乙醇法沉淀茶多糖的抗氧化活性评价

Antioxidant Activity of Tea Polysaccharides Obtained by Ethanol Precipitation

以粗茶多糖提取物(TPs-CK)为原料,设置70%和80%2个乙醇浓度沉淀制备茶多糖样品TPs-70和TPs-80,通过检测其DPPH清除活性和还原力变化,对茶多糖样品进行抗氧化活性评价。结果表明,70%浓度乙醇更适宜于沉淀茶多糖,可溶性蛋白含量低,DPPH清除率和还原力变化试验表明,茶多糖TPs-70和TPs-80极显著性低于TPs-CK和抗坏血酸,两者之间未见显著性差异,TPs-80略低于TPs-70;检测分析茶多糖样品中抗氧化组分含量发现,茶多糖、茶多酚、总黄酮等组分皆有析出,与TPs-CK相比,茶多糖样品TPs-70和TPs-80中茶多酚和总黄酮含量呈极显著性降低。相关性分析表明,茶多糖、茶多酚和总黄酮与茶多糖样品抗氧化活性表达呈正相关,茶多酚呈显著性正相关。综上所述,70%浓度乙醇更适宜于沉淀制备茶多糖样品,且抗氧化活性强。

On the crude tea polysaccharides（TPs-CK）,70% and 80% ethanol were used to precipitate TPs-70 and TPs-80.The antioxidant activities of the precipitated TPs and TPs-CK were compared on their DPPH scavenging abilities and reducibilities.The results showed that the antioxidant activities of TPs-70 and TPs-80 were significantly lower than that of TPs-CK or ascorbic acid.TPs-80 was slightly lower than TPs-70 in antioxidant activity,but not significantly different.The contents of polyphenols and total flavones in TPs-70 and TPs-80 were lower than those in TPs-CK.The correlation analysis suggested that the polysaccharide,polyphenol,and flavone contents all positively,with the tea polyphenols significantly,correlated to the antioxidant activity of the samples.Consequently,70% ethanol was considered appropriate for precipitating TPs in order to intensify the antioxidant activity of the resultant material.