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 ([α]D + 31° in water) and an antitumor polysaccharide AT-AL ([α]D + 209° 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 β-(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 β-(1→3)-linked D-glucopyranosyl residues, while AT-AL molecular weight, 93000) is chiefly composed of α-(1→3)-linked D-glucopyranosyl residues.