Evaluation of Angiotensin-converting Enzyme Inhibitory Potential of SeedProtein Hydrolysates from Muskmelon, Watermelon and Sunflower

INTRODUCTION: Antihypertensive treatments, including diuretics and beta/calcium channel blockers, are associated with a range of adverse effects. Naturally sourced ACE inhibitors may serve as viable alternatives to synthetic medications. Various peptides derived from plants have been assessed for their ACE inhibitory properties through both in vivo and in vitro studies. The objective of this research was to evaluate the ACE inhibitory activity of seed-protein (muskmelon, watermelon, and sunflower) hydrolysates generated using different proteases. METHODS: ACE was extracted from sheep lung tissue, while protein from the mentioned seeds was isolated and hydrolysed using pepsin, trypsin, and crude enzyme from the stem of Wrightia tinctoria. Tricine-SDS PAGE (16%) was conducted to observe the nature of hydrolysis. The method by Cushman and Cheung was used to examine ACE inhibition. The results were compared across different sources and enzymatic treatments. RESULTS: Muskmelon hydrolysate treated with W. tinctoria enzyme exhibited the highest ACE inhibition at 85.17% ± 0.39 after 3 h of incubation (p <0.001), resembling the inhibitory effects observed in the positive control, Lisinopril, at 86.55% ± 1.15. DISCUSSION: The enhanced ACE inhibitory activity observed in muskmelon seed hydrolysate suggests the generation of potent bioactive peptides through enzymatic hydrolysis. Differences in inhibitory potential among seed-derived hydrolysates may be attributed to variations in protein composition and peptide profiles resulting from the use of different proteases. CONCLUSION: Muskmelon seed protein hydrolysate generated using W. tinctoria demonstrated strong in vitro ACE inhibitory activity, which was comparable to that of Lisinopril, a standard drug for ACE inhibition. These findings highlight its potential as a natural source of bioactive peptides for the management of hypertension.