Structural characterization of an active polysaccharide from Phellinus ribis

A water-soluble polysaccharide named as PRP was isolated from the fruiting bodies of Phellinus ribis by hot water extraction, DEAE-cellulose and Superdex 30 column chromatography. Its structural characteristics were investigated by FT-IR, NMR spectroscopy, GLC-MS, methylation analysis, periodate oxidation and Smith degradation. Based on the data obtained, PRP was found to be a β-d-glucan containing a (1→4), (1→6)-linked backbone, with a single β-d-glucose at the C-3 position of (1→6)-linked glucosyl residue every eight residues, along the main chain. The glucan has a weight-average molecular weight of about 8.59kDa by HPGPC determination using dextran samples as the standards. Preliminary activity tests in vitro revealed that PRP could stimulate the proliferation of spleen lymphocyte. [Copyright &y& Elsevier]