Hypoglycemic Effects and Biochemical Mechanisms of Pea Oligopeptide on High-fat Diet and Streptozotocin-induced Diabetic Mice

The aim of this study was to evaluate the hypoglycemic effects of Pea oligopeptide on the glycemic and lipidemic status of mice with type 2 diabetes (T2D) induced by a high-fat diet and streptozotocin (STZ). Using HPLC-MS/MS spectra processing, 70 significant peptide (2-3 amino acids) sequences were identified, noting four peptides from Pea oligopeptide with a proline residue at the C-terminus, which might have dipeptidase-IV (DPP-IV) inhibitory activity for the treatment of T2D. After a 4-week administration of Pea oligopeptide and metformin, various blood biochemical indexes and organic histopathologies were detected to aid the discussion regarding potential mechanisms. The results showed a significant reduction in the levels of blood glucose, lipid profiles, and liver fat deposition in diabetic mice. Furthermore, Pea oligopeptide and metformin improved glucose tolerance, promoted glycogen synthesis, and protected the liver and kidney structures in diabetic mice. The results indicated that Pea oligopeptide played an essential role in the hypoglycemic effect in the T2D mice model. Practical applications This paper examined the preliminary hypoglycemic activities of Pea oligopeptide in a high-fat diet and STZ-induced T2D mice. Furthermore, four kinds of dipeptides and tripeptides that might exhibit antidiabetic functions were detected using HPLC-MS/MS. The results provided practical knowledge regarding the hypoglycemic effects of Pea oligopeptide and established the foundation of its structure-function relationships.