Abstract: AIM To study the protective effects of tea polyphenol (TP) on cerebral ischemia reperfusion injury in rats and its scavenging oxygen free radical(OFR) activities and antilipid peroxidation in vitro. METHODS Cerebral ischemia reperfusion injury was produced by bilateral ligation of the common carotid arteries with vagus nerves and reperfusion for 45 min. The mitochondrial lipid peroxidation of rat brain induced by oxygen free radical was measured by thiobarbituric acid spectrophotometry. Superoxide anion (O2^-) from xanthine-xanthine oxidase system and hydroxyl radical (·OH) from Fe²⁺-H2O2 system were determined with spectrophotometry. RESULTS During Cerebral ischemia reperfusion,TP improved the activities of superoxide dismutase (P<0.05), GSH peroxidase(P<0.01) and catalase(P<0.01), while decreasing the maiondialdchyde content in the brain(P<0.05) and brain water content (P<0.01). Tea polyphenol possessed significantly scavenging effects on ·OH produced by Fenton reaction and O2^- produced by xanthine-xanthine oxidase system (the IC50 were 2.2 mmol·L^-1 and 1.9 mmol·L^-1 respectively). Tea polyphenol could significant inhibit the lipid peroxidation of cerbral mitochondrial membrane induced by ·OH in a concentration dependent manner. CONCLUSION The results indicate that tea polyphenol could protect the injury on cerebral ischemia reperfusion in rats for OFR, these effects may be related to its scavenging effects on oxygen free radicals and antilipid peroxidant.

Key words: Tea polyphenol, Tea polyphenol, Scavenging oxygen free redicals, Scavenging oxygen free redicals, Antilipid peroxidation, Antilipid peroxidation, Ischemia reperfusion, Ischemia reperfusion