As commonly observed events in diabetic patients, glucolipotoxicity induces oxidative stress, apoptosis and functional defects in β-cells. Anthocyanins are well investigated as strong antioxidants and modulators for metabolic syndromes. Therefore, this study examined the protective effects of anthocyanins-rich extracts (BAE) from wild Chinese blueberry (Vaccinium spp.) against glucolipotoxicity in β-cells. Results showed that INS832/13 β-cells subjected to glucolipotoxicity were significantly decreased (p < 0.05) in cell survival rate, which were alleviated by BAE and metformin treatments. Both BAE and metformin reduced reactive oxidative species and improved the antioxidant defense system. Moreover, BAE were effective in reducing intracellular triglycerides (TG) level, restoring intracellular insulin content, lowering basal insulin secretion (BIS) and increasing glucose-stimulated insulin secretion which in turn resulted in an elevated insulin secretion index. However, metformin only demonstrated marginal effect on secretion dysfunction and had no effect (p > 0.05) on BIS or TG. Additionally, TG levels reduced by BAE treatment were correlated with BIS (p < 0.01, r = 0.9755). This study has for the first time demonstrated that anthocyanin enriched extract of wild Chinese blueberry could effectively protect β-cells against glucolipotoxicity in vitro. These results implied the potential efficacy of BAE as a complementary measure for diabetes intervention.
Keywords: Anthocyanins; Apoptosis; Glucolipotoxicity; Insulin secretion; Intracellular triglycerides; β-cells.