Abstract: Water-soluble crude polysaccharide(PIP) was extracted from cultured mycelium of the fungus Phellinus igniarius. After ethanol precipitation and sepharose CL-6B gel filtration, the fraction of PIP₁ was obtained, which was shown to be a homogeneous polysaccharide by means of high-performance liquid chromatography. The structure of PIP₁ was determined by using several methods. GC analysis indicates that PIP₁ is composed of the monosaccharides of glucose, galactose, and mannose. Their molar ratio is 3.70∶4.06∶1.00. The molar weight was estimated to be 17 kd via HPLC. IR, GC, partial hydrolysis with acid, periodate oxidation, Smith degradation, methylation, and GC-MS analysis were used for the structural analyses of PIP₁. The results show that PIP₁ has a small quantity of branch structure. The main glycosidic linkage of PIP₁ has a β-configuration. The main chain is made up of a large mass of glucose(1→3) and few mannose(1→4); the side chain is composed of glucose(1→3) and galactose(1→6); the nonreduced end is composed of galactose and glucose. The side chains are branched at 6-O of glucose(1→3,6) and mannose(1→4,6). On an average, there are three branches among 20 residues. It is presumable that the existence of 1,3-linked Glc in the main and side chains is the main reason for its higher antitumor activity.

Key words: Phellinus igniarius, Cultured mycelium, Polysaccharide, Structural analysis