Evaluation of antioxidant properties of a new compound, pyrogallol-phloroglucinol-6,6'-bieckol isolated from brown algae, Ecklonia cava

In this study, antioxidant and free radical scavenging activities of the natural antioxidative compound, pyrogallol-phloroglucinol-6,6''-bieckol (PPB) isolated from brown algae, Ecklonia cava was assessed in vitro by measuring the radical scavenging activities (DPPH, alkyl, hydroxyl, and superoxide) using electron spin resonance (ESR) spectrometry, intracellular reactive oxygen species (ROS) scavenging activity, and DNA damage assay. According to the results of these experiments, the scavenging activity PPB against difference radicals was in the following order: DPPH, alkyl, hydroxyl, and superoxide radicals (IC₅₀; 0.90, 2.54, 62.93 and 109.05 µM). The antioxidant activities of PPB were higher than that of the commercial antioxidant, ascorbic acid. Furthermore, PPB effectively inhibited DNA damage induced by H₂O₂. These results suggest that the natural antioxidative compound, PPB, can be used by the natural food industry.     

葡多酚对活性氧自由基的清除作用研究

目的 :　探讨葡多酚 ( GPC)对活性氧自由基的清除作用。方法 :　采用电子自旋共振 ( ESR)和自旋捕集技术直接测定不同浓度 GPC对 Fenton反应体系产生的羟自由基 (· OH)、光照核黄素 /EDTA体系产生的超氧阴离子 ( O·2 )及 Fe2 + 启动线粒体膜脂质过氧化产生的脂类自由基 ( LOO· )清除作用。结果 :　 GPC浓度为 1 mg/L、1 0 mg/L、1 0 0 mg/L、1 0 0 0 mg/L对·OH的清除率 ( % )依次为 9.0、2 0 .6、47.7、57.7,对 O·2 的清除率 ( % )分别为 1 0 .9、1 7.0、50 .9、72 .1 ,对LOO·的清除率 ( % )依次为 39.8、49.6、65.9、71 .4。葡多酚对· OH、O·2 及 LOO· 50 %的清除浓度 ( IC50 值 )分别为 1 2 8.9mg/L、89.4mg/L、1 0 .4mg/L。结论 :　葡多酚对三种活性氧自由基均有不同程度的清除作用 ,其中 LOO· >O·2 >· OH。     

Radical scavenging, antibacterial, and antiproliferative activities of Melissa officinalis L. extracts

The aromatic herb Melissa officinalis L. can be used as an easily accessible source of natural antioxidants and as a possible food supplement and as a phytochemical. Radical scavenging, antibacterial, and antiproliferative activities of petroleum ether, chloroform, ethyl acetate, n-butanol, and water extracts of M. officinalis L. extracts were investigated. The results of antioxidative activity, obtained by electron spin resonance spectroscopy, confirmed that investigated extracts suppressed the formation of 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, and lipid peroxyl radicals in all investigated systems in a dose-dependent manner. The maximum DPPH and hydroxyl radical scavenging activities (SA(DPPH) = SA(OH) = 100%) were achieved in the presence of n-butanol extract at concentrations of 0.4 mg/mL and 0.5 mg/mL, respectively. The highest lipid peroxyl scavenging activity (93.20%) was observed at a higher concentration (5 mg/mL) of n-butanol extract in the lipid peroxidation system. The most effective antibacterial activities were expressed by petroleum ether and ethyl acetate extracts on Sarcina lutea. Chloroform extract showed the strongest antiproliferative effect with 50% inhibitory concentration values of 0.09 mg/mL and 0.10 mg/mL for HeLa and MCF-7 cell lines, respectively. The present study demonstrated the high phenolic content and radical scavenging, antibacterial, and antiproliferative activities of extracts of M. officinalis L. originating from Serbia.     

Antioxidant activity of methanolic extract of emblica fruit (Phyllanthus emblica L.) from six regions in China

The phenolic contents of methanolic extracts of emblica (Phyllanthus emblica L.) fruit from six regions in China were measured in this work. The antioxidant activities of these extracts were also evaluated. Total phenolic content was ranged from 81.5 to 120.9 mg gallic acid equivalents (GAE)/g and the flavonoid content was varied from 20.3 to 38.7 mg quecetin equivalents (QE)/g, while proanthocyanidin content was ranged from 3.7 to 18.7 mg catechin equivalents (CE)/g. Among all the methanolic extracts analyzed, the Huizhou sample exhibited a significantly higher phenolic content than other samples (P<0.05). The antioxidant activities were evaluated by in vitro experiments using scavenging assays of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, hydroxyl radicals, and superoxide anion radicals, chelating ability of ferrous ion, reducing power, and inhibition capability of Fe (II)-induced lipid peroxidation, respectively. The Huizhou sample was found to have the strongest antioxidant activities in scavenging DPPH radicals, superoxide anion radicals, and had the highest reducing power, while the Chuxiong sample showed the best performance in chelating iron and inhibiting lipid peroxidation. Furthermore, the Chuxiong sample exhibited a stronger inhibition activity of the hydroxyl radicals compared with other samples. The high correlation coefficient was existed between the phenolic content and superoxide anion radical scavenging activity, but no significant correlation was found between the former and hydroxyl radical scavenging activity. Methanolic extracts of emblica fruit from some selected regions exhibited stronger antioxidant activities compared to those of the commercial compounds (quercetin and BHA). It might be considered as a potential plant source of antioxidants.     

Study on the antioxidant activity of tea flowers (Camellia sinensis)

Major chemical compounds in different extracts from tea flowers (Camellia sinensis) were analyzed. Distilled water or 70% ethanol extracts were then fractionated with chloroform, ethyl acetate and n-butanol, respectively. Each extract fraction was tested its scavenging activities on 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl free radicals. The results showed that ethyl acetate fraction of ethanol-extract of tea flower (EEA) exhibited the highest quenching activity to hydroxyl radicals (SC50 11.6 mug/ml), followed by ethanol-extract (EE) of tea flower (SC50 19.7 microg/ml). Same tea flower extract showed big different scavenging activities on different free radicals. EEA quenched 80% of hydroxyl radicals generated by Fenton's reaction, however, only 40% of DPPH radical was scavenged in the Fe (II)-H2O2 -luminol system. The contents of flavones, polyphenols and catechins in EE and EEA fractions were higher than those in other fractions. We suggest that the stronger scavenging abilities to free radicals might be due to polyphenols, EGCG, ECG and flavones. However, the water extracts of tea flower and their fractions showed lower antioxidant activity for their inhibitory effect on hydroxyl radicals and DPPH radicals.     

In vitro antioxidant and free radical scavenging activity of Cyperus rotundus

Cyperus rotundus (Family Cyperaceae) is used both as a functional food and as a drug. In this study, the antioxidative potential of a hydroalcoholic extract of C. rotundus (CRE) was evaluated by various antioxidant assays, including antioxidant capacity by the phosphomolybdenum method, total antioxidant activity in linoleic acid emulsion systems, 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide, hydroxyl radicals, and nitric oxide (NO) scavenging. We further evaluated the reducing potential of the extract as well as Fe(2+)/ascorbate-induced lipid peroxidation in rat liver homogenate. These various antioxidant activities were compared to standard antioxidants such as butylated hydroxytoluene, tocopherol, L-ascorbic acid, and catechin. Total phenolic and flavonoid content of CRE was also determined by a colorimetric method. The extract exhibited high reduction capability and powerful free radical scavenging, especially against DPPH and superoxide anions as well as a moderate effect on NO. CRE also showed inhibited lipid peroxidation in rat liver homogenate induced by Fe(2+)/ascorbate and prevented deoxyribose degradation in both non-site-specific and site-specific assays showing the hydroxyl radical scavenging and metal chelating activity of the hydroalcoholic extract. Moreover, the peroxidation inhibiting activity of CRE was demonstrated in the linoleic acid emulsion system. These results clearly established the antioxidative potency of C. rotundus, which may account for some of the medical claims attributed to this plant.     

Antioxidative activity of hen egg ovalbumin hydrolysates

To evaluate the antioxidative activity of the hydrolysates of ovalbumin, the antioxidative activities of the enzymatic extracts were evaluated using three different methodologies scavenging assays such as superoxide anion, hydroxyl radical, and inhibitory oxidation of linoleic acid in vitro, and the activities of SOD, GSH-PX, CAT and the level of MDA were determined in serum and liver of aged mice induced by G-gal. The results showed that the hydrolysates had a distinctly inhibitory action to superoxide anion made by alkaline pyrogallic acid, HO. produced by Fenton reaction, the oxidation of linoleic acid in linoleic acid autoxidation system, and presented a positive correlation. The inhibition capacity of hydrolysates against superoxide anion and HO. were more than 45% and 56% respectively at the concentration 5 mg/mL. And the hydrolysates could significantly (p< 0.01) prevented the activities of SOD, GSH-Px, and CAT against reducing and all three concentrations could significantly (p< 0.01) decrease the MDA contents in the serum and liver of aged mice induced by G-gal. The antioxidative activity of high concentration was similar to that of control group.     

Antioxidant properties of enzymatic hydrolysates from royal jelly

Enzymatic hydrolysates were prepared from royal jelly using three enzymes (pepsin, trypsin, and papain), and their antioxidative properties were evaluated. The yield of these hydrolysates was very high, about 20-26% on a raw weight basis. In comparison with the antioxidative activities of water extract and alkaline extract of royal jelly, the antioxidative activities and scavenging activities against active oxygen species such as superoxide anion radical and hydroxyl radical of each hydrolysate were high in the sample with a low protein concentration. These results suggest that once royal jelly is hydrolyzed using enzyme, the hydrolysate possesses much higher antioxidative activity and scavenging activity against active oxygen species. Royal jelly will act as a medicinal food in the human body.     

Radical scavenging activity of flavonoids from Trollius chinensis Bunge

Objective

Flos trollii is considered as functional tea, as well as a traditional medicinal herb, in China. In this study, total phenolic and flavonoid contents of Flos trollii were determined by a colorimetric method. The antioxidative potential of the hydroalcoholic extract of Flos trollii (FTE, extracted by alcohol:water, 80:20) was also evaluated by various antioxidant assays.

Methods

Chemiluminescence technique was used to determine the radical scavenging activities of FTE toward different reactive oxygen species, including superoxide anion (O_-2·), hydroxyl radical (OH·), lipid-derived radicals (R·), and singlet oxygen (¹O₂).

Results

FTE could effectively scavenge O_-2·, OH·, R·, and ¹O₂ at an efficient concentration (EC₅₀) of 46, 5.64, 5.19, and 3.97 mg/mL, respectively. Moreover, the radical scavenging activities of FTE were higher than those of ascorbic acid. Further, FTE had higher 1,1 diphenyl-2-picrylhydrazyl radical (DPPH) radical-scavenging activity with EC₅₀ 44 mg/mL, compared with butylated hydroxytoluenesynthetic antioxidant with EC₅₀ 52 mg/mL.

Conclusion

All results indicated that FTE is a powerful antioxidant, deserving of better utilization of the extracted Flos trollii as antioxidants.     

Antioxidant activity of far-infrared radiated rice hull extracts on reactive oxygen species scavenging and oxidative DNA damage in human lymphocytes

The antioxidant activities of methanolic extracts of far-infrared irradiated rice hull (FRH) and non-irradiated intact rice hull (IRH) were determined. The antioxidant effects against reactive oxygen species (ROS) were evaluated by measuring scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, superoxide, hydrogen peroxide (H2O2), and nitric oxide radical and capacity for chelating metals. Except for H2O2 scavenging activity, FRH showed higher scavenging activity than IRH; for example, the 50% inhibitory concentration (mg/mL) values for DPPH radical scavenging of FRH and IRH were 0.067 and 0.085, respectively, as compared with 0.362 and 0.012 for butylated hydroxytoluene and alpha-tocopherol, respectively. The effect of rice hull extract on DNA damage induced by H2O2 in human lymphocytes was also evaluated by comet assay. The protective effect of rice hull extract increased as its concentration increased from 12.5 to 50 microg/mL, as indicated by DNA strand breakage decreasing from 38% to 22% with FRH and from 49% to 28% with IRH as compared with H2O2-treated positive controls. When human lymphocytes were post-incubated with rice hull extract for 30 minutes after exposure to H2O2, the protective ability of the rice hulls remained unchanged. These results suggest that methanol extracts of rice hulls possess significant ROS scavenging and metal chelating activities and protective effect against oxidative DNA damage.     

紫甘薯花青素的稳定性及抗氧化性研究

目的探明紫甘薯花青素的稳定性和抗氧化性,为紫甘薯花青素在食品中的加工利用提供理论依据。方法采用HPLC和LC-MSn对ZA1紫甘薯花青素成分进行了分析。比较花青素在室内自然光,紫外光,沸水浴高压灭菌和不同pH值条件下的稳定性。研究了其清除超氧阴离子自由基、羟基自由基和DPPH.自由基等抗氧化性能力。结果紫甘薯花青素成分包括有矢车菊素、飞燕草素、锦葵色素、牵牛花色素和甲基花青素。自然光和紫外光照对花青素稳定性影响较小,高温对花青素稳定性影响较大。pH值对花青素稳定性影响非常大,低pH有利于花青素保留。pH为7.0时,花青素具备较好的清除超氧阴离子、羟基自由基和DPPH.自由基能力。结论紫甘薯花青素稳定性受光照、温度、pH值影响。紫甘薯花青素具有较强的抗氧化能力。     

Protective effects of broccoli (Brassica oleracea) and its active components against radical-induced oxidative damage

The radical scavenging effect and protective potential from oxidative damage by radical generator, 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH), in renal epithelial LLC-PK1 cell of broccoli (Brassica oleracea) were investigated and identified the active components under the bioassay-linked fractionation method. The MeOH extract, and fractions of CH2Cl2, BuOH and H2O from broccoli showed the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging effect in a dose-dependent manner. In addition, they exerted the protective effect against LLC-PK1 cellular damage induced by AAPH dose-dependently. In particular, the BuOH fraction was evaluated as the most active fraction, indicating that the BuOH fraction contains the active components with antioxidative capacity. Employing a bioassay-linked fractionation method, the active principles were isolated and characterized as 1,2-disinapoylgentiobiose and 1-sinapoyl-2-feruloylgentiobiose from the BuOH fraction. These two compounds from broccoli displayed potent antioxidant effects against the DPPH radical, showing the IC50 values of 5.18 and 7.52 microg/mL, respectively. Moreover, the compounds significantly and dose-dependently recovered cell viability lowered by AAPH treatment, suggesting the protective roles from cellular oxidative damage. The present study suggests that broccoli has excellent antioxidative potential and the hydroxycinamic acid esters from broccoli, 1,2-disinapoylgentiobiose and 1-sinapoyl-2-feruloylgentiobiose, are considered as the active components with antioxidative effect.     

The antioxidant activity of 2-(4(or 2)-hydroxyl-5-chloride-1,3-benzene-di-sulfanimide)-chitosan

Chitosan (CS) with two different molecular weights was modified by reacting with 4-hydroxyl-5-chloride-1,3-benzene-disulfo-chloride or 2-hydroxyl-5-chloride-1,3-benzene-disulfo-chloride to give new 2-(4(or 2)-hydroxyl-5-chloride-1,3-benzene-di-sulfanimide)-chitosan (2-HCBSAHCS, 2-HCBSALCS, 4-HCBSAHCS, 4-HCBSALCS). The structure of the derivatives was characterized by FT-IR and 13C NMR spectroscopy. The antioxidant activities of the derivatives were investigated employing various established systems, such as hydroxyl radical (.OH)/superoxide anion (O2.-) scavenging/reducing power and chelating activity. All the derivatives showed stronger scavenging activity on hydroxyl radical than chitosan and ascorbic acid (Vc), and IC50 of 4-HCBSAHCS, 4-HCBSALCS, 2-HCBSAHCS and 2-HCBSALCS was 0.334, 0.302, 0.442, 0.346 mg/mL, respectively. The inhibitory activities of the derivatives toward superoxide radical by the PMS-NADH system were strong. The results showed that the superoxide radical scavenging effect of 2-(4(or 2)-hydroxyl-5-chloride-1,3-benzene-di-sulfanimide)-chitosan was higher than chitosan. The derivatives had obviously reducing power and slight chelating activity. The data obtained in in vitro models clearly establish the antioxidant potency of 2-(4(or 2)-hydroxyl-5-chloride-1,3-benzene-disulfanimide)-chitosan.     

The antioxidant and radical scavenging activities of black pepper (Piper nigrum) seeds

Water and ethanol crude extracts from black pepper (Piper nigrum) were investigated for their antioxidant and radical scavenging activities in six different assay, namely, total antioxidant activity, reducing power, 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities. Both water extract (WEBP) and ethanol extract (EEBP) of black pepper exhibited strong total antioxidant activity. The 75 microg/ml concentration of WEBP and EEBP showed 95.5% and 93.3% inhibition on peroxidation of linoleic acid emulsion, respectively. On the other hand, at the same concentration, standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and alpha-tocopherol exhibited 92.1%, 95.0%, and 70.4% inhibition on peroxidation of linoleic acid emulsion, respectively. Also, total phenolic content in both WEBP and EEBP were determined as gallic acid equivalents. The total phenolics content of water and ethanol extracts were determined by the Folin-Ciocalteu procedure and 54.3 and 42.8 microg gallic acid equivalent of phenols was detected in 1 mg WEBP and EEBP.     

Radical scavenging-linked antioxidant activities of commonly used herbs and spices in Korea

Herbs and spices not only variety and racy flavour to Korean foods, they also are the richest source for antioxidant power. The present study evaluates the radical scavenging-linked antioxidant activities of hot water extracts from commonly used herbs and spices in Korea. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical and superoxide anion scavenging activities of bay extract were 39.5% and 22.1%, respectively. The hydroxyl radical scavenging activity was in order of dill (50.0%) > bay (31.3%) > garlic (27.9%) > white pepper and black pepper (15.1-15.3%) > onion (10.1%) extracts. Bay extract had the highest total phenolic content (17.86?μg CE/g). High correlation coefficients were found between the total phenol content and DPPH radical scavenging activity (R?=?0.9162). These results indicate that herbs and spices had high antioxidant activity that is partly due to the phenolic compounds and provide basic data for further development of processed food products.     

Glycoprotein isolated from Solanum nigrum L. kills HT-29 cells through apoptosis

Solanum nigrum L. (SNL) has been used in folk medicine for its anti-inflammatory activity. We previously isolated glycoprotein from SNL and observed that it decreased viable HT-29 cell numbers at a low concentration (60 microg/mL). This study investigated the apoptotic signal pathway triggered by glycoprotein isolated from SNL in HT-29 cells. Treatment of HT-29 cells with SNL glycoprotein (60 microg/mL) for 4 hours resulted in a cytotoxic effect of more than 60%, compared with the control. To explain the apoptotic effects of SNL glycoprotein, we investigated its effects on 12-O-tetradecanoylphorbol 13-acetate (TPA)-stimulated protein kinase C (PKC) alpha activity and DNA-binding activity of nuclear factor (NF) kappaB in HT-29 cells, using western blot analysis and electrophoretic mobility shift assays. Results from these experiments showed that SNL glycoprotein has remarkable inhibitory effects on the activities of TPA (100 nM)-stimulated PKCalpha and NF-kappaB in HT-29 cells. They also substantiated that PKCalpha is a part of the TPA-activated upstream signal pathway of NF-kappaB, since NF-kappaB activity was inhibited by staurosporine (a PKC inhibitor) and pyrrolidine dithiocarbamate (an NF-kappaB inhibitor) in a western blot analysis. Furthermore, to verify the triggering of apoptosis by the SNL glycoprotein, we performed DNA fragmentation, nuclear staining, and protein expression assays of apoptotic-related proteins. The amount of DNA fragmentation and apoptotic cell numbers increased in a dose-dependent manner after treatment with SNL glycoprotein. Apoptosis-related protein assays demonstrated that SNL glycoprotein-induced apoptosis is associated with the regulation of bcl-2 and Bax expression. Taken together, the results of this study showed that the activation of PKCalpha, NF-kappaB, and Bax expression by SNL glycoprotein is possibly involved in the apoptotic process. Consequently, these results indicate that SNL glycoprotein causes HT-29 cell death through apoptosis by its ability to modulate anti-apoptotic signals. We suggest that SNL glycoprotein is a natural anti-cancer agent due to its potential to induce apoptosis in HT-29 cells.     

蛋清的蛋白酶解物清除自由基能力的研究

目的研究胃蛋白酶、胰蛋白酶、木瓜蛋白酶、中性蛋白酶及Alcalase碱性蛋白酶对蛋清蛋白的水解效果以及其酶解物对自由基的清除能力。方法采用茚三酮法分析五种蛋白酶对蛋清蛋白的水解效果;通过Fenton体系和邻苯三酚自氧化体系测定五种蛋白酶水解产物对羟自由基及超氧阴离子的清除能力。结果五种蛋白酶在其最适反应条件下,水解度大小依次为:alcalase碱性蛋白酶>胰蛋白酶>木瓜蛋白酶>中性蛋白酶>胃蛋白酶;羟自由基清除能力强弱依次为:木瓜蛋白酶>alcalase碱性蛋白酶>胰蛋白酶>中性蛋白酶>胃蛋白酶;超氧阴离子清除能力强弱依次为:木瓜蛋白酶>alcalase碱性蛋白酶>中性蛋白酶>胃蛋白酶>胰蛋白酶。木瓜蛋白酶水解3h的产物对两种自由基清除能力最强,对羟自由基的清除率为65.63%,对超氧阴离子的清除率为38.40%。结论蛋清的蛋白酶解物具有清除羟自由基及超氧阴离子的能力,且对羟自由基的清除能力大于超氧阴离子。     

Free radical scavenging activity of a novel antioxidative peptide isolated from in vitro gastrointestinal digests of Mytilus coruscus

A low-molecular-weight peptide with potent antioxidative activity was obtained from Mytilus coruscus muscle protein using an in vitro gastrointestinal digestion system. The potent antioxidant peptide, which was identified as Leu-Val-Gly-Asp-Glu-Gln-Ala-Val-Pro-Ala-Val-Cys-Val-Pro (1.59 kDa), exhibited higher protective activity against polyunsaturated fatty acid (PUFA) peroxidation than the native antioxidants, ascorbic acid and alpha-tocopherol. In a free radical scavenging assay using electron spin resonance spectroscopy, hydroxyl radical formation was quenched by 75.04% in the presence of M. coruscus peptide (50 microg/mL), which was similar to ascorbic acid. In addition, the purified peptide could also quench super-oxide and carbon-centered radicals, but those activities were weaker than for ascorbic acid. This study showed that the low-molecular-weight peptide released from in vitro gastrointestinal digestion of mussel exhibited potent antioxidant potential by inhibiting the formation of reactive oxygen species formed by the peroxidation of PUFAs.     

Antioxidant properties of Viburnum opulus and Viburnum lantana growing in Turkey

In the present study, antioxidant properties of the water extracts of different parts of Viburnum opulus and Viburnum lantana (Caprifoliaceae) were investigated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging and superoxide anion scavenging methods. The extracts were prepared from the fruits, branches, and leaves of V lantana and V opulus species. The branch extracts of V lantana and V opulus inhibited superoxide anion in a concentration-dependent manner. Compared with t-tocopherol, the fruit extract of V lantana did not show any scavenging effect on superoxide anion formation. V lantana leaf extracts, however, showed a moderate scavenging effect on superoxide anion formation, whereas V lantana branch extracts showed a strong scavenging effect (IC50 = 3.1 mg/ml) on superoxide anion in higher concentration. On the other hand, all extracts exhibited a scavenging effect on the DPPH radical with various potencies. When compared with butylated hydroxytoluene, V opulus branch and V lantana leaf extracts, as well as V lantana branch, V opulus fruit and V lantana fruit extracts, showed strong DPPH radical scavenging activity with IC50 values of 0.014, 0.035, 0.052, 0.057 and 0.085 mg/ml, respectively.     

茶多酚清除氧自由基作用研究

用Ｆｅｎｔｏｎ反应产生羟自由基（ＯＨ），用黄瞟吟／黄瞟吟氧化酶反应系统产生超氧阴离子自由基（Ｏ），研究了茶多酚对ＯＨ和Ｏ的清除作用．结果表明，分别向产生ＯＨ和Ｏ的反应系统加入茶多酚后，可使ＯＨ和Ｏ的产生量显著减少，且随茶多酚加入剂量的增加，ＯＨ和Ｏ产生量减少也越显著（Ｐ＜０．０５）。本研究结果提示，茶多酚对ＯＨ和Ｏ具有直接清除作用。茶多酚对氧自由基的直接清除作用可能是其抑制突变和抗氧化作用的分子生物学基础．