Abstract: The water-soluble polysaccharide (CY) was isolated from fermented Cordyceps through hot water extraction.CY,with a molecular weight of 9.3 × 10³ g/mol,was mainly composed of neutral polysaccharide.The backbone of the polysaccharide was connected with β-glucosidic bond.The monosaccharide was consisted of xylose,mannose,glucose and galactose.The antioxidant activities of CY were investigated using reducing power,hydroxyl assay and DPPH scavenging activity assay in vitro. Additionally,the effect of CY on immunization was determined using a macrophage RAW 264.7 model.The results demonstrated that CY had antioxidant activity with a dosedependent manner.Moreover,it induced immune enhancement effects characterized by promoting proliferation of macrophage, cellular secretion of NO and cytokines,such as TNF-α, IL-1, IL-6 and IL-12.

Key words: fermented Cordyceps, polysaccharide, antioxidant activity, immunological enhancement activity