A novel water-soluble β-D-glucan isolated from the spores of Ganoderma lucidum.

Ganoderma lucidum is an edible and medicinal mushroom used widely in East Asia. In recent years, its spores have been used as a supplement in combination with other forms of antitumor therapies. The cell wall of Ganoderma lucidum spores contains a high amount of polysaccharides. In this study, a neutral polysaccharide, GLSA50-1B, was isolated from sporoderm-broken spores of Ganoderma lucidum, by hot-water extraction, graded ethanol precipitation, anion-exchange chromatography, and gel permeation chromatography. Using sugar compositional analysis, methylation analysis, partial acid hydrolysis, acetolysis, and NMR and ESI-MS spectroscopy, GLSA50-1B was elucidated to be a novel β-D-glucan featured by a 1,6-linked β-D-Glcp backbone with different length of branches consisting of terminal and 1,4-linked Glcp residues, attached to O-4 of alternative Glc residues in the backbone.