Fig. 2.

PLE inhibits SARS-CoV-2 replication in Calu-3 cells. The expression of viral RNA and proteins (A–B) and cytokine mRNA (C) in Calu-3 cells was inhibited by PLE. Calu-3 cells were infected with SARS-CoV-2 in presence of various concentrations of PLE with remdesivir serving as positive control. Upon cell harvesting, RNA and viral protein quantification was performed with qRT-PCR (A) and western blotting (B), respectively. (A, C) Expression levels of viral or cytokine RNA were initially normalized to GAPDH mRNA. Moreover, the ratio measured in PLE-treated cells was normalized to the RNA level of virus control (arbitrarily set to 1). Data are expressed as means ± standard error of the mean from at least three independent experiments. ∗p < 0.05, ∗∗p < 0.01, and ∗∗∗p < 0.005.