Characterization of peptides from common bean protein isolates and their potential to inhibit markers of type-2 diabetes, hypertension and oxidative stress

Background: Diabetes and hypertension are diseases affecting a high proportion of the world population; the use of food-based products such as common bean peptides may contribute to reduce the risk of complications associated to chronic diseases. The aim was to produce and characterize peptides from common bean protein isolates and evaluate their potential to inhibit markers of type-2 diabetes, hypertension and oxidative stress.

Results: Mexican black and Brazilian Carioca bean isolated proteins were characterized after pepsin/pancreatin digestion. Also, four synthesized pure peptides, originally found in these beans, were evaluated. Bean protein digests and pure peptides exerted dipeptidyl peptidase-IV (DPP-IV) inhibition (IC₅₀ = 0.03-0.87 mg dry weight (DW) mL^-1 ). Lineweaver-Burk plots and computational modeling showed competitive inhibition of DPP-IV. Angiotensin-converting enzyme (ACE) inhibition ranged from IC₅₀ = 0.09 to 0.99 mg DW mL^-1 , and α-glucosidase inhibition ranged from 36.3 to 50.1% mg^-1 DW. Carioca Perola bean digested proteins presented the highest antioxidant capacity (269.3 mmol L^-1 Trolox equivalent g^-1 DW) as the peptide KTYGL (P > 0.05) with the most potent DPP-IV and ACE inhibition.

Conclusion: Peptides from common bean have antidiabetic and antihypertensive potential regardless of their antioxidant capacity. © 2016 Society of Chemical Industry.