. The antitumour activity was confirmed on an ascitic tumour (Sarcoma-180) implanted in Swiss mice and estimated by means of the tumour inhibition. The results of antitumour activity confirmed that the encapsulation of usnic acid into PLGA-nanocapsules produced a 26.4% increase in tumour inhibition as compared with the standard free usnic acid treatment. Vacuolization of hepatocytes and a mild lymphocytic infiltration in portal spaces were observed in animals treated with free usnic acid. However, this hepatotoxicity was substantially reduced when animals were treated with usnic acid-loaded nanocapsules. No histological changes were noticed in the kidneys or spleen of animals treated either with usnic acid or usnic acid-loaded nanocapsules. These results suggest that nanoencapsulation may be a way of enabling usnic acid to be used in chemotherapy.

Topics: Animals; Benzofurans; Cell Line, Tumor; Chemical and Drug Induced Liver Injury; Disease Progression; Drug Compounding; Injections, Intraperitoneal; Lactic Acid; Liver; Male; Mice; Nanostructures; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Polymers; Sarcoma 180; Survival Analysis

The influence of (+)-usnic acid on rates of gas exchange (photosynthesis, respiration, and transpiration) in long-term cultivation of tomato plants was studied. The effect was dose-dependent. Plants grown in media containing the maximum concentration of (+)-usnic acid (30 muM) had photosynthetic and respiration rates reduced by 41% and 80%, respectively. The effect on photosynthesis rate may be the result of a multidirectional effect at various stages of this process, which at the highest usnic acid concentration underwent reduction: content of chlorophylls by 30%, carotenoids by 35%, and Hill reaction activity by 75%. Usnic acid also raises the susceptibility of chlorophyll to photodegradation. Under some conditions, transpiration was reduced by 2.1-fold in light and 3.7-fold in dark. This result was correlated with (1) an increase in the diffusive resistance of the stomata (3.1-fold in upper and 1.5-fold in lower surface of leaf), (2) a reduction of stomata density (by 60% on upper and 40% on lower surface), and (3) a 12.3-fold decrease in root hydraulic conductance.

Topics: Benzofurans; Carotenoids; Chlorophyll; Gases; Light; Photosynthesis; Plant Leaves; Plant Transpiration; Solanum lycopersicum; Water

This study investigates cytotoxic and genotoxic activities of (+)-Usnic acid and (-)-usnic acid isolated from the lichen Ramalina farinacea and the lichen Cladonia foliacea, respectively. To determine the activities of these acids, we used the MTT assay on V79 (Chinese hamster lung fibroblast like) and A549 (human lung carcinoma epithelial like) cell lines and cytokinesis-blocked micronucleus (CBMN) assay in human lymphocytes in vitro. Our results suggest that both enantiomers of usnic acid are non-genotoxic shown by the absence of micronucleus induction in human lymphocytes and have significant cytotoxic and apoptotic effects to induce cell killing in cultured human lymphocytes, V79 and A549 cell lines. Even low doses of (+)-usnic acid showed high cytotoxic activity against cancerous cells. The MTT results and cell proliferation index (CPI) values based on the CBMN test results are found in good agreement.

Topics: Animals; Antineoplastic Agents; Benzofurans; Cell Line; Cell Line, Tumor; Cricetinae; Fibroblasts; Formazans; Humans; Lichens; Lymphocytes; Male; Micronucleus Tests; Mutagenicity Tests; Stereoisomerism; Tetrazolium Salts

Chemotherapy for Chagas' disease is still unsatisfactory due to toxicity and limited effectiveness of the available drugs. In this work we have investigated the effect of usnic acid, isolated from lichen Cladonia substellata, against Trypanosoma cruzi, in vitro. Incubation of culture epimastigotes with 5-30microg/ml of this compound resulted in growth inhibition in a dosis-dependent manner. Ultrastructural analysis of treated epimastigotes showed damage to mitochondria, with a marked increase in kinetoplast volume and vacuolation of the mitochondrial matrix. Intense lysis of bloodstream trypomastigotes was observed with all drug concentrations tested. Besides mitochondrial and kinetoplast damage, trypomastigotes also presented enlargement of the flagellar pocket, as well as intense cytoplasm vacuolation. Treatment of infected macrophages with 40 or 80microg/ml usnic acid induced marked cytoplasm vacuolation in intracellular amastigote forms, with disorganization of parasite kinetoplast and mitochondria, but with no significant ultrastructural damage to the host cells.

Topics: Animals; Anti-Infective Agents; Antiprotozoal Agents; Benzofurans; Lichens; Macrophages, Peritoneal; Mice; Microscopy, Electron; Mitochondria; Trypanosoma cruzi

The widespread secondary metabolite usnic acid, a dibenzofuran derivative, is the principal acetone-soluble compound in the lichen Flavocetraria nivalis. Seasonal variation in concentrations were studied in four populations of this lichen, three from Arctic-alpine habitats in the Northern Hemisphere, and one from Patagonian heathland in the Southern Hemisphere. Usnic acid is produced in large amounts, making up between 4% and 8% of thallus dry weight. Large seasonal variation is seen, with a trend towards peak levels in late spring and early summer, and generally low levels during autumn and winter. However, at an Arctic steppe in Central West Greenland, remarkably high levels were also detected during late autumn and early winter. Comparisons with environmental data using model selection procedures show that usnic acid levels of three of the populations are positively correlated with time of season, as measured by the proximity in time to nearest summer solstice, solar radiation levels, and temperature conditions. All these three variables are intercorrelated, thus indicating the same overall trend. For the three driest sites, precipitation rates are included in the models that best explain the variation in usnic acid. However, the explanatory powers of the models are generally low, partly due to high variation between thalli growing together and sampled at the same time. This is the first attempt to compare statistically seasonal variation in usnic acid concentrations and environmental variables, and thus also the first time it is shown that the concentration in various populations of the same lichen species shows different types of correlation with seasonal climatic changes.

Topics: Arctic Regions; Argentina; Ascomycota; Benzofurans; Europe; Seasons; Time Factors

The depside atranorin and depsidone fumarprotocetraric acid, isolated from the lichens Stereocaulon alpinum and Cetraria islandica, respectively, were chosen as prototypes for poorly soluble natural compounds in an effort to facilitate testing in pharmacological models. Solubilizing agents previously identified as being non-toxic towards a malignant leukemic (K-562) cell line and suitable for testing of anti-proliferative activity of the dibenzofuran lichen metabolite (+)-usnic acid were used in solubilization studies of the depside and depsidone. Cyclodextrin derivatives were found to be most suitable for solubilizing the lichen compounds, the greatest rise in solubility being witnessed for fumarprotocetraric acid, increasing almost 300-fold from 0.03 mg/ml in water to 8.98 mg/ml in 10% 2-hydroxypropyl-beta-cyclodextrin (HPbetaCD). Subsequently, the lichen compounds, including (+)-usnic acid, were solubilized in 10% HPbetaCD and tested for effects on three malignant human cell lines; T-47D (breast), Panc-1 (pancreas) and PC-3 (prostate) in a standard proliferation assay. Atranorin and fumarprotocetraric acid did not exhibit anti-proliferative effects but usnic acid was active against all test cell lines with EC50 values of 4.3-8.2 microg/ml. The non-toxic solubilizing agents used in this study could prove useful for pharmacological testing of other poorly soluble natural products.

Topics: Benzofurans; Cell Line; Fumarates; Hydroxybenzoates; Lichens; Solubility; Thymidine

Topics: Acute Disease; Adult; Anti-Infective Agents; Benzofurans; Chemical and Drug Induced Liver Injury; Diagnosis, Differential; Female; Humans; Plants, Medicinal; Weight Loss

To study the effects of sodium usnic acid on proliferation of fibroblasts and skin wound healing.. L929 fibroblasts were incubated in culture medium containing sodium usnic acid, the proliferation of fibroblasts were measured by MTT. Skin wound healing promoting action of sodium usnic acid was determined in rats.. Sodium usnic acid does not showed proliferation-promoting activity for L929 fibroblasts, sodium usnic acid by external application accelerated healing of rat backskin wound. The wound-healing rate of sodium usnic acid was higher than that of the control group at the 2th - 12th day after treatment.. Sodium usnic acid can accelerate skin wound healing, the effects was not by stimulating proliferation of fibroblasts.

Topics: Administration, Topical; Animals; Benzofurans; Cell Proliferation; Cells, Cultured; Drugs, Chinese Herbal; Female; Fibroblasts; Male; Plants, Medicinal; Rats; Rats, Sprague-Dawley; Skin; Usnea; Wound Healing

Two beta-orcinol depsidone lactones, the methyl ethers of menegazziaic acid and stictic acid were isolated along with glyceryl trilinolate and usnic acid from an Usnea sp. new to Sri Lanka growing on rotting trees of Acacia decurrans. Usnic acid exhibited potent antitermite activity against a common pest of tea, Glyptotermes dilatatus, at low elevations.

Topics: Animals; Benzofurans; Insect Control; Isoptera; Lactones; Sri Lanka; Trees; Usnea

The majority of human tumors bear inactive p53 or cellular factors that down-regulate the expression and activity of the p53 network. Therefore, finding therapies that are effective in such tumors is of great interest. Usnic acid, a normal component of lichens, showed activity against the wild-type p53 breast cancer cell line MCF7 as well as the non-functional p53 breast cancer cell line MDA-MB-231 and the lung cancer cell line H1299 (null for p53). In MCF7 cells treated with usnic acid, although there was an accumulation of p53 and p21 proteins, the transcriptional activity of p53 remained unaffected. We also found that there was no phosphorylation of p53 at Ser15 after treatment of MCF7 cells with usnic acid, suggesting that the oxidative stress and disruption of the normal metabolic processes of cells triggered by usnic acid does not involve DNA damage. The property of usnic acid as a non-genotoxic anti-cancer agent that works in a p53-independent manner makes it a potential candidate for novel cancer therapy.

Topics: Antineoplastic Agents; Benzofurans; Breast Neoplasms; Cyclin-Dependent Kinase Inhibitor p21; DNA Damage; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms; Oxidative Stress; Phosphorylation; Transcription, Genetic; Tumor Cells, Cultured; Tumor Suppressor Protein p53

Topics: Animals; Anti-Infective Agents; Benzofurans; Food Chain; Food, Organic; Humans; Lichens; Probiotics

Hepatotoxic effect of (+)usnic acid, the active constituent of Usnea siamensis Wainio was studied in rats, isolated rat hepatocytes and isolated rat liver mitochondria. In rats, after treatment with high dose of (+)usnic acid (200 mg/kg per day, i.p.) for 5 days, there was no significant change in serum transaminase activity (serum AST, ALT) while the electron micrographs showed apparent morphological damage of mitochondria and endoplasmic reticulum. (+)Usnic acid at high dose (1 mM) as well as carbon tetrachloride (CCl4, the reference hepatotoxin) induced loss of cell membrane integrity in isolated rat hepatocytes by increasing the release of cellular transaminases (AST, ALT). Increase in lipid peroxidation, decrease in glutathione (GSH) content and increase in aniline hydroxylase activity (CYP 2E1) were also found. Combination of (+)usnic acid and CCl4 showed the additive results. (+)Usnic acid (0.15-6 microM) possessed uncoupling activity in isolated rat liver mitochondria. It stimulated respiration by mitochondria respiring with glutamate plus malate or succinate as substrates and activated ATPase activity. Increasing concentration of (+)usnic acid (>6 microM) exhibited loss of respiratory control and ATP synthesis. In conclusion, hepatotoxic effect of high dose (+)usnic acid may involve its reactive metabolite(s), causing loss of integrity of membrane like structures, resulting in destruction of mitochondrial respiration and oxidative phosphorylation.

Topics: Animals; Benzofurans; Cells, Cultured; Hepatocytes; Liver; Male; Mitochondria, Liver; Rats; Rats, Wistar; Usnea

Usnic acid, a lichen acid, is a compound found in crude medicines and dietary supplements, including Lipokinetix, a supplement marketed as a weight loss agent that caused hepatotoxicity and acute liver failure in patients. In this study, we examined the toxicity of usnic acid and assessed whether usnic acid may be contributing to hepatotoxicity caused by Lipokinetix. In primary cultured murine hepatocytes, usnic acid treatment (5 microM) resulted in 98% necrosis within 16 hr (no apoptosis was detected). Usnic acid treatment was associated with early inhibition and uncoupling of the electron transport chain in mitochondria of cultured hepatocytes. This inhibition of mitochondria by usnic acid corresponded with a fall in ATP levels in hepatocytes. In isolated liver mitochondria, usnic acid was observed to directly inhibit and uncouple oxidative phosphorylation. Oxidative stress appears to be central in usnic acid-induced hepatotoxicity based on the following findings: (1) pretreatment with antioxidants (butylated hydroxytoluene+Vitamin E) decreased usnic acid-induced necrosis by nearly 70%; (2) depletion of mitochondrial GSH with diethylmaleate increased susceptibility of hepatocytes to usnic acid; (3) usnic acid treatment was associated with increase free radical generation, measured using the fluorescent probe, dichlorodihydrofluorescin. The source of reactive oxygen species after usnic acid treatment include autoxidation of usnic acid and increased hydrogen peroxide generation by mitochondria caused by usnic acid inhibition of the respiratory chain, with the latter playing a more prominent role. Taken together, our results suggest that usnic acid is a strong hepatotoxic agent that triggers oxidative stress and disrupts the normal metabolic processes of cells. Usnic acid therefore may contribute to the hepatotoxic effects of Lipokinetix and its use in any supplement must come into question.

Topics: Adenosine Triphosphate; Animals; Anti-Infective Agents; Antioxidants; Benzofurans; Cell Survival; Cells, Cultured; Drug Interactions; Glutathione; Hepatocytes; Hydrogen Peroxide; Mice; Mitochondria, Liver; Necrosis; Oxidation-Reduction; Oxidative Stress; Reactive Oxygen Species; Respiration

The use of complementary and alternative medicine (CAM) in developed countries has increased significantly over the years. Among the most popular are the weight loss supplements or "fat burners." Liver failure due to these popular remedies has been widely recognized. Usnic acid has been an ingredient of dietary supplements that cause liver failure. Its hepatotoxicity has not been recognized because it is usually mixed with other ingredients that are presumably hepatotoxic. We describe a case of a 28-yr-old woman who presented with fulminant liver failure requiring orthotopic liver transplantation, after taking pure usnic acid for weight loss. This is the first report on fulminant liver failure associated with the ingestion of pure usnic acid. A discussion about hepatotoxicity of the different compounds of dietary supplements is presented. This is a reminder for the clinicians about the potential side effects of CAM.

Topics: Adult; Benzofurans; Dietary Supplements; Female; Follow-Up Studies; Humans; Liver Failure; Liver Transplantation; Obesity; Risk Assessment; Weight Loss

In modern medicine, artificial devices are used for repair or replacement of damaged parts of the body, delivery of drugs, and monitoring the status of critically ill patients. However, artificial surfaces are often susceptible to colonization by bacteria and fungi. Once microorganisms have adhered to the surface, they can form biofilms, resulting in highly resistant local or systemic infections. At this time, the evidence suggests that (+)-usnic acid, a secondary lichen metabolite, possesses antimicrobial activity against a number of planktonic gram-positive bacteria, including Staphylococcus aureus, Enterococcus faecalis, and Enterococcus faecium. Since lichens are surface-attached communities that produce antibiotics, including usnic acid, to protect themselves from colonization by other bacteria, we hypothesized that the mode of action of usnic acid may be utilized in the control of medical biofilms. We loaded (+)-usnic acid into modified polyurethane and quantitatively assessed the capacity of (+)-usnic acid to control biofilm formation by either S. aureus or Pseudomonas aeruginosa under laminar flow conditions by using image analysis. (+)-Usnic acid-loaded polymers did not inhibit the initial attachment of S. aureus cells, but killing the attached cells resulted in the inhibition of biofilm. Interestingly, although P. aeruginosa biofilms did form on the surface of (+)-usnic acid-loaded polymer, the morphology of the biofilm was altered, possibly indicating that (+)-usnic acid interfered with signaling pathways.

Topics: Anti-Bacterial Agents; Bacteria; Bacterial Adhesion; Benzofurans; Biofilms; Green Fluorescent Proteins; Microscopy, Confocal; Polymers; Polyurethanes; Staphylococcus aureus; Surface Properties

Microparticles will probably play a promising role in the future of chemotherapy. These polymeric delivery systems are capable of maximizing the therapeutic activity while reducing side effects of anti-cancer agents. Usnic acid (UA) is a secondary metabolite produced by lichens, which exhibits an anti-tumour activity. In this study, PLGA-microspheres containing usnic acid from Cladonia substellata were prepared by the double emulsion method, with or without PEG as stabilizer. The morphology of the microspheres was examined by optical and scanning electron microscopy. The in vitro kinetic profile of usnic acid loaded-microspheres was carried out by dissolution testing. The usnic acid content was analysed by HPLC. The cytotoxicity of free and encapsulated usnic acid was evaluated against HEp-2 cells using the MTT method. The anti-tumour assay was performed in mice against Sarcoma-180 tumour (UA 15 mg kg(-1) weight body/day) during 7 days. Animals were then sacrificed and tumour and organs were excised for histopathological analysis. Microspheres presented a smooth spherical surface with a mean diameter of 7.02 +/- 2.72 microm. The usnic acid encapsulation efficiency was approximately 100% (UA 10 mg 460 mg(-1) microspheres). A maximum release of 92% was achieved at the fifth day. The IC50 values for free and encapsulated usnic acid were 12 and 14 microg ml(-1), respectively. The encapsulation of usnic acid into microspheres promoted an increase of 21% in the tumour inhibition as compared with the free usnic acid treatment. In summary, usnic acid was efficiently encapsulated into PLGA-microspheres and the microencapsulation improved its anti-tumour activity.

Topics: Animals; Antineoplastic Agents; Benzofurans; Cell Proliferation; Chromatography, High Pressure Liquid; Drug Carriers; Drug Compounding; Lactic Acid; Liver; Male; Mice; Mice, Inbred Strains; Microscopy, Electron, Scanning; Microspheres; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Polymers; Sarcoma 180

Topics: Adult; Benzofurans; Chemical and Drug Induced Liver Injury; Diet, Reducing; Dietary Supplements; Drugs, Chinese Herbal; Ephedra sinica; Female; Humans; Male; Middle Aged; Obesity; Plant Preparations

Several lichen compounds, i.e. lobaric acid (1), a beta-orcinol depsidone from Stereocaulon alpinum L., (+)-protolichesterinic acid (2), an aliphatic alpha-methylene-gamma-lactone from Cetraria islandica Laur. (Parmeliaceae), (+)-usnic acid (3), a dibenzofuran from Cladonia arbuscula (Wallr.) Rabenh. (Cladoniaceae), parietin (4), an anthraquinone from Xanthoria elegans (Link) Th. Fr. (Calaplacaceae) and baeomycesic acid (5), a beta-orcinol depside isolated from Thamnolia vermicularis (Sw.) Schaer. var. subuliformis (Ehrh.) Schaer. were tested for inhibitory activity on platelet-type 12(S)-lipoxygenase using a cell-based in vitro system in human platelets. Lobaric acid (1) and (+)-protolichesterinic acid (2) proved to be pronounced inhibitors of platelet-type 12(S)-lipoxygenase, whereas baeomycesic acid (5) showed only weak activity (inhibitory activity at a concentration of 100 microg/ml: (1) 93.4+/-6.62%, (2) 98,5+/-1.19%, 5 14.7+/-2.76%). Usnic acid (3) and parietin (4) were not active at this concentration. 1 and 2 showed a clear dose-response relationship in the range of 3.33-100 microg/ml. According to the calculated IC50 values the highest inhibitory activity was observed for the depsidone 1 (IC50 = 28.5 microM) followed by 2 (IC50 = 77.0 microM). The activity of 1 was comparable to that of the flavone baicalein, which is known as a selective 12(S)-lipoxygenase inhibitor (IC50 = 24.6 microM).

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; 4-Butyrolactone; Benzoates; Benzofurans; Blood Platelets; Depsides; Emodin; Humans; In Vitro Techniques; Lactones; Lichens; Lipoxygenase; Lipoxygenase Inhibitors; Molecular Structure; Resorcinols; Salicylates

There are a large number of species of Antarctic lichens, and several studies describing the secondary metabolites present in these lichens, as well as the advances in understanding the chemistry of these metabolites, have been reported. In addition, some derivatives displaying interesting antibacterial effects have been described. The cytotoxic and apoptotic effects of 15 secondary metabolites (depsides, depsidones and usnic acid) obtained from Continental (Chilean) and Antarctic lichens were evaluated in primary cultures of rat hepatocytes. Intracellular lactate dehydrogenase release, caspase 3 activation and DNA fragmentation were measured. In this study, we have evaluated a set of markers associated with pivotal steps in the execution phase of apoptosis, in order to detect compounds with apoptotic effects on hepatocytes before significant necrosis takes place. Flow cytometric analysis of DNA fragmentation revealed an increase in apoptotic nuclei with sub-diploid DNA content after the exposure of hepatocytes to sub-cytotoxic concentrations of the compounds. Among these, salazinic acid, stictic acid and psoromic acid displayed significant apoptotic activities.

Topics: Animals; Antarctic Regions; Apoptosis; Benzoates; Benzofurans; Carboxylic Acids; Caspase 3; Caspases; Depsides; Enzyme Activation; Flow Cytometry; Hepatocytes; Hydroxybenzoates; Lactones; Lichens; Male; Rats; Rats, Sprague-Dawley

Lichens are ubiquitous organisms formed by symbiotic associations of fungal hyphas and algae that also grow under often extreme environmental conditions. They produce secondary metabolites, the so-called lichen substances, whose structural characterization can give an important contribution to lichen taxonomy. Lichens are also widely employed as biomonitors of atmospheric pollution; being epiphyte organisms they tend, in fact, to accumulate exogenous compounds. Moreover, it could be questioned if the environmental stress alters their secondary metabolites production. Therefore, a new strategy for the analysis of the organic substances absorbed or metabolized by lichens has been developed. This method exploits the dry solid-phase microextraction (SPME) headspace technique coupled with gas chromatography/mass spectrometry (GC/MS). Lichens coating the stone surfaces of monuments, located in small towns between high mountains and far away from urban environments, have been investigated. In the field of cultural heritage, this study can contribute to the knowledge of the state of conservation of outdoor exposed historical monuments.

Topics: Benzofurans; Biosensing Techniques; Environmental Monitoring; Gas Chromatography-Mass Spectrometry; Italy; Lichens; Molecular Structure; Plant Extracts

Responses of concentrations of usnic (UA) and perlatolic (PA) acids and the relative growth rate (RGR) of a mat-forming lichen, Cladina stellaris, to enhanced N and P input were studied in a fertilisation experiment. It was predicted on the basis of carbon-nutrient balance (CNB) hypothesis that the concentrations of these phenolics would decline and the growth rate increase in response to increased nutrient uptake. The concentration of UA showed a convex response pattern to increased N input whereas the concentration of PA was non-responsive. An ecologically realistic, "moderate", N treatment clearly lowered the level of UA both with and without the P application. Applying P alone caused a significant increase in the level of UA. The RGR of C. stellaris did not respond to nutrient addition. The results indicate that even though the CNB hypothesis may be applicable in explaining concentrations of lichen secondary metabolites, it may be applied under a relatively narrow set of conditions. Especially inherited constraints in the growth of lichen fungi may seriously limit the responsiveness of lichens to short-time changes in the availability of resources. These limitations may also apply to other perennials adapted to nutrient-poor conditions.

Topics: Antifungal Agents; Benzofurans; Hydroxybenzoates; Lichens; Nitrogen; Phosphorus

The metal binding properties of a phenolic lichen substance usnic acid (UA) and its acetyl and enamine derivatives 9-O-acetylusnic acid (MAUA), 7,9-di-O-acetylusnic acid (DAUA), Delta(2,11)-enaminousnic acid (EUA), and N-substituted Delta(2,11)-enaminousnic acids have been studied by synthetic and spectroscopic methods, and the structures of copper(II) and palladium(II) complexes have been established by the X-ray diffraction method. Cu(II) reacted with UA and DAUA to give the binary complexes Cu(UA)(2) x H(2)O and Cu(DAUA)(2), respectively, and Cu(bpy) (bpy=2,2'-bipyridine) formed ternary complexes with UA and DAUA. Pd(II) also reacted with UA, DAUA, EUA, and N-substituted Delta(2,11)-enaminousnic acids to give the corresponding binary complexes. All the isolated complexes are insoluble in water and soluble in most organic solvents. They exhibited very strong absorption and circular dichroism spectral peaks in the UV region. The (1)H-NMR spectrum in CDCl(3) of the Pd(II) complex of N-phenyl-Delta(2,11)-enaminousnic acid (PEUA), Pd(PEUA)(2) x C(6)H(6), showed that the C(4)-proton signal suffered a large upfield shift (0.86 ppm) due to the ring current effect of the N-phenyl moiety. X-Ray crystal structure analysis has been performed for Cu(bpy)(UA)(ClO(4)) x CH(3)OH, Pd(MEUA)(2) x C(6)H(6), and Pd(PEUA)(2) x C(6)H(6). Cu(bpy)(UA)(ClO(4)) x CH(3)OH has a square-pyramidal structure with the two nitrogen atoms of bpy and the two oxygen atoms of the mono-deprotonated B ring of UA in the equatorial positions, while Pd(II) binds with two molecules of MEUA or PEUA in the trans configuration through the nitrogen and oxygen atoms with deprotonation. The N-phenyl ring of PEUA in Pd(PEUA)(2).C(6)H(6) was revealed to be located close to the C(4) proton as indicated by (1)H-NMR. Isolation of Cu(2)(bpy)(2)(UA)(NO(3))(2) x 2H(2)O suggests that UA has two metal binding sites that can form polymeric complexes. The present results substantiate the metal binding ability and the structures of the complexes of usnic acid and other substances from lichens as biomonitors of environmental metal ions.

Topics: Anti-Infective Agents; Benzofurans; Circular Dichroism; Copper; Environmental Monitoring; Hydrogen-Ion Concentration; Lichens; Magnetic Resonance Spectroscopy; Molecular Structure; Palladium; X-Ray Diffraction

The pharmacological testing of natural products can often be hampered by the poor solubility of such compounds in non-toxic solvents. There is thus a need for a suitable agent for solubilization of natural substances to allow testing on a variety of cell lines in-vitro. Such an agent should ideally have no direct effects on any of the commonly used cell lines from a variety of tissues and mammalian species to allow proper comparison. In this study, the lichen metabolite (+)-usnic acid, a dibenzofuran derivative, was used as a prototype for an insoluble natural product with the aim of finding a solvent that was both capable of solubilizing usnic acid and was free of direct activity against a test cell line. Solubilization was measured at different pH values in various concentrations of co-solvents (glycofurol 75, propylene glycol, polyethylene glycol 400), surfactants (polysorbate 20 and Cremophor RH40), and the complexing agent 2-hydroxypropyl-beta-cyclodextrin. The solubility achieved in a 20% aqueous solution was 0.11 mg mL(-1) for propylene glycol, 0.19 for PEG 400, 0.27 for glycofurol 75, 0.57 for Cremophor RH40, 0.68 for 2-hydroxypropyl-beta-cyclodextrin and 0.84 for polysorbate 20. The direct effects of the various solvent systems were tested on the human leukaemia cell line K-562 in a standard proliferation assay. Most of the solvents proved toxic with the exception of propylene glycol, PEG 400 and 2-hydroxypropyl-beta-cyclodextrin. Anti-proliferative activity of usnic acid could be demonstrated with an ED50 (amount of substance required to reduce thymidine uptake to 50% of uptake by untreated control culture) of 4.7 microg mL(-1) using PEG 400 and 2-hydroxypropyl-beta-cyclodextrin but only the latter gave satisfactory solubility. 2-Hydroxypropyl-beta-cyclodextrin was thus identified as a solubilizing agent that fulfilled both set criteria of solubility and lack of toxicity against the test cells.

Topics: Analysis of Variance; Benzofurans; Cell Division; Humans; Hydrogen-Ion Concentration; K562 Cells; Lichens; Solubility; Solvents; Thymidine

The fruticose lichen Flavocetraria nivalis and the crustose lichen Ophioparma ventosa, both common in light-exposed arctic-alpine environments, were exposed to ultraviolet radiation (UVR) in growth chambers for 30 days. Treatment with visible light (PAR) served as control. Both species accumulate the UV-absorbing phenolic compound usnic acid in the upper cortex. The latter species also synthesises several UV-absorbing medullary compounds, among them divaricatic acid. The effects of treatment with UVR on the synthesis of these two compounds were investigated by analysing the compounds quantitatively by RP-HPLC. UV-exposed thallus tips of F. nivalis contained higher concentrations of usnic acid than those not grown under UVR. Both treatments had a positive effect on the synthesis of usnic acid in O. ventosa. An additional experiment with O. ventosa was performed by first storing samples in a low-light habitat for 1 year to obtain near-zero levels of phenolics, and thereby exposing the samples to UVR and PAR for 90 days. A rapid resynthesis of usnic acid was observed for both treatments. The amounts of divaricatic acid were highly variable in all groups, and were not correlated with usnic acid concentrations or treatments. A comparison of O. ventosa from three different habitat types showed that the highest usnic acid amounts were found in the habitat with the highest levels of solar radiation. Results indicate that the induction of usnic acid production by UVR depends on the species studied, and on how well acclimatised the lichen samples are to solar radiation before they are exposed to supplementary UVR. In lichens with an already well-developed internal screening capacity, like the population of F. nivalis, enhanced UVR need not induce further accumulation of usnic acid, but removal of UVR may induce a biodegradation of usnic acid. Results also indicate that PAR is just as important as UVR for triggering the resynthesis of usnic acid in shade-adapted lichens. Divaricatic acid seems to be of low importance for the UV-screening properties of O. ventosa.

Topics: Arctic Regions; Benzofurans; Kinetics; Lichens; Light; Ultraviolet Rays

Usnic acid is a normal component of lichen cells. This natural compound has shown different biological and physiological activities that might have a great relevance in pharmacology and clinics. For instance, usnic acid is known for its antibacterial and antiparasitic action. Also, the drug has a potential interest in cancer therapy because of its antimitotic and antiproliferative action. The molecular structure of usnic acid has been validated and further explored in this investigation. Many biological properties of this drug are known; however its potential antiviral action has not yet been evaluated. In this paper, we demonstrate that usnic acid is a potent inhibitor of the proliferation of mouse polyomavirus. Its action is not exerted at the level of virion entry into the host cell. Moreover, the abolition of viral DNA replication is an indirect consequence of the drastic inhibition of RNA transcription.

Topics: Actins; Animals; Antiviral Agents; Benzofurans; Cell Line; DNA, Viral; Fibroblasts; Lipid Bilayers; Mice; Nuclear Magnetic Resonance, Biomolecular; Polyomavirus; RNA, Messenger; Transcription, Genetic; Transfection; Virion; Virus Replication

A capillary zone electrophoretic (CZE) method for the determination of usnic acid is described for the first time. Usnic acid is an antibiotic substance from lichens. Due to its low solubility in water, a high content of methanol in CZE buffer is required. Because of the methanol in the buffer, the electroosmotic flow velocity was lower than the electrophoretic mobility of usnic acid. Accordingly, the use of reversed-polarity (with the anode on the detector side of the capillary) was necessary. The optimal buffer composition was 50 mM NaOH, 20 mM acetic acid and 5% water in methanol. The detection limit of UV detector at 290 nm for usnic acid in the injected extract was 3.5 mg/L and the relative standard deviation of the normalized peak area was 3.3% at 250 mg/L.

Topics: Anti-Infective Agents; Benzofurans; Electrophoresis, Capillary; Molecular Structure; Time Factors

Effects of the nitrogen sources in the medium for the production of secondary metabolites in lichens were examined. The usnic acid production by a mycobiont of the lichen Usnea hirta was higher in the liquid medium containing ammonium and nitrate ions than in those containing amino acids.

Topics: Amino Acids; Anti-Infective Agents; Benzofurans; Culture Media; Lichens; Nitrogen

A 48-year-old clerical officer with a recurrent facial eruption had positive patch test reactions to nickel, fragrance mix and lichen acid mix. On testing to individual ingredients of fragrance mix and lichen acid mix, she had 2+ reactions to oak moss, which is thought to be the main allergen in fragrance mix, and to usnic acid, which is one of a number of lichen acids comprising oak moss. Avoidance of fragrance use resulted in clearing of the eruption but, subsequently, an acute vesicular flare on her face and hands occurred after exposure to lichen on garden shrubs.

Topics: Allergens; Benzofurans; Dermatitis, Allergic Contact; Facial Dermatoses; Female; Humans; Hydroxybenzoates; Lichens; Middle Aged; Patch Tests; Perfume

Topics: Adult; Allergens; Benzofurans; Dermatitis, Allergic Contact; Dermatitis, Occupational; Eczema; Humans; Irritants; Male; Plants; Sesquiterpenes

The lichen secondary metabolite usnic acid exists as a (-) and a (+) enantiomer, indicating a alpha or beta projection of the methyl group at position 9b, respectively. (-)-Usnic caused a dose-dependent bleaching of the cotyledonary tissues associated with a decrease of both chlorophylls and carotenoids in treated plants whereas no bleaching was observed with the (+) enantiomer. (-)-Usnic acid inhibited protophorphyrinogen oxidase activity (I50 = 3 microM), but did not lead to protoporphyrin IX accumulation. Bleaching appears to be caused by irreversible inhibition of the enzyme 4-hydroxyphenylpyruvate dioxygenase by (-)-usnic acid (apparent IC50 = 50 nM).

Topics: 4-Hydroxyphenylpyruvate Dioxygenase; Benzofurans; Carotenoids; Chlorophyll; Cotyledon; Enzyme Inhibitors; Lichens; Molecular Structure

(+)-Usnic acid, isolated from the lichen Roccella montagnei, showed a dose-dependent anti-inflammatory activity when tested on rats, employing acute and chronic models.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Benzofurans; Carrageenan; Dose-Response Relationship, Drug; Edema; Female; Fungi; Gossypium; Granuloma, Foreign-Body; Humans; Ibuprofen; Male; Plants, Medicinal; Rats; Rats, Wistar

The sensitivity of the human keratinocyte cell line HaCaT to several lichen metabolites isolated from Parmelia nepalensis and Parmelia tinctorum was evaluated. The tridepside gyrophoric acid (6), the dibenzofuran derivative (+)-usnic acid (1), and the didepside diffractaic acid (5) were potent antiproliferative agents and inhibited cell growth, with IC50 values of 1.7, 2.1, and 2.6 microM, respectively. Methyl beta-orcinolcarboxylate (2), ethyl hematommate (3), the didepside atranorin (4), and (+)-protolichesterinic acid (7) did not influence keratinocyte growth at concentrations of 5 microM. Keratinocytes were further tested for their susceptibility to the action of the potent antiproliferative agents on plasma membrane integrity. The release of lactate dehydrogenase activity into the culture medium was unchanged as compared to controls, documenting that the activity of gyrophoric acid (6), (+)-usnic acid (1), and diffractaic acid (5) was due to cytostatic rather than cytotoxic effects.

Topics: Anisoles; Antineoplastic Agents; Arachidonic Acid; Benzoates; Benzofurans; Cell Division; Humans; Hydroxybenzoates; Keratinocytes; L-Lactate Dehydrogenase; Lichens; Lipoxygenase; Tumor Cells, Cultured

The presence of usnic acid in the lichen Usnea laevis Nyl. from the Venezuelan Andes was detected through chromotographic (TLC) and spectroscopic (IR, MS, 1H-NMR) methods. This compound was present in a concentration of 2.7% in the thallus. Usnic acid has a reported antibiotic activity and the lichen is utilized for medicinal purposes by Andean farmers.

Topics: Anti-Infective Agents; Benzofurans; Chromatography; Medicine, Traditional; Plant Extracts; Species Specificity; Spectrum Analysis; Venezuela

Hydrazones of R- and S-usnic acid were prepared by condensation of the appropriate enantiomer of usnic acid with hydrazides of aromatic acids. Prepared compounds were characterized by spectral methods. Reaction kinetic was studied with capillary electrokinetic chromatography, enantiomeric purity of products was checked by capillary electrophoresis in the presence of gamma-cyclodextrin. Obtained hydrazones were tested as prospective antimitotic agents. The antitumor activity was screened in vitro on human tumor cell lines. The overall activity of tested compounds was low, however, the R- enantiomers were more active than their opposite stereoisomers.

Topics: Antineoplastic Agents; Benzofurans; Humans; Tumor Cells, Cultured

Several compounds, whose structures represent the most common chemical classes of lichen metabolites, were screened for in vitro activity against Mycobacterium aurum, a non-pathogenic organism with a similar sensitivity profile to M. tuberculosis. Of the compounds tested, usnic acid from Cladonia arbuscula exhibited the highest activity with an MIC value of 32 microg/ml. Atranorin and lobaric acid, both isolated from Stereocaulon alpinum, salazinic acid from Parmelia saxatilis and protolichesterinic acid from Cetraria islandica all showed MIC values >/=125 microg/ml.

Topics: 4-Butyrolactone; Anti-Bacterial Agents; Benzofurans; Depsides; Hydroxybenzoates; Lactones; Lichens; Microbial Sensitivity Tests; Mycobacterium; Salicylates

Three secondary metabolites isolated from Chilean lichens, (+) usnic acid, pannarine and 1'-chloropannarine, were tested against promastigotes forms of three strains of Leishmania ssp. Pannarine and 1'-chloropannarine exhibited in vitro activity at 50 micrograms/ml and (+) usnic acid at 25 micrograms/ml. BALB/c mice infected with Leishmania amazonensis were treated 4 weeks post-infection with (+) usnic acid by subcutaneous or oral routes for 15 days at 25 mg/kg or by five intralesional injections at interval of 4 days at 25 mg/kg of body weight. The reference drug, N-methylglucamine antimonate (Glucantime), was administered by subcutaneous injections (regimens of 28 mg of pentavalent antimony) for 15 days. The subcutaneous and oral treatments with (+) usnic did not produce any effect, but by intralesional administration we observed a significant effect that reduced by 43.34% the weight lesions and by 72.28% the parasites loads in infected footpads.

Topics: Animals; Antiprotozoal Agents; Benzofurans; Benzoxepins; Depsides; Female; Leishmaniasis, Cutaneous; Lichens; Male; Mice; Mice, Inbred BALB C

Usnic acid is a biosynthesis product characteristic of several epiphytic lichens such as Evernia, Cladonia and Parmelia. Usnic acid has several interesting biological properties. It is an antibiotic and it also seems to exert an antimitotic action. It has even been postulated that usnic acid can play a role as an environmental indicator, since its concentration varies according to the presence of toxic agents. A series of tests have been run on different biological systems such as fungi, yeasts, plant cells and neoplastic human cell cultures in order to make a general evaluation of the properties of usnic acid and to highlight any analogy between its effects on phylogenetically distant organisms. The results obtained confirm some of the already known properties of usnic acid and identify concentration ranges that are active against cells from different organisms. Furthermore, at low concentrations, the acid displays a capacity to stimulate cell metabolism in some of the biological systems tested.

Topics: Adenocarcinoma; Antifungal Agents; Antineoplastic Agents; Benzofurans; Cell Division; Cells, Cultured; Endometrial Neoplasms; Female; Fusarium; Humans; Mitosis; Nicotiana; Oxygen Consumption; Plants, Toxic; Protoplasts; Saccharomyces cerevisiae; Tumor Cells, Cultured

Three lichen acids-namely, (+)usnic acid, vulpinic acid, and atranorin-were isolated from three lichen species (Usnea articulata, Letharia vulpina, and Parmelia tinctorum, respectively). The effects of these lichen products on mice-liver mitochondrial oxidative functions in various respiratory states and on oxidative phosphorylation were studied polarographically in vitro. The lichen acids exhibited characteristics of the 2,4-dinitrophenol (DNP), a classical uncoupler of oxidative phosphorylation. Thus, they released respiratory control and oligomycin inhibited respiration, hindered ATP synthesis, and enhanced Mg(+2)-ATPase activity. (+)Usnic acid at a concentration of 0.75 microM inhibited ADP/O ratio by 50%, caused maximal stimulation of both state-4 respiration (100%) and ATPase activity (300%). Atranorin was the only lichen acid with no significant effect on ATPase. The uncoupling effect was dose-dependent in all cases. The minimal concentrations required to cause complete uncoupling of oxidative phosphorylation were as follows: (+)usnic acid (1 microM), vulpinic acid, atranorin (5 microM) and DNP (50 microM). It was postulated that the three lichen acids induce uncoupling by acting on the inner mitochondrial membrane through their lipophilic properties and protonophoric activities.

Topics: 2,4-Dinitrophenol; Adenosine Triphosphate; Animals; Anti-Infective Agents; Benzofurans; Ca(2+) Mg(2+)-ATPase; Dose-Response Relationship, Drug; Furans; Hydroxybenzoates; In Vitro Techniques; Male; Mice; Mitochondria, Liver; Oligomycins; Oxidative Phosphorylation; Oxygen Consumption; Phenylacetates; Polarography; Uncoupling Agents

Topics: Antifungal Agents; Benzofurans; Fungi; Magnetic Resonance Spectroscopy; Microbial Sensitivity Tests

In this paper, an experimental research is reported on the effect of water extract of Cladonia alpestris and S-(-) usnic acid on Trichomonas vaginalis in vitro. The results showed that both the water extract of Cladonia alpestris and S-(-)usnic acid exhibited a strong effect against Trichomonas vaginalis in vitro. As the time of action of the agents was prolonged, the mortality of Trichomonas vaginalis increased. For S-(-) usnic acid, 0.4 mg/ml was the lowest effective concentration against Trichomonas vaginalis in vitro. No remarkable differences were found in the effect of the S-(-)usnic acid and metronidazole at concentrations of 0.4 mg/ml and 0.6 mg/ml.

Topics: Animals; Antitrichomonal Agents; Benzofurans; Drugs, Chinese Herbal; In Vitro Techniques; Trichomonas vaginalis

In vitro protein binding of D(+) usnic acid in rabbit plasma and purified bovine serum albumin was investigated by equilibrium dialysis. The drug was highly protein bound, approximately 99.2%, and the extent of protein binding remained constant at usnic acid concentrations in the range of 1-5 micrograms/ml. The extent of binding, however, tended to decrease at low albumin concentrations and higher drug concentrations; Scatchard plot analysis indicated the existence of two classes of binding sites with association constants of 34.3 x 10(-6) and 1.43 x 10(-6) M respectively. Tissue distribution studies of usnic acid were undertaken in rats following i.p. administration. Usnic acid was well distributed into well perfused organs. The tissue/plasma ratio in lungs was high, which could be advantageous in a therapeutic agent for pulmonary tuberculosis.

Topics: Animals; Benzofurans; Blood Proteins; Dialysis; Male; Protein Binding; Rabbits; Rats; Rats, Wistar; Serum Albumin, Bovine; Tissue Distribution

Diffractaic acid and usnic acid were identified as the analgesic and antipyretic components of a lichen, Usnea diffracta. Both compounds showed an analgesic effect by the acetic acid-induced writhing and tail-pressure methods in mice. Regarding the effect on normal body temperature and LPS-induced hyperthermia in mice, diffractaic acid showed a significant effect only on the former and usnic acid only on the latter.

Topics: Analgesics; Analgesics, Non-Narcotic; Anisoles; Benzofurans; Chromatography, Thin Layer; Hydroxybenzoates; Magnetic Resonance Spectroscopy; Plants, Medicinal; Spectrophotometry, Infrared

Secondary metabolites of different species of lichen were tested for their activities against a variety of microbial species. While gram-negative rods and fungi were not inhibited by these compounds, Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium, and some anaerobic species (Bacteroides and Clostridium species) were susceptible at the concentrations tested. Vulpinic acid generally was less active than usnic acid, regardless of its stereochemistry. The susceptibility to usnic acid was not impaired in clinical isolates of S. aureus resistant to methicillin and/or mupirocin.

Topics: Anti-Bacterial Agents; Anti-Infective Agents; Bacteria, Aerobic; Bacteria, Anaerobic; Bacterial Infections; Benzofurans; Fungi; Furans; Humans; Lichens; Methicillin Resistance; Microbial Sensitivity Tests; Mupirocin; Phenylacetates; Stereoisomerism

Topics: Administration, Intravaginal; Adult; Antitrichomonal Agents; Benzofurans; Dermatitis, Allergic Contact; Female; Humans; Patch Tests

During and after the floods of 1979-80 Niebla ceruchis growing epiphytically on Lycium brevipes was one of the dominant aspects of the vegetation in the coastal dunal complex bordering the microbial mats at Laguna Figueroa, Baja California Norte, Mexico. The lichen on denuded branches of Lycium was far more extensively distributed than Lycium lacking lichen. Unusual traits of this Niebla ceruchis strain, namely localization of lichen compounds in the mycobiont reproductive structures (pycnidia and apothecia) and simultaneous presence of bilocular and quadrilocular ascospores, are reported. The abundance of this coastal lichen cover at the microbial mat site has persisted through April 1988.

Topics: Benzofurans; Environmental Microbiology; Esters; Lichens; Mexico; Microscopy, Electron; Reproduction; Solanaceae; Spores, Fungal; Symbiosis; Triterpenes

Topics: Benzofurans; Dermatitis, Phototoxic; Lichens

Topics: Anti-Bacterial Agents; Anti-Infective Agents; Benzofurans; Drug Therapy; Humans; Pyoderma; Sodium

Topics: Benzofurans; Dermatitis, Allergic Contact; Dermatitis, Contact; Fungi; Humans; Hypersensitivity; Lichens; Occupational Diseases; Pathology

Two forest workers affected with allergic contact dermatitis, which occurred only during work in forest areas, showed positive patch test reactions to lichens containing usnic acid and to isolated usnic acid. Lichens are plants composed of fungi living in symbiosis with algae. Usnic acid, one of the lichenic acids which accumulates in lichenized fungi, is a monobasic acid with dibenzofuran structure and antibiotic properties. Dibenzofuran is chemically related to furocoumarans. Lichens are plentiful in temperate zone forests and allergy to usnic acid represents some part of the "cedar-poisoning" problem in British Columbia. Geographical distribution of lichens containing usnic acid suggests that allergy to usnic acid will be found to be more common than presently recognized.

Topics: Adult; Benzofurans; Dermatitis, Contact; Dermatitis, Occupational; Forestry; Humans; Lichens; Male

Topics: Acids; Benzofurans

Topics: Acids; Anti-Infective Agents; Benzofurans; Chemistry Techniques, Analytical; Chemistry, Pharmaceutical; Lichens; Research

Topics: Acids; Benzofurans; Lichens

Topics: Acids; Benzofurans; Lichens

Topics: Benzofurans; Heterocyclic Compounds

Topics: Anti-Bacterial Agents; Benzofurans; Dermatologic Agents; Skin Diseases; Skin Diseases, Bacterial

Topics: Anti-Bacterial Agents; Benzofurans; Diphtheria; Diphtheria Toxin; Furans; Tetanus

Topics: Benzofurans; Furans; Lichens; Usnea

Topics: Benzofurans; Furans

Topics: Benzofurans; Furans; Humans; Virus Diseases

Topics: Acids; Benzofurans; Furans

Topics: Anti-Bacterial Agents; Anti-Infective Agents, Local; Benzofurans; Humans; Pyoderma

Topics: Acids; Benzofurans; Furans

Topics: Acids; Anti-Bacterial Agents; Bacteria; Benzofurans; Furans

Topics: Acids; Benzofurans; Furans; Humans; Skin Diseases; Skin Diseases, Bacterial

Topics: Acids; Anti-Bacterial Agents; Bacteria; Benzofurans; Furans; Humans

Topics: Acids; Benzofurans; Furans; Humans; Lichens; Tuberculosis; Tuberculosis, Pulmonary

Topics: Benzofurans; Tuberculosis; Tuberculosis, Pulmonary

Topics: Acids; Benzofurans; Dihydrostreptomycin Sulfate; Furans; Guinea Pigs; Streptomycin; Tuberculosis

Topics: Benzofurans; Furans; Mycobacterium tuberculosis; Tuberculosis

Topics: Bacteria; Benzofurans; Furans; In Vitro Techniques; Plants

Topics: Acids; Animals; Benzofurans; Blood Glucose; Cats; Cell Respiration; Humans; Metabolism; Respiration

Topics: Anti-Bacterial Agents; Antibiotics, Antitubercular; Benzofurans; Dermatologic Agents; Plants; Tetanus; Tetanus Toxoid

Topics: Benzofurans

Topics: Benzofurans; Dermatology; Humans; Tuberculosis

Topics: Benzofurans; Humans; Skin; Tuberculosis; Tuberculosis, Cutaneous

Topics: Bacteria; Benzofurans; Growth; Humans

Topics: Anti-Bacterial Agents; Antibiotics, Antitubercular; Bacteria; Benzofurans; Escherichia coli; Micrococcus

Topics: Benzofurans; Streptomycin; Tuberculosis

Topics: Anti-Bacterial Agents; Antibiotics, Antitubercular; Benzofurans; Dermatologic Agents; Humans

Topics: Anti-Bacterial Agents; Benzofurans

Topics: Anti-Bacterial Agents; Antibiotics, Antitubercular; Benzofurans; Dermatologic Agents; Guinea Pigs; Lichens; Tuberculosis

Topics: Acids; Animals; Benzofurans; Guinea Pigs; Streptomycin; Tuberculosis

Topics: Anti-Bacterial Agents; Benzofurans; Dermatologic Agents; Humans; Lichens

Topics: Benzofurans; Cells; Deoxyribonucleases; Mitosis; Nuclear Fusion

Topics: Acids; Benzofurans; Humans; Lupus Vulgaris

Topics: Anti-Bacterial Agents; Bacillus; Benzofurans; Mycobacterium tuberculosis; Tuberculosis

Topics: Animals; Arbacia; Benzofurans; Cytokinesis; Phosphorus; Phosphorus Compounds; Radioisotopes

Topics: Anti-Bacterial Agents; Benzofurans

Topics: Anti-Bacterial Agents; Benzofurans; Humans; Male; Spermatozoa

Topics: Anti-Infective Agents; Bacteria; Benzofurans; Humans