Purification and antioxidant effect of novel fungal polysaccharides from the stroma of Cordyceps kyushuensis

• Cordyceps kyushuensis is regarded as the rich source of active compounds.
• Two polysaccharides were extracted from the stroma of C. kyushuensis.
• The polysaccharides were chemically characterized for the first time.
• Antioxidant properties were evaluated including the protective activity of DNA damage.

Two polysaccharides were isolated from the stroma of cultured Cordyceps kyushuensis by hot water extraction as well as ion-exchange and gel-permeation chromatography. The fourier transform infrared (FTIR) spectra revealed the general characteristic absorption peaks of polysaccharides. Preliminary structural characterizations were conducted by NMR and physicochemical property, whereas their total sugar, sulfate acid and uronic acid contents, molecular weights and monosaccharide compositions were significantly different. Antioxidant properties were evaluated by assays of various antioxidant in vitro systems. The results showed that the two polysaccharides possessed good antioxidant properties in a concentration-dependent manner, especially scavenging abilities on hydroxyl radicals. Both samples showed clearly and strong capacity on protective effect of DNA damage. With current findings, the polysaccharides from C. kyushuensis may have potential applications in health functional food.