Whole genome analysis and homology modeling of SARS-CoV-2 Indian isolate reveals potent FDA approved drug choice for treating COVID-19.

Coronaviruses have caused enough devastation in the last two decades. These viruses have some rare features while sharing some common features. Novel coronavirus disease (nCoV-19) caused an outbreak with a fatality rate of 5%. It emerged from China and spread into many countries. The present research focused on genome analysis of Indian nCoV-19 Isolate and its translational product subjected to homology modeling and its subsequent molecular simulations to find out potent FDA approved drug for treating COVID-19. Phylogenetic analysis of SARS-CoV-2 Indian isolate shows close resemblance with 17 countries SARS-CoV-2 isolates. Homology modeling of four non-structural proteins translational product of Indian SARS-CoV-2 genome shows high similarity and allowed regions with the existing PDB deposited SARS-CoV-2 target proteins. Finally, these four generated proteins show more affinity with cobicistat, remdesivir and indinavir out of 14 screened FDA approved drugs in molecular docking which is further proven by molecular dynamics simulation and MMGBSA analysis of target ligand complex with best simulation trajectories. Overall our present research findings is that three proposed drugs namely cobicistat, remdesivir and indinavir showed higher interaction with the model SARS-CoV-2 viral target proteins from the Indian nCoV-19 isolate. These compounds could be used as a starting point for the creation of active antiviral drugs to combat the deadly COVID-19 virus during global pandemic and its subsequent viral infection waves across the globe.Communicated by Ramaswamy H. Sarma.

All-Trans Retinoic Acid Exhibits Antiviral Effect against SARS-CoV-2 by Inhibiting 3CLpro Activity.

The pandemic of COVID-19 caused by SARS-CoV-2 continues to spread despite the global efforts taken to control it. The 3C-like protease (3CLpro), the major protease of SARS-CoV-2, is one of the most interesting targets for antiviral drug development because it is highly conserved among SARS-CoVs and plays an important role in viral replication. Herein, we developed high throughput screening for SARS-CoV-2 3CLpro inhibitor based on AlphaScreen. We screened 91 natural product compounds and found that all-trans retinoic acid (ATRA), an FDA-approved drug, inhibited 3CLpro activity. The 3CLpro inhibitory effect of ATRA was confirmed in vitro by both immunoblotting and AlphaScreen with a 50% inhibition concentration (IC50) of 24.7 ± 1.65 µM. ATRA inhibited the replication of SARS-CoV-2 in VeroE6/TMPRSS2 and Calu-3 cells, with IC50 = 2.69 ± 0.09 µM in the former and 0.82 ± 0.01 µM in the latter. Further, we showed the anti-SARS-CoV-2 effect of ATRA on the currently circulating variants of concern (VOC); alpha, beta, gamma, and delta. These results suggest that ATRA may be considered as a potential therapeutic agent against SARS-CoV-2.

Comparative analysis of antiviral efficacy of FDA-approved drugs against SARS-CoV-2 in human lung cells.

Drug repositioning represents an effective way to control the current COVID-19 pandemic. Previously, we identified 24 FDA-approved drugs which exhibited substantial antiviral effect against severe acute respiratory syndrome coronavirus 2 in Vero cells. Since antiviral efficacy could be altered in different cell lines, we developed an antiviral screening assay with human lung cells, which is more appropriate than Vero cell. The comparative analysis of antiviral activities revealed that nafamostat is the most potent drug in human lung cells (IC50 = 0.0022 µM).

Review: An insight into coronaviruses: Challenges, security and scope.

SARS-CoV2 is a novel coronavirus; the seventh of its species to infect humans. The spread of this virus emerged in Wuhan, China in late December, 2019. Since then, this virus has spread to more than 200 countries and has caused a worldwide pandemic. Being a new species of coronaviruses, any cure or vaccines for this virus has not yet been obtained. A large amount of scientific studies and clinical trials are being carried out across the world to find a potential vaccine for this virus. Current work reports a review of potential drugs and vaccines that may be effective against this virus. Different scientific therapies that may potentially be effective against the SARS-CoV2 virus are also reviewed. The mechanisms of various drugs, their efficiency in various clinical trials and their side effects are also studied.

Virtual screening, molecular dynamics and structure-activity relationship studies to identify potent approved drugs for Covid-19 treatment.

Computer-aided drug screening by molecular docking, molecular dynamics (MD) and structural-activity relationship (SAR) can offer an efficient approach to identify promising drug repurposing candidates for COVID-19 treatment. In this study, computational screening is performed by molecular docking of 1615 Food and Drug Administration (FDA) approved drugs against the main protease (Mpro) of SARS-CoV-2. Several promising approved drugs, including Simeprevir, Ergotamine, Bromocriptine and Tadalafil, stand out as the best candidates based on their binding energy, fitting score and noncovalent interactions at the binding sites of the receptor. All selected drugs interact with the key active site residues, including His41 and Cys145. Various noncovalent interactions including hydrogen bonding, hydrophobic interactions, pi-sulfur and pi-pi interactions appear to be dominant in drug-Mpro complexes. MD simulations are applied for the most promising drugs. Structural stability and compactness are observed for the drug-Mpro complexes. The protein shows low flexibility in both apo and holo form during MD simulations. The MM/PBSA binding free energies are also measured for the selected drugs. For pattern recognition, structural similarity and binding energy prediction, multiple linear regression (MLR) models are used for the quantitative structural-activity relationship. The binding energy predicted by MLR model shows an 82% accuracy with the binding energy determined by molecular docking. Our details results can facilitate rational drug design targeting the SARS-CoV-2 main protease.Communicated by Ramaswamy H. Sarma.

Identification of Antiviral Drug Candidates against SARS-CoV-2 from FDA-Approved Drugs.

Drug repositioning is the only feasible option to immediately address the COVID-19 global challenge. We screened a panel of 48 FDA-approved drugs against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which were preselected by an assay of SARS-CoV. We identified 24 potential antiviral drug candidates against SARS-CoV-2 infection. Some drug candidates showed very low 50% inhibitory concentrations (IC50s), and in particular, two FDA-approved drugs-niclosamide and ciclesonide-were notable in some respects.