Non-Nucleotide RNA-Dependent RNA Polymerase Inhibitor That Blocks SARS-CoV-2 Replication

Figures

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  Scheme 1. Synthetic pathway to HeE1-2Tyr (16) and its derivatives.

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  Figure 1. Inhibitions of SARS-CoV-2 RdRp by compounds 16, 17, and 18. (left) IC50 values were established for each tested compound using a radioactive primer extension assay. Error bars represent the standard error of the mean (n = 3). (right) A fluorescence-based primer extension assay. Formation of the 40-nt product decreases with increasing concentration of the compound.

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  Figure 2. Antiviral efficacy and cytotoxicity of the studied RdRp inhibitors in cell-based assays. (A) Cytotoxicity of the indicated compounds in Vero and CRFK cells. The cell monolayers were treated with the compounds (50 µM) and incubated for 48 h. The cell-mediated conversion of tetrazolium salt WST-8 to formazan was monitored by absorbance measurement (450 nm). Cytotoxicity was expressed in terms of cell viability percentage. (B) Anti-SARS-CoV-2 and anti-FIPV efficacies of the indicated compounds in Vero and CRFK cells, respectively. The cell monolayers were treated with the compounds (50 µM), infected with the respective virus at a MOI of 0.1, and incubated for 48 h. The supernatant media were collected, and viral titers were determined by plaque assays. (C–E) Dose-dependent cytotoxic effects of the compounds in Vero (C), CaCo-2 (D), and CRFK (E) cells. The cell monolayers were treated with the compounds in the concentration range from 0 to 50 µM and incubated for 48 h. Cytotoxicity was determined, as described for (A). (F,G) Dose-dependent anti-SARS-CoV-2 activity of the compounds in Vero (F) and CaCo-2 (G) cells. The cell monolayers were treated with the compounds in the…