In vitro antioxidant and free-radical scavenging activities of polar leaf extracts of Vernonia amygdalina

Abstract

Background

Plants are able to deliver a huge number of differing bioactive compounds which may supplement the requirements of the human body by acting as natural antioxidants. Antioxidants are mindful for the defense component of the life form against the pathologies related to the assault of free radicals. The main purpose of this study was to investigate the qualitative phytochemical composition of Vernonia amygdalina leaf extract and its antioxidant activity.

Method

The powdered plant sample was successively extracted with aqueous, methanol and ethanol solvents using Soxhlet apparatus. The antioxidant activities of the crude leaf extract were determined using 1, 1- diphenyl-2-picryl hydrazyl (DPPH) radical, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical, phosphomolybdate (PM) and hydrogen peroxide (H ₂O ₂) scavenging assay. All the examinations were drained triplicates and average values of each test were taken.

Results

Phytochemical investigation of the plant revealed that the three solvent extracts contained numerous bioactive compounds namely alkaloids, tannins, saponins, phenols, terpenoids, steroids, glycosides and sugars. The result showed that, the leaf extracts of V. amygdalina obtained from methanol extract exhibit the maximum antioxidant activity compared ethanol and aqueous extracts. The IC50 values of DPPH assay for the H ₂O, MeOH and EtOH extracts were 111.4, 94.92 and 94.83 μg/ml; of ABTS assay were 334.3, 179.8 and 256.9 μg/ml; of H ₂O ₂ assay were 141.6, 156 and 180.6 μg/ml, respectively. The maximum radical scavenging activity was obtained in DPPH assay while the lowest scavenging activity was obtained in ABTS assay method. The data obtained in the in vitro models clearly suggest that methanol extract has higher antioxidant activity due to a higher presence of phenolic constituents in the extract.

Conclusion

This study revealed that V. amygdalina leaf has a noteworthy antioxidant and free radical scavenging activity mitigating the traditional use of the plant for different aliments.