Structural analysis and antioxidant activities of polysaccharides from cultured Cordyceps militaris

The polysaccharides extracted by hot water and precipitated by 50% ethanol from the fruiting bodies of cultured Cordyceps militaris (W-CBP50) were introduced. Antioxidant activities of W-CBP50, W-CBP50 I (obtained from W-CBP50 purified by Sephadex G-100 chromatography) and W-CBP50 II (obtained from W-CBP50I purified by Sephadex G-200 chromatography) were evaluated and structural features of W-CBP50 II were analyzed. The polysaccharide W-CBP50 II was able to scavenge the stable free radical 1,1-diphenyl-2-picrylhyrazyl (DPPH), while W-CBP50 and W-CBP50I could scavenge DPPH, hydroxyl and superoxide radical. Structural characteristics of W-CBP50 II were investigated using GPC, GC–MS, 1H NMR and IR. The results showed that it was mainly composed of α-glucose, α-mannose, α-galactose and α-arabinose with α-type glycosidic linkage and the molecular weight of its main component was 8.97kD.