ascorbic-acid and taxifolin

Quercetin (QT) and Taxifolin (TF) are structurally similar plant polyphenols. Both have been reported to have therapeutic potential as anti-cancer drugs and antioxidants. Mutagenic effects of QT and TF were evaluated using Salmonella typhimurium TA102 and Escherichia coli WP-2 uvrA tester strains. Either in the presence or absence of S9 mix, QT was mutagenic to TA102 and WP2 uvrA. However, the mutagenicity of QT was significantly enhanced in the presence of S9 mix. Likewise, in the presence of Iron (Fe2+) and NADPH generating system (NGS) and absence of S9 mix, QT induced significantly high mutations in both TA102 and WP-2 uvrA. Mutagenicity of QT decreased in both strains in the presence of Iron (Fe2+) or NGS alone. TF was not mutagenic in the presence or absence of S9 mix in both TA102 and WP-2 uvrA 2, regardless of the presence of iron or NGS. Incorporation of antioxidants (ascorbate, superoxide dismutase (SOD), catalase (CAT)) and/or iron chelators (desferroxamine (DF) and ethylenediamine-tetraacetate (EDTA)) in the test systems markedly decreased QT-induced mutations in both tester strains. These results suggest that QT but not TF, could induce mutations in the presence or absence of rat liver S9 or Iron (Fe2+) and NGS in both tester strains by redox cycling and Fenton reactions to produce oxygen free radicals. Our results indicate that a minor structural variation between the two plant polyphenols could elicit a marked difference in their genotoxicities. These results provide a basis for further study into the potential use of QT in combination with iron supplements.

Topics: Animals; Antioxidants; Ascorbic Acid; Catalase; Deferoxamine; Edetic Acid; Escherichia coli; Iron; Iron Chelating Agents; Liver Extracts; Microbial Sensitivity Tests; Mutagenesis; Mutagenicity Tests; Mutation; NADP; Quercetin; Rats; Salmonella typhimurium; Superoxide Dismutase

Peroxidation processes in male outbred albino rats were studied 1, 2, and 3 months after 90-fold administration of dihydroquercetin in doses of 86, 860, and 3000 mg/kg and flavonoid rutin (reference preparation) in a dose of 86 mg/kg. Dihydroquercetin in a dose of 86 mg/kg was as potent as rutin in modulating the process of peroxidation. Changes in the nonenzymatic antioxidant system and activation of lipid peroxidation were not observed in the delayed period after administration of dihydroquercetin.

Topics: Analysis of Variance; Animals; Antioxidants; Ascorbic Acid; Lipid Peroxidation; Male; Quercetin; Rats

Light exposure (6000 lux, 6 h) caused reactive changes in rat retinal pigmented epithelium and radial glia on day 1. Foci of lesions with virtually complete absence of the layers formed by neurosensory cells appeared on day 7. The number of destructively changed radial gliocytes in these foci was by one order of magnitude higher than in the control. Carovertin reduced destruction of pigmented epithelium and radial glia and reduced the area of lesion foci.

Topics: Animals; Ascorbic Acid; beta Carotene; Flavonols; Light; Male; Neuroglia; Pigment Epithelium of Eye; Quercetin; Rats

Using the methods of light and electron microscopy, morpho-functional changes of the ovaries of albino rats after their monopolar coagulation were studied. Electrocoagulation was shown to cause hemodynamic changes in a perifocal area and short-term stimulation of follicular growth, but starting already at postoperational day 3, their atresia was increased, while by day 30 a significant reduction in number of both primordial and growing follicles, as well as of corpora lutea, was found. Ultrastructural changes of oocytes in primary and secondary follicles outside the coagulation zone were demonstrated at early stages and included the reduction of porous plate, cortical and yolk granule numbers, and the increase in numbers of lysosomes and multivesicular bodies. Ascovertin, due to its antioxidant properties and by improving hemorheological parameters, exerts a protective action on ovarian generative apparatus and the state of microcirculation in the organ.

Topics: Animals; Antioxidants; Ascorbic Acid; Drug Combinations; Electrocoagulation; Female; Flavonols; Ovary; Quercetin; Rats; Regeneration

Experiments on rats showed that high-intensity light exposure (6000 lux, 6 h) caused focal injuries in the retina. The most sensitive structures were neurosensory cells, pigmented epithelium, radial gliocytes, and choroid capillaries. Injection of ascovertin led to disappearance of foci of injuries, limited blood supply disorders in the retina, and destruction of neurosensory and glial cells.

Topics: Animals; Ascorbic Acid; Flavonols; Free Radicals; Light; Male; Quercetin; Radiation Injuries, Experimental; Rats; Retina; Time Factors

Patients with stages I and II of vascular encephalopathy developing on the background of atherosclerosis were treated with ascovertin during 21 days. Ascovertin is a complex of flavonoid dihydroquercetin and ascorbic acid. The study group included 21 patients aged 45-65 years and a comparison group consisted of 10 age-matched patients un treated with ascovertin. The ascovertin treatment relieved headache, reduced vertigo and fatigability, improved cognitive functions. The reliable diminishing of whole blood viscosity due to improvement of cellular rheology indices (decrease of aggregation and increase of erythrocyte deformability as well as decrease of indices of lipid peroxidation in erythrocyte membrane and blood plasma) was observed in the stydy group but not in the comparison one.

Topics: Aged; Antioxidants; Ascorbic Acid; Blood Viscosity; Drug Combinations; Erythrocyte Aggregation; Erythrocyte Deformability; Flavonols; Headache; Hemorheology; Humans; Intracranial Arteriosclerosis; Lipid Peroxidation; Middle Aged; Neuropsychological Tests; Quercetin; Sleep Wake Disorders; Tinnitus; Vertigo

A course of ascovertin therapy reduced manifestations of perifocal inflammation and atresia of growing follicles, corrected vascular disorders and changes in the tissue volume ratios outside the necrotic zone after monopolar coagulation of the ovaries in rats. The drug prevented the increase in blood viscosity, erythrocyte aggregation, and LPO activation in the early postoperation period.

Topics: Animals; Antioxidants; Ascorbic Acid; Blood Viscosity; Drug Combinations; Erythrocyte Aggregation; Erythrocytes; Fallopian Tubes; Female; Flavonols; Gynecologic Surgical Procedures; Hematocrit; Ovarian Diseases; Ovary; Postoperative Period; Quercetin; Rats

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

The effect of alpha-tocopherol, ascorbate, rutin and dihydroquercetin on chemiluminescence (CL) accompanying the Fe2+-induced peroxidation of unsaturated fatty acids in phospholipid liposomes has been investigated. The amplitude of CL decreased and the latent period increased in the presence of alpha-tocopherol, rutin and dihydroquercetin which is typical of peroxide radical traps. Ascorbate also reduced the CL amplitude but only at small concentrations up to about 4 microM. A further increase of ascorbate concentration had a negligible effect on the amplitude. At the same time, the latent period in CL development increased with the growth of ascorbate concentration, apparently, as a result of recycling of divalent iron oxidized in the course of lipid peroxidation. The effects of rutin and dihydroquercetin on the liposomal CL in the presence of alpha-tocopherol and ascorbate in all experiments were almost the same as when these compounds were added individually. The antioxidant effects were merely summed up without any mutual enhancement or inhibition of each other's action.

Topics: Antioxidants; Ascorbic Acid; Cations, Divalent; Ferrous Compounds; Flavonols; Lipid Peroxidation; Liposomes; Phospholipids; Quercetin; Rutin; Vitamin E

Radicals from the flavonoids quercetin, (+)-catechin, (+/-)-taxifolin and luteolin, and from all-rac-alpha-tocopherol have been generated electrochemically by one-electron oxidation in deaerated dimethylformamide (DMF), and characterised by electron spin resonance spectroscopy (ESR) after spin-trapping by 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). Simulations of the ESR spectrum based on estimated coupling constants of the spin-trapped quercetin radical, confirmed that this antioxidant radical is oxygen-centered. The complex mixture of radicals, quinoid intermediates and stable two-electron oxidation products, were for each antioxidant allowed to react with each of the four other antioxidants, and the progression of reaction followed by ESR after addition of DMPO, and the product solution further analysed by HPLC. All-rac-alpha-tocopherol was found to be most efficient in regenerating each of the other antioxidants from their oxidation products with a regeneration index (defined as moles regenerated of the oxidised phenolic antioxidant divided with moles of all-rac-alpha-tocopherol consumed) of 0.90+/-0.16 for quercetin, 0.48+/-0.11 for (+)-catechin, 0.48+/-0.06 for (+/-)-taxifolin and 0.50+/-0.10 for luteolin in equimolar 1.00 mM solution. Quercetin was found to have the highest regeneration index among the flavonoids: 0.88+/-0.13 for (+/-)-catechin, 0.41+/-0.03 for (+/-)-taxifolin and 0.41+/-0.02 for luteolin. The antioxidant hierarchy based on the reduction potentials determined by cyclic voltammetry under similar conditions (0.93 V for all-rac-alpha-tocopherol, 1.07 V for quercetin, 1.15 V for luteolin, 1.16V for (+)-catechin and 1.20 V for (+/-)-taxifolin) is compared with the observed over-all regeneration (34% for quercetin, 34% for (+)-catechin, 52% for (+/-)-taxifolin and 43% for luteolin by all-rac-alpha-tocopherol).

Topics: Antioxidants; Ascorbic Acid; Catechin; Chromatography, High Pressure Liquid; Electrochemistry; Electron Spin Resonance Spectroscopy; Flavonoids; Flavonols; Free Radicals; In Vitro Techniques; Luteolin; Oxidation-Reduction; Phenols; Quercetin; Vitamin E

The antioxidant properties of the carotenoid lycopene were compared in three different model oxidative systems. In egg yolk liposomes, in the presence of 2.5 mM FeSO4 and 200 mM ascorbate, lycopene, alpha-tocopherol, and beta-carotene inhibited the accumulation of lipid peroxidation products reacting with 2-thiobarbituric acid (TBARS) in a dose-dependent mode, with the concentration of half-inhibition being 80, 30 and 130 mM, respectively. In the liposomes subjected to illumination with a He-Ne laser (632.8 nm) at a dose of 10.5 J/cm2, in the presence of 32.5 micrograms/ml hematoporphyrin derivatives (Fotogem, NIOPIC, Russia) TBARS accumulated, and this effect was inhibited by lycopene, alpha-tocopherol, and dihydroquercetin with approximately equal efficiencies (the half-inhibition concentrations were 10(-5) mM). In both systems studied, sodium azide at a concentration of 10 mM inhibited the TBARS accumulation by no more than 20%. Apparently, the inhibitory action of not only alpha-tocopherol, but also beta-carotene and lycopene was the result of their antiradical action, rather than quenching of the singlet oxygen in an aqueous medium. The introduction of lycopene, as well as beta-carotene in liposomes subjected to Fe(2+)-induced lipid peroxidation decreased the chemiluminescence (CL) intensity at the stage of CL slow flash, with no essential influence on the lag period. These data suggest that the effect of lycopene on lipid peroxidation was the result of its interaction with free radicals rather than chelating ferrous ions. The antiradical activity of lycopene was also confirmed by the method of luminol photochemiluminescence (PCL). Lycopene increased the PCL lag period (L) and decreased the PCL amplitude (A), which implies its antiradical and SOD-like activity in this system.

Topics: Animals; Antioxidants; Ascorbic Acid; beta Carotene; Butylated Hydroxytoluene; Carotenoids; Chick Embryo; Flavonols; Free Radicals; Kinetics; Lipid Peroxidation; Liposomes; Luminescent Measurements; Luminol; Lycopene; Quercetin; Rutin; Sodium Azide; Superoxide Dismutase; Uric Acid; Vitamin E

Information about types of vegetative raw material for flavonoid dihydroquercetin manufacture are given. Data of a wide spectrum of biological activity of dihydroquercetin are systematized. Two directions of use dihydroquercetin in food industry: as antioxidant and as biologically active supplement for creation different types of parapharmaceutical production is shown. Dihydroquercetin in the capacity of antioxidant may be compared or exceeds many synthetic and natural antioxidants and, in particular, known bioflavonoids (quercetin). High antioxidant activity of dihydroquercetin is combined with absence embryotoxicity, teratogenicity, allergenicity and mutability. Dihydroquercetin used as efficient antioxidant with regard to vegetable oils, animal fat, milk powder, fat contain pastry. Parapharmaceutical production with dihydroquercetin is intended for prophylactic of "oxidative stress" diseases (cardiovascular, bronchopulmonary, etc.). Practical application of new types of products containing dihydroquercetin was described. Dihydroquercetin is an available commercial food additive, producing domestic industry.

Topics: Animals; Antioxidants; Ascorbic Acid; Dietary Supplements; Dose-Response Relationship, Drug; Drug Synergism; Flavonols; In Vitro Techniques; Kinetics; Lipid Peroxidation; Luminescent Measurements; Quercetin; Rats

Concurrent pulse-radiolytic generation of flavonoid aroxyl radicals and ascorbyl radicals causes a complex kinetic interplay of competing and parallel reactions. Evaluation by "kinetic modelling," that is, taking into account all possible reactions by a set of differential equations, allowed us to determine equilibria constants for the univalent steps by a novel method. From these kinetic data we were able to calculate the redox potentials for dihydroquercetin, quercetin, rutin (a quercetin 3-glycoside), kaempferol, fisetin, and luteolin. Despite the limited number of substances, two structural criteria became apparent: all substances containing the B-ring catechol group and the 2,3-double bond have a higher redox potential than ascorbate and are consequently able to oxidize it to the ascorbyl radical. With fisetin and kaempferol having values very similar to ascorbate, only the flavanone dihydro-quercetin was capable of reducing the ascorbyl radical, thus fulfilling the so-called "ascorbate-protective" function, originally proposed by Szent-Györgyi. While flavonoids are effective radical scavengers, these rather high redox potentials for most flavonols may explain their occasional prooxidative behavior.

Topics: Ascorbic Acid; Flavonoids; Flavonols; Hydrogen-Ion Concentration; Kaempferols; Kinetics; Luteolin; Molecular Structure; Oxidation-Reduction; Pulse Radiolysis; Quercetin; Rutin