绿茶多糖抗血浆脂蛋白脂质过氧化作用的研究

研究绿茶多糖体外清除氧自由基与抗脂蛋白氧化作用。采用化学发光法测定绿茶多糖对ROO·、O₂^-·及OH·的清除作用,采用比色法测定对H₂O₂的清除作用。给20名健康受试者空腹食用绿茶多糖前和2βh后抽取静脉血,采用序列超速离心法分离血浆极低密度脂蛋白（VLDL）、低密度脂蛋白（LDL）和高密度脂蛋白（HDL）,并观察各血浆脂蛋白过氧化程度以及氧化易感性的变化。结果表明,绿茶多糖对ROO·、O₂^-·、OH·及H₂O₂均有清除作用;食用绿茶多糖后受试者血浆及VLDL、LDL和HDL过氧化脂质水平明显降低;在体外进行氧化修饰时,LDL氧化延滞时间明显延长,提示LDL氧化易感性下降。研究结果提示,绿茶多糖可增强血浆及脂蛋白抗氧化能力,能够起到预防心血管疾病和延缓衰老的积极作用。

Study of Green Tea Polysaccharides on Lipid Peroxidation of Plasma Lipoproteins

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 0 h and 2 h 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.