Heteroglycan of an edible mushroom Entoloma lividoalbum: Structural characterization and study of its protective role for human lymphocytes

Abstract

A water soluble heteroglycan (PS-II) of an average molecular weight ∼5.2×104Da was isolated from the alkaline extract of an edible mushroom Entoloma lividoalbum (Kühner & Romagn) Kubička. Structural characterization of PS-II was carried out using sugar and methylation analysis, periodate oxidation study, and 1D/2D NMR experiments. Sugar analysis indicated the presence of glucose, mannose, galactose, and fucose in a molar ratio of nearly 5:1:2:1. The repeating unit of the PS-II had a backbone consisting of two (1→3)-β-d-glucopyranosyl, one (1→6)-β-d-glucopyranosyl, one (1→2)-α-L-fucopyranosyl, one (1→6)-α-d-glucopyranosyl, and two (1→6)-α-d-galactopyranosyl residues, out of which one (1→3)-β-d-glucopyranosyl residue was branched at O-6 position with terminal β-d-glucopyranosyl residue and one (1→6)-α-d-galactopyranosyl residue was branched at O-2 position with terminal β-d-mannopyranosyl residue. PS-II showed ameliorative activities at different concentrations (50, 100, 200, 400μg/ml) and maintained the redox balance as well as reduced the lipid peroxidation to protect the cell destruction.