Inhibitory activity of Angiotensin-I converting enzyme (ACE-I) from partially purified Phaseolus lunatus peptide fractions

Abstract

Phaseolus lunatus have proven to be a likely source of peptides with bioactivities that could be used to prevent and treat chronic degenerative diseases like arterial hypertension (AHT). Angiotensin-I converting enzyme (ACE-I) inhibition is essential for the AHT pathophysiology. In this work, the kinetic study of inhibition and inhibitory activity of ACE-I from peptide fractions partially purified from a protein hydrolysate from Phaseolus lunatus was performed. Hydrolysis was done by sequential enzymatic treatments with Pepsin-Pancreatin. The hydrolysates were ultrafiltered with 3 kDa and 5 kDa membranes, obtaining a fraction of 3–5 kDa which was later purified by gel filtration chromatography (GFC) and high-performance liquid chromatography (HPLC). The GFC fractions exhibited ACE-I inhibitory activities (ACE-I_I) up to 37.86% with an IC50 of 6.34 μg/mL. From HPLC purification, ACE-I_I up to 26.23% were obtained with an IC50 of 2.69 μg/mL. The kinetic parameters of the inhibition indicated that the peptides inhibit ACE-I through a competitive mechanism. The amino acids of the fractions evaluated presented Pro, Ala, Leu, and Ile, which can be part of the peptide fractions with ACE-I_I; with these results obtained these peptides could be used as functional foods related to the control and prevention of diseases related to AHT.