Analysis of Constituent Sugars in a Polysaccharide of Hsian-tsao, Mesona procumbens Hemsl

The polysaccharide of Hsian-tsao (HTP), Mesona procumbens Hemsl., does not itself form a gel, but induces gel formation in the presence of added starch, although the mechanism is still unclear. To understand the effect of a HTP on gel formation, we investigated its constituent sugars by methylation analysis. HTP was found to consist of rhamnose, arabinose, xylose, mannose, glucose, galactose, and galacturonic acid. Although methylation may not have proceeded to completion, rhamnose was found as 2-O-, 3-O-, and 4-O-methyl derivatives. Incomplete methylation suggests that HTP has a compact conformation of high heterogeneity.