Fig. 3.

Antiviral activity of compound 12 and 16 against SARS-CoV-2 in cell-based assays. a. Vero E6 cells were infected with SARS-CoV-2 at a multiplicity of infection (MOI) of 0.1 and treated with different concentrations of test compounds (0.064 μM, 0.32 μM, 1.6 μM, 8 μM, 40 μM and 200 μM). At 3 dpi the cytopathic effect caused by SARS-CoV-2 infection was quantitatively analyzed using CCK8, according to the manufacturer's protocol. Data are means ± SD; n = 3 biological replicates. b. Vero E6 cells were infected with SARS-CoV-2 at an MOI of 0.01 and treated with different concentrations of test compounds (3.125 μM, 6.25 μM, 12.5 μM, 25 μM, 50 μM, and 100 μM). At 2 dpi, viral RNA copies (per ml) were quantified from cell culture supernatants by RT-qPCR. Data are means ± SD; n = 3 biological replicates. c. The EC₅₀, CC₅₀ and SI of compounds 12 and 16.