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 5.42×10⁴ 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-linked-Glucose. The backbone was partially substituted at O⁶ of glucosyl residues with mannose, and the non-reducing end were Glc(1- and Gal(1- which were attached to O⁴ 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.

Key words: Artemisia sphaerocephala Krasch seeds, polysaccharide, isolation and purification, structure, immunological activity