沙蒿籽水溶性胶多糖ASPI-A的结构与免疫活性的初步研究

Structure Elucidation and Preliminary Immunological Activity Studies of the Water-soluble Gum Polysaccharide ASPI-A Isolated from Artemisia sphaerocephala Krasch Seeds

从沙蒿籽中提取出水溶性胶多糖,经柱色谱分离纯化得到一种中性多糖组分ASPI-A.采用高效凝胶渗透色谱法(HPGPC)测定其为均一性多糖,平均分子量为5.42×104Da.经IR,GC部分酸水解、甲基化分析等方法对该多糖的化学结构进行了表征.结果表明,该多糖由阿拉伯糖、甘露糖、葡萄糖及半乳糖组成,其物质的量的比为1∶2.8∶4.9∶1.9.ASPI-A为多分支结构,以(1→4)-β-Glc构成主链,部分葡萄糖C6存在分支,由甘露糖以-4)Man(1-连接在葡萄糖C6位,Glc(1-和Gal(1-连接在甘露糖C4位构成.免疫活性实验结果表明,ASPI-A在10～50μg·mL-1浓度范围内对ConA诱导的小鼠T淋巴细胞增殖反应具有促进作用.

Artemisia sphaerocephala Krasch is an important resource of northwest in China, and it has potential pharmaceutical value and environment protective function. Our purpose to the study of Artemisia seeds polysaccharide is to get more theory support to illustrate the structure-function relationship in molecule research. A water-soluble gum polysaccharide ASPI-A was isolated from Artemisia seeds with water extraction and column chromatography. ASPI-A was determined to be homogeneous with average molecular weight of 5.42 × 10^4 Da by high performance gel permeation chromatography （HPGPC）. Monosaccharide analysis by gas chromatography （GC） showed that it was composed of arabinose, mannose, glucose and galactose at a molar ratio of 1 ： 2.8 ： 4.9 ： 1.9. Based on IR, GC, partial hydrolysis with acid, methylation and GC-MS analysis, ASPI-A was shown to be a highly branched polysaccharide with a backbone of β-1,4-1inked-Glucose. The backbone was partially substituted at O^6 of glucosyl residues with mannose, and the non-reducing end were Glc（1- and Gal（1- which were attached to O^4 of mannose. The immunological activity assay revealed that ASPI-A 10-50 μg·mL^-1 can enhance the Con A induced T lymphocyte proliferation of mice.