Fig. 5. Dose-dependent inhibition of SARS-CoV-2 3CLpro activity by selected PIs, VNIs, and OTDs.

The drug candidates that exhibited more than 50% of inhibitory activity at 50 µM concentration were selected for dose-dependent and IC₅₀ calculation studies. A serial dilution of drugs ranging from 0 to 100 µM in assay buffer was used. The percent activity was calculated as described in Fig. 1 legend. Representative of three individual experiments with triplicate values were presented graphically (n = 3). Non-linear regression (curve fit) with four variable dose vs inhibition was used to calculate the IC₅₀ values using GraphPad Prism.