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SOD inhibition of antioxidants autoxidation

SOD 抑制抗氧化剂的自氧化

基本信息

批准号：
10660132
负责人：
NAKAYAMA Tsutomu
金额：
$ 2.11万
依托单位：
University of Shizuoka
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10660132/
关键词：
hydrogen peroxide HPLC ECD electrochemistry analytical chemistry SOD catechins EGCg EGCg electro chemistry antioxidant cigarette smoke

项目摘要

We developed a new method to measure hydrogen peroxide(H_2O_2)by HPLC-ECD.By this method, we investigated effects of superoxide dismutase(SOD) on H_2O_2 formation in aqueous solutions of antioxidants such as ubiquinols, flavonols and catechins.(1)The method to measure H_2O_2 by HPLC-ECD is convenient, selective and sensitive. It also enables us to measure H_2O_2 concentration in aqueous solutions of cigarette tar, coffee, and ascorbic acid.(2)CoQ_0H_2 and myricetin are typical examples of a ubiquinol and a flavonol, respectively. Epigallocatechin gallate(EGCg), epigallocatechin(EGC), epicatechin gallate(ECg), and epicatechin(EC) are common catechins found in green tea. These compounds show antioxidant activity. But, they also show prooxidant activity under certain conditions owing to H_2O_2 formation. We measured H_2O_2 formed in aqueous solutions of these compounds by the HPLC-ECD method. SOD inhibited the H_2O_2 formation. The inhibition of H_2O_2 formation by SOD seems contradictory to the function of SOD, because H_2O_2 is a product of its enzyme reaction. This problem is solved by postulating a chain reaction in the formation of H_2O_2 with surperoxide as the chain carrier. We investigated cytotoxicity of myricetin, EGCg and EGC by a colony formation assay with Chinese hamster V79 cells. Inhibitory effects of catalase and SOD indicate that the cytotoxic effects were attributable to H_2O_2 formation where superoxide was involved.

建立了一种测定过氧化氢(H_2O_2)的新方法--高效液相色谱-电子捕获检测器，并用该方法研究了超氧化物歧化酶(SOD)对泛喹酚、黄酮醇、儿茶素等抗氧化剂水溶液中H_2O_2生成的影响。它还使我们能够测量卷烟焦油、咖啡和抗坏血酸水溶液中的H_2O_2浓度。(2)辅酶Q_0H_2和杨梅素分别是泛喹酚和黄酮醇的典型例子。表没食子儿茶素没食子酸酯(EGCG)、表没食子儿茶素(EGC)、表没食子儿茶素没食子酸酯(CG)和表儿茶素(EC)是绿茶中常见的儿茶素。这些化合物显示出抗氧化活性。但是，由于H_2O_2的生成，它们在一定条件下也表现出促氧化活性。我们用高效液相色谱-电子捕获检测器测定了这些化合物在水溶液中生成的H_2O_2。超氧化物歧化酶抑制H_2O_2的生成。SOD对H_2O_2生成的抑制作用似乎与其功能相矛盾，因为H_2O_2是其酶反应的产物。这个问题是通过假设过氧化氢作为链载体形成H_2O_2的链式反应来解决的。用中国仓鼠V79细胞集落形成实验研究了杨梅素、EGCG和EGC的细胞毒性。过氧化氢酶和超氧化物歧化酶的抑制作用表明，细胞毒作用与过氧化氢的形成有关，超氧化物参与了细胞毒作用。