乙醇分级沉淀提取黄芪多糖及其理化性质和抗氧化活性研究

Graded ethanol precipitation method on physicochemical properties and antioxidant activities of polysaccharides extracted from Astragalus Radix

该文采用乙醇分级沉淀法提取不同浓度乙醇层的黄芪多糖,并探讨黄芪多糖相对分子质量、构效及活性之间的关系。采用不同浓度的乙醇(30%,50%,70%,75%,80%,90%)沉淀,以获得不同相对分子质量的黄芪多糖;采用红外及电子扫描显微镜观察各层多糖的形态特征;采用DPPH自由基清除率,还原力和β-胡萝卜素/亚油酸体系检测各层的抗氧化活性。结果显示该法所得黄芪多糖随乙醇浓度增加,相对分子质量降低,抗氧化活性增强,90%乙醇沉淀层多糖表面光滑,相对分子质量较小,三股螺旋链构象特异,抗氧化活性最强(P<0.05)。

Astragalus polysaccharide has been widely used in food and medicinal industry owing to its health-promoting properties. In order to characterize better the relationship among molecular weight, structure-activity and activities, a simple method was used different concentration of ethanol including 30% （PW30）, 50% （PW50）, 70% （PW70）, 75% （PW75）, 80% （PW80） and 90% （PW90） to precipitate Astragalus polysaccharides into different molecular weight. As a result, PW90 showed smooth surface and the strongest antioxidant activity among these six fractions （P〈0.05）. In conclusion, graded ethanol precipitation was a simple method to separate Astragalus polysaccharides into different molecular weight with different antioxidant activity fractions.