Antihypertensive and Antioxidant Properties of Moringa Oleifera Seed Enzymatic Protein Hydrolysate and Ultrafiltration Fractions

Abstract

The aim of this study was to evaluate the in vitro antioxidant and antihypertensive as well as potential cardioprotective properties of peptides generated from enzymatic hydrolysis of Moringa oleifera seed. Moringa protein isolate was digested with alcalase and the hydrolysate fractionated by ultrafiltration using 1, 3, 5, and 10 kDa molecular weight cut-off membranes. Results showed that membrane separation led to decreased free radical (DPPH, hydroxyl) scavenging but enhanced ferric reducing antioxidant power and metal ion chelation properties. The 1–3 kDa peptide fraction was the most active against angiotensin converting enzyme and renin with 6.70% and 24.62% increases, respectively when compared to the hydrolysate. Oral administration (200 mg/kg body weight) to spontaneously hypertensive rats (SHR) resulted in significant decreases in systolic (SBP), diastolic and mean arterial (MAP) blood pressure for the hydrolysates and peptide fractions when compared to the negative control. The 1–3 kDa peptide fraction also showed the greatest (–35 mm Hg) in SBP along with fastest (2 h) reduction of SBP and MAP in the SHR. The hydrolysate produced the most persistent SBP reduction with up to –34 mm Hg after 24 h. However, the longer peptides (>10 kDa) were the most effective (–78 beats per min) in reducing SHR heart rate. The results suggest that the alcalase-hydrolyzed M. oleifera seed peptides could function as potential ingredients for the formulations of functional foods and nutraceuticals with antihypertensive benefits.