Extracellular Polysaccharopeptides from Fermented Turkey Tail Medicinal Mushroom, Trametes versicolor (Agaricomycetes), Mitigate Oxidative Stress, Hyperglycemia, and Hyperlipidemia in Rats with Type 2 Diabetes Mellitus

The antihyperglycemic activity of extracellular polysaccharopeptides (ePSP) obtained from Trametes versicolor (TV) strain LH-1 has been reported to increase cellular glucose uptake in HepG2 cells in an insulin-independent manner. Evidence indicates that oxidative stress plays a pivotal role in the development of diabetic complications. We aimed to use an in vivo model to investigate the effects of TV-ePSP on oxidative stress and glucose homeostasis in type 2 diabetes mellitus (T2DM). Male Wistar rats fed with a high fat diet followed by a streptozotocin injection to induce T2DM were orally administered water or 0.1, 0.5, or 1.0 g/kg of TV-ePSP per day. After a 4-week administration of TV-ePSP, T2DM rats had attenuated elevations in blood glucose levels, areas under the curve in oral glucose tolerance tests, insulin resistance indices, and serum fructosamine and triglyceride in a dose-dependent manner (P < 0.05, one-way ANOVA). In addition, TV-ePSP significantly alleviated oxidative stress in T2DM rats, as shown by the decreased lipid peroxidation and the increased activity of superoxide dismutase in the plasma, and by the elevated glutathione levels in the plasma and erythrocytes. The antihyperglycemia and antihypertriglyceridemia activities of TV-ePSP may be associated with the improved oxidative stress, suggesting the beneficial effects of TV-ePSP in preventing the development of diabetic complications in T2DM patients.