黄茶多糖的分离纯化及其抗氧化活性研究

Extraction,Purification and Antioxidative Activity of Polysaccharides from Yellow Tea

该文对黄茶进行分离纯化,并对其抗氧化活性进行研究。对黄茶进行热水浸提、70%乙醇醇沉得到黄茶70部位的粗多糖(YT70),利用阴离子交换柱对YT70进行分离纯化得到YT70-1,进一步对YT70-1进行DPPH·、ABTS^(+)·、·OH的清除试验以及总还原力能力测定试验。结果表明YT70的糖含量为43.3%,YT70-1的单糖组成为甘露糖、鼠李糖、葡萄糖醛酸、葡萄糖、半乳糖、木糖、阿拉伯糖及岩藻糖。YT70-1对DPPH·、ABTS^(+)·和·OH的清除率与质量浓度呈量效关系,且总还原能力与浓度成正比。在浓度为20 mg/mL时,YT70-1对DPPH·、ABTS^(+)·和·OH的清除率分别为48.7%、77.01%和39.67%,还原力为0.415。YT70-1对ABTS^(+)·的IC_(50)值为3.87 mg/mL。因此YT70-1具有一定的体外抗氧化活性,能够清除DPPH·、ABTS^(+)·和·OH,并且清除能力随多糖浓度的增大而增加。

In this study,yellow tea was separated and purified,and its antioxidant activity was investigated.Yellow tea was subjected to water extraction and alcohol precipitation to obtain YT70. It was then separated and purified to obtain YT70-1 by anion-exchange column. The scavenging effects of YT70-1 on DPPH·,ABTS^(+)·,and ·OH from scavenging experiments,as well as the total reduction power,were all evaluated. The results showed that the sugar content of YT70 was 43.3%,and the monosaccharide composition of YT70-1 was mannose,rhamnose,glucuronic acid,glucose,galactose,xylose,arabinose and fucose. YT70-1 had a dose-dependent effect on DPPH·,ABTS^(+)·and·OH,and the total reduction ability of YT70-1 was proportional to the concentration. When the concentration of YT70-1 was 20 mg/mL,the scavenging rates of DPPH·,ABTS^(+)·,and OH· were 48.7%,77.01% and 39.67%,respectively,and the reduction force was 0.415. The IC_(50) of YT70-1 to ABTS^(+)·was 3.87 mg/mL. YT70-1 exhibited specific antioxidant activity in vitro,and its scavenging ability increased with an increase in polysaccharide concentration. YT70-1 thus had dose-dependent effects on DPPH·,ABTS^(+)·,·OH,and the total reduction ability.