Comparative in vitro assessment of drumstick (Moringa oleifera) and neem (Azadiracta indica) leaf extracts for antioxidant and free radical scavenging activities

Abstract

The current research was aimed at comparing the leaf extracts of two medicinal plants (Moringa oleifera and Azadiracta indica) for antioxidant and free radical scavenging potentials in different extracting solvents (absolute ethanol, 70 and 50% ethanol). Different in vitro assays such as total phenolic and flavonoid content, 2-2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, metal chelating activity, reducing power and total antioxidant capacity were employed in the study. The results revealed that A. indica contained more phenols and flavonoids than M. oleifera with the different extracting solvents. The amount of phenols and flavonoids in A. indica played a pivotal role in scavenging more of the DPPH radical at a lower inhibitory concentration, IC 50 of 77.94 µg mL· 1 than in M. oleifera at 118.96 µg mL· 1 in absolute ethanol. Moringa oleifera was a better scavenger of the DPPH radical in 70 and 50% ethanol. In absolute ethanol, A. indica also chelated 50% of the metal ion at IC 50 of 0.22 µg mLG 1 which was even better than ascorbic acid (5.95 µg mL· 1) and gallic acid (0.503 µg mL· 1) standards. The values for A. indica were also comparably better than those of M. oleifera for reducing power and total antioxidant capacity at the respective concentrations. The results are indicative of the antioxidant and free radical scavenging potentials of M. oleifera and A. indica. Comparatively, A. indica was better than M. oleifera in doing the job and absolute ethanol extracts were better than 70 and 50% ethanol extracts in the scavenging potential.