Protective effect of a polysaccharide isolated from a cultivated Cordyceps mycelia on hydrogen peroxide-induced oxidative damage in PC12 cells.

Cordyceps sinensis as a well-known traditional Chinese tonic has many therapeutic functions. In the present study, an acid polysaccharide (APS) was isolated from cultivated Cordyceps mycelia by ion-exchange and sizing chromatography. The protective capacity of APS against H(2)O(2)-induced oxidative damage in rat pheochromocytoma PC12 cells was investigated by measuring cell viability, lactate dehydrogenase (LDH) release, antioxidant enzyme activity, malondialdehyde (MDA) levels and intracellular accumulation of reactive oxygen species (ROS) and Ca(2+). The results demonstrated that pretreatment of PC12 cells with APS, prior to H(2)O(2) exposure, significantly increased the survival of cells and the activities of glutathione peroxidase (GSH-Px), catalase (CAT) and superoxide dismutase (SOD), and reduced the levels of LDH and MDA. Intracellular accumulation of reactive oxygen species (ROS) and Ca(2+) were also inhibited by APS treatment. In conclusion, APS was found to increase the cellular antioxidant defence capacity, thereby protecting PC12 cells against oxidative stress.