Polysaccharides in fungi. XXIX. Structural features of two antitumor polysaccharides from the fruiting bodies of Armillariella tabescens.

An antitumor polysaccharide containing peptide moieties AT-HW ([alpha]D + 31 degrees in water) and an antitumor polysaccharide AT-AL ([alpha]D + 209 degrees in 1 M sodium hydroxide) were isolated from hot-water extract and the alkaline extract of the fruiting bodies of Armillariella tabescens, respectively. Chemical structures of AT-HW and AT-AL were investigated by a combination of chemical and spectroscopic methods. The results indicate that the major constituent of AT-HW (molecular weight, 105000), a heteroglycan, is composed primarily of beta-(1----6)-linked D-glucopyranosyl and D-galactopyranosyl residues, and contains their branched residues and terminal sugar (gluco-, manno-, and fucopyranose) residues, in addition to beta-(1----3)-linked D-glucopyranosyl residues, while AT-AL (molecular weight, 93000) is chiefly composed of alpha-(1----3)-linked D-glucopyranosyl residues.