Structural analysis of a neutral (1-->3),(1-->4)-beta-D-glucan from the mycelia of Cordyceps sinensis.

The extracellular polysaccharide (1) extracted from the mycelia of Cordyceps sinensis with hot water was fractionated and purified by ion-exchange and gel-filtration chromatography. The structure was investigated using methylation and hydrolysis analysis, periodate oxidation, NMR spectroscopy, and reaction with beta-D-glucanase, and the results indicated that this D-glucan consisted of a backbone composed of (1-->3)-beta-D-glucosyl residues and carried a single (1-->4)-beta-linked D-glucosyl residue. NMR and IR spectroscopic measurements showed that the sugar residues were beta-glycosidically linked.