Structural characterization and antioxidant activity of purified polysaccharide from cultured Cordyceps militaris

The polysaccharide fraction, CM-hs-CPS2, was isolated from fruiting bodies of culturedCordyceps militaris grown on solid rice medium by hot water extraction and ethanol precipitation, and purified by ion exchange column (DEAE-cellulose-52) and gel filtration column (Sephadex G-100) chromatography. Its structural characterizations were analyzed by gas chromatograph (GC) and fourier transform infrared spectroscopy (FT-IR). Results indicated that CM-hs-CPS2 was a kind of sulfating acidic polysaccharide containing acetamido group. The monosaccharide composition analysis showed that CM-hs-CPS2 was composed mainly of mannose, glucose and galactose in a molar ration of 1.35: 8.34: 1.00, and linked by α-glycosidic linkage. The studies on antioxidant activities of CM-hs-CPS2 were evaluated by various methods in vitro. Results showed that DPPH· scavenging activity, reducing power and ferrous ion chelating activity of CM-hs-CPS2 (8 mg/ml) were 89%, 1.188 and 85%, respectively.   Key words: Cordyceps militaris, polysaccharide, structure, bioactivity.