Exploring the Blood Glucose-Lowering Potential of the Umami Peptides LADW and EEAEGT Derived from Tuna Skeletal Myosin: Perspectives from α-Glucosidase Inhibition and Starch Interaction

This study aimed to explore the potential of umami peptides for lowering blood glucose. Molecular docking results showed that the peptides LADW and EEAEGT bound to the active amino acid residues of α-glucosidase via hydrogen bonds and Van der Waals forces, a finding supported by an independent gradient model (IGM). Molecular dynamics (MD) simulations demonstrated that the peptides LADW and EEAEGT can decelerate the outward expansion of α-glucosidase and reduce amino acid fluctuations at the active site. In vitro findings indicated that the peptides LADW and EEAEGT showed potent inhibitory activity against α-glucosidase, with IC50 values of 4.40 ± 0.04 and 6.46 ± 0.22 mM, respectively. Furthermore, MD simulation and morphological observation results also revealed that LADW and EEAEGT alter starch structure and form weak interactions with starch through intermolecular hydrogen bonding, leading to the inhibition of starch hydrolysis. Peptides inhibit the ability of starch to produce reducing sugars after simulated gastrointestinal digestion, providing additional evidence of the inhibition of starch hydrolysis by the added peptides. Taken together, these findings suggest that consuming the umami peptides LADW and EEAEGT may alleviate postprandial blood glucose elevations via inhibiting α-glucosidase and starch hydrolysis.