In-vitro antioxidant activities of different stem bark extracts of Irvingia gabonensis (Irvingiaceae)

Abstract

Oxidative stress is implicated in the pathogenesis of many diseases. Irvingia gabonensis is used in Nigeria for the management of diabetes mellitus, inflammation, liver diseases, viral infections and dementia. In order to explore the antioxidant potential of the stem bark of I. gabonensis, the powdered plant was subjected to soxhlet extraction with solvents of varying polarities (petroleum ether, butanol, and water) to obtain the various extracts. The extracts were subjected to phytochemical screening and evaluated for antioxidant activities, total phenolic and flavonoid contents using established protocols. Phytochemical screening revealed the presence of flavonoids, tannins, triterpenes, steroids, and saponins. Total phenolic contents (TPCs) of the petroleum ether, butanol and aqueous extracts were 109.3, 147.7 and 96.3 μg of gallic acid equivalent per mL, respectively, while the total flavonoid contents (TFCs) were 56.3, 43.3, and 20.3 μg of rutin equivalents per mL for the petroleum ether, butanol and aqueous extracts, respectively. Antioxidant activities of the three extracts using ferric ion reducing power were significant compared to ascorbic acid. In the phosphomolybdate assay, the petroleum ether extract at 500 μg/mL was not different from ascorbic acid. In the hydrogen peroxide scavenging assay, the petroleum ether and butanol extracts at 250 and 500 μg/mL were significantly increased compared to ascorbic acid. In the DPPH assay, the butanol extract at 500 μg/mL showed antioxidant activity compared to ascorbic acid. The findings of this research indicate that I. gabonensis possesses in vitro antioxidant activity which was prominent in the petroleum ether and butanol extracts.