Polysaccharide of an edible truffle Tuber rufum: Structural studies and effects on human lymphocytes

A water-soluble heteroglycan (PS-II) with average molecular weight ∼7.27×10⁴Da, was isolated from the fruiting bodies of an edible truffle mushroom Tuber rufum (Pico) var. by hot water extraction. The structural investigation of PS-II has been carried out using acid hydrolysis, methylation analysis, periodate oxidation, and 1D/2D NMR experiments. It was composed of d-glucose, d-galactose, l-fucose in a molar ratio of nearly 4:3:1 respectively. On the basis of these experiments, the repeating unit of the PS-II was found to contain a backbone of two (1→6)-α-d-galactopyranosyl, one (1→4)-α-d-glucopyranosyl, two (1→6)-β-d-glucopyranosyl, and one (1→4)-β-d-glucopyranosyl residues, out of which (1→4)-α-d-glucopyranosyl residue was branched at O-2 position with terminal α-l-fucopyranosyl residue and at O-6 position with terminal α-d-galactopyranosyl residue. Ameliorative activities of the PS-II was observed at different concentrations (25, 50, 100, 200, 400μg/ml) and it maintained the redox balance as well as reduced the lipid peroxidation to protect the cell damage.