4.16. Artesunate
It is a polycyclic natural product with endoperoxide moiety (Figure S6). It is parenterally used to treat malaria. Initially, there was not enough information about its efficacy against SARS-CoV, except the results of herbal extract screening [246]. It is now being evaluated in few clinical trials alone (NCT04387240; n = 22) or in combination with pyronaridine, another antimalarial drug (NCT04475107; n = 76 and NCT04532931; n = 250). In particular, the combination exhibited antiviral activity against SARS-CoV-2 and influenza viruses in human lung epithelial Calu-3 cells [247]. Other artemisinin-based combinations that appear to be on the rise for potentially treating COVID-19 are mefloquine-artesunate [248] and arteannuin B and lumefantrine [249].