STUDIES ON THE POLYSACCHARIDES OF “HUANG QI” (ASTRAGALUS MONGHOLICUS BUNGE.)

Two glacans AG-1, AG-2 and two heterosaccharides AH-1, AH-2 were isolated and purified from water extract of Chinese drug Huang Qi.By electrophoretic and gel chromatography, the four polysaccfiarides were shown to be single substances.According to IR data and acid hydrolysis, AG-1 was identified as a α-glucan. Result of periodate oxidation, Smith type degradation, acetolysis and C-13 NMR showed that the glucan has a structure as α-(1→4) (1→6)glucan. The ratio of α-(1→4) and α-(1→6) linkage was about 5∶2.AG-2 was insoluble in water, on the basis of IR, acid hydrolysis, periodate oxidation, acetolysis and C-13 NMR estimation, it was elucidated as α-(1→4) glucan.AH-1 was an acidic polysaccharide, the component sugars after hydrolysis of the polysaccharide were identified as hexouronic acid (galacturonic acid and glucuronic acid), glucose, rhamnose, and arabinose, their molecular ratio was about 1∶0.04∶0.02∶0.01.AH-2 was soluble in water, the result obtained from acid hydrolysis and identified by PC, GC, the polysaccharide composed of glucose and arabinose, the molecular ratio of these sugars was 1∶0.15.AG-1 and AH-1 showed some activity in immunological study.