b Compounds were serially 2-fold or 4-fold diluted from 100 μM, except ribavirin which was started at 500 μM. Cytopathic effects (CPE) of SARS-CoV-2 virus in Vero E6 cells under increasing concentration of the compounds were observed at 48 h post-infection. The lowest concentration of the compound with 100% CPE inhibition (eg. exhibiting comparable CPE of non-infected controls) was recorded.