Objective:To explore the possible inhibitory potentials and mechanism by Mobola plum (Parinari curatellifolia) seeds crude methanol (CE) and flavonoid-rich (FE) extracts on angiotensin-1-converting enzyme (ACE I).Methods:The sensitivity and kinetic model of inhibition of CE and FE on ACE I using N-[3-(2-furyl)-acryloyl]-Phe-Gly-Gly as enzyme substrate for ACE I was evaluated by Michealis Menten approach.The inhibition mechanism was explored from LineweaverBurk model and IC50 was determined from Cheng-Prusoff empirical analysis.Results:The IC50 of CE and FE were 13.54 and 39.38 μg/mL,respectively.Both extracts exhibited mixed type inhibition with the inhibitory constant (Ki) of CE was between 0.38 and 0.37 μg/mL while that of FE showed a two-fold increase (1.62 μg/mL and 0.28 μg/mL).FE on ACE I demonstrated positive cooperativity with a Hill's coefficient of 1.89.Conclusions:The study reveals the superior ACE I inhibitory potential of CE over FE and suggest that mixed inhibition pattern of the enzyme might be the underlying mechanism of antihypertensive activity.

Objective To explore the possible inhibitory potentials and mechanism by Mobola plum (Parinari curatellifolia) seeds crude methanol (CE) and flavonoid-rich (FE) extracts on angiotensin-1-converting enzyme (ACE ). Methods The sensitivity and kinetic model of inhibition of CE and FE on ACE using N-[3-(2-furyl)-acryloyl]-Phe-Gly-Gly as enzyme substrate for ACE was evaluated by Michealis Menten approach. The inhibition mechanism was explored from Lineweaver–Burk model and IC