Purification, structure and immunobiological activity of a new water-soluble polysaccharide from the mycelium of Polyporus albicans (Imaz.) Teng

A new water-soluble intracellular polysaccharide named as PTP, with a molecular mass of 3.7 × 104 Da, was obtained from the mycelium of Polyporus albicans (Imaz.) Teng. Structure features of the purified polysaccharide were investigated by a combination of chemical and instrumental analysis. The results indicated that PTP consisted of a backbone composed of (1 → 3)-linked-β-d-mannopyranosyl, (1 → 3,6)-linked-β-d-mannopyranosyl and (1 → 6)-linked-α-d-galactopyranosyl residues in the ratio of 3:1:1, and terminated with a single non-reducing terminal (1→)-β-d-mannopyranosyl residues at the C-6 position of (1 → 3,6)-linked-β-d-mannopyranosyl, along the main chain. This is the first report describing the isolation and structure elucidation of a new intracellular polysaccharide produced from the mycelium of P. albicans (Imaz.) Teng. Preliminary tests in vitro showed PTP have potent stimulating effects on murine lymphocyte proliferation induced by concanavalin A or lipopolysaccharide and its branches are extremely important for the expression of the enhancement of the immunological activity.