ascorbic-acid and caffeic-acid

The present study investigated whether storage under modified-atmosphere packaging (MAP) affected the antioxidant properties of fresh lettuce (Lactuca sativa). Eleven healthy volunteers (six men, five women) consumed 250 g fresh lettuce, and blood was sampled before (0 h) and 2, 3 and 6 h after consumption. The protocol was repeated 3 d later with the same lettuce stored at 5 degrees C under MAP conditions (O2-N2 (5:95, v/v)). Results showed that after ingestion of fresh lettuce, plasma total radical-trapping antioxidant potential (TRAP), measured as area under the curve, was significantly higher (1.3 (sem 0.3) mmol/l per 6 h; P<0.05) than the value obtained with MAP-stored lettuce (0.1 (sem 0.2) mmol/l per 6 h). Plasma TRAP, quercetin and p-coumaric acid were significantly different from baseline values (P

Topics: Adult; Analysis of Variance; Antioxidants; Area Under Curve; Ascorbic Acid; Biological Availability; Caffeic Acids; Carotenoids; Coumaric Acids; Eating; Female; Flavonoids; Food Handling; Food Packaging; Free Radicals; Humans; Lactuca; Male; Middle Aged; Oxidation-Reduction; Phenols; Polymers; Quercetin; Time Factors

In this study, the antioxidative capacity of caffeic acid (CA), ascorbyl palmitate (AP), α-tocopherol (α-TO), and caffeic acid phenethyl ester (CAPE) was evaluated under the thermal oxidation model, in which 200 ppm of each compound was added to soybean oil, followed by thermal oxidation at 180°C for 32 h. Change of viscosity, acid value (AV), conjugated dienoic acid value (CDAV), p-anisidine value (p-AV), total polar materials (TPM), and the ratio of C18:2 to C16:0 (LA/PA) were evaluated during the reaction. All antioxidants showed significantly lower viscosity, TPM, and p-AV, and higher LA/PA, than the control (without antioxidant, CON), indicating that thermal oxidation was delayed. Among them, CAPE showed significantly lower viscosity, TPM, and p-AV, and higher LA/PA, than the other antioxidants (p < 0.05). In the correlation between the oxidation parameters measured from CON and CAPE, the correlation coefficient between p-AV and viscosity was rather low at r = 0.7603 (in CON) and r = 0.7338 (in CAPE), respectively.

Topics: alpha-Tocopherol; Ascorbic Acid; Caffeic Acids; Esters; Oxidation-Reduction

The intestinal epithelium of the gastrointestinal (GI) tract constantly renews itself to absorb nutrients and provide protection for the body from the outside world. Since the intestinal epithelium is constantly exposed to various chemicals and dietary components, it is critical to determine which constituents promote or inhibit intestinal epithelium health and growth rate. Intestinal organoids, three-dimensional miniature models of the intestines, represent an ex vivo tool to investigate intestinal physiology and growth patterns. In this study, we measured the growth rates of murine intestinal organoids exposed to various concentrations of different dietary constituents. Results indicate that caffeic acid inhibited organoid growth in a concentration-dependent manner, curcumin exhibited variable effectiveness, and vitamin C had no effect on organoid growth.

Topics: Animals; Ascorbic Acid; Caffeic Acids; Chlorogenic Acid; Coumaric Acids; Curcumin; Diet; Gastrointestinal Tract; Mice; Sodium Glutamate; Stem Cells

A phytochemical study on the aerial parts of

Topics: Antioxidants; Ascorbic Acid; Caffeic Acids; Free Radical Scavengers; Mikania; Parabens; Phenols; Plant Extracts

Substantial studies have shown that curcumin, a dietary compound from turmeric, has beneficial effects on many diseases. However, curcumin rapidly degrades at physiological pH, making it difficult to interpret whether the observed actions of curcumin are from curcumin itself or its degradation products. Therefore, it is important to better understand the mechanisms involved in curcumin degradation and the roles of degradation in its biological actions.. Here, we show that a series of redox active antioxidants with diverse chemical structures, including gallic acid, ascorbate (vitamin C), tert-butylhydroquinone (TBHQ), caffeic acid, rosmarinic acid, and Trolox (a water-soluble analog of vitamin E), dramatically increased curcumin stability in phosphate buffer at physiological pH. When treated in basal cell culture medium in MC38 colon cancer cells, curcumin rapidly degraded with a half-life of several minutes and showed a weak antiproliferative effect; co-addition of antioxidants enhanced stability and antiproliferative effect of curcumin. Finally, co-administration of antioxidant significantly increased plasma level of curcumin in animal models.. Together, these studies strongly suggest that a redox-dependent mechanism plays a critical role in mediating curcumin degradation. In addition, curcumin itself, instead of its degradation products, is largely responsible for the observed biological actions of curcumin.

Topics: Animals; Antioxidants; Ascorbic Acid; Caffeic Acids; Cell Line, Tumor; Cell Proliferation; Chromans; Cinnamates; Curcumin; Depsides; Drug Stability; Gallic Acid; Hydrogen-Ion Concentration; Hydroquinones; Male; Mice; Oxidation-Reduction; Rosmarinic Acid

A new method is proposed for measuring the antioxidant capacity by electron spin resonance spectroscopy based on the loss of electron spin resonance signal after Cu(2+) is reduced to Cu(+) with antioxidant. Cu(+) was removed by precipitation in the presence of SCN(-). The remaining Cu(2+) was coordinated with diethyldithiocarbamate, extracted into n-butanol and determined by electron spin resonance spectrometry. Eight standards widely used in antioxidant capacity determination, including Trolox, ascorbic acid, ferulic acid, rutin, caffeic acid, quercetin, chlorogenic acid, and gallic acid were investigated. The standard curves for determining the eight standards were plotted, and results showed that the linear regression correlation coefficients were all high enough (r > 0.99). Trolox equivalent antioxidant capacity values for the antioxidant standards were calculated, and a good correlation (r > 0.94) between the values obtained by the present method and cupric reducing antioxidant capacity method was observed. The present method was applied to the analysis of real fruit samples and the evaluation of the antioxidant capacity of these fruits.

Topics: Antioxidants; Ascorbic Acid; Caffeic Acids; Chlorogenic Acid; Chromans; Copper; Coumaric Acids; Electron Spin Resonance Spectroscopy; Fruit and Vegetable Juices; Gallic Acid; Linear Models; Oxidation-Reduction; Quercetin; Rutin; Thiocyanates; Time Factors

This study aimed to characterize the effects of chitosan-g-caffeic acid (CTS-g-CA) on improving the quality and extending the shelf life of postharvest mulberry fruit during storage at 4 °C for 18 d. CTS-g-CA was enzymatically synthesized using laccase from Pleurotus ostreatus as a catalyst. The synergistic effects of CTS-g-CA treatment on mulberry fruit were evaluated using a co-toxicity factor (cf). The results showed that the rotting rate of CTS-g-CA-treated fruit was 37.67% (compared with that of the control at 97.67%) on day 18. The weight loss and malondialdehyde (MDA) contents of the CTS-g-CA-treated mulberry fruit were significantly lower (P < 0.05) than those of the control, CA, CTS, and CA+CTS treatments. Moreover, the DPPH and ABTS radical scavenging activities of the CTS-g-CA treatment were both higher than those of the control. Furthermore, the CTS-g-CA treatment also maintained higher levels of main active substances, such as anthocyanins, ascorbic acid, polyphenols and flavones, in mulberry fruit than the other treatments. Therefore, CTS-g-CA could be used to improve the quality and extend the shelf life of postharvest mulberry fruit during cold storage.

Topics: Anthocyanins; Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Caffeic Acids; Chitosan; Cold Temperature; Food Handling; Food Preservation; Food Storage; Fruit; Humans; Malondialdehyde; Morus; Picrates; Polyphenols; Refrigeration; Sulfonic Acids

Solanum diploconos is an unexploited Brazilian native fruit that belongs to the same genus of important food crops, such as tomato (Solanum lycorpersicum) and potato (Solanum tuberosum). In this study, we determined, for the first time, the profile of bioactive compounds (phenolic compounds, carotenoids, ascorbic acid and tocopherols) of the freeze-dried pulp and peel of Solanum diploconos fruits, as well as of an extract obtained from the whole fruit. Additionally, the antioxidant potential of the whole fruit extract was evaluated in vitro, against reactive oxygen species (ROS) and reactive nitrogen species (RNS). Eighteen phenolic compounds were identified in the peel and pulp and 6 compounds were found in the whole fruit extract. Coumaric, ferulic and caffeic acid derivatives were revealed to be the major phenolic constituents. All-trans-β-carotene was the major carotenoid (17-38 μg g(-1), dry basis), but all-trans-lutein and 9-cis-β-carotene were also identified. The peel and pulp presented <2 μg per mL of tocopherols, and ascorbic acid was not detected. The whole fruit extract exhibited scavenging capacity against all tested ROS and RNS (IC50 = 14-461 μg mL(-1)) with high antioxidant efficiency against HOCl. Thus, Solanum diploconos fruits may be seen as a promising source of bioactive compounds with high antioxidant potential against the most physiologically relevant ROS and RNS.

Topics: Antioxidants; Ascorbic Acid; Brazil; Caffeic Acids; Carotenoids; Chromatography, High Pressure Liquid; Coumaric Acids; Free Radical Scavengers; Fruit; Hydrogen Peroxide; Hypochlorous Acid; Lutein; Nitric Oxide; Peroxynitrous Acid; Phenols; Plant Extracts; Reactive Nitrogen Species; Reactive Oxygen Species; Singlet Oxygen; Solanum; Superoxides; Tocopherols

The Eurasian grapevine (Vitis vinifera L.) is the most widely cultivated and economically important horticultural crop in the world. As a one of the origin area, Anatolia played an important role in the diversification and spread of the cultivated form V. vinifera ssp. vinifera cultivars and also the wild form V. vinifera ssp. sylvestris ecotypes. Although several biodiversity studies have been conducted with local cultivars in different regions of Anatolia, no information has been reported so far on the biochemical (organic acids, sugars, phenolic acids, vitamin C) and antioxidant diversity of local historical table V. vinifera cultivars grown in Igdir province. In this work, we studied these traits in nine local table grape cultivars viz. 'Beyaz Kismis' (synonym name of Sultanina or Thompson seedless), 'Askeri', 'El Hakki', 'Kirmizi Kismis', 'Inek Emcegi', 'Hacabas', 'Kerim Gandi', 'Yazen Dayi', and 'Miskali' spread in the Igdir province of Eastern part of Turkey.. Variability of all studied parameters is strongly influenced by cultivars (P < 0.01). Among the cultivars investigated, 'Miskali' showed the highest citric acid content (0.959 g/l) while 'Kirmizi Kismis' produced predominant contents in tartaric acid (12.71 g/l). The highest glucose (16.47 g/100 g) and fructose (15.55 g/100 g) contents were provided with 'Beyaz Kismis'. 'Kirmizi Kismis' cultivar had also the highest quercetin (0.55 mg/l), o-coumaric acid (1.90 mg/l), and caffeic acid (2.73 mg/l) content. The highest ferulic acid (0.94 mg/l), and syringic acid (2.00 mg/l) contents were observed with 'Beyaz Kismis' cultivar. The highest antioxidant capacity was obtained as 9.09 μmol TE g(-1) from 'Inek Emcegi' in TEAC (Trolox equivalent Antioxidant Capacity) assay. 'Hacabas' cultivar had the highest vitamin C content of 35.74 mg/100 g.. Present results illustrated that the historical table grape cultivars grown in Igdir province of Eastern part of Turkey contained diverse and valuable sugars, organic acids, phenolic acids, Vitamin C values and demonstrated important antioxidant capacity for human health benefits. Further preservation and use of this gene pool will be helpful to avoid genetic erosion and to promote continued agriculture in the region.

Topics: Acids; Antioxidants; Ascorbic Acid; Caffeic Acids; Citric Acid; Coumaric Acids; Crops, Agricultural; Dietary Carbohydrates; Fruit; Gallic Acid; Hydroxybenzoates; Polyphenols; Tartrates; Turkey; Vitis

In this study, firstly, antioxidant and polyphenol oxidase (PPO) properties of Yomra apple were investigated. Seventeen phenolic constituents were measured by reverse phase-high-performance liquid chromatography (RP-HPLC). Total phenolic compounds (TPCs), ferric reducing antioxidant power (FRAP) and 2, 2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activities were performed to measure antioxidant capacity. Some kinetic parameters (Km, Vmax), and inhibition behaviors against five different substrates were measured in the crude extract. Catechin and chlorogenic acid were found as the major components in the methanolic extract, while ferulic acid, caffeic acid, p-hydroxybenzoic acid, quercetin and p-coumaric acid were small quantities. Km values ranged from 0.70 to 10.10 mM in the substrates, and also 3-(4-hydroxyphenyl) propanoic acid (HPPA) and L-DOPA showed the highest affinity. The inhibition constant of Ki were ranged from 0.05 to 14.90 mM against sodium metabisulphite, ascorbic acid, sodium azide and benzoic acid, while ascorbic acid and sodium metabisulphite were the best inhibitors.

Topics: Antioxidants; Ascorbic Acid; Biphenyl Compounds; Caffeic Acids; Catechin; Catechol Oxidase; Chlorogenic Acid; Coumaric Acids; Enzyme Inhibitors; Fruit; Kinetics; Levodopa; Malus; Oxidation-Reduction; Parabens; Phenylpropionates; Picrates; Plant Extracts; Plant Proteins; Polyphenols; Propionates; Quercetin; Sulfites

A method is proposed and tested concerning the characterization of antioxidants by means of their reaction with electrogenerated HO radicals in galvanostatic assays with simultaneous O2 evolution, using a Pt anode fairly oxidized. The consumption of a set of species with antioxidant activity, ascorbic acid (AA), caffeic acid (CA), gallic acid (GA) and trolox (T), is described by a first order kinetics. The rate of the processes is limited by the kinetics of reaction with HO radicals and by the kinetics of charge transfer. Information regarding the scavenger activity of antioxidants is obtained by the relative value of the rate constant of the reaction between antioxidants and HO radicals, k(AO,HO)/k(O2). The number of HO radicals scavenged per molecule of antioxidant is also estimated and ranged from 260 (ascorbic acid) to 500 (gallic acid). The method is applied successfully in the characterization of the scavenger activity of ascorbic acid in a green-tea based beverage.

Topics: Antioxidants; Ascorbic Acid; Beverages; Caffeic Acids; Chromans; Chromatography, High Pressure Liquid; Electrochemistry; Electrolysis; Food Analysis; Free Radical Scavengers; Gallic Acid; Hydroxyl Radical; Oxygen; Phenol; Tea

Coconut water contains several uncharacterized substances and is widely used in the human consumption. In this paper we detected and quantified ascorbic acid and caffeic acid and total phenolics in several varieties of coconut using HPLS/MS/MS (25.8 ± 0.6 µg/mL and 1.078 ± 0.013 µg/mL and 99.7 µg/mL, respectively, in the green dwarf coconut water, or 10 mg and 539 µg and 39.8 mg for units of coconut consumed, 500 ± 50 mL). The antioxidant potential of four coconut varieties (green dwarf, yellow dwarf, red dwarf and yellow Malaysian) was compared with two industrialized coconut waters and the lyophilized water of the green dwarf variety. All varieties were effective in scavenging the DPPH radical (IC₅₀=73 µL) and oxide nitric (0.1 mL with an IP of 29.9%) as well as in inhibiting the in vitro production of thiobarbituric acid reactive substances (1 mL with an IP of 34.4%), highlighting the antioxidant properties of the green dwarf which it is the most common used. In cell culture, the green dwarf water was efficient in protecting against oxidative damages induced by hydrogen peroxide.

Topics: Antioxidants; Ascorbic Acid; Caffeic Acids; Cells, Cultured; Cocos; Fibroblasts; Humans; Lipid Peroxidation; Lung; Phenols; Tandem Mass Spectrometry

A carbon-paste electrode modified with multiwall carbon nanotubes (MWCNTs) was used for the sensitive and selective voltammetric determination of ascorbic acid (AA) in the presence of 3,4-dihydroxycinnamic acid (3,4-DHCA) as mediator. The mediated oxidation of AA at the modified electrode was investigated by cyclic voltammetry (CV), chronoamperommetry and electrochemical impedance spectroscopy (EIS). Also, the values of catalytic rate constant (k), and diffusion coefficient (D) for AA were calculated. Using square wave voltammetry (SWV), a highly selective and simultaneous determination of AA, acetaminophen (AC) and tryptophan (Trp) has been explored at the modified electrode. The modified electrode displayed strong function for resolving the overlapping voltammetric responses of AA, AC and Trp into three well-defined voltammetric peaks. In the mixture containing AA, AC and Trp, the three compounds can well separate from each other with potential differences of 200, 330 and 530 mV between AA and AC, AC and Trp and AA and Trp, respectively, which was large enough to determine AA, AC and Trp individually and simultaneously.

Topics: Acetaminophen; Ascorbic Acid; Beverages; Caffeic Acids; Catalysis; Dielectric Spectroscopy; Electrochemical Techniques; Electrodes; Nanotubes, Carbon; Oxidation-Reduction; Tablets; Tryptophan

Grafting technique is increasingly being employed in order to obtain high production in difficult soils and to reduce chemical application. The present experimental work addressed the effect of grafting of tomato, cv. "Profitto" (P), on to the rootstocks "Beaufort" (B) and "Big Power" (BP) on fruit quality. Both fruit left to ripen on the plant and fruit stored at low temperature (4 °C) were included in the quality assessment.. Vitamin C and fructose content decreased in B and BP in fruits stored at 4 °C, whereas fruits ripened on the plant showed higher sugar concentrations. The free phenolic acids extracted were identified as caffeic acid, p-coumaric acid, chlorogenic acid and ferulic acid. Higher antioxidant compound content was consistently shown by P. Cold storage conditions caused a higher phenolic acid production due to the increase of ferulic acid. Compared with ripening on the plant, percentage differences ranged between 14.3% (caffeic acid) and 12.5% (p-coumaric and chlorogenic acids). Total phenol content was also affected by maturation, showing higher values in fruits ripened on the plant than under cold storage conditions.. It was possible to observe a significant relationship between tomato fruit quality and grafting and relevant differences in fruit ripening conditions.

Topics: Agriculture; Antioxidants; Ascorbic Acid; Caffeic Acids; Chlorogenic Acid; Cold Temperature; Coumaric Acids; Diet; Food Quality; Food Storage; Fructose; Fruit; Humans; Phenols; Plant Development; Plant Roots; Propionates; Solanum lycopersicum; Species Specificity

Phytochemical analysis of lyophilised aqueous extract of the stem bark of Scutia buxifolia (SBSB) was carried out by determining total phenolics (0.280 ± 0.02 mg of gallic acid equivalents/g of extract), flavonoids (17.42 ± 2.95 mg of quercetin equivalents/g of extract) and tannins (1.28 ± 0.15 mg of catechin equivalents/g of extract) contents followed by a high-performance liquid chromatography/diode array detection (HPLC/DAD) analysis. The HPLC profile showed caffeic acid, being the major constituent of SBSB (247.21 ± 2.17 mg g⁻¹ of extract). The antioxidant scavenging capacity of SBSB was determined by 2,2-diphenyl-2-picrylhydrazyl (DPPH) assay. The antioxidant power of SBSB was comparable with that of the antioxidant ascorbic acid. Acute toxicity was assayed in rats whereas catalase activity and malondialdehyde production were determined in rats' liver. The SBSB showed safety in the dose tested. This report is the first realised in animals for S. buxifolia.

Topics: Animals; Antioxidants; Ascorbic Acid; Caffeic Acids; Catechin; Chromatography, High Pressure Liquid; Flavonoids; Liver; Phenols; Plant Bark; Plant Extracts; Plant Stems; Rats; Rhamnaceae; Tannins

5-Caffeoylquinic acid (5-CQA) is generally referred to as chlorogenic acid and exhibits various biological activities such as antioxidant activity and porcine pancreas α-amylase inhibitory activities. 5-CQA may be useful as an antioxidant for food and to prevent diabetes and obesity. The degradation of 5-CQA and caffeic acid (CA) in an aqueous solution at 37 °C and pH 5.0-9.0 was studied. The degradation of 5-CQA and CA, demonstrating time and pH dependence (i.e., the rate constant, k, was higher at higher pH), was satisfactorily described by the Weibull equation. The stability of 5-CQA at pH 7.4 and 9.0 was improved by adding (-)-epigallocatechin gallate (EGCG) and ascorbic acid (AA). Moreover, the degradation of 5-CQA in the presence of EGCG or AA could be described by the Weibull equation. The k value in the presence of EGCG or AA was dependent on their concentration.

Topics: Ascorbic Acid; Caffeic Acids; Catechin; Chlorogenic Acid; Drug Stability; Hydrogen-Ion Concentration; Kinetics; Quinic Acid

The present study evaluated the antioxidant (AA), antimicrobial and preservation effects of five plant derived natural products viz., Rosmarinic Acid (RA), p-Coumaric Acid (pCA), Trans-Cinnamic Acid (TCA), Hydroxyphenyllactic Acid (HPA) and Caffeic acid (CA) along with synthetic compounds (Ascorbic acid, gallic acid, citric acid and BHA) on fresh cut apple slices. Antimicrobial efficacy of these compounds against Bacillus licheniformis, Pseudomonas vulgaris, Shigella boydii, Salmonella typhi, Staphylococcus aureus, Listeria monocytogenes and Escherichia coli was found to be concentration dependent with the maximum inhibition observed at 500 microg mL(-1). A considerable AA potential of these compounds was observed in in vitro based assay system, with RA exhibiting significantly higher effect than the other compounds at 500 microg mL(-1). Furthermore the compounds at 500 microg mL(-1) significantly reduced the browning, maintained the acidic pH and restricted growth of L. monocytogenes even after 10 days of treatment. Ethanol accumulation in fresh cut apple slices increased significantly throughout the experimental period. Over all RA exhibited maximum effect in all the food preservation parameters studied suggesting that it has synchronized food protection effect and can be recommended as food additive.

Topics: Anti-Infective Agents; Antioxidants; Ascorbic Acid; Biological Products; Butylated Hydroxyanisole; Caffeic Acids; Cinnamates; Citric Acid; Coumaric Acids; Depsides; Ethanol; Food Preservatives; Fruit; Gallic Acid; Hydrogen-Ion Concentration; Listeria monocytogenes; Malus; Propionates; Rosmarinic Acid

Low positive temperature (chilling) is frequently linked to the promotion of oxidative stress conditions, and is of particular importance in the coffee plant due to its severe impact on growth, development, photosynthesis and production. Nevertheless, some acclimation ability has been reported within the Coffea genus, and is possibly related to oxidative stress control. Using an integrated biochemical and molecular approach, the characterization of the antioxidative system of genotypes with different cold acclimation abilities was performed. Experiments were carried out using 1.5-year-old coffee seedlings of Coffea canephora cv. Apoatã, C. arabica cv. Catuaí, C. dewevrei and 2 hybrids, Icatu (C. arabicaxC. canephora) and Piatã (C. dewevreixC. arabica) subjected to a gradual cold treatment and a recovery period. Icatu showed the greatest ability to control oxidative stress, as reflected by the enhancement of several antioxidative components (Cu,Zn-SOD and APX activities; ascorbate, alpha-tocopherol and chlorogenic acids (CGAs) contents) and lower reactive oxygen species contents (H(2)O(2) and OH). Gene expression studies show that GRed, DHAR and class III and IV chitinases might also be involved in the cold acclimation ability of Icatu. Catuaí showed intermediate acclimation ability through the reinforcement of some antioxidative molecules, usually to a lesser extent than that observed in Icatu. On the other hand, C. dewevrei showed the poorest response in terms of antioxidant accumulation, and also showed the greatest increase in OH values. The difference in the triggering of antioxidative traits supports the hypothesis of its importance to cold (and photoinhibition) tolerance in Coffea sp. and could provide a useful probe to identify tolerant genotypes.

Topics: Acclimatization; alpha-Tocopherol; Antioxidants; Ascorbate Peroxidases; Ascorbic Acid; Caffeic Acids; Catalase; Coffea; Cold Temperature; Genotype; Oxidative Stress; Peroxidases; Polymerase Chain Reaction; Reactive Oxygen Species; Superoxide Dismutase

Myocardial infarction affects a large population in the world. Lipid peroxide metabolism plays an important role in the pathology of myocardial infarction. This study aims to evaluate the preventive effect of caffeic acid on lipid peroxides, antioxidants, cardiac marker enzymes, and histopathological findings in isoproterenol (ISO)-induced myocardial-infarcted male Wistar rats. Myocardial infarction was induced in rats by subcutaneous injection of ISO (100 mg/kg) at an interval of 24 hours for 2 days. The ISO-induced rats showed significant increase in the levels of thiobarbituric acid reactive substances, lipid hydroperoxides in the heart, plasma uric acid, and serum cardiac marker enzymes, and significant decrease in the activities of heart superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, and the levels of reduced glutathione, vitamin E, and vitamin C in the plasma and heart. Oral pretreatment with caffeic acid (15 mg/kg) daily for 10 days showed significant decrease in the levels of serum cardiac marker enzymes, heart lipid peroxidation products and plasma uric acid and significant increase in the levels of antioxidant system. Histopathology of myocardium also confirmed the protective effect of caffeic acid in myocardial-infarcted rats. In vitro study on total antioxidant activity (2,2'-azinobis-[3-ethylbenzothiazoline-6-sulfonic acid](+) assay) confirmed the strong antioxidant action of caffeic acid. Thus, the present study revealed that caffeic acid ameliorates cardiac damage in ISO-induced myocardial infarction by maintaining lipid peroxide metabolism due to its free radical scavenging and antioxidant effects. A diet containing caffeic acid may be beneficial to myocardial infarction.

Topics: Animals; Ascorbic Acid; Biomarkers; Caffeic Acids; Isoproterenol; Lipid Peroxidation; Male; Myocardial Infarction; Myocardium; Rats; Rats, Wistar; Uric Acid; Vitamin E

In an emulsion of corn oil in water with the addition of caffeic acid (Caf-OH) and alpha-tocopherol (alpha-TOH), Caf-OH was found to be very active in delaying lipid oxidation without affecting significantly the kinetics for alpha-TOH degradation. In contrast, Caf-OH addition to fish muscle retarded both the degradation of endogenous alpha-TOH and the propagation of lipid oxidation, measured by peroxide value (PV) and thiobarbituric acid reactive substances (TBARS), with increasing effect with increasing Caf-OH addition (55.5-555.1 micromol/kg). Electron spin resonance (ESR) spectroscopy confirmed a higher capacity of Caf-OH to regenerate alpha-TOH via reduction of the alpha-tocopheroxyl radical compared to other cinnamic acid derivatives (o-coumaric, ferulic, and chlorogenic acids). Degradation of endogenous ascorbate (AscH(-)) was accelerated at higher concentration of Caf-OH in fish tissue, suggesting a role of AscH(-) in the regeneration of Caf-OH. These results indicate that the antioxidant mechanism of Caf-OH implies the protection of endogenous alpha-TOH localized in tissue membranes where lipid oxidation is initiated and, at the same time, Caf-OH regeneration by the endogenous AscH(-). These combined effects result in a stronger antioxidant protection against lipid oxidation by favoring, as a final point, the protection of alpha-TOH, which is suggested as the last defense of fish muscle against lipid oxidation.

Topics: alpha-Tocopherol; Animals; Antioxidants; Ascorbic Acid; Caffeic Acids; Drug Synergism; Fishes; Lipid Peroxidation; Muscle, Skeletal; Oxidation-Reduction

High levels of oxidative stress were reported in obesity-linked type 2 diabetes and were associated with elevated formation of advanced glycation end products (AGEs). Many studies have focused on the effect of antioxidants on vascular and circulating cells such as macrophages. However, despite the major role of adipocytes in the etiology of diabetes, little is known about the effect of natural antioxidants on adipocyte response to oxidative stress. The present study reports the differential protective effects of plant nutrients toward adipose cells subjected to oxidative stress. Caffeic acid, quercetin, L: -ascorbic acid, and alpha-tocopherol were tested on SW872 liposarcoma cells subjected to a free radical generator or to AGEs. Proliferation, viability, free radical formation, and superoxide dismutase expression were assessed in treated cells. Caffeic acid and quercetin appeared as the most potent antioxidant nutrients. Our findings clearly show a novel antioxidant role for caffeic acid and quercetin at the adipose tissue level. These new data confirm the beneficial role of phytotherapy as an interesting alternative mean for the development of novel therapeutical and nutritional strategy to prevent metabolic disorders inherent to obesity-linked diabetes.

Topics: Adipocytes; Amidines; Animals; Antioxidants; Ascorbic Acid; Caffeic Acids; Cattle; Cell Line; Cell Proliferation; Cell Survival; Diabetes Mellitus, Type 2; Free Radicals; Glycation End Products, Advanced; Humans; Obesity; Oxidants; Oxidative Stress; Phytotherapy; Quercetin; Serum Albumin, Bovine; Superoxide Dismutase; Tocopherols; Up-Regulation

Bee products (including propolis, royal jelly, and bee pollen) are popular, traditional health foods. We compared antioxidant effects among water and ethanol extracts of Brazilian green propolis (WEP or EEP), its main constituents, water-soluble royal jelly (RJ), and an ethanol extract of bee pollen.. The hydrogen peroxide (H2O2)-, superoxide anion (O2.-)-, and hydroxyl radical (HO.)- scavenging capacities of bee products were measured using antioxidant capacity assays that employed the reactive oxygen species (ROS)-sensitive probe 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate, acetyl ester (CM-H2DCFDA) or aminophenyl fluorescein (APF).. The rank order of antioxidant potencies was as follows: WEP > EEP > pollen, but neither RJ nor 10-hydroxy-2-decenoic acid (10-HDA) had any effects. Concerning the main constituents of WEP, the rank order of antioxidant effects was: caffeic acid > artepillin C > drupanin, but neither baccharin nor coumaric acid had any effects. The scavenging effects of caffeic acid were as powerful as those of trolox, but stronger than those of N-acetyl cysteine (NAC) or vitamin C.. On the basis of the present assays, propolis is the most powerful antioxidant of all the bee product examined, and its effect may be partly due to the various caffeic acids it contains. Pollen, too, exhibited strong antioxidant effects.

Topics: Acetylcysteine; Animals; Ascorbic Acid; Bees; Caffeic Acids; Chromans; Cinnamates; Coumaric Acids; Fatty Acids; Fatty Acids, Monounsaturated; Free Radical Scavengers; Phenylpropionates; Plant Extracts; Pollen; Propolis; Quinic Acid; Trichothecenes

A new strategy to evaluate accessibility of antioxidants to radical proteins has been developed using nitroxide prefluorescent probes anchored into human serum albumin (HSA). Binding association constants for the nitroxide probes C(343)T and QT with HSA were 5 x 10(4) and 9 x 10(4)M(-1), respectively. Rate constants for the nitroxide reduction by antioxidants in HSA were determined finding k(HSA)/k(buffer) ratio of 0.8, 1.9, and 0.075 for ascorbic acid, Trolox, and caffeic acid, respectively, for the nitroxide C(343)T reduction.

Topics: Albumins; Anaerobiosis; Antioxidants; Ascorbic Acid; Caffeic Acids; Humans; Nitric Oxide; Serum Albumin; Thermodynamics

In the paper, a new kind of vitamin B(12) (acquo-cobalamine) chemically modified electrode was fabricated and applied in capillary zone electrophoresis coupled with amperometric detection (CZE-AD) for simultaneous determination of six antioxidants in fruits and vegetables. The catalytic electrochemical properties of the chemically modified electrode could obviously enhance oxidation peak heights responses by about five times to glutathione, ascorbic acid, vanillic acid, chlorogenic acid, salicylic acid, and caffeic acid compared with common carbon disk electrode. Furthermore, the effects of working electrode potential, pH and concentration of running buffer, separation voltage and injection time on CZE-AD were investigated. Under the optimum conditions, the six analytes could be completely separated and detected in a borate-phosphate buffer (pH 8.4) within 15 min. Their linear ranges were from 2.5x10(-7) to 1.0x10(-4) mol L(-1) and the detection limits were as low as 10(-8) mol L(-1) magnitude (S/N=3). The proposed method has been successfully employed to monitor the six analytes in practical samples with recoveries in the range 96.0-106.0% and RSDs less than 5.0%. Above results demonstrate that capillary zone electrophoresis coupled with electrochemical detection using vitamin B(12) modified electrode as detector is of convenient preparation, high sensitivity, good repeatability, and could be used in the rapid determination of practical samples.

Topics: Antioxidants; Ascorbic Acid; Caffeic Acids; Chlorogenic Acid; Citrus sinensis; Electrochemistry; Electrodes; Electrophoresis, Capillary; Glutathione; Hydrogen-Ion Concentration; Oxidation-Reduction; Reproducibility of Results; Salicylates; Solanum lycopersicum; Vanillic Acid; Vitamin B 12

The rate of ascorbate and nicotinamide adenine dinucleotide plus hydrogen (NADH) cooxidation (i.e., their nonenzymic oxidation by peroxidase/H2O2-generated phenoxyl radicals of three hydroxycinnamates: caffeate, ferulate and p-coumarate) was studied in vitro. The reactions initiated by different sources of peroxidase (EC 1.11.1.7) [isolates from soybean (Glycine max L.) seed coat, maize (Zea mays L.) root-cell wall, and commercial horseradish peroxidase] were monitored. Native electrophoresis of samples and specific staining for peroxidase activity revealed various isoforms in each of the three enzyme sources. The peroxidase sources differed both in the rate of H2O2-dependent hydroxycinnamate oxidation and in the order of affinity for the phenolic substrates. The three hydroxycinnamates did not differ in their ability to cooxidize ascorbate, whereas NADH cooxidation was affected by substitution of the phenolic ring. Thus, p-coumarate was more efficient than caffeate in NADH cooxidation, with ferulate not being effective at all. Metal ions (Zn2+ and Al3+) inhibited the reaction of peroxidase with p-coumarate and affected the cooxidation rate of ascorbate and the peroxidase reaction in the same manner with all substrates used. However, inhibition of p-coumarate oxidation by metal ions did not affect NADH cooxidation rate. We propose that both the ascorbate and NADH cooxidation systems can function as mechanisms to scavenge H2O2 and regenerate phenolics in different cellular compartments, thus contributing to protection from oxidative damage.

Topics: Ascorbic Acid; Caffeic Acids; Coumaric Acids; Glycine max; Hydrogen Peroxide; NAD; Oxidation-Reduction; Peroxidases; Phenols; Propionates; Zea mays

The objective of this study was to understand the respective impact of ripening stage, temperature, and irradiance on seasonal variations of tomato fruit quality. During ripening, concentrations in reducing sugars, carotenes, ascorbate, rutin, and caffeic acid derivates increased, whereas those in titratable acidity, chlorophylls, and chlorogenic acid content decreased. Fruit temperature and irradiance affected final fruit composition. Sugars and acids (linked to fruit gustative quality) were not considerably modified, but secondary metabolites with antioxidant properties were very sensitive to fruit environment. Increased fruit irradiance enhanced ascorbate, lycopene, beta-carotene, rutin, and caffeic acid derivate concentrations and the disappearance of oxidized ascorbate and chlorophylls. Increasing the temperature from 21 to 26 degrees C reduced total carotene content without affecting lycopene content. A further temperature increase from 27 to 32 degrees C reduced ascorbate, lycopene, and its precursor's content, but enhanced rutin, caffeic acid derivates, and glucoside contents. The regulation by light and temperature of the biosynthesis pathways of secondary metabolites is discussed.

Topics: Antioxidants; Ascorbic Acid; Caffeic Acids; Carbohydrates; Carotenoids; Chlorogenic Acid; Food Irradiation; Nutritive Value; Rutin; Seasons; Solanum lycopersicum; Temperature; Time Factors

Nitrite may be a source for nitric oxide (*NO), particularly in highly acidic environments, such as the stomach. Diet products contribute also with reductants that dramatically increase the production of *NO from nitrite. Red wine has been attributed health promoting properties largely on basis of the reductive antioxidant properties of its polyphenolic fraction. We show in vitro that wine, wine anthocyanin fraction and wine catechol (caffeic acid) dose- and pH-dependently promote the formation of *NO when mixed with nitrite, as measured electrochemically. The production of *NO promoted by wine from nitrite was substantiated in vivo in healthy volunteers by measuring *NO in the air expelled from the stomach, following consumption of wine, as measured by chemiluminescence. Mechanistically, the reaction involves the univalent reduction of nitrite, as suggested by the formation of *NO and by the appearance of EPR spectra assigned to wine phenolic radicals. Ascorbic and caffeic acids cooperate in the reduction of nitrite to *NO. Moreover, reduction of nitrite is critically dependent on the phenolic structure and nitro-derivatives of phenols are also formed, as suggested by caffeic acid UV spectral modifications. The reduction of nitrite may reveal previously unrecognized physiologic effects of red wine in connection with *NO bioactivity.

Topics: Antioxidants; Ascorbic Acid; Caffeic Acids; Diet; Electron Spin Resonance Spectroscopy; Flavonoids; Gastric Mucosa; Humans; Nitric Oxide; Nitrites; Nitrogen Oxides; Phenols; Polyphenols; Spectrophotometry, Ultraviolet; Wine

A stable electroactive thin film of poly(caffeic acid) has been deposited on the surface of a glassy carbon electrode by potentiostatic technique in an aqueous solution containing caffeic acid. Poly(caffeic acid) was used as a modified electrode for the detection of ascorbic acid (AA), epinephrine (EP), uric acid (UA) and their mixture by cyclic voltammetry. This modified electrode exhibits potent and persistent electron-mediating behavior followed by well-separated oxidation peaks towards AA, EP and UA with activation overpotential. For the ternary mixture containing AA, EP and UA, the three compounds can well separate from each other at the scan rate of 20 mVs(-1) with a potential difference of 156, 132 and 288 mV between AA and EP, EP and UA and AA and UA, respectively, which was large enough to determine AA, EP and UA individually and simultaneously. The catalytic peak current obtained, was linearly dependent on the AA, EP and UA concentrations in the range of 2.0 x 10(-5) to 1.0 x 10(-3) mol l(-1), 2.0 x 10(-6) to 8.0 x 10(-5) mol l(-1) and 5.0 x 10(-6) to 3.0 x 10(-4) mol l(-1), and the detection limits for AA, EP and UA were 7.0 x 10(-6), 2.0 x 10(-7) and 6.0 x 10(-7) mol l(-1), respectively. The modified electrode shows good sensitivity, selectivity and stability, and has been applied to the determination of EP in practical injection samples and that of EP, UA and AA simultaneously with satisfactory results.

Topics: Ascorbic Acid; Biosensing Techniques; Caffeic Acids; Carbon; Coated Materials, Biocompatible; Complex Mixtures; Electrochemistry; Epinephrine; Glass; Microelectrodes; Uric Acid

The polyphenolic and ascorbate (ASC) components as well as the antioxidant capacity of Kei-apple (Dovyalis caffra) juice were analyzed and compared to three other fruit juices. The Kei-apple juice had significantly the highest total polyphenolic concentrations (1013 mg gallic acid equivalent/L), and solid phase (C(18)) fractionation identified the majority of these polyphenols to be phenolic acids. The Kei-apple juice also had significantly the highest ASC concentrations (658 mg/L), which showed exceptional heat stability with very little conversion to dehydroascorbate (DHA). Antioxidant capacities of both the unfractionated fruit juices and their solid phase-extracted fractions, as determined by oxygen radical absorbance capacity and ferric reducing antioxidant power analyses, correlated well to the polyphenol concentrations. Gas chromatography-mass spectrometry analyses showed caffeic acid as the most abundant polyphenol present (128.7 mg/L) in the Kei-apple juice; it contributed to 63% of the total antioxidant capacity (of all of the individual compounds identified). Other notable polyphenols identified in higher concentrations included p-coumaric acid, p-hydroxyphenylacetic acid, and protocatechuic acid. Our results therefore support the putative high antioxidant value linked to this fruit and better define this potential in terms of the major antioxidants that exist in the Kei-apple.

Topics: Antioxidants; Ascorbic Acid; Beverages; Caffeic Acids; Drug Stability; Flavonoids; Fruit; Gallic Acid; Gas Chromatography-Mass Spectrometry; Hot Temperature; Phenols; Polyphenols; Reactive Oxygen Species; Salicaceae

Assessment of the antioxidant activity of vitamins and other compounds is of interest in the understanding of their in vivo effects. In this study, we have investigated the activity of several lipid and water-soluble vitamins in human whole blood. Measurements were carried out using a biological test that enables the evaluation of both red blood cells and plasma resistance against free radical activity induced by 2,2'-azobis (2-amidinopropane)hydrochloride (AAPH). Antioxidant activity of vitamins has been determined by using the biological test versus chemical methods (chemiluminescence, DMPD radical). We have observed strong anti-oxidant potentials for vitamins B6 and B9 with biological tests, but not with chemical methods. At 10 microM, the vitamin B9 efficiency in inhibiting radical-induced red blood cell hemolysis was almost three times higher than vitamin C efficiency and two times higher than alpha-tocopherol efficiency. Antioxidant activity was not observed for vitamins B1 or B2, nor for retinol. The weak activity of beta-carotene still remains to be investigated particularly in relation to oxygen pressure. Our study demonstrated that the biological test is more useful than the chemical methods employed in this instance, for the evaluation of antioxidant capacity of lipophilic and putatively biologically active compounds.

Topics: alpha-Tocopherol; Amidines; Antioxidants; Ascorbic Acid; beta Carotene; Biological Assay; Caffeic Acids; Dose-Response Relationship, Drug; Fluorescent Dyes; Hemolysis; Humans; Luminescent Measurements; Oxidants; Phenylenediamines; Reference Values; Solubility; Vitamin A; Vitamin B Complex; Vitamins

Natural occurrence of yellow mosaic disease was observed on bitter gourd (Momordica charantia). Association of geminivirus with the disease was investigated through polymerase chain reaction using geminivirus-specific primers and Southern hybridization with a probe prepared from the cloned DNA of a known geminivirus. The fruits, leaves and stem of infected and healthy plants were studied for phytochemical composition. The amounts of protein were 49%, 50% and 66% higher, total carotenoids were 36%, 33% and 40% lower, vitamin C were 23%, 48% and 50% lower, total phenols were 28%, 31% and 43% lower, and antioxidant activity were 36%, 48% and 43% lower in the severely virus infected fruits, leaves and stem, respectively, as compared with healthy plants. The loss in the quantity of these phytochemicals was also observed even in mild infected plants, which further increased with the severity of the symptoms. Similarly, ethanol and 50% ethanol soluble extractive were also 25-43% lower in the fruits, leaves and stem of infected plants as compared with the healthy plants. A 45% and 54% lower caffeic acid, and 78% and 59% lower amounts of ferulic acid in the fruits and stem, respectively, and a 25% loss of gallic acid were noticed in the leaves of the severely infected plants.

Topics: Antioxidants; Ascorbic Acid; Blotting, Southern; Caffeic Acids; Carotenoids; Chromatography, High Pressure Liquid; Coumaric Acids; Ethanol; Free Radical Scavengers; Gallic Acid; Momordica charantia; Phenols; Plant Diseases; Plant Leaves; Plant Proteins; Plant Stems; Polymerase Chain Reaction

To establish a method for screening active substance with scavenging effects on superoxide anion in vitro by designed superoxide dismutase biosensor.. The enzyme sensor was built by connecting the immobilized CuZnSOD with optical oxygen sensor through a special way. Superoxide anions were generated by auto-oxidation of pyrogallol. The auto-oxidation speed was examined before and after adding samples into the system, and the Vit C having the scavenging radical activities was served as a positive control.. The limit of biosensor detection was 7.0 U in activity, and lifetime of the immobilized enzyme in the reaction-cell was above 2 weeks. The scavenging effects on superoxide radicals of fifteen active substance were studied in vitro by the sensor, and some of them presented scavenging activities.. The signal from biosensor is stable, easy to be determined, and the kinetic information on scavenging superoxide radicals could be obtained directly. The biosensor system can be used for screening drugs simply and rapidly.

Topics: Ascorbic Acid; Benzaldehydes; Biosensing Techniques; Caffeic Acids; Enzymes, Immobilized; Free Radical Scavengers; Pyrogallol; Superoxide Dismutase

Phenolic compounds, vitamin C (L-ascorbic acid and L-dehydroascorbic acid), and antioxidant capacity were evaluated in orange juices manufactured by different techniques. Five processes at industrial scale (squeezing, mild pasteurization, standard pasteurization, concentration, and freezing) used in commercial orange juice manufacturing were studied. In addition, domestic squeezing (a hand processing technique) was compared with commercial squeezing (an industrial FMC single-strength extraction) to evaluate their influences on health components of orange juice. Whole orange juice was divided into soluble and cloud fractions after centrifugation. Total and individual phenolics were analyzed in both fractions by HPLC. Commercial squeezing extracted 22% more phenolics than hand squeezing. The freezing process caused a dramatic decrease in phenolics, whereas the concentration process caused a mild precipitation of these compounds to the juice cloud. In pulp, pasteurization led to degradation of several phenolic compounds, that is, caffeic acid derivatives, vicenin 2 (apigenin 6,8-di-C-glucoside), and narirutin (5,7,4'-trihydroxyflavanone-7-rutinoside) with losses of 34.5, 30.7, and 28%, respectively. Regarding vitamin C, orange juice produced by commercial squeezing contained 25% more of this compound than domestic squeezing. Mild and standard pasteurization slightly increased the total vitamin C content as the contribution from the orange solids parts, whereas concentration and freezing did not show significant changes. The content of L-ascorbic acid provided 77-96% of the total antioxidant capacity of orange juice. Mild pasteurization, standard pasteurization, concentration, and freezing did not affect the total antioxidant capacity of juice, but they did, however, in pulp, where it was reduced by 47%.

Topics: Antioxidants; Apigenin; Ascorbic Acid; Beverages; Caffeic Acids; Centrifugation; Chemical Precipitation; Chromatography, High Pressure Liquid; Citrus; Coumaric Acids; Flavonoids; Food Handling; Food-Processing Industry; Freezing; Glucosides; Luteolin; Phenols

As a powerful natural antioxidant, lipoic acid exerts significant antioxidant activities in vivo and in vitro by deactivation of reactive oxygen and nitrogen species. In this study we present a novel synergistic interaction of lipoic acid with other endogenous or exogenous antioxidants. Antioxidants vitamins C and E analogue (Trolox C) and hydroxycinnamic acid derivatives were found to recycle lipoic acid by donating electrons to lipoic acid radical cations, thereby increasing the antioxidant capacity of lipoic acid in vivo and in vitro. The rate constant of the electron transfer is in the order 10(9)dm(3)mol(-1)s(-1), close to the diffusion-controlled limit, and transfer quantum yield is above 95%.

Topics: Ascorbic Acid; Caffeic Acids; Chlorogenic Acid; Coumaric Acids; Free Radicals; Kinetics; Molecular Structure; Particle Accelerators; Structure-Activity Relationship; Thioctic Acid; Vitamin E

A number of natural phenolic compounds display antioxidant and cell protective effects in cell culture models, yet in some studies show prooxidant and cytotoxic effects. Pancreatic beta-cells have been reported to exhibit particular sensitivity to oxidative stress, a factor that may contribute to the impaired beta-cell function characteristic of diabetes. The aim of this study was to examine the potential of natural phenolics to protect cultured pancreatic beta-cells (betaTC1 and HIT) from H(2)O(2) oxidative stress. Exposure of cells to H(2)O(2) led to significant proliferation inhibition. Contrary to what one should expect, simultaneous exposure to H(2)O(2) and the phenolics, quercetin (10-100 microM), catechin (50-500 microM), or ascorbic acid (100-1000 microM), led to amplification of proliferation inhibition. At higher concentrations, these compounds inhibited proliferation, even in the absence of added H(2)O(2). This prooxidant effect is attributable to the generation of H(2)O(2) through interaction of the added phenolic compounds with as yet undefined componenets of the culture media. On the other hand, inclusion of metmyoglobin (30 microM) in the culture medium significantly reduced the prooxidant impact of the phenolics. Under these conditions, quercetin and catechin significantly protected the cells against oxidative stress when these components were present during the stress period. Furthermore, significant cell protection was observed upon preincubation of cells with chrysin, quercetin, catechin, or caffeic acid (50 microM, each) prior to application of oxidative stress. It is concluded that provided artifactual prooxidant effects are avoided, preincubation of beta-cells with relatively hydrophobic natural phenolics can confer protection against oxidative stress.

Topics: Animals; Antioxidants; Ascorbic Acid; Caffeic Acids; Catechin; Cell Division; Cell Line; Flavonoids; Hydrogen Peroxide; Islets of Langerhans; Lipid Peroxidation; Metmyoglobin; Mice; Oxidants; Oxidative Stress; Phenols; Quercetin

The protective effect of fruits and vegetables against cancer is well established. It is believed that this effect is mediated by antioxidants and decreased oxidative damage to DNA. However, the identity of the antioxidant(s) responsible is not clear. Moreover, a potentially damaging pro-oxidant effect of some antioxidants has been reported. In this study the ex vivo effects of several dietary antioxidants, including quercetin, various catechins, ascorbic acid and alpha-tocopherol, were investigated, at concentrations up to 200 microM, using the single cell gel electrophoresis (comet) assay for DNA damage. Lymphocytes from three healthy subjects were pre-incubated with these antioxidants, and the comet assay was performed on treated, untreated, challenged and unchallenged cells in parallel, oxidant challenge being induced by 5 min exposure to hydrogen peroxide (final concentrations H2O2: 30, 45, or 60 microM). Results using this ex vivo cellular assay showed protection by some antioxidants (quercetin, caffeic acid), no effect by some (catechin, epicatechin, catechin gallate, epicatechin gallate) and an apparently damaging effect by others (epigallocatechin, epigallocatechin gallate). Damage may have been caused by production of H2O2 from these polyphenolics. Neither ascorbic acid nor alpha-tocopherol protected or damaged DNA. Further study of the role of quercetin and caffeic acid in DNA protection is needed.

Topics: alpha-Tocopherol; Antioxidants; Ascorbic Acid; Caffeic Acids; Catechin; Cells, Cultured; Comet Assay; DNA; DNA Damage; Dose-Response Relationship, Drug; Female; Free Radical Scavengers; Humans; Hydrogen Peroxide; Lymphocytes; Male; Oxidative Stress; Quercetin; Time Factors

The inhibitory activity of berberine on the DNA single-strand cleavage induced by hydrogen peroxide and cytochrome c was measured. Berberine effectively inhibited single-strand cleavage of DNA and its effectiveness was concentration-dependent. As the berberine concentration increased, the inhibitory activity against the DNA single-strand cleavage increased. The treatments with 1, 5, 10, 50, and 100 microM berberine showed 7.7, 10.8, 32.2, 39.5, and 51.6% inhibition of DNA cleavage. This inhibitory activity of berberine against the DNA single-strand cleavage has never been reported previously. The inhibitory activity of berberine against DNA cleavage was stronger than caffeic acid and ascorbic acid. Berberine did not show strong hydroxyl radical scavenging activity, but showed strong superoxide anion radical quenching ability.

Topics: Antioxidants; Ascorbic Acid; Berberine; Caffeic Acids; Cytochrome c Group; DNA Damage; DNA, Bacterial; Free Radical Scavengers; Hydrogen Peroxide; Oxygen; Singlet Oxygen

Topics: Ascorbic Acid; Caffeic Acids; Chromatography, High Pressure Liquid; Humans; Lipid Peroxidation; Lipoproteins, LDL; Oxidation-Reduction; Spectrum Analysis; Vitamin E

Given the paradoxical effects of phenolics in oxidative stress, we evaluated the relative pro-oxidant and antioxidant properties of four natural phenolic compounds in DNA nicking. The phenolic compounds differed dramatically in their ability to nick purified supercoiled DNA, with the relative DNA nicking activity in the order: 1,2,4-benzenetriol (100% nicking) > gallic acid > caffeic acid > gossypol (20% nicking). Desferrioxamine (0.02 mM) decreased DNA strand breakage by each phenolic, most markedly with gallate (85% protection) and least with caffeic acid (26% protection). Addition of metals accelerated DNA nicking, with copper more effective (approximately 5-fold increase in damage) than iron with all four phenolics. Scavengers revealed the participation of specific oxygen-derived active species in DNA breakage. Hydrogen peroxide participated in all cases (23-90%). Hydroxyl radicals were involved (32-85%), except with 1,2,4-benzenetriol. Superoxide participated (81-86%) with gallic acid and gossypol, but not with caffeic acid or 1,2,4-benzenetriol. With 1,2,4-benzenetriol, scavengers failed to protect significantly except in combination. Thus, in the presence of desferrioxamine, catalase or superoxide dismutase inhibited almost completely. When DNA breakage was induced by Fenton's reagent (ascorbate plus iron) the two catechols (caffeic acid and gossypol) were protective, whereas the two triols (1,2,4-benzenetriol and gallic acid) exacerbated damage.

Topics: Antioxidants; Ascorbic Acid; Caffeic Acids; Chelating Agents; Copper; Deferoxamine; DNA Damage; DNA, Superhelical; Electrophoresis, Agar Gel; Free Radical Scavengers; Gallic Acid; Gossypol; Hydroquinones; Iron; Mutagens; Oxidants; Oxidation-Reduction; Phenols

This study addresses the dynamic interactions among alpha-tocopherol, caffeic acid, and ascorbate in terms of a sequence of redox cycles aimed at accomplishing optimal synergistic antioxidant protection. Several experimental models were designed to examine these interactions: UV irradiation of alpha-tocopherol-containing sodium dodecyl sulfate micelles, one-electron oxidations catalyzed by the hypervalent state of myoglobin, ferrylmyoglobin, and autoxidation at appropriate pHs. These models were assessed by ultraviolet (UV) and electron paramagnetic resonance (EPR), entailing direct- and continuous-flow experiments, spectroscopy and by separation and identification of products by HPLC. The alpha-tocopheroxyl radical EPR signal generated by UV irradiation of alpha-tocopherol-containing micelles was suppressed by caffeic acid and ascorbate; in the former case, no other EPR signal was observed at pH 7.4, whereas in the latter case, the alpha-tocopheroxyl radical EPR signal was replaced by a doublet EPR spectrum corresponding to the ascorbyl radical (A*-). The potential interactions between caffeic acid and ascorbate were further analyzed by assessing, on the one hand, the ability of ascorbate to reduce the caffeic acid o-semiquinone (generated by oxidation of caffeic acid by ferrylmyoglobin) and, on the other hand, the ability of caffeic acid to reduce ascorbyl radical (generated by autoxidation or oxidation of ascorbate by ferrylmyoglobin). The data presented indicate that the reductive decay of ascorbyl radical (A*-) and caffeic acid o-semiquinone (Caf-O*) can be accomplished by caffeic acid (Caf-OH) and ascorbate (AH-), respectively, thus pointing to the reversibility of the reaction Caf-O* + AH- <--> Caf-OH + A*-. Continuous-flow EPR measurements of mixtures containing ferrylmyoglobin, alpha-tocopherol-containing micelles, caffeic acid, and ascorbate revealed that ascorbate is the ultimate electron donor in the sequence encompassing transfer of the radical character from the micellar phase to the phase. In independent experiments, the effects of caffeic acid and ascorbate on the oxidation of two low-density lipoprotein (LDL) populations, control and alpha-tocopherol-enriched, were studied and results indicated that alpha-tocopherol, caffeic acid, and ascorbate acted synergistically to afford optimal protection of LDL against oxidation. These results are analyzed for each individual antioxidant in terms of three domains: its localization and that of the a

Topics: Ascorbic Acid; Caffeic Acids; Electron Spin Resonance Spectroscopy; Humans; Kinetics; Lipoproteins, LDL; Metmyoglobin; Micelles; Oxidation-Reduction; Ultraviolet Rays; Vitamin E

Two diet-derived phenolic acids, caffeic and p-coumaric acids, interplayed with ascorbate in the protection of low density lipoproteins (LDL) from oxidation promoted by ferrylmyoglobin. Ferrylmyoglobin, a two-electron oxidation product from the reaction of metmyoglobin and H2O2, was able to oxidize LDL, degrading free cholesterol and cholesteryl esters. Upon exposure to ferrylmyoglobin, LDL became rapidly depleted of cholesteryl arachidonate and linoleate, which turn into the corresponding hydroperoxides. Cholesteryl oleate and cholesterol were, comparatively, more resistant to oxidation. Caffeic (2 microM) and p-coumaric (12 microM) acids efficiently delayed oxidations, as reflected by an increase in the lag times required for linoleate hydroperoxide and 7-ketocholesterol formation as well as for cholesteryl linoleate consumption. At the same concentration, ascorbate, a standard water-soluble antioxidant, was less efficient than the phenolic acids. Additionally, phenolic acids afforded a protection to LDL that, conversely to ascorbate, extends along the time, as inferred from the high levels of cholesteryl linoleate and cholesteryl arachidonate left after 22 hr of oxidation challenging. Significantly, the coincubation of LDL with ascorbate and each of the phenolic acids resulted in a synergistic protection from oxidation. This was inferred from the lag phases of cholesteryl linoleate hydroperoxide (the major peroxide found in LDL) formation in the presence of mixtures of ascorbate with phenolic acids longer than the sum of individual lag phases of ascorbate and the phenolic acids. A similar description could be drawn for the accumulation of a late product of oxidation, 7-ketocholesterol. It is concluded that ferrylmyoglobin induces a typical pattern of LDL lipid peroxidation, the oxidation rate of cholesteryl esters being a function of unsaturation; furthermore, there is a synergistic antioxidant activity of diet-derived phenolic acids with ascorbate in the protection of LDL from oxidation, a finding of putative physiological relevance.

Topics: Animals; Ascorbic Acid; Caffeic Acids; Catalysis; Cholesterol; Cholesterol Esters; Coumaric Acids; Drug Synergism; Horses; Hydrolysis; Hydroxybenzoates; Lipoproteins, LDL; Metmyoglobin; Propionates

Ascorbate-dependent detoxification of hydrogen peroxide by guaiacol-type peroxidases is increased considerably in the presence of 3,4-dihydroxyphenolic compounds, suggesting that ascorbate is the natural substrate for many types of peroxidase in situ and not just the ascorbate-specific peroxidases. The ascorbate-dependent destruction of hydrogen peroxide in the more acidic cellular compartments such as the vacuole may be an important function of such non-specific peroxidases. The stress-induced production of phenolic compounds would render the guaiacol peroxidases in other less acidic-cellular sites effective as ascorbate-dependent H2O2-detoxifying enzymes.

Topics: Antibodies; Ascorbate Peroxidases; Ascorbic Acid; Caffeic Acids; Chlorogenic Acid; Electron Spin Resonance Spectroscopy; Electrophoresis, Polyacrylamide Gel; Horseradish Peroxidase; Hydrogen Peroxide; Isoelectric Focusing; Kinetics; Peroxidases; Phenols; Plants; Substrate Specificity; Tea

The character of reactive metabolites formed from carbamazepine (CBZ) was sought in incubations of [14C]CBZ in hepatic microsomes prepared from adult female mice of a strain (SWV/Fnn) susceptible to CBZ-induced teratogenicity. The formation of radio-labeled protein adducts was used as an index of reactive metabolite exposure. A dependence on cytochrome P450 was shown by a requirement for NADPH and inhibition by carbon monoxide, 1-aminobenzotriazole, piperonyl butoxide, and stiripentol. The addition of ascorbic acid, caffeic acid, N-acetylcysteine, and glutathione decreased the rate of binding of the radiolabel from [14C]CBZ to microsomal protein by more than 50%. The addition of glutathione transferases diminished protein adduct formation beyond that seen with glutathione alone. Evidence for the formation of an arene oxide was sought through the use of inhibitors of epoxide hydrolases, including cyclohexene oxide, chalcone oxides (with the addition of cytosol as appropriate), and by the addition of recombinant human soluble and microsomal epoxide hydrolases and recombinant rat microsomal epoxide hydrolase. The microsomal epoxide hydrolases decreased the velocity of 14C-labeled protein adduct formation by approximately 23%, whereas inhibitors had no effect, most likely because of the low native activity of microsomal epoxide hydrolase in mice. Both DT-diaphorase and catechol-O-methyltransferase diminished 14C-labeled protein adduct formation by 54% and 45%, respectively. The data suggest that the major reactive metabolites formed from CBZ by adult female SWV/Fnn liver microsomes are quinones and arene oxides.

Topics: Animals; Anticonvulsants; Ascorbic Acid; Caffeic Acids; Carbamazepine; Carbon Monoxide; Catechol O-Methyltransferase; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Dioxolanes; Enzyme Inhibitors; Epoxide Hydrolases; Female; Glutathione Transferase; Mice; Mice, Inbred Strains; Microsomes, Liver; NAD(P)H Dehydrogenase (Quinone); NADP; Piperonyl Butoxide; Sulfhydryl Compounds; Triazoles

The fluorescent polyunsaturated parinaric acid incorporated in LDL particles is highly sensitive to the concentration of peroxyl radicals in the aqueous medium, undergoing rapidly oxidative degradation, as detected by a quenching of fluorescence, without delay after radical generation in solution. Ascorbate, cysteine, and urate suppress the parinaric acid fluorescence decay promoted by peroxyl radicals generated at a constant rate (thermal decomposition of 2,2'-azo-bis(2-amidino-propane hydrochloride)) in a concentration-dependent manner. The chain-breaking efficiencies of these antioxidants are evaluated from the time interval (inhibition period) of parinaric acid protection from oxidative degradation. The results correlate with the inhibition periods of LDL oxidation as monitored by O2 consumption. Therefore, the sensitive and simple parinaric acid assay can be used as a semiquantitative screening test for the detection of potentially important water-soluble chain-breaking antioxidants. Conversely to O2 consumption, the absence of any initial lag phase of probe degradation attests to the sensitivity of the assay. An improved methodology based on second-derivative spectroscopy to follow the formation of conjugated diene isomers directly in the preparation without the need for lipid extraction also confirms the sensitivity of this assay. To assess the usefulness of parinaric acid assay, strong chain-breaking activities of caffeic and chlorogenic acids are reported.

Topics: Antioxidants; Ascorbic Acid; Caffeic Acids; Chlorogenic Acid; Fatty Acids, Unsaturated; Free Radicals; Humans; Kinetics; Lipid Peroxidation; Lipoproteins, LDL; Oxygen Consumption; Spectrometry, Fluorescence; Vitamin E

The effect of ascorbic, ferulic and caffeic acids on dimethylamine and amidopyrine nitrosation in a medium containing 3 samples of total gastric juice taken from 10 humans (pH = 6.1; 3.2 and 1.7) was studied versus the amount of inhibitor added to the medium. The resultant relationship proved bizarre, the inhibitor at low concentrations stimulating nitrosation in some situations. When gastric juice concentration in the medium was further lowered by dilution with a buffer at relevant value of pH, the paradoxical effect of inhibition gradually disappeared.

Topics: Aminopyrine; Animals; Ascorbic Acid; Caffeic Acids; Chromatography, Gas; Coumaric Acids; Dimethylamines; Gastric Juice; Humans; Hydrogen-Ion Concentration; In Vitro Techniques; Mice; Mice, Inbred Strains; Nitrosamines; Sodium Nitrite