Abstract:To investigate the effect of tartary buckwheat polyphenols on glucose metabolism in insulin resistant HepG2 cells, a model of IR was established by inducing HepG2 cells with glucosamine (GluN), then intervened with purified tartary buckwheat polyphenols to clarify the improvement effect and potential mechanism of tartary buckwheat polyphenols on insulin resistance. The results showed that tartary buckwheat polyphenols significantly improved the glucose consumption level of insulin resistant HepG2 cells, which was equivalent to the positive control drug, metformin. In terms of improving oxidative stress, tartary buckwheat polyphenols significantly enhanced the activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px), inhibited the production of malondialdehyde, and protected pancreatic β-cells from free radical damage. In the gluconeogenic pathway, the intervention of tartary buckwheat polyphenols resulted in a reduction to 24.56% and 50.69% of glucose-6-phosphatase (G-6-P) and phosphoenolpyruvate carboxyl kinase (PEPCK) activity, respectively, compared to the model group. Concurrently the expression of FOXO1 gene, which regulates G-6-P and PEPCK, was down regulated by 49.66% compared to the model group. In terms of glycogen synthesis, tartary buckwheat polyphenols promoted a 74.55% increase in glycogen synthesis in insulin resistant HepG2 cells, while significantly downregulating GSK-3β gene expression. Overall, tartary buckwheat polyphenols showed a strong potential to improve oxidative stress and hepatic glucose metabolism.
