Introduction Drug repurposing is the need of the hour considering the medical emergency caused by the COVID-19 pandemic. Recently, cytokine storm by the host immune system has been linked with high viral load, loss of lung function, acute respiratory distress syndrome (ARDS), multiple organ failure, and subsequent fatal outcome. Objective This study aimed to identify potential FDA approved drugs that can be repurposed for COVID-19 treatment using an in-silico analysis. Methods In this study, virtual screening of selected FDA approved drugs was performed by targeting the main protease (M pro ) of SARS-CoV-2 and the key molecules involved in the ‘Cytokine storm’ in COVID-19 patients. Based on our preliminary screening supported by extensive literature search, we selected FDA approved drugs to target the SARS-CoV-2 main protease (M pro ) and the key players of cytokine storm, TNF-α, IL-6, and IL-1β. These compounds were examined based on systematic docking studies and further validated using a combination of molecular dynamics simulations and molecular mechanic/generalized/Born/Poisson-Boltzmann surface area (MM/G/P/BSA) free energy calculations. Results Based on the findings, Rifampicin and Letermovir appeared as the most promising drug showing a very good binding affinity with the main protease of SARS-CoV-2 and TNF-α, IL-6, and IL-1β. However, it is pertinent to mention here that our findings need further validation by in vitro analysis and clinical trials. Conclusion This study provides an insight into the drug repurposing approach in which several FDA approved drugs were examined to inhibit COVID-19 infection by targeting the main protease of SARS-COV-2 and the cytokine storm. Graphic abstract Supplementary Information The online version contains supplementary material available at 10.1007/s43440-021-00228-0.

Objective: To explore natural compounds as potential inhibitors against main protease (Mpro) of SARS-CoV-2. Methods: In the current study, systematic molecular docking analysis was conducted using AutoDock 4.2 to determine the binding affinities and interactions between natural compounds and Mpro. Selected natural compounds were further validated using a combination of molecular dynamic (MD) simulations and molecular mechanic Poisson-Boltzmann surface area (MM/PBSA) free energy calculations. Results: Out of twenty natural compounds, four natural metabolites namely, amentoflavone, guggulsterone, puerarin, and piperine were found to have strong interaction with Mpro of SARS-CoV-2 based on docking analysis. During MD simulations, all four natural compounds bound to Mpro at 50 ns and MM/G/P/BSA free energy calculations showed that all four shortlisted ligands had stable and favorable energies with strong binding to Mpro protein. Conclusions: Guggulsterone is a potential inhibitor of COVID- 19 main protease Mpro. Further in vitro and pre-clinical studies are needed.

: The Coronavirus Disease 2019 (COVID-19), also known as a novel coronavirus (2019-nCoV), reportedly originated from Wuhan City, Hubei Province, China. Coronavirus Disease 2019 rapidly spread all over the world within a short period. On January 30th, 2020, the World Health Organization (WHO) declared it a global epidemic. COVID-19 is a severe acute respiratory syndrome coronavirus (SARS-CoV) virus that evolves to respiratory, hepatic, gastrointestinal, and neurological complications, and eventually death. SARS-CoV and the Middle East Respiratory Syndrome coronavirus (MERS-CoV) genome sequences similar identity with 2019-nCoV or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, few amino acid sequences of 2019-nCoV differ from SARS-CoV and MERS-CoV. COVID-19 shares about 90% amino acid sequence similarity with SARS-CoV. Effective prevention methods should be taken in order to control this pandemic situation. Till now, there are no effective treatments available to treat COVID-19. This review provides information regarding COVID-19 history, epidemiology, pathogenesis, and molecular diagnosis. Also, we focus on the development of vaccines in the management of this COVID-19 pandemic and limiting the spread of the virus.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has taken over the world, and more than 38 lakh deaths have been reported till now due to this infectious disease. It has been declared a global pandemic by the world health organization. SARS-CoV-2 causes coronavirus disease of 2019 (COVID-19), and the major problem called "Cytokine storm" is reported, which may lead to death among the COVID-19 patients. This study aimed to review the Cytokine storm and its mechanism along with few immunomodulatory therapies for SARS-CoV-2 infection suppression effectively. Methods: The recently published works of literature were selected and reviewed based on the subject of this study. The databases, including Pubmed, ScienceDirect, Scopus, and Google Scholar, were searched extensively. Results: The review of the literature showed that an uncontrolled immune response causes excess inflammation. Evidence from recent trials has demonstrated that cytokine storms can be an important factor in the COVID-19 severity, leading to multiple organ failure and death. Conclusion: This study reviewed immunomodulatory therapies and strategies for SARS-CoV-2 infected patients to suppress the immune response. Ultimately, the cytokine storm can prove to be a boon and reduce the significant death tolls to SARS-CoV-2 infection.