Analysis of the oxidative stress inhibition potentials of Artemisia annua and its bioactive compounds through in vitro and in silico studies

Oxidative stress overwhelms the antioxidant mechanisms of living systems, with active involvement in the pathogenesis of several diseases. Natives of Gangnim in the Plateau State of Nigeria may be unknowingly endowed with some protective advantages against oxidative stress for their habitual consumption of Artemisia annua tea. The antioxidant activities of A. annua extracts were determined using in vitro methods and the inhibitory potentials of twenty-nine (29) bioactive compounds of the plant against oxidative stress target proteins were assessed through molecular docking analysis. These extracts showed significantly high activities in scavenging nitric oxide, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and reducing ferric (Fe3+) to ferrous (Fe2+) iron. Virtually, none of the bioactive compounds binds to the active site of the antioxidant protein targets. Rather, 72.41, 93.10 and 75.86% of these compounds bind with high binding affinity to the activator binding sites of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) respectively. 7,8-dimethylalloxazine (-8.10 kcal/mol) ranked highest as a prospective inhibitor of xanthine oxidase (XOX). The antioxidant activity exhibited by the extracts of the locally cultivated A. annua and the molecular interactions of its bioactive compounds against the protein targets used predict that oxidative stress inhibition could be effectively achieved with these phytochemicals.