An unusual water-soluble β-glucan from the basidiocarp of the fungus Ganoderma resinaceum

An unusual water-soluble glucan was isolated from the fruiting bodies of Ganoderma resinaceum following alkaline extraction. Its structure was determined using NMR spectroscopy (13C, 1H, and 1H (obs.), 13C HMQC), methylation analysis, and controlled Smith degradation. It was a highly branched β-d-glucan containing a (1 → 3)-linked β-d-glucopyranosyl main chain, partially substituted at O-6, principally, by side chains of 4-O-substituted β-d-glucopyranosyl groups, on average to every two residues of the backbone.