板蓝根多糖A的分离纯化及结构研究

目的:提取分离板蓝根中均一分子量多糖成分,并对其结构进行研究。方法:从板蓝根中提取水溶性粗多糖,经柱色谱分离纯化得到板蓝根多糖A。采用高效凝胶色谱法检测纯度及相对分子量。经UV、IR、NMR和高碘酸氧化、Smith降解法研究各多糖的化学结构。结果:板蓝根多糖A的相对分子量为11700,主要单糖组成为阿拉伯糖和半乳糖,糖苷键构型以α为主,连接方式以1→3键连接为主,并同时存在1→2和(或)1→4的连接方式。结论:板蓝根多糖A的纯度均在96%以上,是一个新化合物。

Isolation and Purification of Polysaccharide A from Isatidis indigotica and Study on Its Structure

OBJECTIVE： To extract and isolate Isatidis indigotica polysaccharide A （with uniform molecular weight） and to study its structure. METHODS： Hydrosoluble crude polysaccharides were extracted from Isatidis indigotica before being separated and purified by column chromatography to obtain polysaccharide A. The purity and relative molecular weight of polysaccharide A were determined by high performance gel chromatography （HPGPC） and the chemical structure each polysaccharide constituent was studied by UV detection, IR spectral analysis, NMR detection, periodate oxidation and Smith degradation methods. RESULTS： The average molecular weight of polysaccharide A was 11 700.Arabinose and galactose were the major monosaccharide; a was the major configuration of glycosidic bond was predominantly, and 1→3 was the main linkage while 1→4 and/or 1→2 linkages were also presented in polysaccharides A. CONCLUSION： Isatidis indigotica polysaccharides A is a new compound, and its purity remains as high as above 96%.