Fig. 1. (A) Identification of inhibitory metallodrugs for SARS-CoV-2 3CLpro. Bar charts show the relative protease activities of 3CLpro after incubation with 50 μM sodium stibogluconate (SSG), colloidal bismuth subcitrate (CBS), bismuth gluconate, cis-platinum, Auranofin, AuP(CH₂CH₃)₃Cl and four Au(i)-based complexes. (B) Inhibition of the protease activities of 3CLpro by CBS at varying concentrations in vitro. Dose–response curves for half-maximum inhibitory concentration (IC₅₀) values were determined by nonlinear regression. (C) Inhibition of SARS-CoV-2 proteases by CBS in cellulo. Schematic illustration of the cell-based luciferase reporter assay. (D) The cells that expressed 3CLpro are treated with varying concentrations of CBS. NC represents negative control. Bar charts show the relative luciferase activity of cell lysate. Each experiment were performed in triplicates. The data are shown in mean ± sd. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.