Phenolic compounds and in vitro antioxidant activity of Moringa stenopetala grown in South Ethiopia

Abstract

Moringa stenopetala is a traditional medicinal and nutritional plant in Ethiopia. The aim of this work was to carry out a chemical analysis focusing on secondary metabolites, particularly phenolic compounds, and antioxidant activity of aqueous and methanol extracts of Moringa stenopetala leaf. The phenolic compounds were analyzed by high-performance liquid chromatography diode array detector (HPLC-DAD). Hydroxycinnamic acid (538 ± 6 µg/g), 3-Hydroxbenzoic acid (31 ± 6 µg/g), and quercetin-3-O-rutinoside (1155 ± 65 µg/g) were the major components in methanol extract. Whereas, syringic (84 ± 13 µg/g), chlorogenic (165 ± 19 µg/g), succinnic (1811 ± 105 µg/g), and fumaric (1582 ± 65 µg/g) acids were the major organic acids in the aqueous extract. Methanol extract had higher total flavonoid (11 ± 2 mg of catechin equivalent per gram of dried extract) and total phenolic (39 ± 3 mg of gallic acid equivalent per gram of dried extract) contents. This extract showed stronger DPPH scavenging (EC50 = 78 ± 6 μg/mL) and ferrous chelating (EC50 = 239 ± 12 μg/mL) activities. Due to the abundance sources of bioactive compounds and antioxidant activity, the dried leaf of M. stenopetala could be used for the development of nutraceuticals or incorporated into functional foods.

Keywords

• antioxidant
• chelating
• hplc-dad
• moringa
• phenolic compounds