香薷多糖的乙醇分级纯化及其性质

Ethanol Fractional Precipitation and Characterization of Polysaccharides from Herba Moslae

采用热水浸提法从香薷中得到多糖提取物,然后采用乙醇分级沉淀法纯化香薷多糖,收集得到乙醇体积分数为20%、30%、40%、50%、60%、70%条件下析出的多糖沉淀物。之后经Sevag法脱除多糖中的游离蛋白,得到纯化后的6个香薷多糖组分HMP-1、HMP-2、HMP-3、HMP-4、HMP-5和HMP-6。应用紫外和红外光谱检测HMP-1、HMP-2、HMP-3、HMP-4、HMP-5和HMP-6的光谱性质,测定糖含量、可溶性蛋白质含量和糖醛酸含量,并用气相色谱法测定单糖组成。结果表明:HMP-1、HMP-2、HMP-3、HMP-4、HMP-5和HMP-6均为酸性多糖,蛋白含量较高。HMP-1和HMP-2主要含有阿拉伯糖和葡萄糖,HMP-3主要含有阿拉伯糖、葡萄糖、半乳糖和核糖,HMP-4主要含有阿拉伯糖、葡萄糖和半乳糖,HMP-5和HMP-6主要含有阿拉伯糖、葡萄糖、半乳糖和甘露糖。此外,6个多糖组分均含有少量的鼠李糖、木糖,但单糖间物质的量比相差较大。

A polysaccharide-rich extract was obtained from Herba Moslae by hot water extraction and purified by fractional precipitation with gradient concentrations of ethanol （20%,30%,40%,50%,60% and 70%）. The separated fractions were deproteinized by Sevag method and six purified polysaccharide fractions,named HMP-1 through 6 were obtained. These fractions were subjected to UV-visible spectral analysis,the determination of sugar,soluble protein and uronic acid contents and monosaccharide composition analysis by gas chromatography （GC）. Each of these fractions was an acidic polysaccharide,with high protein content. Arabinose and glucose were the main monosaccharides in HMP-1 and HMP-2,arabinose,glucose,galactose and ribose were the main monosaccharides in HMP-3,arabinose,glucose and galactose were the main monosaccharides in HMP-4,and arabinose,glucose,galactose and mannose were the main monosaccharides in HMP-5 and HMP-6. In addition,small amounts of rhamnose and xylose were also detected in each of the six fractions.