Exploiting Modeling Studies for Evaluating the Potential Antiviral Activities of some Clinically Approved Drugs and Herbal Materials against SARS-CoV-2: Theoretical Studies toward Hindering the Virus and Blocking the Human Cellular Receptor

Abstract

This research theoretically modeled the binding interaction of the Sars-Cov-2 (Spike protein) utilizing molecular docking with some potential repurposed antiviral medications and two botanical products (Curcumin and Quercetin). Molecular docking between the drugs and the Sars-Cov-2 proteins reflecting the pure electrostatic forces and H-bond formation is complemented with the DFT results that shed light on the electronic nature of the interactions. Moreover, DFT computations provide invaluable information about the drug reactivity indices calculated from the energies of the frontier orbitals. The DFT results indicate intermolecular electron donor-acceptor interaction besides the H-bond formation. Most of the considered medication molecules act as electron-sink candidates except EIDD-2801 (molnupiravir), the electron donor. The theoretical results show the high possibility of blocking the human cellular entry against Sare-Cov-2 via strong interaction of the drugs with its peptide sequence (β6) measured by the high binding energy of docking or weakening its activity due to the electronic donor-acceptor interactions indicated by reactivity indices computed from the frontier molecular orbitals.