芦荟多糖及其衍生物的制备与抗氧化活性研究

Preparation and Antioxidant Activity of Aloe Polysaccharide and Its Derivatives

以新鲜芦荟为原料,采用热水提取多糖,Sevage法除蛋白,再经过透析处理制备得到精制的芦荟多糖,并对其衍生物和生物活性进行研究。芦荟多糖分子质量采用GPC-RI-MALS法测定,多糖结构经过^(13)C NMR表征确证。为了研究芦荟多糖构效关系,对芦荟多糖进行了衍生化,其衍生物包括乙酰化芦荟多糖、磷酸化芦荟多糖和羧基化芦荟多糖。结构表征结果表明,芦荟多糖含有1→4糖苷键,并且为甲基化多糖。分子质量测定结果显示,芦荟多糖的平均分子质量为112381 u。抗氧化活性测试结果表明,芦荟多糖及其衍生物具有良好的抗氧化活性,其中磷酸化多糖的抗氧化活性与阳性对照品VC相当。构效关系研究表明,磷酸化芦荟多糖其体外抗氧化活性最好。试验为进一步研究芦荟多糖结构、开发功能性食品与药物提供一定的理论依据。

Using fresh aloe as raw material,the polysaccharides were extracted by hot water.Protein in the polysaccharide solution was removed by Sevage method,and then the refined aloe polysaccharide was prepared by dialysis.Finally,the structure and biological activities of polysaccharide derivatives were studied.The molecular weight of aloe polysaccharide was determined by GPC-RI-MALS.The structure of aloe polysaccharide was confirmed by ^(13)C NMR.In order to study the structure-activity relationship of aloe polysaccharides,the aloe polysaccharides were derived.The derivatives include acetylated aloe polysaccharides,phosphorylated aloe polys-accharides and carboxylated aloe polysaccharides.The structure characterization showed that aloe polysaccharide contained 1→4 glycosidic bond and was methylatedpolysaccharide.The molecular weight of aloe polysaccharide was 112381 u.Results of activity test showed that aloe polysaccharide and its derivatives had excellent antioxidant activity,which was similar to that of positive control VC.Structure-activity relationship study showed that phosphorylated aloe polysaccharides had the best antioxidant activity compared with the aloe polysaccharides and the other two derivatives in vitro.This study provides a theoretical basis for further study of aloe polysaccharides structure and development of functional food and medicine.