Structure and immunological activity of a novel polysaccharide from the spores of Ganoderma lucidum

The water-soluble polysaccharide (GLP) was obtained from the spores of Ganoderma lucidum by hot water extraction and gel chromatography. The molecular weight was estimated to be 143 KD determined by using HPGPC. Structure features of GLP were investigated by a combination of chemical and instrumental analysis. The results indicated that GLP consisted of a backbone composed of (1-->6)-linked-alpha-d-glucopyranosyl, (1-->3)-linked-beta-d-glucopyranosyl and (1-->3,6)-linked-beta-d-glucopyranosyl residues in the ratio of 1:2:1, and terminated with one single terminal (1-->)-beta-d-glucopyranosyl at the O-6 position of (1-->3,6)-linked-beta-d-glucopyranosyl, along the main chain. Preliminary tests in vitro showed that GLP has stimulating effects on murine lymphocyte proliferation induced by concanavalin A (ConA) and lipopolysaccharide (LPS) in a dose-dependent manner. It is a possible potential immunopotentiating agent for use in functional foods or medicine against both pathogens and cancer.