A Glucan Having Reticuloendothelial System-Potentiating and Anti-complementary Activities from the Tuber of Pinellia ternata

A glucan, called pinellian G, was isolated from the tuber of Pinellia ternata Breit. It was homogeneous on electrophoresis and gel chromatography, and its molecular mass was estimated to be 1.5 x 10⁴. It is composed solely of D-glucose, in addition to a few O-acetyl groups. Methylation analysis, nuclear magnetic resonance and enzymic degradation studies indicated that it is a branched glucan mainly composed of α-l,4-linked D-glucopyranose residues with partially α-l,3-linked units and 4,6-branching points. The glucan showed significant reticuloendothelial system-potentiating activity in a carbon clearance test, as well as pronounced anti-complementary activity.