Figure 3.

Anti-SARS-CoV and anti-SARS-CoV-2 activity of digitoxin, bufalin, cinobufagin, telocinobufagin, bufotalin, cinobufotalin, and resibufogenin. The dose–response curve analysis using immunofluorescence staining was performed to determine the anti-SARS-CoV (A) and anti-SARS-CoV-2 (B) activity of cardiotonic steroids in Vero cells (ranging between 0.001 and 10 μM). Inhibition of SARS-CoV and SARS-CoV-2 infection (%, blue circles) and cell viability (%, red squares) were indicated. IC₅₀ values were calculated using non-linear regression analysis. The data represent duplicate experiments and are presented as the mean ± SEM.