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Reactive oxygen species (ROS : 02-,H202, OH) and peroxynitrite (ONOO-) are proposed as agents attacking fatty acids in cells, tissues, or organism (including human beings), giving rise to an oxidative damage of biologically important molecules. Especially, ONOO- formed from superoxide(02-) and nitric oxide(NO) acts as a strong cytotoxicant giving carcinogenesis, cell death and low density lipoprotein oxidation.
Green tea is now one of the most popular consumed beverage in the world. Some major green tea catechins are (-)-epicatechin 3-O-gallate(ECG), (-)-gallocatechin 3-O-gallate(GCG), (-)-epigallocatechin 3-O- gallate(EGCG), (-)-epigallocatechinm(EGC), (-)-epicatechin(EC), and (+)- catechin(C). Green tea and its components have a wide range of biological and pharmacological activities that may contribute to chemopreventive effects.
In the present study, 21 kinds of several teas including cereal teas, fruit teas, leaf teas and root teas were screened for the scavenging effects against peroxynitrite formation by SIN-1 and peroxynitrite itself. Green tea showed the strongest peroxynitrite scavenging activity. In addition, among the green tea compoments, catechins with galloyl group inhibited peroxynitrite formation by SIN-1 and scavenged peroxynitrite itself. Especially, when compared with phenicillamine as a positive GCG and EGCG, which have two galloyl groups showed the most potent peroxynitrite scavenging, which indicates that galloyl group maybe contribute to peroxynitrite scavenging activity.
Moreover, 21 kinds of teas including cereal teas, fruit teas, leaf teas and root teas were screened for the scavenging effects against total free radical formation. Among the several teas and constituents. green tea and ECG, GCG. EGCG from green tea showed the strongest scavenging activity respectively. To elucidate the mechanism of scavenging activity. the effects of ECG, GCG, EGCG on ROS(02-, H202, OH) were investigated. EGCG showed remarkably scavenging activity against 02- and H202. Also GCG had the strongest scavenging activity against OH.
The treatment with ECG. GCG and EGCG reduced cell damage induced by SIN-I. AMVN, H202 and t-BHP in cultured AcF2 liver cell. But, in case of SNP, cell viability was not dependent on concentration and green tea components. Therefore, we can postulated that green tea components inhibited peroxynitrite formation through their 02- scavenging activity.
In vivo assay, peroxynitrite level. total free radical generation, AAPH-induced TBARS and TBARS itself were increased by t-BHP(120mg/kg, i.p.) and SIN-1 (100mg/kg, i.p.), but 2-BE(120mg /kg t-BHP, i.p. + 2mg/kg EGCG, i.p.). 10-BE(120mg/kg t-BHP, i.p. + 10mg/kg EGCG. i.p.), 2-SE(100mg/kg SIN-1, i.p. + 2mg/kg EGCG. i.p.), and 10-SE(100mg/kg SIN-1, i.p. + 10mg/kg EGCG, i.p.) were decreased in dose-independent manner. Namely. EGCG isolated from green tea strongly inhibited lipid peroxidation and total free radical generation in rat liver.
These results suggested that ECG. GCG and EGCG isolated from green tea might show cytoprotective action through antioxidant and peroxynitrite scavenging activity.

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