Molecular docking results of top ranking compounds savinin, betulinic acid, and curcumin with (A) SARS-CoV-2 M^pro monomer and (B) SARS-CoV-2 M^pro dimer, respectively, based on affinity of binding.

The top-energy pose (according to Total Energy) of each compound is presented (with an RMSD of 0.0). The DockThor molecular docking program was used for analysis of interactions between SARS-CoV-2 Mpro monomer and dimer and the three compounds, using default settings. Ligplot was used to reveal the residues involved in binding and the mode of interaction with the ligands. The SARS-CoV-2 Mpro monomer and SARS-CoV-2 Mpro dimer (chain A) used in this study were from PDB IDs 6yb7 and 7ali, respectively.