In vitro antihypertensive and antioxidative properties of alcalase-derived Moringa oleifera seed globulin hydrolysate and its membrane fractions

Moringa seed peptides were tested for antioxidant properties through free radical scavenging abilities (1,1-diphenyl-2-picrylhydrazyl [DPPH] and hydroxyl radical scavenging assays [HRSAs]), inhibition of metal iron (ferric reducing antioxidant power [FRAP] and metal chelation tests) and in vitro antihypertensive properties through angiotensin converting enzyme (ACE) and renin inhibition tests. Compared to the hydrolysates, membrane fractionation led to improved antioxidative properties. Significant among the samples are <1 kDa (67.77%), 3–5 kDa (44.15%), 5–10 kDa (0.153 mmol Fe2+), and 3–5 kDa (11%) for DPPH, HRSAs, FRAP, and metal chelation ability, respectively. While there was a progressive increase in inhibition of the membrane fraction against ACE with the 5–10 kDa having significantly (p < 0.05) higher (73%) inhibition compared to other, there was no particular trend for the renin inhibition. However, the 5–10 kDa still showed better inhibition (57%) ability compared to others membrane fraction. We concluded that alcalase globulin hydrolysate and its membrane fractions possessed potent bioactive peptides. Practical applications Consumers more than ever before are getting concerned about the food they consume. This has resulted in the development and growth of functional foods. Functional foods are foods that are able to provide some physiological benefits such as antioxidative, antidiabetes, antihypertensive, and antiinflammatory among others besides their normal provision of nutrition. The growth of functional food market is due to the discovery of bioactive components in foods and viable opportunities still exist unexplored, especially with respect to the locally available and cheap underutilized crops such as Moringa oleifera seed. Plant-derived antioxidants (such as bioactive peptides) have gained considerable importance due to their potential health benefits; also epidemiological studies have shown that consumption of plant foods is beneficial. This benefit could readily be provided by peptides from Moringa oleifera seed; a cheap and commonly available but underutilized crop.