Studies on isolation and structural features of a polysaccharide from the mycelium of an Chinese edible fungus (Cordyceps sinensis)

The mycelium of an Chinese edible fungus (Cordyceps sinensis) was found to contain a d-glucan. Methylation, Smith degradation, acetolysis, NMR spectroscopy (1H, 13C, 13C–1H 2D-COSY) and acid hydrolysis studies were conducted to elucidate its structure. The results indicated that the d-glucan consisted of a backbone composed of (1→4)-d-glucosyl residues and carried a single (1→6)-linked d-glucosyl residue. α-d-glucosidic linkages were present in the polysaccharide according to i.r. and NMR spectra. The d-glucan gave with iodine a faint blue color that had λmax 564 nm, indicating the polysaccharide of α-(1→4)-linkages with short, exterior chains.