Molecular Mechanism for the α-Glucosidase Inhibitory Effect of Wheat Germ Peptides

Wheat germ peptides (WGPs) have various benefits to human health, while their antidiabetes mechanism remains unknown. In this study, the α-glucosidase inhibition activity of WGPs was identified, exhibiting an IC₅₀ value of 6.87 mg/mL. By further filtrating them into five groups according to molecular weight (M_w), the fraction with M_w < 1 kDa displayed the highest inhibitory activity with an IC₅₀ of 2.10 mg/mL. The addition of 2 mg/mL WGPs with M_w < 1 kDa effectively reduced the glucose-releasing rate on everted intestine sleeves. By virtual screening and HPLC-QTOF-MS/MS, LDLQR, AGGFR, and LDNFR were identified and synthesized for the first time, and their IC₅₀ values were 8.59, 8.66, and 9.21 mM, respectively. Molecular docking and amino acid composition analysis results showed that the high content of C-terminal Arg residues in the peptides could be the essential reason for their α-glucosidase inhibition activity. This study paved a way to utilize WGPs as potential antidiabetes ingredients for the food industry.