Peptides from 'Vaina Morada' Black Bean Inhibit α-Amylase and α-Glucosidase: A Combined In Silico-In Vitro Study

The objective of this work was to evaluate the antidiabetes potential of protein hydrolysates derived from "vaina morada" black bean (Phaseolus vulgaris L.). Bioactive peptide sequences were identified after in silico digestion. The biological activities and molecular interactions of peptides with targeted enzymes were assayed. The degree of hydrolysis and protein profile were evaluated throughout the processing stages, including protein extraction, hydrolysis, and dialysis. Biological potential assays, including antioxidant potential (DPPH and ABTS•+), and inhibition of α-amylase and α-glucosidase enzymes, were performed. Identified bioactive peptides showed potential for inhibiting ACE and DPP-IV, as well as exhibiting antioxidant potential. Molecular docking indicated that several peptide sequences showed equal or stronger binding affinities compared to acarbose. Notably, sequence VNDNGEPTL exhibited binding energies of -10.0 kcal/mol (α-amylase) and -11.8 kcal/mol (α-glucosidase). Protein hydrolysates showed the lowest IC₅₀ (113.16 µM TE/mg for ABTS•+), while dialyzed protein hydrolysates demonstrated the strongest activity for DPPH (IC₂₅ of 38.83 µM TE/mg). Also, the dialyzed hydrolysate demonstrated the highest enzyme inhibition, with IC₅₀ values of 0.78 mg/mL for α-amylase and 0.60 mg/mL for α-glucosidase. "Vaina morada" black bean protein hydrolysates are a rich source of multifunctional peptides, supporting their potential application in functional food formulations aimed at preventing or managing type 2 diabetes.