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Antioxidant Compounds (antioxidant + compound)
Selected AbstractsCHANGES IN MAJOR ANTIOXIDANT COMPOUNDS DURING AGING OF TRADITIONAL BALSAMIC VINEGARJOURNAL OF FOOD BIOCHEMISTRY, Issue 1 2010ELENA VERZELLONI ABSTRACT Traditional balsamic vinegar (TBV) shows antioxidant capacity that increases passing from cask 5, containing the youngest vinegar, to cask 1 containing the oldest vinegar. This increase in antioxidant capacity is a consequence of both the concentration of compounds already present and of new antioxidants formation and is positively related to the increase in the polyphenolic content and in the Maillard reaction/caramellization products. During TBV aging, some reactions involving flavonoids and tannins take place. Tannins can undergo acid-catalyzed cleavage of their interflavonoid bonds with subsequent condensation of other flavonoid molecules. In addition, the low pH, the decrease of the water content and the presence of aldehydes, may promote flavonoids polycondensation. These reactions explain the observed increase in polymeric phenolic compounds and the decrease in monomeric flavonoids. During TBV aging an increase in the browning index is observed as a consequence of the polycondensation reactions of flavonoids and of brown melanoidins accumulation. PRACTICAL APPLICATIONS Traditional balsamic vinegar is a potentially healthy seasoning with high antioxidant capacity that increases during the aging resulting in a product with a strong antioxidant capacity and rich in phenolic compounds such as phenolic acids, monomeric catechins, flavonols and tannins. It also contains other antioxidants such as melanoidins derived from the Maillard and caramelization reaction that occur during must boiling and traditional balsamic vinegar aging. Independently of their bioavailability, traditional balsamic vinegar can contribute to supply antioxidant molecules that play an important role in protecting the gastrointestinal tract itself against peroxidation, thereby limiting the formation of detrimental lipid degradation products. [source] Antioxidant compounds in green and red peppers as affected by irrigation frequency, salinity and nutrient solution compositionJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 8 2009Alicia Marín Abstract BACKGROUND: There is a need to encourage more sustainable agricultural practices, reducing inputs of water and fertilisers while minimising any negative impact on fruit quality. The effect of irrigation frequency, salinity and potassium and calcium fertilisation on the content of bioactive compounds and quality attributes of green and red peppers grown with and without substrate was evaluated. RESULTS: Low irrigation frequency and salinity improved the quality attributes (dry matter, soluble solids content and titratable acidity) of pepper. Low irrigation frequency increased vitamin C content by 23% in green peppers, while in red fruits it was not affected. In contrast, total carotenoids and provitamin A only increased in red fruits by 30% and 15%, respectively, as a consequence of low irrigation frequency. When the effect of potassium and calcium doses was investigated, it was shown that a high proportion of potassium increased the vitamin C, provitamin A and total phenolic content of red and green peppers, whereas pepper grown at low calcium doses, presented the highest content in carotenoids and provitamin A. CONCLUSION: Low irrigation frequency and fertilisation with high potassium and low calcium doses improved pepper quality increasing the content of bioactive compounds. Copyright © 2009 Society of Chemical Industry [source] Novel role of curcumin in the prevention of cytokine-induced islet death in vitro and diabetogenesis in vivoBRITISH JOURNAL OF PHARMACOLOGY, Issue 5 2008M Kanitkar Background and purpose: Oxidative stress caused by cytokine exposure is a major cause of pancreatic islet death in vitro and of diabetogenesis. Antioxidant compounds may prevent cytokine-induced damage to islet cells. Hence, we studied the potential of curcumin, an antioxidant and anti-inflammatory compound, in vitro to protect islets against pro-inflammatory cytokines and in vivo to prevent the progression of diabetes induced by multiple low doses of streptozotocin (MLD-STZ). Experimental approach: Pancreatic islets from C57/BL6J mice were pretreated with curcumin (10 ,M) and then exposed to a combination of cytokines. Islet viability, reactive oxygen species (ROS), NO, inducible NO synthase and NF-,B translocation were studied. Curcumin pretreated (7.5 mg kg,1 day,1) C57/BL6J mice were given MLD-STZ (40 mg kg,1), and various parameters of diabetes induction and progression were monitored. Key results: Curcumin protected islets from cytokine-induced islet death in vitro by scavenging ROS and normalized cytokine-induced NF-,B translocation by inhibiting phosphorylation of inhibitor of kappa B alpha (I,B,). In vivo, curcumin also prevented MLD-STZ, as revealed by sustained normoglycaemia, normal glucose clearance and maintained pancreatic GLUT2 levels. Pro-inflammatory cytokine concentrations in the serum and pancreas were raised in STZ-treated animals, but not in animals pretreated with curcumin before STZ. Conclusions and implications: Here, we have demonstrated for the first time that curcumin in vitro protects pancreatic islets against cytokine-induced death and dysfunction and in vivo prevents STZ-induced diabetes. British Journal of Pharmacology (2008) 155, 702,713; doi:10.1038/bjp.2008.311; published online 11 August 2008 [source] Protective effects of melatonin against oxidative stress in Fmr1 knockout mice: a therapeutic research model for the fragile X syndromeJOURNAL OF PINEAL RESEARCH, Issue 2 2009Yanina Romero-Zerbo Abstract:, Fragile X syndrome is the most common form of inherited mental retardation. It is typically caused by a mutation of the Fragile X mental-retardation 1 (Fmr1) gene. To better understand the role of the Fmr1 gene and its gene product, the fragile X mental-retardation protein in central nervous system functions, an fmr1 knockout mouse that is deficient in the fragile X mental-retardation protein was bred. In the present study, fragile X mental retardation 1-knockout and wild-type mice are used to determine behaviour and oxidative stress alterations, including reduced glutathione, oxidized glutathione and thiobarbituric acid-reactive substances, before and after chronic treatment with melatonin or tianeptine. Reduced glutathione levels were reduced in the brain of fmr1-knockout mice and chronic melatonin treatment normalized the glutathione levels compared with the control group. Lipid peroxidation was elevated in brain and testes of fmr1-knockout mice and chronic melatonin treatment prevents lipid peroxidation in both tissues. Interestingly, chronic treatment with melatonin alleviated the altered parameters in the fmr1-knockout mice, including abnormal context-dependent exploratory and anxiety behaviours and learning abnormalities. Chronic treatment with tianeptine (a serotonin reuptake enhancer) did not normalize the behaviour in fmr1-knockout mice. The prevention of oxidative stress in the fragile X mouse model, by an antioxidant compound such as melatonin, emerges as a new and promising approach for further investigation on treatment trials for the disease. [source] Effects of Rutin on Lipid Profile in Hypercholesterolaemic RatsBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 3 2009Amir Ziaee Rutin is found in many plants and is also an important dietary constituent of food and plant-based beverages. Rutin has several pharmacological properties including antioxidant and cardioprotective activities. Also, it was identified that rutin is the major low-density lipoprotein (LDL) antioxidant compound of mulberry in an in vitro study. The effects of rutin were tested by using it as a supplement in a high-cholesterol diet. Male rats were fed a high-cholesterol diet (1 ml/100 g) for 4 weeks with rutin (10 or 100 mg/kg) or rutin 100 mg/kg and lovastatin supplementation to study the hypocholesterolaemic effects of rutin on plasma lipid levels, hepatic enzyme activity, and liver tissue. Feeding the animals a high-cholesterol diet resulted in marked hypercholesterolaemia and increased the serum level of LDL cholesterol (LDL-C). Rutin (at 100 mg/kg) alone or in combination with lovastatin significantly reduced the levels of total cholesterol, and LDL-C and also markedly decreased liver enzymes and weight in animals with a high-cholesterol diet. Our findings show that 100 mg/kg of rutin alone or with lovastatin supplementation lowered liver weight and enzymes as well as plasma total cholesterol and LDL. The hepatic histopathological results reflect the correlation of rutin and lovastatin combination with both liver weight and the levels of plasma total cholesterol and LDL-C. These results indicate that rutin in combination with lovastatin has increased anti-hypercholesterolaemic effects in an animal model. [source] Electron- and Energy-Transfer Properties of Hydrophilic CarotenoidsCHEMISTRY - A EUROPEAN JOURNAL, Issue 16 2007Hans-Richard Sliwka Abstract The antioxidant activities,expressed as the electron-donating properties,of five hydrophilic carotenoids (carotenoid surfactants) and three related hydrophobic carotenoids were investigated by flash photolysis. The electron-transfer rates of the carotenoids to the triplet state of the sensitizer 2-nitronaphthalene and the energy transfer rates of triplet 2-nitronaphthalene to the carotenoids were determined. The results demonstrate that the electron-donating effects of the hydrophilic and hydrophobic carotenoids were comparable when evaluated in acetonitrile. In the presence of water, however, electron transfer (i.e., antioxidant efficiency) was enhanced by a factor of four for the hydrophilic carotenoids. The increased hydrophilicity of carotenoids, therefore, could expand their antioxidant properties, thus facilitating their use as aqueous-phase radical scavengers. At the same time, it was shown that supramolecular assembly ("aggregation") of the amphiphilic carotenoids prevented electron transfer, thus deactivating the antioxidant function. Modulation of the biophysical properties of carotenoids through synthetic modification is capable of increasing the biological and medical utility of this natural class of predominantly hydrophobic antioxidant compound. [source] A prospective study of dietary flavonoid intake and incidence of epithelial ovarian cancerINTERNATIONAL JOURNAL OF CANCER, Issue 10 2007Margaret A. Gates Abstract Flavonoids are antioxidant compounds found in plants, including fruits, vegetables and tea. No prior prospective studies have examined the association between intake of flavonoids in the flavonol and flavone subclasses and ovarian cancer risk. We analyzed the association between intake of 5 common dietary flavonoids and incidence of epithelial ovarian cancer among 66,940 women in the Nurses' Health Study. We calculated each participant's intake of myricetin, kaempferol, quercetin, luteolin and apigenin from dietary data collected at multiple time points, and used Cox proportional hazards regression to model the incidence rate ratio (RR) of ovarian cancer for each quintile of intake. Our analysis included 347 cases diagnosed between 1984 and 2002, and 950,347 person-years of follow-up. There was no clear association between total intake of the 5 flavonoids examined and incidence of ovarian cancer (RR = 0.75 for the highest versus lowest quintile, 95% confidence interval [CI] = 0.51,1.09). However, there was a significant 40% decrease in ovarian cancer incidence for the highest versus lowest quintile of kaempferol intake (RR = 0.60, 95% CI = 0.42,0.87; p -trend = 0.002), and a significant 34% decrease in incidence for the highest versus lowest quintile of luteolin intake (RR = 0.66, 95% CI = 0.49,0.91; p -trend = 0.01). There was evidence of an inverse association with consumption of tea (nonherbal) and broccoli, the primary contributors to kaempferol intake in our population. These data suggest that dietary intake of certain flavonoids may reduce ovarian cancer risk, although additional prospective studies are needed to further evaluate this association. If confirmed, these results would provide an important target for ovarian cancer prevention. © 2007 Wiley-Liss, Inc. [source] Vinylic telluride derivatives as promising pharmacological compounds with low toxicityJOURNAL OF APPLIED TOXICOLOGY, Issue 7 2008V. C. Borges Abstract The aim of the present study was to evaluate pharmacological and toxicological properties of (Z)-2-(methylthio)-1-(butyltelluro)-1-phenylethene 1a, (Z)-1-(4-methylphenylsulfonyl)-2-(phenyltelluro)-2-phenylethene 1b, (Z)-2-(butyltelluro)-1-(benzylthio)-1-heptene 1c and (Z)-2-(phenylthio)-1-(butyltelluro)-1-phenylethene 1d. In vitro, vinylic telluride derivatives 1a, 1d and 1c were more effective in reducing lipid peroxidation than compound 1b. The maximal inhibitory effect of vinylic telluride derivatives on lipid peroxidation was in the following order: 1a = 1d > 1c > 1b. Compound 1b was more potent in inhibiting , -ALA-D activity (, -aminolevulinate dehydratase) than compounds 1c and 1d. Based on the in vitro properties presented by compounds 1a (an antioxidant) and 1b (a pro-oxidant), toxicological parameters were assessed in vivo and ex vivo in rats. Calculated LD50 of compounds 1a and 1b, administered by oral route, were 20.5 and 1.44 µmol kg,1, respectively. Compound 1b induced behavioral alterations in the open field test. Renal and spleenic , -ALA-D activities were inhibited in rats treated orally with compound 1a. Compound 1b stimulated , -ALA-D activity in liver and spleen of rats. Rats treated with compound 1b had increased hepatic, renal and spleenic lipid peroxidation. Renal and hepatic markers were not altered when compounds 1a and 1b were administered to rats at doses of around LD50, while compound 1a at high doses changed aspartate aminotransferase activity and urea levels. Based on in vitro results, this study demonstrated that compounds 1a and 1d are promising antioxidant compounds. Ex vivo data reinforce compound 1a as a promising drug for more detailed pharmacological studies. Copyright © 2008 John Wiley & Sons, Ltd. [source] EFFECT OF STORAGE PERIOD AND EXPOSURE CONDITIONS ON THE QUALITY OF BOSANA EXTRA-VIRGIN OLIVE OILJOURNAL OF FOOD QUALITY, Issue 2 2006VINCENZO VACCA ABSTRACT Changes in quality parameters, antioxidant compounds, oxidative stability and antioxidant activity during 18 months of storage of a monovarietal extra-virgin olive oil from Bosana cultivar, and exposed to light and dark, were studied. Analysis of data showed that all the parameters underwent significant changes during storage: free acidity, peroxide and ultraviolet (UV) spectrophotometric indexes remained below the limits reported in the EEC Regulations 2568/91 and 1989/03, and these are: ,0.8% for acidity, ,20 meq O2/kg for peroxide and ,2.50 and ,0.22 for K232 and K270, respectively. Phenol and, -tocopherol content decreased during storage (42.0 and 29.6%, respectively) while chlorophylls and carotenoids underwent a decrease until 8 months of storage (49% and 30%, respectively); after that, the values remained constant. Oxidative stability and antioxidant activity had not changed dramatically during 18 months. Phenols were significantly correlated to the antioxidant activity of the oil, while oxidative stability measured by Rancimat did not show any correlation with carotenoids, chlorophylls, phenols and, -tocopherol. Regarding exposure conditions, storage in the dark was better in retaining the quality of the oil, as expected. [source] Methodology Optimization for Quantification of Total Phenolics and Individual Phenolic Acids in Sweetpotato (Ipomoea batatas L.) RootsJOURNAL OF FOOD SCIENCE, Issue 7 2007M.S. Padda ABSTRACT:, Phenolic acids are one of the several classes of naturally occurring antioxidant compounds found in sweetpotatoes. Simplified, robust, and rapid methodologies were optimized to quantify total and individual phenolic acids in sweetpotato roots. Total phenolic acid content was quantified spectrophotometrically using both Folin,Denis and Folin,Ciocalteu reagents. The Folin,Ciocalteu reagent gave an overestimation of total phenolic acids due to the absorbance of interfering compounds (that is, reducing sugars and ascorbic acid). Individual phenolic acids were quantified by high-performance liquid chromatography (HPLC) using the latest in column technology. Four reversed-phase C18 analytical columns with different properties (dimensions, particle size, particle shape, pore size, and carbon load) were compared. Three different mobile phases using isocratic conditions were also evaluated. A column (4.6 × 150 mm) packed with 5-,m spherical silica particles of pore size 110 Å combined with 14% carbon load provided the best and fast separation of individual phenolic acids (that is, chlorogenic acid, caffeic acid, and 3 isomers of dicaffeoylquinic acid) with a total analysis time of less than 7 min. Among the 3 mobile phases tested, a mobile phase consisting of 1% (v/v) formic acid aqueous solution: acetonitrile: 2-propanol, pH 2.5 (70:22:8, v/v/v) gave adequate separation. Among the solvents tested, aqueous mixtures (80:20, solvent:water) of methanol and ethanol provided higher phenolic acid extraction efficiency than the aqueous mixture of acetone. [source] Rapid identification and preparative isolation of antioxidant components in licoriceJOURNAL OF SEPARATION SCIENCE, JSS, Issue 4-5 2010Yeon Sil Lee Abstract This study employed the online HPLC-2,2,-azinobis-(3-ethylbenzothiazoline-6-sulfonate radical cation (ABTS+·) bioassay to rapidly determine antioxidant compounds occurring in the licorice extract of Glycyrrhiza uralensis. The negative peaks of the ABTS+· radical scavenging detection system, which indicated the presence of antioxidant activity, were monitored by measuring the decrease in absorbance at 734,nm. The ABTS+ -based antioxidant activity profile showed that three peaks exhibited antioxidant activity, and then the high-speed counter-current chromatography technique of preparative scale was successfully applied to separate the three peaks I-III in one step from the licorice extract. The high-speed counter-current chromatography was performed using a two-phase solvent system composed of n -hexane,ethyl acetate,methanol,water (6.5:5.5:6:4, v/v). Yields of the three peaks, dehydroglyasperin C (I, 95.1% purity), dehydroglyasperin D (II, 96.2% purity), and isoangustone A (III, 99.5% purity), obtained were 10.33, 10.43, and 6.7% respectively. Chemical structures of the purified dehydroglyasperin C (I), dehydroglyasperin D (II), and isoangustone A (III) were identified by ESI-MS and 1H- and 13C-NMR analysis. [source] The ripening and aging of noni fruits (Morinda citrifolia L.): microbiological flora and antioxidant compoundsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2007Yanine Chan-Blanco Abstract The juice of noni fruit (Morinda citrifolia L.) is claimed to be a natural functional beverage with a growing market both in the USA and Europe. It is traditionally produced by keeping harvested fruit in closed containers for several weeks as the fruit senesces or ages. Little is known about the changes that occur in the juice's microbiological, physicochemical, and functional characteristics during this treatment. Traditional processing was simulated in the laboratory, with samples being recovered and analyzed at various time intervals. At first, fermentation occurred and populations of molds, yeasts, and mesophilic bacteria increased significantly. After 2 weeks, microbial growth changed abruptly, stopping for yeasts, molds, and mesophilic bacteria, and decreasing suddenly for lactic bacteria. Analyses of pH, soluble solids, ethanol, and lactic acid in the fruits confirmed the microbial analyses, indicating initial sensitive variations, followed by values remaining comparatively steady during aging. Vitamin C and total phenol contents also remained constant at 300 ± 60 mg and 50 ± 20 mg GAE, respectively, per 100 g of pulp. Antioxidant capacity likewise remained relatively high at 8 ± 1.5 µmol Trolox® g,1. All phenolic compounds, including scopoletin and rutin, varied significantly immediately after harvest but remained more or less steady during aging. Copyright © 2007 Society of Chemical Industry [source] Impact of enzymatic treatment on chemical composition, physicochemical properties and radical scavenging activity of goldenberry (Physalis peruviana L.) juiceJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 3 2007Mohamed Fawzy Ramadan Abstract Tropical pulpy juices play an important role in nutrition as an excellent base for low-calorie and dietetic products. Goldenberry (Physalis peruviana L.) is one of the most promising exotic fruits and many interesting functional products could be developed from these berries. In this work we are reporting, for the first time, on the chemical composition and some physicochemical parameters of the goldenberry fruit juice. We have also investigated how some of these properties are affected by enzymatic treatment and pasteurisation. By enzymation, not only is the yield of juice increased, but also the macro- and micro-components. Application of enzymes, moreover, leads to juices with higher pulp content, higher acidity and higher total soluble solids. On the other side, enzyme-treated juices were characterised by lower alcohol-soluble solids and pH values. Water- and fat-soluble bioactives were estimated in appreciable amounts in the juice. The antioxidative potential of different processed juices was assessed by means of bleaching of the stable 1,1-diphenyl-2-picrylhydrazyl radicals and the resulting values were correlated with each of the antioxidant compounds. The results obtained can be considered very satisfactory and the juice could be widely appreciated when compared with other products commonly available on the market. The data are helpful for the optimisation of goldenberry juice production. It was the purpose to present a comprehensive assessment of the goldenberry juice and to address the potential for its delivery in functional drinks. Copyright © 2006 Society of Chemical Industry [source] Total antioxidant capacity and content of flavonoids and other phenolic compounds in canihua (Chenopodium pallidicaule): An Andean pseudocerealMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 6 2008J. Mauricio Peñarrieta Abstract Total antioxidant capacity (TAC), total phenolic compounds (TPH), total flavonoids (TF) and individual phenolic compounds were determined in canihua collected at approx. 3850 m altitude. The TAC values varied among samples from 2.7 to 44.7 by the ferric reducing antioxidant power (FRAP) method and from 1.8 to 41 by the 2,2,-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) method expressed as ,mol of Trolox equivalents/g dw. The content of TPH was 12.4,71.2 ,mol gallic acid equivalents/g dw and that of the TF ranged between 2.2 and 11.4 ,mol of catechin equivalents/g dw. The data obtained by the four methods showed several significant correlations. Prior to analysis by HPLC, the samples were subjected to acid hydrolysis and in the water-soluble extracts this led to an up to 20-fold increase in the TAC values in comparison with the values of the nonhydrolysed samples. HPLC analysis showed the presence of eight major compounds identified as catechin gallate, catechin, vanillic acid, kaempferol, ferulic acid, quercetin, resorcinol and 4-methylresorcinol. Their estimated contribution to the TAC value (FRAP method) indicated that resorcinols contributed most of the antioxidant capacity of the water-soluble extract. The results show that canihua is a potential source of natural antioxidant compounds and other bioactive compounds which can be important for human health. [source] Characterization of antioxidant compounds of red and white rice and changes in total antioxidant capacity during processingMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 8 2007Franca Finocchiaro Abstract Although most rice cultivars have whitish kernel, some varieties have a red testa. Aim of this work was to compare the total antioxidant capacity (TAC) and the antioxidant chemical composition (namely tocols, ,-oryzanols, and polyphenols) of red and white rices. In addition, the effect of milling and cooking on antioxidants was investigated in both rices. Dehulled red rice showed a TAC more than three times greater than dehulled white rice and its high TAC was essentially characterized by the presence of proanthocyanidins (PA) and associated phenolics. Milling caused a significant loss of TAC, even if red rice maintained a higher TAC. Cooking caused a further loss of antioxidants, but when there was a full uptake of cooking water by the grains ("risotto") this loss was limited. Thus, the consumption of whole or partially milled rice cooked as risotto would be preferred to preserve its nutritional properties. [source] Differential response of antioxidant compounds to salinity stress in salt-tolerant and salt-sensitive seedlings of foxtail millet (Setaria italica)PHYSIOLOGIA PLANTARUM, Issue 4 2000N. Sreenivasulu The modulation of antioxidant components was comparatively analysed in a salt-tolerant (cv. Prasad) and salt-sensitive (cv. Lepakshi) cultivar of foxtail millet (Setaria italica L.) under different NaCl concentrations. Under conditions of salt stress, the salt-tolerant cultivar exhibited increased total superoxide dismutase (SOD) and ascorbate peroxidase (APX) activity, whereas both enzyme activities decreased in acutely salt-stressed seedlings of the sensitive cultivar. At 200 mM NaCl, the tolerant foxtail millet cultivar responded with induction of cytosolic Cu/Zn-SOD and the Mn-SOD isoform at the protein level. The induced accumulation of the cytosolic Cu/Zn-SOD protein/activity is positively correlated with an elevated level of the cytosolic APX gene activity. The elevated cytosolic Cu/Zn-SOD and cytosolic APX activity correlates with an induced accumulation of their transcripts. Tolerant 5-day-old seedlings grown during high salinity treatment (200 mM NaCl) contained a lower amount of Na+ ions and showed a lower electrolyte leakage than sensitive seedlings. In conclusion, our comparative studies indicate that salt-induced oxidative tolerance is conferred by an enhanced compartment-specific activity of the antioxidant enzymes in response to compartment-specific signals. [source] Effect of celery (Apium graveolens) extracts on some biochemical parameters of oxidative Stress in mice treated with carbon tetrachloridePHYTOTHERAPY RESEARCH, Issue 7 2006Mira Popovi Abstract Extracts of celery leaves and roots in ether, chloroform, ethyl acetate, n -butanol and water were evaporated to dryness and dissolved in 50% ethanol to make 10% (w[sol ]v) solutions. The potential protective action of the extracts was assessed by the corresponding in vitro and in vivo tests. In the in vitro experiments crude methanol extracts were tested as potential scavengers of free OH, and DPPH, radicals, as well as inhibitors of liposomal peroxidation (LPx). Analogous experiments were also carried out with the extracts of celery root, for comparison. The results obtained show that both the extracts of root and leaves are good scavengers of OH, and DPPH, radicals and reduce LPx intensity in liposomes, which points to their protective (antioxidant) activity. In vivo experiments were concerned with antioxidant systems (activities of GSHPx, GSHR, Px, CAT, XOD, GSH content and intensity of LPx) in liver homogenate and blood of mice after their treatment with extracts of celery leaves, or in combination with CCl4. On the basis of the results obtained it can be concluded that the examined extracts showed a certain protective effect. Of all the extracts the n -butanol extract showed the highest protective effect. Combined treatments with CCl4 and extracts showed both positive and negative synergism , inducing or suppressing the impact of CCl4 alone. The differences observed in the action of particular extracts are probably due to the different contents of flavonoids and some other antioxidant compounds. Copyright © 2006 John Wiley & Sons, Ltd. [source] Linking isoprene with plant thermotolerance, antioxidants and monoterpene emissionsPLANT CELL & ENVIRONMENT, Issue 3 2005J. PEÑUELAS ABSTRACT The purpose of the present study was to test the possible plant thermotolerance role of isoprene and to study its relationship with non-enzymatic antioxidants and terpene emissions. The gas exchange, chlorophyll fluorescence, extent of photo- and oxidative stress, leaf damage, mechanisms of photo- and antioxidant protection, and terpene emission were measured in leaves of Quercus ilex seedlings exposed to a ramp of temperatures of 5 °C steps from 25 to 50 °C growing with and without isoprene (10 µL L,1) fumigation. The results showed that isoprene actually conferred thermotolerance (shifted the decrease of net photosynthetic rates from 35 to 45 °C, increased Fv/Fm at 50 °C from 0.38 to 0.65, and decreased the leaf area damaged from 27 to 15%), that it precluded or delayed the enhancement of the antioxidant non-enzymatic defence conferred by , -tocopherol, ascorbic acid or , -carotene consumption in response to increasing temperatures, and that it decreased by approximately 70% the emissions of monoterpenes at the highest temperatures. This suggests that there are inducible mechanisms triggered by the initial stages of thermal damage that up-regulate these antioxidant compounds at high temperatures and that these mechanisms are somehow suppressed in the presence of exogenous isoprene, which seems to already exert an antioxidant-like behaviour. [source] Production and detoxification of H2O2 in lettuce plants exposed to seleniumANNALS OF APPLIED BIOLOGY, Issue 1 2009J.J. Ríos Abstract Selenium is considered an essential element for animals. Despite that it has not been demonstrated to be essential for higher plants, it has been attributed with a protective role against reactive oxygen species in plants subjected to stress. In this study, lettuce plants (Lactuca sativa cv. Philipus) received different application rates (5, 10, 20, 40, 60, 80 and 120 ,M) of selenite or selenate, with the aim of testing the effect of Se on the production and detoxification of H2O2 in non-stressed plants. The results indicate that the form selenate is less toxic than selenite; that is, the plants tolerated and responded positively to this element, and even increasing in growth up to a rate of 40 ,M for the form selenate. On the contrary, the application of selenite triggered a higher foliar concentration of H2O2 and a higher induction of lipid peroxidation [malondialdehyde content and lipoxygenase activity] in comparison to that observed after the selenate application. Also, the plants treated with selenate induced higher increases in enzymes that detoxify H2O2, especially ascorbate peroxidase and glutathione (GSH) peroxidase, as well as an increase in the foliar concentration of antioxidant compounds such as ascorbate and GSH. These data indicate that an application of selenate at low rates can be used to prevent the induction in plants of the antioxidant system, thereby improving stress resistance. [source] | ||||||||||||||||