Purification, Structure And Immunobiological Activity Of A New Water-soluble Polysaccharide From The Mycelium Of Polyporus Albicans (Imaz.) Teng

Polyporus albicans (Imaz.) Teng is a traditional Chinese medicinal and edible fungus distributed in Jilin Province of China, which is a Polyporaceae fungus belonging to the Basidiomycetes. The polysaccharide of Grifola f rondosa is widely proved that posess striking anti-tumor activity,which is also from Polyporaceae fungus. So far there is not any information published about the chemical component isolated from this fungus. Because the polysaccharide is the main active component of Polyporus albicans (Imaz.) Teng . We make a research on purification, structure and immunobiological activity of a new water-soluble polysaccharide from the mycelium of Polyporus albicans (Imaz.) Teng for the purpose of looking for new medicinall resource and immunopotentiator.A water soluble crude polysaccharide is extracted from the mycelium of Polyporus albicans(Imaz.) Teng, and its content is 30.3%. After graded by freezing, ultrafiltration, alcohol- precipitation and purified by the combined deprotionization methods of enzyme and sevage,and purified by Sepharose CL-6B gel filitration, one new water-soluble intracellular polysaccharide(PTP) is obtained, with a molecular mass of 4×104 Da as determined by high-performance size-exclusion chromatography (HPSEC). Its homogeneity was verified by texts: Gel filtration on DEAE-Sepharose CL-6B,Gel filtration on Sepharose CL-6B , Determination of specific rotation, HPSEC analyse and Cellulose acetate pellicle electrophoresis.Methylation, Smith degradation, acetolysis, 1H and 13C NMR spectroscopy and acid hydrolysis studies were conducted to elucidate its structure. 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)-α-D-Gal residues in the ratio of 3:1:1, The PTP is branched with a single non-reducing terminal (1→)-β-D-Man at the C-6 position ofβ-D-mannopyranosyl very five residues, on average, along the main chain. Many antitumor polysaccharides from Basidiomycetes mushrooms are characterized asβ-(1→3) linkages in the main chain of the glucan and additionalβ-(1→6) branch points. In our research, we get a novel stuture of polysaccharide with antitumor activity from the mycelium of Polyporus albicans (Imaz.) Teng, which is a Polyporaceae fungus belonging to the Basidiomycetes.In immunological test, we find PTP in vitro showed potent stimulating effects on murine lymphocyte proliferation induced by concanavalin A or lipopolysaccharide and can enhance macrophage phagocytosis, which branches are extremely important for the expression of the enhancement of the immunological activity. In vivo PTP also can promote antibody level to change or strengthen organism specific immune response against antigen,by the way of Th1 and Th2 immune response system. The Th1 response is required for protective immunity against intracellular infectious agents, such as viruses, certain bacteria and protozoa, and presumably against cancer cells. Th2 immunity is effective for protection against most bacterial as well as certain viral infections. The currently available adjuvants mainly stimulate the Th2 type immune response, which is frequently ineffective against intracellular pathogens and malignant cells. So, PTP is a potential adjuvant in place of traditional Alum adjuvant.