Separation, identification, and design of α‐glucosidase inhibitory peptides based on the molecular mechanism from Paeonia ostii ‘Feng Dan’ seed protein

Peptides are considered promising sources of nutraceuticals. In this study, a mixture of peptides was prepared from Paeonia ostii ‘Feng Dan’ seed meal protein by continuous enzymolysis. Successive separation and purification procedures, including ultrafiltration and reversed‐phase high‐performance liquid chromatography (RP‐HPLC), were performed, and six novel peptides were identified by liquid chromatography–electrospray ionization source–mass spectrometry/mass spectrometry (LC‒ESI‒MS/MS). In an in vitro antidiabetic activity test, Tyr–Phe–Phe–Met exhibited stronger α‐glucosidase inhibitory activity (48.17 ± 3.34% at 1 mg/mL) than the other peptides. Docking studies of this peptide into the active site of α‐glucosidase showed that the formation of hydrogen bonds could be critical for the enzymatic trapping of inhibitory peptides. Furthermore, two novel peptides, Phe–Phe–Phe–Met (IC50 = 245.46 ± 44.01 µM) and Tyr–Tyr–Phe–Met (IC50 = 306.71 ± 48.17 µM), with improved α‐glucosidase inhibitory activity, were designed based on molecular docking. Therefore, the seed meal of Paeonia ostii could be considered a functional food ingredient for the management of hyperglycemia, and three novel peptides were identified as α‐glucosidase inhibitors.