中文摘要：

采用1，1-二苯基-2-三硝基苯肼（1，1．dipheny1-2-picrylhydrazyl，DPPH）自由基清除实验和氧化损伤酵母细胞实验模型，对不同纯度的茶多酚和茶黄素的抗氧化活性进行比较研究。结果表明，茶多酚和茶黄素均对DPPH自由基具有一定的清除能力。氧化损伤酵母细胞实验结果表明，茶多酚和茶黄素对酵母细胞氧化损伤具有一定的保护作用，且在一定浓度范围内其保护能力呈剂量依赖关系。98％茶多酚对DPPH自由基清除率最高；60％茶黄素和90％茶多酚对H2O2氧化损伤酵母细胞保护作用相当；60％茶黄素对紫外氧化损伤酵母细胞保护作用最强。茶多酚和茶黄素具有一定的体外和细胞抗氧化活性，且不同方法测得的抗氧化活性存在一定的差异。

英文摘要：

The antioxidant activities of green tea polyphenols （GTPs or TPs） and theaflavins （TFs） of varied purities were investigated by measuring the 1,1-diphenyl-2-picrylhydrazyl （DPPH） radical scavenging ability and protective activity against oxidative damage in yeast cells. Both TPs and TFs were able to scavenge DPPH radical. Results of protection against oxidative damage showed that the survival rate of yeast cells was increased significantly by the addition of either TPs or TFs, and their protective effects were positively correlated with their doses. It was found that 98% TPs showed the strongest scavenging ability on DPPH radicals while 60% TFs showed comparable protective effect on yeast injured by H2O2 cells to that of 90% TPs. Moreover, 60% TFs showed the strongest protect effect on UV damaged yeast cells. Thus, it could be concluded that TPs and TFs possess in vitro and intraceUular antioxidant activity, and there existed differences between the antioxidant activities by varied assay methods.