Heteroglycan of an edible mushroom Pleurotus cystidiosus: Structural characterization and study of biological activities.

A water soluble heteroglycan (PCPS) was isolated from the aqueous extract of an edible mushroom Pleurotus cystidiosus. Structural characterization of the heteroglycan was carried out using total hydrolysis, methylation analysis, periodate oxidation, Smith degradation, and 1D/2D NMR experiments. Sugar analysis indicated the presence of glucose, galactose, and mannose in a molar ratio of nearly 6:2:1 respectively. The chemical and NMR analysis of the PCPS indicated the presence of a repeating unit with a backbone consisting of one unit of (1→6)-β-d-glucopyranosyl, two (1→3)-β-d-glucopyranosyl, one (1→3)-α-d-glucopyranosyl, one (1→6)-α-d-glucopyranosyl, and two (1→6)-α-d-galactopyranosyl moieties respectively, out of which one (1→3)-β-d-glucopyranosyl residue was branched at O-6 with terminal β-d-glucopyranosyl and another (1→6)-α-d-galactopyranosyl residue was branched at O-2 with terminal β-d-mannopyranosyl moiety. The polysaccharide was found to exhibit cellular activities at different concentrations (10, 25, 50, 100, 200, 400μg/mL) and maintained the redox balance as well as reduced lipid per oxidation which protect the cell destruction.