In a recent study, researchers from Germany tested the effectiveness of the sweet wormwood plant including artemisinin, artesunate, and artemether derivatives against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Extracts and purified bioactive compounds from the plant Artemisia annua are found in various combination therapies that are used to successfully treat malaria since they are known to rapidly reduce the parasite burden in infected individuals.
Due to their excellent safety nature and wide availability in addition to rare side effects and low cost, artemisinin-based drugs could indeed be attractive repurposing candidates for the treatment of COVID-19. In the beginning, the researchers had screened artemisinin for antiviral activity by engaging a plaque-reduction assay in a pretreatment setting.
The researchers, based on this, selected three extracts that were pure, synthetic artemisinin, artesunate, and artemether to study in detail. After the incubation period, the diseased cells were visualized by immunostaining for coronavirus spike glycoprotein (at room temperature) and counted automatically. Cell viability has also been monitored in detail. The treatment with extracts of artemisinin inhibited SARS-CoV-2 infection of Vero E6 cells. More precisely, artesunate was more potent than the tested plant extracts, artemisinin, or artemether in treatment assays, whereas generally EC50 values in pretreatment assays were somewhat higher.
Additionally, the selectivity index was highest for artemisinin and roughly equal for the extracts, artesunate, and artemether. The results thus obtained in human hepatoma Huh7.5 cells were similar to those in the Vero E6 cell line. In this study, the researchers confirm the efficacy of artemisinin-based treatment for two European SARS-CoV-2 strains from Germany and Denmark, which are more closely related to the majority of SARS-CoV-2 strains circulating worldwide than the Wuhan strain.
However, if these findings are translated to clinical conditions, then only artesunate showed EC50 values in the range of clinically achievable plasma and tissue concentrations among the tested extracts and pure compounds. Hence, further clinical studies are obligatory to adequately evaluate the usefulness of these compounds as a potential COVID-19 treatment option.
Ref link: https://www.biorxiv.org/content/10.1101/2020.10.05.326637v1