Virtual screening and molecular dynamics simulation study of plant-derived compounds to identify potential inhibitors of main protease from SARS-CoV-2.

The new coronavirus (SARS-CoV-2) halts the world economy and caused unbearable medical emergency due to high transmission rate and also no effective vaccine and drugs has been developed which brought the world pandemic situations. The main protease (Mpro) of SARS-CoV-2 may act as an effective target for drug development due to the conservation level. Herein, we have employed a rigorous literature review pipeline to enlist 3063 compounds from more than 200 plants from the Asian region. Therefore, the virtual screening procedure helps us to shortlist the total compounds into 19 based on their better binding energy. Moreover, the Prime MM-GBSA procedure screened the compound dataset further where curcumin, gartanin and robinetin had a score of (-59.439, -52.421 and - 47.544) kcal/mol, respectively. The top three ligands based on binding energy and MM-GBSA scores have most of the binding in the catalytic groove Cys145, His41, Met165, required for the target protein inhibition. The molecular dynamics simulation study confirms the docked complex rigidity and stability by exploring root mean square deviations, root mean square fluctuations, solvent accessible surface area, radius of gyration and hydrogen bond analysis from simulation trajectories. The post-molecular dynamics analysis also confirms the interactions of the curcumin, gartanin and robinetin in the similar binding pockets. Our computational drug designing approach may contribute to the development of drugs against SARS-CoV-2.

phytochemdb: a platform for virtual screening and computer-aided drug designing.

The phytochemicals of medicinal plants are regarded as a rich source of diverse chemical spaces that have been used as supplements and alternative medicines in the millennium. Even in this era of combinatorial chemical drugs, phytomedicines account for a large share of the statistics of newly approved drugs. In the field of computational aided and rational drug design, there is an urgent need to develop and build a useful phytochemical database management system with a user-friendly interface that allows proper data storage, retrieval and management. We showed 'phytochemdb', a manually managed database that compiles 525 plants and their corresponding 8093 phytochemicals, aiming to incorporate the activities of phytochemicals from medicinal plants. The database collects molecular formula, three-dimensional/two-dimensional structure, canonical SMILES, molecular weight, no. of heavy atoms, no. of aromatic heavy atoms, fraction Csp3, no. of rotatable bonds, no. of H-bond acceptors, no. of H-bond donors, molar refractivity, topological polar surface area, gastrointestinal absorption, Blood-Brain Barrier (BBB) permeant, P-gp substrate, CYP1A2 inhibitor, CYP2C19 inhibitor, CYP2C9 inhibitor, CYP2D6 inhibitor, CYP3A4 inhibitor, Log Kp, Ghose, Veber, Egan, Muegge, bioavailability scores, pan-assay interference compounds, Brenk, Leadlikeness, synthetic accessibility, iLOGP and Lipinski rule of five with the number of violations for each compound. It provides open contribution functions for the researchers who screen phytochemicals in the laboratory and have released their data. 'phytochemdb' is a comprehensive database that gathers most of the information about medicinal plants in one platform, which is considered to be very beneficial to the work of researchers on medicinal plants. 'phytochemdb' is available for free at https://phytochemdb.com/.

Targeting SARS-CoV-2 nonstructural protein 15 endoribonuclease: an in silico perspective.

The newly emerged human coronavirus, SARS-CoV-2, had begun to spread last year and sparked worldwide. In this study, molecular docking is utilized to test some previously approved drugs against the SARS-CoV-2 nonstructural protein 15 (Nsp15). We screened 23 drugs, from which three (saquinavir, valrubicin and aprepitant) show a paramount predicted binding affinity (-9.1, -9.6 and -9.2 kcal/mol, respectively) against SARS-CoV-2 Nsp15. Moreover, saquinavir and aprepitant make nonbonded interactions with Leu201 in the active site cavity of Nsp15, while the drug valrubicin interacts with Arg199 and Leu201. This binding pattern may be effective against the targeted protein, leading to Nsp15 blockage and virus abolition. Additionally, the pharmacological properties of the screened drugs are known since they have been approved against different viruses.

Computational discovery of plant-based inhibitors against human carbonic anhydrase IX and molecular dynamics simulation.

Carbonic anhydrase IX (hCAIX) is a membrane-spanning metalloenzyme, encoded by CA9 gene, which can lead to various carcinomas if upregulated. Due to its overexpression in many cancer tissues, hCAIX has become a promising target for developing anticancer therapeutics. Furthermore, several classes of small-molecules have shown to inhibit the hCAIX expression. In this study, therefore, we screened (n = 42) plant-derived compounds to identify the most potent hCAIX inhibitors and to understand their interactions with hCAIX and drug candidacy through in silico approaches. Among all, only three compounds (i.e. fraxoside, scopolin, and xanthone,) provided higher binding affinity toward hCAIX protein as compared to the native ligand. In standard docking, scopolin showed -4.97 kcal/mol of binding energy with hCAIX while control ligand provided -4.45 kcal/mol. In precise docking, the highest binding affinity was found for fraxoside (-7.67 kcal/mol) as compared to -3.04 kcal/mol of the control. The Gibbs free energy (ΔG) of these potent leads was also consistent and in support of the docking studies. The binding interactions were also found to be stable in dynamics simulation. Furthermore, analysis of protein-protein interactions and co-expression revealed the possible association of CA9 gene with other tumorous genes, especially angiogenesis factor HIF1A which will most likely be affected by the identified inhibitors. With further experimental validation, therefore, these potential inhibitors could be effective against hCAIX protein, thereby, paving the way for prospective anticancer therapeutics.Communicated by Ramaswamy H. Sarma.