Identification of potential inhibitors of SARS-CoV-2 from Artemisia annua compounds by In silico evaluation and their density functional theory (DFT)

The genus Artemisia has recognized medicinal value and its use by humans Dates back to centuries ago. With the appearance of the new coronavirus, end of 2019, several countries have recommended the use of herbal teas consisting mainly of Artemisia. The individual analysis of the constituents of this species is crucial to characterize and optimize its antiSARS-Cov-2 action. We evaluated by molecular docking the inhibitory action of major compounds of the Artemisia genus (Artemisinin, Arteannuin B, Alpha Thujone, P-Hydroxyacetophenone, Fisetin, Cirsimaritin, Capillin, β-Sitosterol, and Quercetin) against three targets namely SARS-CoV-2 main protease (Mp), SARS-CoV-2 receptor binding domain (RBD) and human furin protease (HF protease). The two flavonols, quercetin and fisetin, have the best binding energies with the three targets. Quercetin/Fisetin possesses binding energy of -7.17/-6.9, -6.3/-6.15 and –5.98/-5.49 kcal/mol with MP, RBD and HF protease respectively. Their physicochemical properties meet the requirements of an oral active principle and are not toxic according to predictive simulations. Thereby DFT calculation has been used to analyze the electronic and geometric characteristics of these two compounds. The gap energies were also deduced for the stable structure and their reactivity. The abundance of Quercetin in different plants may be another advantage in the use of this bio-compound in the treatment of coronavirus.