Antioxidant Properties of Various Solvent Extracts of Total Phenolic Constituents from Three Different Agroclimatic Origins of Drumstick Tree (<i>Moringa oleifera </i>Lam.) Leaves

TLDR

The study evaluated the radical‑scavenging and antioxidant activities of water, aqueous methanol, and aqueous ethanol extracts of freeze‑dried Moringa oleifera leaves from various agroclimatic regions. Extracts were prepared by freeze‑drying leaves and extracting with water, methanol, or ethanol, then tested for peroxyl, superoxyl, and DPPH radical scavenging, β‑carotene‑linoleic acid bleaching, and reducing power. All extracts scavenged peroxyl, superoxyl, and DPPH radicals, with methanol and ethanol extracts from Indian samples showing the highest antioxidant activity (65–67 % in the β‑carotene assay); increasing concentration enhanced reducing power, and flavonoids such as quercetin and kaempferol were identified as major phenolics, confirming Moringa leaves as a potent natural antioxidant source and establishing methanol (80 %) and ethanol (70 %) as the most effective solvents.

Abstract

Water, aqueous methanol, and aqueous ethanol extracts of freeze-dried leaves of Moringa oleifera Lam. from different agroclimatic regions were examined for radical scavenging capacities and antioxidant activities. All leaf extracts were capable of scavenging peroxyl and superoxyl radicals. Similar scavenging activities for different solvent extracts of each collection were found for the stable 1,1-diphenyl 2-picrylhydrazyl (DPPH(*)) radical. Among the three different moringa samples, both methanol and ethanol extracts of Indian origins showed the highest antioxidant activities, 65.1 and 66.8%, respectively, in the beta-carotene-linoleic acid system. Nonetheless, increasing concentration of all the extracts had significantly (P < 0.05) increased reducing power, which may in part be responsible for their antioxidant activity. The major bioactive compounds of phenolics were found to be flavonoid groups such as quercetin and kaempferol. On the basis of the results obtained, moringa leaves are found to be a potential source of natural antioxidants due to their marked antioxidant activity. This is the first report on the antioxidant properties of the extracts from freeze-dried moringa leaves. Overall, both methanol (80%) and ethanol (70%) were found to be the best solvents for the extraction of antioxidant compounds from moringa leaves.