Immunomodulatory and Antioxidant Effects of Polysaccharides from the Parasitic Fungus Cordyceps kyushuensis

The ascomycete Cordyceps genus has been used as valued traditional Chinese medicine. Cordyceps kyushuensis is a unique species of Cordyceps, which parasitizes on the larvae of Clanis bilineata Walker, and its major component cordycepin and aqueous extract are known to have many pharmacological effects. However, the physiological function of water-soluble polysaccharides has not been explored in detail. In this study, to resolve these doubts, we extracted and separated Cordyceps-derived polysaccharides and then evaluated the immunomodulatory and antioxidant activities. Four polysaccharide fractions were purified from Cordyceps-cultured stroma by DEAE-cellulose 23 and Sephadex G-150 column chromatography. Basic structural information was elucidated on the basis of physicochemical property and spectroscopic evidences. The antioxidant activities were evaluated by a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical method and protective effect of DNA damage. The qualified immunologic activities were also determined in vivo and in vitro. The polysaccharides could stimulate the proliferation of mouse splenocytes whether concanavalin A (ConA) and lipopolysaccharide (LPS) existed or not, strengthen peritoneal macrophages to devour neutral red, and increase the content of interleukin-2 (IL-2) and tumor necrosis factor-alpha (TNF-α) in serum. The research provides the corresponding evidence for Cordyceps polysaccharides as a potential candidate for functional foods and therapeutic agents.