Antioxidant and anti-inflammatory properties of novel peptides from Moringa oleifera Lam. leaves

Moringa oleifera is a tree used as a medicinal herb by several populations. Due to their curative and preventive properties, all parts have been studied, especially the leaves. They have been found to act as antithrombotic, antihypertensive, anticancer, immunomodulating, and antioxidant agents. This study was aimed to characterize and evaluate the antioxidant and anti-inflammation activities of Moringa oleifera leaves protein hydrolysate obtained by in vitro gastrointestinal digestion. The antioxidant activity of these peptides was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and Oxygen Radical Absorbance Capacity (ORAC) assays. RAW 264.7 macrophages were stimulated with lipopolysaccharides, and the effect of the peptides over nitric oxide production was measured to assess the anti-inflammatory effect. Furthermore, peptides were identified by nanoscale liquid chromatography coupled to tandem mass spectrometry. Moringa oleifera leaves peptides (1.33 mg/ml) inhibited DPPH and ABTS radicals by 45.70 and 93.09%, respectively, and had an ORAC activity of 3.27 mM Trolox equivalent/g. They were not cytotoxic to lipopolysaccharides-induced RAW 264.7 macrophages and, at a concentration of 100 μg/ml, inhibited the nitric oxide production by 30.51%. The sequences of 14 novel peptides were identified. Our findings suggest that Moringa oleifera leaves peptides released by in vitro gastrointestinal digestion might be a potential resource for natural antioxidant and anti-inflammatory components. However, further in vivo experiments are needed.