Structural, immunological, and antioxidant studies of β-glucan from edible mushroom Entoloma lividoalbum

A water soluble β-glucan having molecular weight ∼2 × 105 Da was isolated from hot water extract of the fruit bodies of an edible mushroom Entoloma lividoalbum (Kühner & Romagn) Kubička. This polysaccharide (ELPS) contains (1 → 3,6)-β-D-Glcp, (1 → 3)-β-D-Glcp, (1 → 6)-β-D-Glcp, and terminal β-D-Glcp moieties in a molar ratio of nearly 1:1:3:1. Chemical and spectroscopic analysis showed that the backbone of glucan consists of three (1 → 6)-β-D-glucopyranosyl and two (1 → 3)-β-D-glucopyranosyl residues, out of which one (1 → 3)-β-D-glucopyranosyl moiety was branched at O-6 with a terminal β-D-glucopyranosyl residue. This β-glucan exhibited macrophage, splenocyte, and thymocyte stimulations. It possesses promising antioxidant activities as evidenced from its hydroxyl and superoxide radical scavenging activities and reducing properties.