A glucan with immunological activities from the tuber of Alisma orientale

A glucan, called alisman SI, was isolated from the tuber of Alisma orientale Juzepcz. It was homogeneous on electrophoresis and gel chromatography, and its molecular mass was 1.1 x 10(4). It is composed solely of D-glucose. Methylation analysis, nuclear magnetic resonance and enzymic degradation studies indicated that it has a high-branched glucan type structure mainly composed of alpha-1,4-linked D-glucopyranosyl residues with partially alpha-1,6-linked units and both 3,4- and 4,6-branching points. The polysaccharide exhibited significant reticuloendothelial system-potentiating activity in a carbon clearance test, as well as a pronounced anti-complementary activity.