Chemical Analysis and Antioxidant Activity in vitro of Polysaccharides Extracted from Lower Grade Green Tea

摘要

Tea is a well-known and important agricultural product in the world. The Crude Polysaccharides from tea leaves (CP) probably have good antioxidant activities. However, whether or not the antioxidant abilities of CP depend on tea polyphenols in the CP is not understanded. In this study, four CP fractions (TPF30, TPF50, TPF70 and TPF90) were isolated from CP and their antioxidant activities were compared. Meanwhile, Chemical and physical characteristics of CP and four CP fractions were investigated by the combination of chemical and instrumental analysis methods. Their antioxidant activities were investigated in vitro systems, including hydroxyl radical assay, 1, 1-Diphenyl-2-Picrylhydrazyl (DPPH·) scavenging activity, reducing power and chelating activity. Among CP and these four polysaccharides, TPF90 showed more significant DPPH· scavenging activity and highest reducing power, chelating activity and inhibitory effects on hydroxyl radical. Thus, it can be concluded that polysaccharides extracted from the lower grade green tea might be employed as ingredients in healthy and functional food to alleviate the oxidative stress.