1-1-diphenyl-2-picrylhydrazyl and kaempferol

Phenolamines and flavonoids are two important components in bee pollen. There are many reports on the bioactivity of flavonoids in bee pollen, but few on phenolamines. This study aims to separate and characterize the flavonoids and phenolamines from rape bee pollen, and compare their antioxidant activities and protective effects against oxidative stress. The rape bee pollen was separated to obtain 35% and 50% fractions, which were characterized by HPLC-ESI-QTOF-MS/MS. The results showed that the compounds in 35% fraction were quercetin and kaempferol glycosides, while the compounds in 50% fraction were phenolamines, including di-p-coumaroyl spermidine, p-coumaroyl caffeoyl hydroxyferuloyl spermine, di-p-coumaroyl hydroxyferuloyl spermine, and tri-p-coumaroyl spermidine. The antioxidant activities of phenolamines and flavonoids were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), and ferric reducing antioxidant power (FRAP) assays. It was found that the antioxidant activity of phenolamines was significantly higher than that of flavonoids. Moreover, phenolamines showed better protective effects than flavonoids on HepG2 cells injured by AAPH. Furthermore, phenolamines could significantly reduce the reactive oxygen species (ROS), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, and increase the superoxide dismutase (SOD) and glutathione (GSH) levels. This study lays a foundation for the further understanding of phenolamines in rape bee pollen.

Topics: Alanine Transaminase; Amidines; Animals; Antioxidants; Aspartate Aminotransferases; Bees; Benzothiazoles; Biphenyl Compounds; Gene Expression; Glutathione; Glycosides; Hep G2 Cells; Humans; Kaempferols; Oxidants; Oxidative Stress; Picrates; Plant Extracts; Pollen; Quercetin; Reactive Oxygen Species; Spermidine; Spermine; Sulfonic Acids; Superoxide Dismutase

Kaempferol (Kae) is a natural flavonoid with potent antioxidant activity, but its therapeutic use is limited by its low aqueous solubility. Here, a series of Kae derivatives were synthesized to improve Kae dissolution property in water and antioxidant activity. These compounds included sulfonated Kae (Kae-SO₃), gallium (Ga) complexes with Kae (Kae-Ga) and Kae-SO₃ (Kae-SO₃-Ga). The compound structures were characterized by high-resolution mass spectrometry (HRMS), nuclear magnetic resonance (NMR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and thermal methods (TG/DSC). The results showed that a sulfonic group (-SO₃) was successfully tethered on the C3' of Kae to form Kae-SO₃. And in the metal complexation, 4-CO and 3-OH of the ligand participated in the coordination with Ga(III). The metal-to-ligand ratio 1:2 was suggested for both complexes. Interestingly, Kae-SO₃-Ga was obviously superior to other compounds in terms of overcoming the poor water-solubility of free Kae, and the solubility of Kae-SO₃-Ga was about 300-fold higher than that of Kae-Ga. Furthermore, the evaluation of antioxidant activities in vitro was carried out for Kae derivatives by using α,α-diphenyl-β-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS) free radical scavenging. The results showed that Kae-SO₃-Ga was also optimal for scavenging free radicals in a dose-dependent manner. These data demonstrate that sulfonate kaempferol-gallium complex has a promising future as a potential antioxidant and as a potential therapeutic agent for further biomedical studies.

Topics: Antioxidants; Biphenyl Compounds; Calorimetry, Differential Scanning; Carbon-13 Magnetic Resonance Spectroscopy; Free Radical Scavengers; Kaempferols; Mass Spectrometry; Picrates; Proton Magnetic Resonance Spectroscopy; Solubility; Spectrophotometry, Ultraviolet; Spectroscopy, Fourier Transform Infrared; Sulfonic Acids; Temperature; Thermogravimetry; Water

Diabetes complications, including peripheral neuropathy, cataracts, impaired wound healing, vascular damage, arterial wall stiffening and retinopathy diseases, are among the most predominant health problems facing the world's population today. The 22 Peruvian plant extracts were screened for their potential inhibitory activity against rat lens aldose reductase (RLAR) and DPPH radical scavenging. Among them, we have found that

Topics: Aldehyde Reductase; Animals; Apigenin; Biphenyl Compounds; Chromatography, High Pressure Liquid; Coumaric Acids; Flavones; Glucosides; Kaempferols; Luteolin; Picrates; Plants, Medicinal; Rats; Sorbitol; Tanacetum parthenium

Irvingia gabonensis stem bark is a medicinal plant used in most parts of Africa to manage a number of ailments including neurodegenerative diseases that occur without scientific basis. This work characterized the phenolic composition, evaluated the cholinergic enzymes (acetylcholinesterase, AChE and butyrylcholinesterase, BChE) inhibition, and assessed the antioxidant activity of phenolic extracts from I. gabonensis (Aubry-Lecomte ex O'Rorke) Baill bark.. Total phenol and flavonoids content was evaluated in addition to antioxidant activity as shown by Fe2+ chelation, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability, and 2,2-azino-bis-(3-ethylbenthiazoline-6-sulfonic acid) (ABTS) radical scavenging ability. Inhibitory activities on AChE and BChE were evaluated.. The extract was found to be rich in phenolic acid (ellagic acid) and flavonoids (quercetrin, kaempferol, and apigenin). The phenolic extracts displayed DPPH radical scavenging ability (IC50=19.98 μg/mL), ABTS radical scavenging ability (IC50=18.25 μg/mL), iron chelation (IC50=113.10 μg/mL), and reducing power (Fe3+ to Fe2+) (5.94 mg ascorbic acid equivalent/100 g). Extracts of I. gabonensis inhibited AChE (IC50=32.90 μg/mL) and BChE (IC50=41.50 μg/mL) activities in concentration-dependent manner.. Hence, possible mechanism through which the stem bark executes their anti-Alzheimer's disease activity might be by inhibiting cholinesterase activities in addition to suppressing oxidative-stress-induced neurodegeneration.

Topics: Acetylcholinesterase; Antioxidants; Apigenin; Benzothiazoles; Biphenyl Compounds; Butyrylcholinesterase; Cellulose; Cholinesterase Inhibitors; Flavonoids; Free Radical Scavengers; Kaempferols; Phenols; Picrates; Plant Bark; Plant Extracts; Plants, Medicinal; Quercetin; Sulfonic Acids

Quorum sensing (QS) is a cell density dependent expression of species in bacteria mediated by compounds called autoinducers (AI). Several processes responsible for successful establishment of bacterial infection are mediated by QS. Inhibition of QS is therefore being considered as a new target for antimicrobial chemotherapy. Flavonoid compounds are strong antioxidant and antimicrobial agents but their applications are limited due to their poor dissolution and bioavailability. Our objective was to investigate the effect of kaempferol loaded chitosan nanoparticles on modulating QS mediated by AI in model bioassay test systems. For this purpose, kaempferol loaded nanoparticles were synthesized and characterized in terms of hydrodynamic diameter, hydrogen bonding, amorphous transformation and antioxidant activity. QS inhibition in time dependent manner of nanoparticles was measured in violacein pigment producing using the biosensor strain Chromobacterium violaceum CV026 mediated by AI known as acylated homoserine lactone (AHL). Our results indicated that the average kaempferol loaded chitosan/TPP nanoparticle size and zeta potential were 192.27±13.6nm and +35mV, respectively. The loading and encapsulation efficiency of kaempferol into chitosan/TPP nanoparticles presented higher values between 78 and 93%. Kaempferol loaded chitosan/TPP nanoparticle during the 30 storage days significantly inhibited the production of violacein pigment in Chromobacterium violaceum CV026. The observation that kaempferol encapsulated chitosan nanoparticles can inhibit QS related processes opens up an exciting new strategy for antimicrobial chemotherapy as stable QS-based anti-biofilm agents.

Topics: Acyl-Butyrolactones; Anti-Bacterial Agents; Antioxidants; Biofilms; Biphenyl Compounds; Chitosan; Chromobacterium; Drug Compounding; Hydrogen Bonding; Indoles; Kaempferols; Nanoparticles; Picrates; Quorum Sensing

Edible flowers are receiving renewed interest as rich sources of bioactive compounds. Ethanol extracts of eight edible flowers were phytochemically characterized and investigated for their bioactivity. Rutin, quercetin, luteolin, kaempferol, and myricetin were selected as standards and quantified by HPLC. The fatty acid profile was analyzed by GC and GC-MS. Antioxidant properties were evaluated by using different in vitro tests. The hypoglycemic effects were investigated via the inhibition of α-amylase and α-glucosidase. Sambucus nigra exhibited the highest radical-scavenging activity (IC50 of 1.4 μg/mL), followed by Hedysarum coronarium (IC50 of 1.6 μg/mL). Both species contained high quercetin and rutin contents. S. nigra extract exerted the highest activity in preventing lipid oxidation. Malva sylvestris extract inhibited both α-amylase and α-glucosidase with IC50 values of 7.8 and 11.3 μg/mL, respectively. These findings support the consumption of edible flowers as functional foods and their use as sources of natural antioxidants by the food industry.

Topics: alpha-Amylases; Antioxidants; Biphenyl Compounds; Chromatography, High Pressure Liquid; Fatty Acids; Flavonoids; Flowers; Gas Chromatography-Mass Spectrometry; Glycoside Hydrolase Inhibitors; Hypoglycemic Agents; Inhibitory Concentration 50; Kaempferols; Luteolin; Phenols; Phytochemicals; Picrates; Plants, Medicinal; Quercetin; Rutin; Sambucus nigra

Hancornia speciosa Gomes (Apocynaceae) is a fruit tree, popularly known as mangabeira, and it is widely distributed throughout Brazil. Several parts of the plant are used in folk medicine, and the leaf and bark extracts have anti-inflammatory, antihypertensive, antidiabetic, and antimicrobial properties. In this study, we investigated the chemical composition of the ethanolic extract of Hancornia speciosa leaves (EEHS) and its antioxidant, antimicrobial, and cytotoxic activities as well as the mechanisms involved in cell death. The chemical compounds were identified by liquid chromatography coupled to mass spectrometry (LC-MS/MS). The antioxidant activity of the EEHS was investigated using the method that involves the scavenging of 2,2-diphenyl-1-picrylhydrazyl free radicals as well as the inhibition of oxidative hemolysis and lipid peroxidation induced by 2,2'-azobis (2-amidinopropane) in human erythrocytes. The antimicrobial activity was determined by calculating the minimum inhibitory concentration, minimum bactericidal concentration, minimum fungicidal concentration, and zone of inhibition. Kasumi-1 leukemic cells were used to assess the cytotoxic activity and mechanisms involved in cell death promoted by the EEHS. The chemical compounds identified were quinic acid, chlorogenic acid, catechin, rutin, isoquercitrin, kaempferol-rutinoside, and catechin-pentoside. The EEHS demonstrated antioxidant activity via the sequestration of free radicals, inhibition of hemolysis, and inhibition of lipid peroxidation in human erythrocytes incubated with an oxidizing agent. The antimicrobial activity was observed against American Type Culture Collection (ATCC) and hospital strains of bacteria and fungi, filamentous fungi and dermatophytes. The cytotoxic activity of the EEHS was induced by apoptosis, reduction of the mitochondrial membrane potential, and activation of cathepsins. Together, these results indicate the presence of phenolic compounds and flavonoids in the EEHS and that their antioxidant, antimicrobial, and cytotoxic activities in acute myeloid leukemia cells are mediated by apoptosis.

Topics: Anti-Infective Agents; Antioxidants; Apocynaceae; Biphenyl Compounds; Candida albicans; Catechin; Cell Line, Tumor; Cell Survival; Chlorogenic Acid; Cytotoxins; Erythrocytes; Gram-Negative Bacteria; Gram-Positive Bacteria; Hemolysis; Humans; Kaempferols; Microbial Sensitivity Tests; Phenols; Picrates; Plant Extracts; Plant Leaves; Quercetin; Quinic Acid; Rutin

Naturally occurring flavonoids have been reported to possess various pharmacological properties. The aim of this study was to evaluate the antimicrobial and antioxidant activities of the MeOH extract and flavonoids from the leaves of Oncoba spinosa, a plant used for the treatment of syphilis, wounds and sexual impotence.. The plant extract was prepared by maceration in methanol and sequentially fractionated by column chromatography. The structures of isolated compounds were elucidated on the basis of spectral studies and comparison with published data. The MeOH extract and its isolated compounds were evaluated for their antibacterial and antifungal activities by broth microdilution method. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) and trolox equivalent antioxidant capacity (TEAC) assays were used to detect the antioxidant activity. The samples were tested spectrophotometrically for their hemolytic properties against human red blood cells.. The fractionation of the MeOH extract afforded five known flavonoids including kaempferol (1), quercetin (2), apigenin-7-O-β-D-glucuronopyranoside (3), quercetin 3-O-β-D-galactopyranoside (4) and quercetin 3-O-α-L-rhamnopyranosyl (1 → 6) β-D-glucopyranoside (5). The MeOH extract displayed weak to moderate antimicrobial activities (MIC = 256-2048 μg/ml). Quercetin 3-O-α-L-rhamnopyranosyl (1 → 6) β-D-glucopyranoside (5) and quercetin (2) were respectively the most active compounds against bacteria (MIC = 8-64 μg/ml) and fungi (MIC = 64 - 128 μg/ml). These tested samples also showed high radical-scavenging activities (EC50 = 5.08 - 70.56 μg/ml) and gallic acid equivalent antioxidant capacities (TEAC = 53.76 - 89.86 μg/ml) when compared with vitamin C (EC50 = 4.72 μg/ml). The MeOH extract and compounds 2-5 were non-toxic to human red blood cells indicating their high selectivity to be used as antimicrobial and antioxidant drugs.. The MeOH extract of O. spinosa as well as compounds 2 - 5 could be a potential source of natural antimicrobial and antioxidant products.

Topics: Anti-Infective Agents; Antioxidants; Apigenin; Bacteria; Biphenyl Compounds; Flavonoids; Fungi; Humans; Kaempferols; Male; Picrates; Plant Extracts; Plant Leaves; Quercetin; Salicaceae

This study was performed to evaluate the phenolic profile, antioxidant and diuretic effects of black cumin and lady-in-a-mist seeds. In the phenolic profile, differences between the two species are significant. Qualitative and quantitative analyses of the phenolic compounds were performed using a HPLC-UV/MS method. Hyperoside was the only identified flavonoid glycoside (1.08 ± 0.01 μg∙g-1 dw plant material), in the N. damascena extract. Regarding the flavonol profile, kaempferol was identified before the hydrolysis, only in the N. sativa extract (6.06 ± 0.02 μg∙g-1 dw plant material) and quercetin only in N. damascena seeds (14.35 ± 0.02 μg∙g-1 dw plant material). The antioxidant potential of the two species was tested through several electron transfer assays, which indicated, excepting for the FRAP assay, N. damascena as exhibiting a higher free radical scavenging activity. The diuretic activity of the two extracts was tested using a rat-experimental model on acute diuresis. Administration of the ethanolic extract of N. sativa (100 mg∙kg-1) resulted in a significant increase in urine volume, although less than found with the reference drug; in addition N. damascena extract did not present a diuretic effect. In reference to the elimination of Na+, K+ and uric acid, the black cumin extract exhibited a higher natriuretic than kaluretic effect and a similar uricosuric effect with control and N. damascena. For N. damascena, the Na+/K+ ratio was sub unitary, but not due to an increasing of the kaluretic effect, but mostly to a decrease of Na+ excretion.

Topics: Animals; Antioxidants; Biphenyl Compounds; Chromatography, High Pressure Liquid; Diuretics; Flavonoids; Kaempferols; Male; Nigella damascena; Nigella sativa; Picrates; Plant Extracts; Polyphenols; Potassium; Quercetin; Rats; Rats, Wistar; Seeds; Sodium; Species Specificity; Uric Acid

Roscoea purpurea (Zingiberaceae) is commonly known as "kakoli". Traditionally, various parts like leaves, roots and flower etc. are used for the treatment of diabetic, hypertension, diarrhea, fever, inflammation etc. In Nepal tubers are boiled for edible purpose and also used in traditional veterinary medicine. The study aims for nutritional characterization, chemical profiling of R. purpurea (tubers) methanol extract (RPE) along with evaluation of its anti-oxidant activity. Physicochemical and nutritional content were estimated as per standard protocols. Chemical profiling of markers includes method optimization, identification & quantification of bioactive poly phenolics through HPTLC. Anti oxidant potential RPE was analyzed via. Total phenolics (TPC), total flavonoids (TFC), reducing power assay, DPPH and β-carotene bleaching model.. Physicochemical and nutritional standards were established. Kaempferol (0.30%), vanillic acid (0.27%), protocatechuic (0.14%), syringic (0.80%) and ferulic acid (0.05%) were identified and then quantified. TPC and TFC content were found to be 7.10 ± 0.115 and 6.10 ± 0.055%, reducing power of extract also increases linearly (r(2) = 0.946) with concentration, similar to standards. IC50 value of extract in DPPH and β-carotene bleaching model was observed at 810.66 ± 1.154 and 600.66 ± 1.154 µg/ml, which is significantly different from standards (p < 0.05). Although there is a positive, significant correlation between the phenolic and flavonoid content with anti oxidant activity of extract.. Thus, study will authenticates the identity, utility of herb as nutrient supplement and an important medicinal plant having promising pharmacological activities for further elaborated/extended investigation work.

Topics: Antioxidants; beta Carotene; Biphenyl Compounds; Chromatography, High Pressure Liquid; Coumaric Acids; Hydroxybenzoates; Kaempferols; Phenols; Picrates; Plant Extracts; Plant Tubers; Vanillic Acid; Zingiberaceae

The types of wild mint (Mentha spicata L.) were sampled from different geographical regions in Tunceli (Turkey) in order to find out their vitamin, mineral, phenolic contents and their antioxidant properties. The total phenol varied from 77.7±0.242 to 52.34±0.351 mg of GAEs/g of dry mint. The highest radical effect of scavenging was observed in Mazgirt parting of the ways 7.5 km with 6.17±0.245 mg/mL. The highest reducing power and metal chelating were observed in the mint from Cicekli parting of the ways 6.5 km Demirkapı. Among the various macronutrients which were estimated in the plant samples, potassium was presented in the highest quantity followed by calcium and phosphate. Although rutin and resveratrol were not determined in any samples, kaempferol and catechin levels were found out in almost all samples. The concentrations of vitamin A ranged between 42,14±5.70 and 13.61±3.00 (mg/kg dry weight). These results show that plants of mint are quite rich in phenolic compounds, and these have been appeared to have antioxidant activity, which agrees with this work, since the extract showed a higher content of phenolic compounds and higher antioxidant activity and mint may be considered as a natural alternative source for food, pharmacology and medicine sectors.

Topics: Biphenyl Compounds; Calcium; Catechin; Chromatography, High Pressure Liquid; Free Radical Scavengers; Kaempferols; Mentha; Oxidation-Reduction; Phenols; Phosphates; Picrates; Plant Extracts; Plant Leaves; Potassium; Turkey; Vitamin A

Seven flavonoids new for the genus Jovibarba, kaempferol 1, kaempferol 3-O-galactopyranosyl-(1 → 2)-O-α-L-rhamnopyranoside 2, kaempferol 3-O-β-D-glucoside 3, kaempferol 3-O-α-L-rhamnopyranosyl-7-O-α-D-glucofuranosyl-(1 → 2)-O-α-L-rhamnopyranoside 4, kaempferol 3-O-β-D-glucopyranoside-7-O-α-L-rhamnopyranoside 5, kaempferol 3,7,4'-O-trimethyl ether 6 and quercetin 7, were isolated from fresh and dried leaves of J.ovibarba globifera subsp. globifera. The structures of these compounds were established by analysis of their spectroscopic ((1)H and (13)C NMR) and spectrometric (MS) data, as well as by comparison of these with those reported in the literature. All of the flavonoids are reported for the first time from the investigated taxon. In addition the antioxidant activities in DPPH test of selected compounds were evaluated.

Topics: Antioxidants; Biphenyl Compounds; Crassulaceae; Flavonoids; Kaempferols; Molecular Structure; Picrates; Plant Leaves

In the current study, changes in secondary metabolite synthesis and the pharmaceutical quality of sabah snake grass leaves and buds were considered in relation to plant age (1 month, 6 months, and 1 year old). The activity of the enzyme chalcone synthase (CHS, EC 2.3.1.74) was measured, as it is a key enzyme for flavonoid production. Significant differences in total flavonoid (TF) production were observed between the three plant growth periods and the different plant parts. The highest contents of TF (6.32 mg/g dry weight [DW]) and total phenolic (TP) (18.21 mg/g DW) were recorded in 6-month-old buds. Among the flavonoids isolated in this study the most important ones based on concentration were from high to low as follows: catechin > quercetin > kaempferol > luteolin. Production of phenolic acids increased from 1 to 6 months, but after 6 months up to 1 year of age, they decreased significantly. The highest contents of caffeic acid (0.307 mg/g DW) and gallic acid (5.96 mg/g DW) were recorded in 1-year and 6-month-old buds, respectively. The lowest and highest activity of CHS was recorded in 1-month and 6-month-old buds with values of 3.6 and 9.5 nkat/mg protein, respectively. These results indicate that the increment in flavonoids and phenolic acids in 6-month-old buds can be attributed to an increase in CHS activity. The highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) activity was observed in the extract of 1-year-old buds followed by 6-month-old buds, with 50% of free radical scavenging (IC50) values of 64.6 and 73.5 µg/mL, respectively. Interestingly, a ferric reducing antioxidant power (FRAP) assay showed a higher activity in 6-month-old buds (488 μM of Fe(II)/g) than in 1-year-old buds (453 μM of Fe(II)/g), in contrast to the DPPH result. Significant correlations (p < 0.05) were observed between CHS enzyme activity and FRAP activity, TF, catechin, and kaempferol content. Extracts of 6-month-old bud exhibited a significant in vitro anticancer activity against HeLa cancer cells with IC50 value of 56.8 µg/mL. These results indicate that early harvesting of snake grass (6-month-old) may yield increased concentrations of secondary metabolites, which are potent antioxidant compounds.

Topics: Acanthaceae; Acyltransferases; Antioxidants; Biphenyl Compounds; Caffeic Acids; Catechin; Cell Line, Tumor; Flavonoids; Free Radical Scavengers; Gallic Acid; HeLa Cells; Humans; Hydroxybenzoates; Kaempferols; Luteolin; Phenols; Picrates; Plant Extracts; Plant Leaves; Poaceae; Quercetin

Two new diarylheptanoids, 1-(3',5'-dihydroxy-4'-methoxyphenyl)-7-phenyl-3-heptanone (1) and 1-(2',4'-dihydroxy-3'-methoxyphenyl)-7-(4″-methoxyphenyl)-3-heptanone (2), along with known diarylheptanoid yakuchinone A (3), and five flavanoids, tectochrysin (4), chrysin (5), izalpinin (6), kaempferol 7, 4'-dimethyl ether (7), and kaempferide (8) were isolated from the fruits of Alpinia oxyphylla Miq. Their structures were determined by means of spectroscopic methods. Antioxidant activities of all the isolated compounds were evaluated using a 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Compounds 1-3 and 6-8 exhibited potent antioxidant activities in the DPPH assay.

Topics: Alpinia; Antioxidants; Biphenyl Compounds; Diarylheptanoids; Drugs, Chinese Herbal; Flavonoids; Fruit; Guaiacol; Kaempferols; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Picrates

In this study, the protective effects of Brussels sprouts extract and its major constituents against oxidative stress-induced damages were investigated in rat pheochromocytoma cells and Institute of Cancer Research mice. The major constituents of Brussels sprouts (3,4',5,7-tetrahydroxyflavone (kaempferol), indole-3-carbinol, and phenethyl isothiocyanate) were selectively tested. Of these, the flavonoid compound, kaempferol exhibited the highest potency in radical scavenging activity (1,1-diphenyl-2-picryl hydrazyl assay and oxygen radical absorbance capacity assay) and was most protective against oxidative stress in neuronal cell assays (measurement of intracellular oxidative stress levels and cell viability). In mice, after 4 weeks of kaempferol administration, significant protection against amyloid beta (Aβ) peptide-induced neurotoxicity was also observed, as assessed through the passive avoidance test. Taken together, the results suggest that Brussels sprouts could be protective against Aβ-induced neurotoxicity, possibly due to the antioxidative capacity of its major constituent, kaempferol.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Antioxidants; Biphenyl Compounds; Brain; Brassica; Cell Survival; Indoles; Isothiocyanates; Kaempferols; Mice; Mice, Inbred ICR; Neuroprotective Agents; Neurotoxicity Syndromes; Oxidative Stress; PC12 Cells; Picrates; Plant Extracts; Rats

Annona dioica St. Hill (Annonacaeae) is a Brazilian plant used in folk medicine for the treatment of several types of rheumatisms and diarrhoea. The focus of this work was to evaluate the in vitro antiproliferative and antioxidant activity and the in vivo hypoglycaemic and anti-inflammatory activity of A. dioica and identify the principal constituents of this plant.. The crude methanol extract (EAD) and hexane (HF), chloroform (CF), ethyl acetate (EAF) and hydromethanol fractions (HMF) were evaluated for free radical scavenging activity using the DPPH assay. The EAD and EAF were assayed for hypoglycaemic activity in rats. The EAD was tested in an antiproliferation assay and for anti-inflammatory effects in paw oedema, in addition to myeloperoxidase activity induced by carrageenan (Cg) in mice. The EAF was assayed using chromatographic methods.. The fractionation of the EAF through chromatographic methods identified derivatives of the flavonoids quercetin and kaempferol. Among all the tested fractions, the ethyl acetate and hydromethanol fractions were the most potent, exhibiting an IC50 of 8.53 and 10.57 μg/mL, respectively, which is comparable to that of the commercial antioxidant butylated hydroxytoluene (BHT). The oral administration of the EAD (100 mg/kg) and EAF (15 mg/kg) inhibited the increase of glucose levels, resulting in a hypoglycaemic effect. The EAD (30 to 300 mg/kg) exhibited an anti-oedematogenic effect in Cg-induced paw oedema in a time- and dose-dependent manner. The results showed a reduction of MPO activity by A. dioica 6 h after the induction of paw oedema at all doses tested with maximal inhibition at 300 mg/kg.. Our results reveal for the first time that compounds contained in the A. dioica leaves exert anti-inflammatory, hypoglycaemic, antiproliferative, and antioxidant effects. The antioxidant activity may be associated with the presence of flavonoids.

Topics: Animals; Annona; Anti-Inflammatory Agents; Antineoplastic Agents, Phytogenic; Biphenyl Compounds; Blood Glucose; Carrageenan; Cell Line, Tumor; Dose-Response Relationship, Drug; Edema; Free Radical Scavengers; Hypoglycemic Agents; Inhibitory Concentration 50; Kaempferols; Male; Mice; Neoplasms; Peroxidase; Phytotherapy; Picrates; Plant Extracts; Quercetin; Rats; Rats, Wistar

Natural flavonoids are secondary phenolic plant metabolites known for their bioactivity as antioxidants. The evaluation of this property is generally done by the estimation of their direct free radical-scavenging activity as hydrogen or electron donating compounds. This paper reviews experimental results available in the literature for a selection of flavonoids and compares them with calculated quantities characteristic of the hydrogen or electron donation. For that purpose, bond dissociation energies, ionization potentials and electron transfer enthalpies are computed by using DFT methods and the ONIOM procedure implemented in the ab initio program Gaussian. This process has been chosen because it can be extended to the study of large molecules. When acid dissociation and interaction with the solvent are taken into account, the results present very good concordance with experimental results, enlightening the complexity of the processes involved in the classical assays which measure the ability of compounds to scavenge the (2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt) radical cation (ABTS (+)) or the 2,2-diphenyl-1-picryl-hydrazyl radical (DPPH(·)). This study demonstrates the good accuracy of theoretical calculations in obtaining the relative energies involved in free radical scavenging abilities and its capacity for predictive behaviour. It also highlights the necessity to take into account the pK(a) of the compounds and the solvent interaction. The ability of the method to calculate the antioxidant properties of larger molecules are tested on glycosylated flavonoids and the effects of sugar substitution on the antioxidant properties of flavonoids are investigated, pointing out the importance of the charges on the oxygen atoms.

Topics: Antioxidants; Apigenin; Benzothiazoles; Biphenyl Compounds; Electrons; Flavonoids; Free Radical Scavengers; Glycosylation; Hydrogen; Hydrolysis; Kaempferols; Models, Chemical; Models, Molecular; Molecular Structure; Oxidation-Reduction; Picrates; Quercetin; Solvents; Structure-Activity Relationship; Sulfonic Acids; Thermodynamics

The functionality of spring mountain herbs, which were collected in the Kajigamori mountain area of Shikoku area in Japan, was investigated in the course of our studies for utilizing local plant resources. The radical scavenging activity of the extracts from seventeen herbs was measured. Among these herbs, two extracts from Polystichym ovato-paleaceum (Japanese name: Tsuyanashiinode) and Sambucus racemosa subsp. sieboldiana (Japanese name: Niwatoko) showed potent DPPH radical scavenging activity. The material evidence for the potent activity of the extracts was studied by a combination of our developed method for detecting antiradical compounds, LC-MS/MS, and enzymatic hydrolysis.

Topics: Biphenyl Compounds; Caffeic Acids; Chromatography, Liquid; Free Radical Scavengers; Free Radicals; Japan; Kaempferols; Natural Springs; Picrates; Plant Components, Aerial; Plant Extracts; Plant Roots; Plants, Medicinal; Polystichum; Quercetin; Sambucus; Tandem Mass Spectrometry

The present study evaluated the radical scavenging and angiotensin converting enzyme (ACE) inhibitory activity of cold and hot aqueous extracts of Ficus racemosa (Moraceae) stem bark. The extracts were standardized using HPLC. Radical scavenging activity was determined using 1,1-diphenyl-2-picrylhydrazyl radical and angiotensin converting enzyme inhibitory activity using rabbit lung and partially purified porcine kidney ACE. HPLC profiles of cold aqueous extract (FRC) showed the presence of bergenin, an isocoumarin, while hot aqueous extract (FRH) was found to contain ferulic acid, kaempferol and coumarin in addition to bergenin. FRH showed significantly higher (p ≤ 0.01) radical scavenging activity than FRC and butylated hydroxytoluene (BHT), consequently resulting in a significantly lower (p ≤ 0.01) IC₅₀ value than FRC and BHT. Both the extracts exhibited a dose dependent inhibition of porcine kidney and rabbit lung ACE. FRH showed significantly higher (p ≤ 0.01) activity than FRC with lower IC(50) values of 1.36 and 1.91 μg/mL respectively, for porcine kidney and rabbit lung ACE, compared with those of FRC (128 and 291 μg/mL). Further, a significant correlation (r = 0.893; p ≤ 0.05) was observed between radical scavenging activity and ACE-inhibitory activity. This is the first report on the ACE-inhibitory activity of F. racemosa stem bark suggesting its potential to be utilized as a therapeutic alternative for hypertension.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Benzopyrans; Biphenyl Compounds; Coumaric Acids; Coumarins; Ficus; Free Radical Scavengers; Kaempferols; Lung; Picrates; Plant Bark; Plant Extracts; Rabbits; Swine

From the leaves of Brassica juncea, three kaempferol glycosides, kaempferol-3-O-(2-O-sinapoyl)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside-7-O-beta-D-glucopyranoside (1), kaempferol-3-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside-7-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside (2), and kaempferol-3-O-(2-O-sinapoyl)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside-7-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside (3) were isolated and the structures elucidated on the basis of spectral and chemical evidences. Antioxidant activities were determined by measuring the scavenging activities on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and peroxynitrite (ONOO(-)). Compounds 1 and 3 showed good antioxidant activities with respective IC(50) values of 28.61 and 36.93 microM toward DPPH; respective IC(50) values of 9.79 and 11.40 microM toward ONOO(-). However, compound 2 showed no DPPH scavenging activity and weak ONOO(-) scavenging activity with an IC(50) value of 32.00 microM.

Topics: Antioxidants; Biphenyl Compounds; Free Radicals; Glycosides; Kaempferols; Molecular Structure; Mustard Plant; Peroxynitrous Acid; Picrates; Plant Leaves

In the present study the polyphenolic compound has been isolated from methanol extract of Acacia nilotica Willd. Ex. Del. which has been identified as kaempferol (AN-5) by NMR and mass spectroscopy. The antioxidant potential of the AN-5 was demonstrated in several in vitro assays: measuring the proton radical scavenging activity (DPPH scavenging assay), hydroxyl radical scavenging activity (deoxyribose degradation assay), metal chelating activity, reducing power and inhibition of lipid peroxidation. It was found that the effect of the compound AN-5 was strongly dose dependent up to the concentrations 1-50 microg/ml in DPPH assay and 1-100 microg/ml in deoxyribose degradation assay but did not show further change above the highest concentrations.

Topics: Acacia; Biphenyl Compounds; Chelating Agents; Deoxyguanosine; Dose-Response Relationship, Drug; Free Radical Scavengers; Kaempferols; Lipid Peroxidation; Magnetic Resonance Spectroscopy; Mass Spectrometry; Picrates; Plant Extracts

Atherosclerosis is a chronic inflammatory disease of the arterial wall. Kaempferol and rhamnocitrin (kaempferol 7-O-methyl ether) are two anti-inflammatory flavonoids commonly found in plants. The aim of this study is to investigate the function of kaempferol and rhamnocitrin on prevention of atherosclerosis. Chemical analyses demonstrated that kaempferol and rhamnocitrin were scavengers of DPPH (1,1-diphenyl-2-picrylhydrazyl) with IC50 of 26.10 +/- 1.33 and 28.38 +/- 3.07 microM, respectively. Copper-induced low-density lipoprotein (LDL) oxidation was inhibited by kaempferol and rhamnocitrin, with similar potency, as measured by decreased formation of malondialdehyde and relative electrophoretic mobility (REM) on agarose gel, while rhamnocitrin reduced delayed formation of conjugated dienes better than kaempferol. Cholesterol-laden macrophages are the hallmark of atherogenesis. The class B scavenger receptor, CD36, binds oxidized low-density lipoprotein (oxLDL), is found in atherosclerotic lesions, and is up-regulated by oxLDL. Addition of kaempferol and rhamnocitrin (20 microM) caused significant reductions in cell surface CD36 protein expression in THP-1-derived macrophages (p < 0.05). Reverse transcription quantitative PCR (RT-Q-PCR) showed that kaempferol and rhamnocitrin (20 microM) decreased oxLDL-induced CD36 mRNA expression (p < 0.01 and p < 0.05, respectively). Kaempferol- and rhamnocitrin-treated macrophages also showed reduction in 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanide perchlorate (DiI)-labeled oxLDL uptake. Current evidences indicate that kaempferol and rhamnocitrin not only protect LDL from oxidation but also prevent atherogenesis through suppressing macrophage uptake of oxLDL.

Topics: Anti-Inflammatory Agents; Atherosclerosis; Biphenyl Compounds; CD36 Antigens; Dose-Response Relationship, Drug; Flavonoids; Gene Expression; Humans; Inhibitory Concentration 50; Kaempferols; Lipid Peroxidation; Lipoproteins, LDL; Macrophages; Oxidation-Reduction; Picrates; RNA, Messenger

Hippophae rhamnoides or seabuckthorn is used extensively in Indian and Tibetan traditional medicine for the treatment of circulatory disorders, ischemic heart disease, hepatic injury, and neoplasia. In the present study, we have evaluated the radioprotective potential of REC-1001, a fraction isolated from the berries of H. rhamnoides. Chemical analysis of the extract indicated that REC-1001 was approximately 68% by weight polyphenols, and contained kaempferol, isorhamnetin, and quercetin. The effect of REC-1001 on modulating radiation-induced DNA damage was determined in murine thymocytes by measuring nonspecific nuclear DNA damage at the whole genome level using the alkaline halo assay and by measuring sequence/gene-specific DNA damage both in nuclear DNA (beta-globin gene) and in mitochondrial DNA using a quantitative polymerase chain reaction. Treatment with 10 Gy resulted in a significant amount of DNA damage in the halo assay and reductions in the amplification of both the beta-globin gene and mitochondrial DNA. REC-1001 dose-dependently reduced the amount of damage detected in each assay, with the maximum protective effects observed at the highest REC-1001 dose evaluated (250 micro g/ml). Studies measuring the nicking of naked plasmid DNA further established the radioprotective effect of REC-1001. To elucidate possible mechanisms of action, the antioxidant properties and the free-radical scavenging activities of REC-1001 were evaluated. REC-1001 dose-dependently scavenged radiation-induced hydroxyl radicals, chemically-generated superoxide anions, stabilized DPPH radicals, and reduced Fe(3+) to Fe(2+). The results of the study indicate that the REC-1001 extract of H. rhamnoides protects mitochondrial and genomic DNA from radiation-induced damage. The polyphenols/flavonoids present in the extract might be responsible for the free radical scavenging and DNA protection afforded by REC-1001.

Topics: Animals; Biphenyl Compounds; DNA; DNA Damage; DNA, Mitochondrial; Flavonols; Free Radical Scavengers; Gamma Rays; Hippophae; Hydrazines; Hydroxyl Radical; In Vitro Techniques; Kaempferols; Male; Mice; Oxidation-Reduction; Phenols; Picrates; Plant Extracts; Quercetin; Superoxides; Thymus Gland

A new lavandulylated flavonoid, 8-lavandulylkaempferol (1), was isolated from the roots of Sophora flavescens AITON (Leguminosae). The structure of this compound was determined via spectroscopic analysis. Compound 1 was determined to be a scavenger on both 1,1-diphenyl-2-picrylhydrazyl radicals and ONOO-.

Topics: Biphenyl Compounds; Drugs, Chinese Herbal; Flavonoids; Free Radical Scavengers; Hydrazines; Kaempferols; Molecular Structure; Peroxynitrous Acid; Picrates; Plant Extracts; Plant Roots; Plants, Medicinal; Solvents; Sophora; Spectroscopy, Fourier Transform Infrared

Flavonoids are found universally in plants and act as free radical scavenging and chelating agents with antiinflammatory, antiischemic, vasodilating and chemoprotective properties. In this study, the antilipoperoxidative and cytoprotective effects of apigenin, baicalein, kaempferol, luteolin and quercetin against doxorubicin-induced oxidative stress were investigated in isolated rat heart cardiac myocytes, mitochondria and microsomes. After preincubation of cardiomyocytes with the test compounds for 1 h the cardiomyocytes were treated with the toxic agent, doxorubicin (100 micro M for 8 h). Cardiomyocyte protection was assessed by extracellular LDH and cellular ADP and ATP production. Cytoprotection was concentration dependent for baicalein > luteolin congruent with apigenin > quercetin > kaempferol. All test compounds had signi fi cantly better protective effects than dexrazoxan, an agent currently used for adjuvant therapy during anthracycline antibiotic therapy. In microsomes/mitochondria the IC(50) values of lipid peroxidation inhibition for quercetin, baicalein, kaempferol, luteolin, and apigenin were 3.1 +/- 0.2/8.2 +/- 0.6, 3.3 +/- 0.3/9.6 +/- 0.5, 3.9 +/- 0.3/10.1 +/- 0.8, 22.9 +/- 1.7/18.2 +/- 0.7, and 338.8 +/- 23.1/73.1 +/- 6.4 mM, respectively. The antilipoperoxidative activity of apigenin differed from its cytoprotective effects, but correlated with the free radical scavenging of 2,2-diphenyl-1-picrylhydrazyl radical and half peak oxidation potential (E(p/2)). Apigenin was the least effective of the flavonoids studied in all models except the cardiomyocyte model where its cardiomyocyte cytoprotective effect was comparable to other compounds.

Topics: Animals; Apigenin; Biphenyl Compounds; Dose-Response Relationship, Drug; Flavanones; Flavonoids; Free Radical Scavengers; Kaempferols; Lipid Peroxidation; Luteolin; Male; Microsomes; Myocytes, Cardiac; Phytotherapy; Picrates; Plants, Medicinal; Protective Agents; Quercetin; Rats; Rats, Wistar

In this study, we irradiated the antioxidant kaempferol in ethanol and methanol solutions with gamma rays at doses ranging from 0.2-20 kGy. NMR and ES-MS spectroscopy were used to identify radiolysis products. Two depsides, [2-[(4'-hydroxybenzoyl)oxy]-4,6-dihydroxyphenyl](oxo) methyl acetate and [2-[(4'-hydroxybenzoyl)oxy]-4,6-dihydroxyphenyl](oxo) ethyl acetate, were the major compounds of kaempferol degradation in methanol and in ethanol, respectively. Other products formed in low concentrations were identified as [4-hydroxyphenyl](oxo) methyl acetate, [4-hydroxyphenyl](oxo) ethyl acetate, and depside [2-[(4'-hydroxybenzoyl)oxy]-4,6-dihydroxyphenyl](oxo) acetic acid. The formation of the latter was observed in both solvents. We propose degradation mechanisms that suggest that (.)CH(2)OH and CH(3)(.)CHOH, produced by solvent radiolysis, react with the 3-OH kaempferol group because of its high H-donor capacity. pi-Electron delocalization in the flavonoxy formed after the first H-transfer leads to C-ring opening and consequently to the formation of depsides. G calculation of the degradation products and of (.)CH(2)OH and CH(3)(.)CHOH radicals confirmed the proposed mechanism of kaempferol radiolysis. The rate constants for the reaction between kaempferol and these free radicals were also calculated. Formation of depside has also been observed in many studies of the oxidation of flavonoids; those studying human metabolism have suggested similar redox transformation of flavonols. The antioxidant activities of radiolysis products were evaluated and compared to those of kaempferol.

Topics: Antioxidants; Biphenyl Compounds; Chromatography, High Pressure Liquid; Depsides; Dose-Response Relationship, Radiation; Ethanol; Flavonoids; Free Radicals; Gamma Rays; Hydroxybenzoates; Kaempferols; Magnetic Resonance Spectroscopy; Mass Spectrometry; Methanol; Models, Chemical; Oxygen; Picrates; Superoxides; Time Factors; Ultraviolet Rays

The antioxidant and prooxidant activities of flavonoids belonging to several classes were studied to establish their structure-activity relationships against different oxidants. Special attention was paid to the flavonoids quercetin (flavone), taxifolin (flavanone) and catechin (flavanol), which possess different basic structures but the same hydroxylation pattern (3,5,7,3'4'-OH). It was found that these three flavonoids exhibited comparable antioxidant activities against different oxidants leading to the conclusion that the presence of ortho-catechol group (3',4'-OH) in the B-ring is determinant for a high antioxidant capacity. The flavone kaempferol (3,5,7,4'-OH), however, in spite of bearing no catechol group, also presents a high antioxidant activity against some oxidants. This fact can be attributed to the presence of both 2,3-double bond and the 3-hydroxyl group, meaning that the basic structure of flavonoids becomes important when the antioxidant activity of B-ring is small.

Topics: Amidines; Antioxidants; Ascorbic Acid; Biphenyl Compounds; Catechin; Edetic Acid; Flavonoids; Flavonols; Free Radicals; Iron; Kaempferols; Liposomes; Metmyoglobin; Picrates; Quercetin; Structure-Activity Relationship