The present study discloses the identification of phenolic compounds in Moringa oleifera hot water extract (MOH) and the evaluation of its antioxidant activity on H2O2-induced oxidative stress in Vero cells. Upon analysis, MOH was found to contain phenolic compounds and indicated 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS+) radical scavenging with IC50 values of 102.52 and 122.55 µg/mL, respectively. The ferric reducing antioxidant power (FRAP) of MOH indicated a dose-dependent increase with a maximum absorbance at 125 μg/mL and the oxygen radical absorbance capacity (ORAC) of MOH was 1004.95 µmol TE/mg. Results showed that MOH dose-dependently reduced intracellular ROS generation in H2O2-stimulated Vero cells while increasing the cell viability. Fluorescence microscopy and flowcytometric analyses have supported the above findings. MOH markedly suppressed the H2O2-induced mitochondrial depolarization and apoptosis through suppression of the mitochondrial-mediated apoptosis pathway and activated the Nrf2/HO-1 signaling pathway by possibly involving H2O2 generation in cell media. Findings of western blot were supported by immunocytochemistry of Nrf2 nuclear translocation. Thus, MOH bioactivity would potentiate its applications in manufacturing functional food.
Keywords: Moringa oleifera; Vero; antioxidants; oxidative stress; polyphenols.