Protective effects of dietary polyphenols from black soybean seed coats on islet and renal function in streptozotocin-induced diabetic rats.

BACKGROUND

The aim of this study was to investigate the antidiabetic effects of the crude polyphenol extract (BSCP) from black soybean seed coats (BSC) and the whole flour of BSC and illustrate the mechanism in terms of islet and renal protection.

RESULTS

BSCP and BSC effectively controlled the increased blood glucose level and impaired glucose tolerance in streptozotocin (STZ)-induced diabetic rats after 8 weeks of treatment. They increased the concentrations of serum insulin, C-peptide and Glp-1 (P < 0.05) by improving the STZ-induced damage of islet β-cells and increasing their insulin expression (P < 0.05). Lipid profiles and antioxidant activities were also improved. Moreover, BSCP and BSC tended to decrease serum creatinine (0.05 < P < 0.1), and blood urea nitrogen was decreased by BSC significantly (P < 0.05). They also led to significantly lower glomerular volume (P < 0.05).

CONCLUSION

Long-term intervention with BSC at a low dose of polyphenols plays a role in controlling blood glucose and lipids levels by promoting insulin secretion and restoring islet β-cell function, the same as BSCP. These benefits are accompanied by their potential protection of diabetic renal dysfunction. BSCP is mainly responsible for the antidiabetic effect of BSC. © 2017 Society of Chemical Industry.