FIG 1.

Cytotoxicity for Vero E6 cells and inhibition of SARS-CoV-2 progeny production by Rib. (A) Determinations of cytotoxic concentration 50 (CC₅₀); percent cell death is plotted as a function of Rib concentration. (B) Inhibition of SARS-CoV-2 infectious progeny production by Rib. The experiments and titrations were performed in triplicate; values and standard deviations were calculated using the program SigmaPlot. (C) Determinations of inhibitory concentration 50 (IC₅₀); percent inhibition is plotted as a function of Rib concentration. (D) Function and values that correspond to the discontinuous lines depicted in panels A and C. Mock infections were carried out in parallel (negative control). Experimental conditions for cell growth, SARS-CoV-2 infection, determination of cell viability, and SARS-CoV-2 infectivity are described in Materials and Methods.