| Summary: | 碩士 === 元培科技大學 === 醫學檢驗生物技術研究所 === 100 === The cause of excessive oxidative stress is modern environment and diet patterns, because the body produces more oxidative material. Additionally, the dependence of endogenous antioxidant systems to against the oxidative stress brings about the need for multiple exogenous antioxidant agents to assist. It would cause chronic disease. Thus, the maintenance of balanced oxidation and antioxidant levels is a critical issue. Previous research of longan flowers indicates a variety of materials such as phenolic antioxidants are present. This study aims to assess the antioxidant effect of longan flower water extract in human platelets. We conducted three experiments, including the determination of lipid peroxidation, the measuring of catalase activity and glutathione peroxidase (GPx) activity. We used platelets as targets, sodium nitroprusside (SNP) as an oxidative inducer, with or without longan flower water extract for the detection of lipid peroxidation and enzyme activity. First, platelet reaction with SNP was used to determine the platelet lipid peroxidation phenomenon by the determination of MDA. We showed that different concentrations of SNP were caused by different levels of lipid peroxidation. In addition, we found that fresh platelets were easier for lipid peroxidation than non-fresh platelets. We added longan flower water extract at different intervals and found that longan flower water extract can protect cells from oxidative damage of platelets. Besides, we found that mild peroxidative platelets could be protected from oxidative damage, but for high level of peroxidation of platelets could be not protected from oxidative damage by longan flower water extract. The catalase activity indicated that SNP decreased catalase activity of platelets, when we added longan flower water extract. Our results indicated that SNP treatment reduced the catalase activity have been recovered. In GPx activity, SNP also cause platelet GPx activity decreased, longan flower water extract added, the same has been reduced by SNP treatment and GPx activity has been recovered. We concluded that longan flower water extract can protect cells from oxidative damage and recover antioxidant system activity in vivo.
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