ACE2 and hepatocellular carcinoma: Since the active antiviral substance may be an artemisinin metabolite, such that the artemisinin derivatives and extracts can be considered prodrugs, we used the human hepatoma cell line Huh7.5 and a human lung carcinoma cell line A549 constitutively expressing the SARS-CoV-2 entry receptor human ACE2 (A549-hACE2 cells) to confirm the EC50 determined in VeroE6 cells.