Structural Studies on the Anti-tumor Active Polysaccharides from Coriolus versicolor (Basidiomycetes). II. Structures of β-D-Glucan Moieties of Fractionated Polysaccharides

Structural examination was made on the glucan moiety of the three fractions composed of β-D-glucan and 12-14% protein, among the five fractions of the water-soluble polysaccharide mixture obtained from the mycelium of Coriolus versicolor. On periodate oxidation, each fraction consumed about 1.5mol of the oxidant with formation of about 0.5mol of formic acid. Periodate oxidation followed by reduction with potassium borohydride and subsequent hydrolysis of each fraction gave glycerol, erythritol, and glucose. Complete methylation and hydrolysis afforded 2, 3, 4, 6-tetra-, 2, 3, 6-tri-, 2, 4, 6-tri-, 2, 3-di-, 2, 4-di-, and 2, 6-di-O-methyl-D-glucoses in the proportion different for each fraction. Identification of these hydrolysis products was carried out on the crystalline basis as well as by gas-liquid chromatography. These results suggested that the glucan moiety of the fraction with highest antitumor activity is composed of 1→4 linked β-D-glucose residues, which are occasionally branched at 3- and 6-positions, and that two other fractions with lower antitumor activity have a more complicated ramified glucans with increasing proportions of 1-3 and 1-6 linkages.