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 (H-1, C-13, C-13- H-1 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. alpha-(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 lambda(max) 564 nm, indicating the polysaccharide of alpha-(1 -> 4)-linkages with short, exterior chains. (c) 2005 Elsevier Ltd. All rights reserved.