Polyphenols from sorbus aucuparia ameliorate insulin resistance and metabolic disorders in diabetic mice

The aim of this study was designed to evaluate the effects of Sorbus aucuparia fruit Polyphenols (SAFP) against high-glucose-fat diet (HGFD) combined with Streptozocin (STZ) induced diabetes in Kunming mice. The model mice were fed by water or SAFP (10, 50 or 100 mg.L^sup -1^) fluid for 4 weeks. As a comparison, mice were fed by a normal-fat (ND) and water. The HGFD group developed more severe symptoms of metabolic syndrome than the ND group. SAFP treatment significantly ameliorated metabolic disorders such as hyperglycemia, dyslipidemia and insulin resistance in diabetic mice. Furthermore, SAFP lowered MDA and improved the activity of SOD and GSH-Px in serum. Histopathological examination indicated that the impaired hepatic tissues were effectively restored in diabetic mice following the SAFP treatment. Moreover, SAFP markedly up-regulated protein levels for insulin receptor (IR), insulin receptor substrate-1 (IRS-1), p-AKT and p-GSK3β in the liver and enhanced the insulin signaling pathway. This is the first report documenting that S. aucuparia fruit Polyphenols can ameliorate the HGFD combined with STZ induced insulin resistance and metabolic syndrome.