The Medicinal Cracked-Cap Polypore Mushroom Phellinus rimosus (Higher Basidiomycetes) Attenuates Alloxan-Induced Hyperglycemia and Oxidative Stress in Rats

Abstract

Diabetes is usually associated with increased production of reactive oxygen species (ROS), impaired antioxidant defense systems, or both, which result in oxidative damage and lead to ROS-mediated diabetic pathogenesis. This investigation was undertaken to evaluate the role of extract from the wood-inhabiting polypore medicinal mushroom Phellinus rimosus in an alloxan-induced diabetic model and the oral glucose tolerance test in rats. Oral administration of extract at doses of 50 and 250 mg/kg body weight/day for 10 days to rats with alloxan-induced diabetes was found to possess significant dose-dependent hypoglycemic activity. In the oral glucose tolerance test, hypoglycemic effect of P. rimosus (250 mg/kg) was significant (P < 0.01) and maximum at 90 minutes after the glucose challenge when compared with that of control group. The effect of extract on antioxidant status in the pancreas, liver, and kidney was estimated. The diabetic control rats exhibited elevated levels of lipid peroxidation and lower activities of copper/zinc superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and reduced glutathione (GSH) content in pancreatic, hepatic, and renal tissues compared with normal tissues. The activities of SOD, CAT, GPx, and GSH were found to be increased in diabetic rats treated with the extract. The increased level of lipid peroxidation in diabetic rats also was found to revert to near-normal status in groups treated with the extract. The findings thus suggest the therapeutic efficiency of Ph. Rimosus against declined antioxidant status as well as hyperglycemia associated with diabetes.