Effects of polysaccharides from Inonotus obliquus and its chromium (III) complex on advanced glycation end-products formation, alpha-amylase, alpha-glucosidase activity and H2O2-induced oxidative damage in hepatic L02 cells

In the present study, the antioxidant activity, anti-glycation activity, alpha-amylase, alpha-glucosidase inhibitory activity of polysaccharides from Inonotus obliquus (UIOPS) and its chromium (III) complex (UIOPC) were investigated. Their protective effects against H2O2-induced oxidative damages in hepatic L02 cells were also assessed. Results demonstrated that UIOPC and UIOPS exhibited remarkable DPPH scavenging activity, ferric reducing power and hemolysis inhibitory activity. UIOPC also showed significant inhibitory capacity on alpha-amylase and alpha-glucosidase than UIOPS (P < 0.05), suggesting a good regulation of the postprandial hyperglycemia. Three phases of advanced glycation end products (AGEs) formation were effectively inhibited by UIOPC and UIOPS. Moreover, pretreatment with UIOPC and UIOPS markedly attenuated the oxidative damage induced by H2O2 in hepatic L02 cells via enhancing the cell viability, inhibiting the morphology alteration and maintaining the integrity of mitochondria. These results indicated that the anti-diabetic mechanism of UIOPC might involve in the homoeostasis of blood glucose and the recovery of endogenous antioxidant system. The elucidation of the potential anti-diabetic mechanism will facilitate the further study and application of the polysaccharides-metal complex in the functional food industry.