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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 H2O2‐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 Ca2+. The results demonstrated that pretreatment of PC12 cells with APS, prior to H2O2 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 Ca2+ 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. Copyright © 2010 John Wiley & Sons, Ltd.