Inhibition of Lycium barbarum polysaccharides and Ganoderma lucidum polysaccharides against oxidative injury induced by γ-irradiation in rat liver mitochondria

Lycium barbarum and Ganoderma lucidum, the two precious traditional Chinese medicines, possesses the antitumor activity, antioxidant activity and the capability of modulating the immune system. In the present study, the possible antioxidant effects of L. barbarum polysaccharides (LBP) isolated from dried L. barbarum fruits and Ganoderma lucidum polysaccharides (GLP) isolated from dried G. lucidum against membrane damage induced by the free radicals generated during γ-irradiation were examined in rat liver mitochondria. Using an effective dose of 450 Gy, antioxidant effects of GLP and LBP were studied against oxidative damage in terms of protection against lipid peroxidation, protein oxidation, depletion of protein thiols and the levels of the antioxidant enzyme, such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px). The results showed that both GLP and LBP significantly protects against irradiation-induced loss of protein thiols and inactivation of SOD, CAT and GSH-Px in a dose-dependent manner. The inhibitory effects of GLP, at the entire concentration range, are stronger than LBP. Moreover, the two polysaccharides are more effective than α-tocopherol (VE) in inhibiting irradiation-induced oxidative injury. Hence our results indicate that GLP and LBP have potent antioxidant properties in vitro in mitochondrial membranes of rat liver.