In Silico Inhibitory Potential of Isolated Molecules of Scoparia dulcis L. (Scrophulariaceae) on SARS-CoV-2 Main Protease M^pro

Background: The Coronavirus disease 2019 (COVID-19) pandemic, caused by the SARS-CoV-2 coronavirus, remains a global threat despite lifting the health emergency. Scientists from all continents have been mobilized to develop vaccines and medicines for prevention and cure. In Burkina Faso, traditional healers proposed using Scoparia dulcis L., a medicinal plant, to manage COVID-19. Method: In silico screening offers a quick drug-likeness evaluation of Scoparia dulcis L.-isolated biomolecules toward SARS-CoV-2 targets, such as M^pro protease. A review of the literature retrieved 35 biomolecules isolated from Scoparia dulcis. The potential interactions of these biomolecules with the amino acid residues of the SARS-CoV-2 M^pro protease were visualized. Affinities and probable oral route delivery were assessed using reference molecules such as remdesivir and nelfinavir. Results: The screening allowed the retention of 20 hit molecules, which had a better affinity for the target than the reference molecules remdesivir and nelfinavir, and analysis of the results identified height lead molecules with a significant interaction with the M^pro protease and being druggable. There are six flavonoids: cirsimarin, cynaroside, hydroxy-tetramethoxyflavone, gossypetin, luteolin, vitexin, one diterpene, glutinol, and one glycoside, eugenyl-glucoside. These molecules interact with methionine 6 and tyrosine 126 of SARS-CoV-2 M^pro. These two amino acids are essential for the dimerization of M^pro protease. Inhibitory action on M^pro protease can be expected from these biomolecules. Conclusion: Scoparia dulcis L. could help manage COVID-19 because it contains biomolecules that can inactivate SARS-CoV-2 M^pro.