六堡茶多糖理化性质、体外抗氧化及其对人脐静脉血管内皮细胞的保护作用

以六堡茶为原料,利用水提醇沉法制得茶多糖粗品,经脱蛋白纯化后用30%、50%、70%的乙醇溶液进行分段,得到3种六堡茶多糖LTPS-30、LTPS-50和LTPS-70,并分析了其化学组成、分子量分布等理化性质;以自由基清除法(ABTS)和铁离子还原法(FRAP)评价其抗氧化活性;并以Na2S2O3损伤的人脐静脉血管内皮细胞(HUVEC)为模型,探讨了它们对HUVEC氧化损伤的保护作用。结果表明,3种六堡茶多糖样品均为主要含有2个组分的非均一酸性多糖,平均分子量和总糖含量均为LTPS-70LTPS-50LTPS-30;而在蛋白质和总酚含量及两种抗氧化体系下的抗氧化活力均为LTPS-70LTPS-50LTPS-30,且LTPS-70表现出最强的细胞保护作用。说明茶多糖粗品经70%乙醇纯化后具有较强的生物活性,具有良好的应用前景。

Physicochemical Properties,in vitro Antioxidant Activities and Protective Effects of Liubao Tea Polysaccharides on HUVEC

Tea Polysaccharides were extracted and purified from Liubao tea. Three fractions of polysaccharides namely LTPS-30, LTPS-50 and LTPS-70 were then obtained from Liubao Tea Polysaccharides (LTPS) by 30%, 50%and 70% ethanol respectively. The main chemical compounds and monosaccharide compositions of these LTPS were investigated. The in vitro antioxidant activities of LTPS were determined by ABTS and FRAP assays. The potentially protective effects of LTPS on human umbilical vascular endothelial cells (HUVEC) were investigated according to the Na2S2O3-induced model. The results showed that there were two main acidic polysaccharides in LTPS-70, LTPS-50 and LTPS-30. The order of molecular weight and total sugar content was LTPS-70