Fig. 4.

Antiviral efficacy of the selected compounds against HCoV-OC43. The antiviral activity of compounds was evaluated by focus reduction assay, infecting MRC-5 cells in presence of increasing concentration of compounds. Cell viability assays were performed in the same conditions as for antiviral assays, in absence of viral inoculum. The percentage of infectivity inhibition (white dots) and the percentage of cell viability (blue triangles) were calculated by comparing treated and untreated wells. Error bars represent the standard deviation (SD) of 3 independent experiments. Treated and untreated samples for the infectivity inhibition curves were compared with one-tailed Student's T-test. * = p-value <0.05. ** = p-value <0.01. *** = p-value <0.001.