Immunomodulatory effect of polysaccharides from submerged cultured Cordyceps gunnii

The genus Cordyceps (Clavicipitaceae) is a group of entomopathogenic fungi that is widely used as tonic food or invigorant with broad-spectrum medicinal properties in China. Cordyceps gunnii (Berk.)Berk (C. gunnii), is also well known as the Chinese rare caterpillar fungus and has similar pharmacological activities with Cordyceps sinensis (C. sinensis). Polysaccharides (PS) from various Cordyceps species have demonstrated many interesting biological activities, including antitumor, immunopotentiation, hypoglycemic, and hypocholesterolemic activities.

To investigate the effect of C. gunnii PS on the immunostimulatory antitumor function and expression of immune related cytokines in normal, immuno-suppressive, and H22-bearing mice, respectively.

C. gunnii PS were extracted with hot water at 80°C for 2 h. Normal, immuno-suppressive, and H22-bearing mice were treated with PS respectively. By detecting the value of macrophage phagocytic index, proliferation of lymphocytes, natural killer (NK) cell activity and expression of related cytokines, interleukin (IL-4), tumor necrosis factor-α (TNF-a) and interferon-γ (IFN-γ), and tumor inhibition index in H22-bearing mice additionally, the effect of PS on immunostimulatory antitumor function and its mechanism were studied.

The total sugar content of the PS was determined to be 95% after purification. PS markedly increased the thymus and spleen indexes, the macrophage phagocytosis, the proliferation of splenic cells, and the level of IFN-γ and TNF-α. In tumor growth inhibition test, PS showed remarkable inhibition effects.

PS from the C. gunnii could enhance nonspecific immunological function, humoral immunity, cellular immunity in mice, and inhibit tumor growth.