Sequestering ability of butylated hydroxytoluene,propyl gallate,resveratrol, and vitamins C and E against ABTS,DPPH, and hydroxyl free radicals in chemical and biological systems

The antioxidant capacity of butylated hydroxytoluene (BHT; 2,6-di-tert-butyl-p-cresol), propyl gallate (3,4,5-trihydroxybenzoic acid n-propyl ester), resveratrol (trans-3,4',5-trihydroxystilbene), and vitamins C (l-ascorbic acid) and E [(+)-alpha-tocopherol] was studied in chemical and biological systems. The chemical assays evaluated the capacity of these antioxidants to sequester 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS.) and 1,1 diphenyl-2-picrylhydrazyl (DPPH.). A new colorimetric method to determine hydroxyl radical scavenging is also described. The biological tests use the eucaryotic cells of Saccharomyces cerevisiae treated with the antioxidants in the presence of the stressing agents apomorphine, hydrogen peroxide, and paraquat dichloride (methylviologen; 1,1'-dimethyl-4,4'-bipyridinium dichloride). The results in chemical systems showed that all of the antioxidants were able to significantly inhibit the oxidation of beta-carotene by hydroxyl free radicals. The assays in yeast showed that the antioxidant activity of the tested compounds depended on the stressing agent used and the mechanism of action of the antioxidant.     

高湿贮藏对茄子冷害及抗氧化系统的影响

为探讨高湿贮藏对减轻茄子冷害的作用及其与抗氧化系统的关系,本试验将茄子果实分别放置于4℃的干雾控湿高湿冷库(相对湿度96%~99%)和低湿冷库(相对湿度70%~75%)中贮藏15 d,每隔3 d进行取样测定,比较分析相关指标的变化。结果表明,与低湿贮藏相比,高湿贮藏能显著抑制茄子果实冷害指数、相对电导率和失重率的上升(P<0.05),保持茄子果实较高的硬度及总酚和花青素含量。同时,高湿贮藏能显著提高茄子果实中超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、过氧化氢酶(CAT)和过氧化物酶(POD)等抗氧化酶的活性(P<0.05),抑制过氧化氢(H₂O₂)和超氧阴离子( {\mathrm{O}}_2^{\frac{-}{·}} )的产生,保持更高的1,1-二苯基-2-三硝基苯肼(DPPH)和羟基自由基清除能力。上述结果表明,高湿贮藏可维持茄子果实较高的抗氧化系统活性,从而抑制活性氧对茄子的伤害,减轻果实冷害。本研究为高湿贮藏在茄子果实采后保鲜中的应用提供了一定的依据。     

Antioxidant activity of extracts from Acacia confusa bark and heartwood.

The antioxidant activity of extracts from bark and heartwood of Acacia confusa was evaluated by various antioxidant assays, including free radical and superoxide radical scavenging assays and lipid peroxidation assay as well as hydroxyl radical-induced DNA strand scission assay. In addition, an ex vivo antioxidant assay using a flow cytometric technique was also employed in this study. The results indicate that both bark and heartwood extracts clearly have strong antioxidant effects. Similar inhibitory activities for each test sample were found for both 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical generation and lipid peroxidation. As for the superoxide radical scavenging activity, the heartwood extract was more effective than the bark extract. Furthermore, the heartwood extract protected PhiX174 supercoiled DNA against strand scission induced by ultraviolet photolysis of H2O2, and it reduced the amounts of intracellular hydrogen peroxide, a reactive oxygen species, when it was co-incubated with human promyelocytic leukemia (HL-60) cells under oxidative stress.     

In vitro antioxidant activity and antigenotoxicity of 5-n-alkylresorcinols

Incubation with 5-n-alkylresorcinols (chain lengths C15:0, C17:0, C19:0, C21:0, and C23:0) increased the self-protection capacity of HT29 human colon cancer cells against DNA damage induced by hydrogen peroxide and genotoxic fecal water samples using comet assay (single-cell gel electrophoresis assay). The alkylresorcinols did not exert potent antioxidant activity in the FRAP (ferric reduction ability of plasma) and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical assays. However they were able to significantly inhibit copper-mediated oxidation of human LDL (low-density lipoprotein) in vitro, and pentadecylresorcinol at 25 micromol/L increased lag time by 65 min. The results show that alkylresorcinols have antigenotoxic and antioxidant activity under in vitro conditions.     

Antioxidant protection of resveratrol and catechin in Saccharomyces cerevisiae

Moderate consumption of red wine reduces the risk of heart disease and extends lifespan, but the relative contribution of wine polyphenols to these effects is unclear. In this work, the capacity of resveratrol and catechin to protect the eukaryotic microorganism Saccharomyces cerevisiae against oxidative stress caused by different agents, hydrogen peroxide, carbon tetrachloride, and cadmium, was evaluated. Under all stress conditions, both polyphenols increased tolerance, although their protection was more evident under peroxide exposure. By using mutant strains deficient in specific antioxidant defense systems (superoxide dismutases, catalase, or glutathione), it was observed that increased H2O2 tolerance produced by both polyphenols was associated with catalase, as well as the rise in survival rates caused by resveratrol under CCl4. The acquisition of tolerance was correlated with a reduction in lipid peroxidation, indicating that the antioxidant property of resveratrol and catechin involves protection against membrane oxidation.     

Impact of delphinidin on the maintenance of DNA integrity in human colon carcinoma cells

Delphinidin has been found to possess DNA strand-breaking properties in cell culture. In the present study, we demonstrated that the extent of DNA damage by delphinidin is not affected by the expression of tyrosyl-DNA-phosphodiesterase 1, indicating that the induction of DNA strand breaks is not predominantly topoisomerase-mediated. However, the DNA-damaging properties of delphinidin were decreased by the addition of catalase to the cell culture medium, counteracting delphinidin-mediated hydrogen peroxide formation. Under these conditions, delphinidin showed clearly antioxidative properties in HT29 cells, preventing menadione-induced oxidative DNA damage. In contrast, in the absence of catalase, delphinidin lacked antioxidative properties. In conclusion, delphinidin acted as an effective antioxidant within intact cells if the formation of hydrogen peroxide was prevented. In the absence of catalase, the accumulated hydrogen peroxide appears to play a substantial role for the observed DNA-damaging properties of delphinidin and the apparent lack of antioxidative properties of this anthocyanidin.     

Hydrogen peroxide induced oxidative stress damage and antioxidant enzyme response in Caco-2 human colon cells

Studies were conducted to evaluate the cell damage caused by exposing human colon carcinoma cells, Caco-2, to hydrogen peroxide at concentrations varying from 0 to 250 microM for 30 min. Evaluation of cell viability, as measured by trypan blue dye exclusion test, showed that the loss of viability was < 5% at concentrations up to 250 microM hydrogen peroxide. Cell membrane damage and DNA damage as measured by the leakage of lactate dehydrogenase and the comet assay, respectively, were significantly high at concentrations >100 microM hydrogen peroxide compared to those of the control. Antioxidant mechanisms in Caco-2 cells were evaluated by measuring catalase, superoxide dismutase, and glutathione peroxidase activities. Catalase activities remained constant in cells treated with 50-250 microM hydrogen peroxide. Superoxide dismutase activity decreased, whereas glutathione peroxidase activity increased in cells treated with H(2)O(2) concentrations of >50 microM. This study showed that with increasing hydrogen peroxide concentration, cell membrane leakage and DNA damage increased, whereas the three antioxidant enzymes responded differently, as shown by mathematical models.     

Chemical composition and antioxidant property of holy basil (Ocimum sanctum L.) leaves, stems, and inflorescence and their in vitro callus cultures

In this study, the chemical constituents and antioxidant property of holy basil (Ocimum sanctum Linn.) field-grown plant parts (leaves, stems, and inflorescence) were compared with those of respective callus cultures induced from each explant in in vitro. The callus cultures were successfully initiated on Murashige and Skoog (MS) medium supplemented with 2,4-dichlorophenoxy acetic acid (2,4-D) (1 mg/L) combined with different concentrations (0.1-0.5 mg/L) of kinetin as plant growth regulators. The distribution of phenolic compounds in these extracts was analyzed using reverse phase high-performance liquid chromatography with reference standards. Interestingly, rosmarinic acid (RA) was found to be the predominant phenolic acid in all callus extracts in comparison with field-grown plant parts. In this study, the antioxidant activity of the extracts was evaluated with six different in vitro antioxidant-testing systems. Their activities of scavenging superoxide anion radicals, 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH), hydroxyl radicals, hydrogen peroxide, chelating ferrous iron, and ferric ion reducing potential were assessed. The antioxidant activity was increased in all testing systems with increasing amounts of extract. However, at the same concentration, the callus extracts exhibited higher antioxidant activity in all of the testing systems than the extract obtained from field-grown plant parts. The data obtained from this study suggested the possibility of the isolation of a high content of RA from in vitro callus cultures rather than field-grown plant organs of holy basil.     

Antioxidant activity of A-type proanthocyanidins from Geranium niveum (Geraniaceae)

Geranium niveum S. Watson (Geraniaceae) is a medicinal herb widely used by the Tarahumara Indians of Mexico. This species is rich in proanthocyanidins and other phenolics. Previous in vitro assays have demonstrated that proanthocyanidins exhibited antiinflammatory, antiviral, antibacterial, enzyme-inhibiting, antioxidant, and radical-scavenging properties. In view of its medicinal use and chemical composition, the aim of the present study was to determine the in vitro antioxidant activity of the extracts and two proanthocyanidins (geranins A and D) from the roots of G. niveum by using seven different assay systems, namely, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide anion (O2*-), hydrogen peroxide (H2O2), hydroxyl radical (OH*), hypochlorous acid (HOCl), and singlet oxygen ((1)O2). Two known antioxidants, resveratrol and ascorbic acid, were used as positive controls. The results showed that geranins A and D and the extracts were able to scavenge ABTS, DPPH, O2*-, OH*, and HOCl. The scavenging ability of geranins A and D was similar to that of resveratrol and ascorbic acid in the following assays: ABTS, O2*-, and HOCl. The scavenging capacity of ascorbic acid for DPPH was higher than that of both geranins and resveratrol. On the other hand, the OH* scavenging action of both geranins and resveratrol was similar. The methanol-CHCl3 (1:1) extract had a higher ability to scavenge ABTS, DPPH, and O2*- radicals than the chloroform extract. In turn, the latter was more potent than the methanol-CHCl3 (1:1) extract as OH* or HOCl scavenger agent. Neither geranins A and D nor the extracts were able to scavenge H2O2 and (1)O2. In conclusion, G. niveum roots have proanthocyanidins with powerful radical scavenging in vitro activity. This property may partially explain the wide use of this plant in the Tarahumara indigenous system of medicine for the treatment of gastrointestinal illnesses (other than spasms), pain, and fevers associated with oxidative stress.     

Antioxidant and antimelanogenic activities of polyamine conjugates from corn bran and related hydroxycinnamic acids

The antioxidant activity of three major polyamine conjugates, N,N'-dicoumaroyl-putrescine (DCP), N-p-coumaroyl-N'-feruloylputrescine (CFP), and N,N'-diferuloyl-putrescine (DFP) isolated from corn bran, and their related hydroxycinnamic acids, p-coumaric acid and ferulic acid, were evaluated by three antioxidant in vitro assay systems, including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and superoxide and hydroxyl radicals generated by enzymatic and nonenzymatic reactions. Additionally, five phenolic compounds were evaluated for melanogenesis inhibitory activity using mushroom tyrosinase and B16 melanoma cells. Most of the phenolic compounds significantly scavenged DPPH, superoxide, and hydroxyl radicals in a dose-dependent manner. Particularly, DFP showed potent DPPH (IC50 = 38.46 microM) and superoxide (IC50 = 291.62 microM) radical scavenging activities, while DCP exhibited the strongest hydroxyl radical scavenging activity (IC50 = 120.55 microM). CFP also exerted moderate DPPH, superoxide, and hydroxyl radical scavenging activities. Meanwhile, DCP (IC50 = 181.73 microM) showed potent tyrosinase inhibitory activity toward l-tyrosine as the substrate, whereas DFP (IC50 = 733.64 microM) significantly inhibited melanin synthesis in B16 melanoma cells. These current results indicate that these three polyamine conjugates from corn bran may be useful potential sources of natural antioxidants and skin-whitening agents.     

Role of the cultivar in choosing Clementine fruits with a high level of health-promoting compounds

Thirteen cultivars and two hybrids of Clementine fruits (Citrus clementina Hort. Ex. Tan) cultivated in Italy were characterized according to pH, titratable acidity, total soluble solids, total polyphenols, carotenoids, vitamin C, hesperidin, rutin, narirutin and naringin and radical scavenging activity. The presence of rutin in Clementine fruit juice is reported for the first time here. The results indicated that all chemical parameters statistically differentiated each cultivar (P < 0.001). In particular, principal component analysis showed a clear discrimination of five cultivars from all the other varieties based on vitamin C and total polyphenols for the Caffin cultivar, which showed also the highest antioxidant activity; narirutin for the Etna hybrid cultivar; hesperidin, rutin and total soluble solids for the SRA 89 cultivar; and naringin, hesperidin and rutin for the Esbal cultivar. Moreover, the Mandalate hybrid cultivar showed the lowest antioxidant activity as well as vitamin C and total polyphenols content, while titratable acidity and naringin level were the highest. The antioxidant activity assessed in all the fruits was closely correlated with vitamin C and total polyphenols content, rather than with the flavonoid compounds.     

山楂黄酮提取物对辐照肉糜脂肪氧化的抑制能力

试验研究山楂黄酮的抗氧化性以及对辐照肉糜的抗氧化作用.结果表明,山楂黄酮提取物对DPPH·具有一定清除作用,每110g肉糜中添加0.525mg山楂黄酮粗提物对DPPH自由基的清除率可达到56%.山楂黄酮提取物可有效降低辐照肉糜的脂肪氧化程度,且山楂黄酮提取物与Vc复配添加使用效果明显优于山楂黄酮提取物或茶多酚单独处理....     

Metabolic profiling of strawberry grape ( Vitis × labruscana cv. 'Isabella') components by nuclear magnetic resonance (NMR) and evaluation of their antioxidant and antiproliferative properties

In the assessment of the antioxidant properties of edible plants, the widely consumed Vitis × labruscana cv. 'Isabella', known in Italy as "fragola" (strawberry) grape, was of interest. Phenol and flavonoid contents of the methanolic extracts of peel, pulp, seed, leaf, and stalk components of the plant were determined. The metabolic profile of the extracts was performed by 1D and 2D NMR. Quantitative analysis, obtained in the presence of 0.01% of internal standard trimethylsilyl propionate, evidenced the presence of catechins in both stalk and seed extracts, whereas caffeic acid and quercetin were the main metabolites of the leaf extract. Furthermore, the extracts were tested for their radical scavenging and reducing capacities by measuring their capacity to scavenge DPPH(?) and ABTS(?+) and to reduce Fe(III) and Mo(VI) salts. The antioxidant efficacy of the extracts in cell-free systems and their antiproliferative activity toward HepG2 and A549 cells were also evaluated. Seed and stalk components are able to reduce by 39.6 and 40.6%, respectively, the amount of the metabolically active HepG2 cells after only 24 h of exposure.     

Screening for antioxidant activity in edible plant products: comparison of low-density lipoprotein oxidation assay, DPPH radical scavenging assay, and Folin-Ciocalteu assay

Oxidation of low-density lipoprotein (LDL) has been implicated in atherogenesis. Antioxidants that prevent LDL from oxidizing may reduce atherosclerosis. This study investigated LDL antioxidant activity in edible plant products for development of dietary supplementation to prevent atherosclerosis. Fifty-two kinds of edible plants were extracted using 70% aqueous ethanol solution, and the antioxidant activity of the extracts, which inhibit human LDL oxidation induced by copper ion, was determined on the basis of the oxidation lag time and represented as epigallocatechin 3-gallate equivalent. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and total phenolic content were also measured for comparisons with antioxidant activity in LDL. Plant products showing the greatest activity in LDL oxidation assay were akamegashiwa (Mallotus japonicus) leaf, Japanese privet (Ligustrum japonicum) leaf, green tea [Camellia sinensis (L.) O. Kuntze], and astringent persimmon (Diospyros kaki). The present study revealed high levels of LDL antioxidant activity in plant products for which such activity levels are underestimated in the DPPH radical scavenging assay and Folin-Ciocalteu assay.     

热水处理对采后鲜食蚕豆荚褐变及活性氧代谢的影响

为了提高鲜食蚕豆的保鲜效果,本试验以鲜食蚕豆果实为材料,研究了 45℃热水处理10 min对鲜食蚕豆果实在常温(20℃)贮藏过程中豆荚褐变、种子品质及豆荚活性氧(ROS)代谢的影响.结果表明,45℃热水处理10 min能显著提高豆荚中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)的活性,以...     

Neuroprotective effects of the citrus flavanones against H2O2-induced cytotoxicity in PC12 cells

The citrus flavanones hesperidin, hesperetin, and neohesperidin are known to exhibit antioxidant activities and could traverse the blood-brain barrier. H2O2 formation induces cellular oxidative stress associated with neurodegenerative diseases. In this study, protective effects of pretreatments (6 h) with hesperidin, hesperetin, and neohesperidin (0.8, 4, 20, and 50 microM) on H2O2-induced (400 microM, 16 h) neurotoxicity in PC12 cells were evaluated. The results showed that hesperetin, hesperidin, and neohesperidin, at all test concentrations, significantly ( p < 0.05) inhibited the decrease of cell viability (MTT reduction), prevented membrane damage (LDH release), scavenged ROS formation, increased catalase activity, and attenuated the elevation of intracellular free Ca2+, the decrease of mitochondrial membrane potential (except those of 0.8 microM neohesperidin-treated cells) and the increase of caspase-3 activity in H2O2-induced PC12 cells. Meanwhile, hesperidin and hesperetin attenuated decreases of glutathione peroxidase and glutathione reductase activities and decreased DNA damage in H2O2-induced PC12 cells. These results first demonstrate that the citrus flavanones hesperidin, hesperetin, and neohesperidin, even at physiological concentrations, have neuroprotective effects against H2O2-induced cytotoxicity in PC12 cells. These dietary antioxidants are potential candidates for use in the intervention for neurodegenerative diseases.     

Comparative studies on some quality attributes of firm tofu sterilized with traditional and autoclaving methods

An innovative retort cooking method was developed for firm tofu sterilization to replace the traditional hydrogen peroxide treatment. The caramelized firm tofu was sterilized by autoclaving at 105 degrees C for 20 min, which led to a 3 log cycle reduction of total plate count. Shelf life of the processed firm tofu was extended at least 3 months. As compared with chemical treatment, thermal treatment degraded total and individual isoflavones to a lesser extent, and only minor changes were observed. The percent DPPH free radical scavenging capacity of autoclaved firm tofu was significantly higher than that of the hydrogen peroxide treated samples. Even after prolonged heat treatment, the three-dimensional network structure of the autoclaved firm tofu did not change significantly. Texture profile analysis and sensory evaluation confirmed autoclaved firm tofu to be acceptable.     

Cocoa has more phenolic phytochemicals and a higher antioxidant capacity than teas and red wine

Black tea, green tea, red wine, and cocoa are high in phenolic phytochemicals, among which theaflavin, epigallocatechin gallate, resveratrol, and procyanidin, respectively, have been extensively investigated due to their possible role as chemopreventive agents based on their antioxidant capacities. The present study compared the phenolic and flavonoid contents and total antioxidant capacities of cocoa, black tea, green tea, and red wine. Cocoa contained much higher levels of total phenolics (611 mg of gallic acid equivalents, GAE) and flavonoids (564 mg of epicatechin equivalents, ECE) per serving than black tea (124 mg of GAE and 34 mg of ECE, respectively), green tea (165 mg of GAE and 47 mg of ECE), and red wine (340 mg of GAE and 163 mg of ECE). Total antioxidant activities were measured using the 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays and are expressed as vitamin C equivalent antioxidant capacities (VCEACs). Cocoa exhibited the highest antioxidant activity among the samples in ABTS and DPPH assays, with VCEACs of 1128 and 836 mg/serving, respectively. The relative total antioxidant capacities of the samples in both assays were as follows in decreasing order: cocoa > red wine > green tea > black tea. The total antioxidant capacities from ABTS and DPPH assays were highly correlated with phenolic content (r2 = 0.981 and 0.967, respectively) and flavonoid content (r2 = 0.949 and 0.915). These results suggest that cocoa is more beneficial to health than teas and red wine in terms of its higher antioxidant capacity.     

Profiling and characterization antioxidant activities in Anoectochilus formosanus hayata

Phytochemical characteristics and antioxidant activities of the crude and fractionated plant extracts of Anoectochilus formosanus were evaluated using five different assay systems. An acid-treatment (2 N HCl in 95% ethanol) was employed to treat a butanol fraction (BuOH), creating an acid-hydrolyzed BuOH fraction. The IC(50) values for DPPH radicals in the BuOH and acid-hydrolyzed BuOH fractions were 0.521 and 0.021 mg/mL, respectively. The acid-hydrolyzed BuOH exhibited approximately 5-fold higher activity in scavenging superoxide anion than catechin. The acid-hydrolyzed BuOH fraction also effectively protected phi x174 supercoiled DNA against strand cleavage induced by H(2)O(2) and reduced oxidative stress in HL-60 cells. Metabolite profiling showed that the aglycones of flavonoid glycosides in BuOH were produced after acid hydrolytic treatment, and this resulted in a significant increase in antioxidant activities of acid-hydrolyzed BuOH. One new diarylpentanoid, kinsenone, and three known flavonoid glycosides and their derivatives were identified for the first time from A. formosanus, with strong antioxidant properties.     

Antioxidant properties of various solvent extracts of total phenolic constituents from three different agroclimatic origins of drumstick tree (Moringa oleifera Lam.) leaves

Water, aqueous methanol, and aqueous ethanol extracts of freeze-dried leaves of Moringa oleifera Lam. from different agroclimatic regions were examined for radical scavenging capacities and antioxidant activities. All leaf extracts were capable of scavenging peroxyl and superoxyl radicals. Similar scavenging activities for different solvent extracts of each collection were found for the stable 1,1-diphenyl 2-picrylhydrazyl (DPPH(*)) radical. Among the three different moringa samples, both methanol and ethanol extracts of Indian origins showed the highest antioxidant activities, 65.1 and 66.8%, respectively, in the beta-carotene-linoleic acid system. Nonetheless, increasing concentration of all the extracts had significantly (P < 0.05) increased reducing power, which may in part be responsible for their antioxidant activity. The major bioactive compounds of phenolics were found to be flavonoid groups such as quercetin and kaempferol. On the basis of the results obtained, moringa leaves are found to be a potential source of natural antioxidants due to their marked antioxidant activity. This is the first report on the antioxidant properties of the extracts from freeze-dried moringa leaves. Overall, both methanol (80%) and ethanol (70%) were found to be the best solvents for the extraction of antioxidant compounds from moringa leaves.