Abstract: The oxygen free radical scavenging activities and anti-lipoprotein oxidative effects of green tea polysaccharides were studied. ROO·, O₂^-· and OH· scavenging activities were studied with chemiluminescence analysis, H₂O₂ scavenging activity was determined by spectrophotometry. Very low density lipoprotein (VLDL), low density lipoprotein (LDL) and high density lipoprotein (HDL) were isolated from fasting plasma by sequential ultracentrifugation at 0βh and 2βh after 20 healthy volunteers ingested green tea polysaccharides and degrees of peroxidization and susceptibilities of lipoproteins to oxidation were investigated. The results showed that green tea polysaccharides exhibited scavenging effects on ROO·, O₂^-·, OH· and H₂O₂ in vitro, significantly decreased lipid peroxides of plasma, VLDL, LDL and HDL; noticeably prolonged lag phage of LDL oxidation curve, indicating reduced susceptibility of LDL to oxidation. It is suggested that green tea polysaccharides can increase antioxidant capacities of plasma and lipoproteins, therefore may show the function of preventing cardiovascular disorders and delaying ageing.

Key words: green tea polysaccharides, free radical scavenging, lipid peroxidation, lipoproteins