The Public Health Emergency of International Concern declared the widespread outbreak of SARS-CoV-2 as a global pandemic emergency, which has resulted in 1,773,086 confirmed cases including 111,652 human deaths, as on 13 April 2020, as reported to World Health Organization. As of now, there are no vaccines or antiviral drugs declared to be officially useful against the infection. Saikosaponin is a group of oleanane derivatives reported in Chinese medicinal plants and are described for their anti-viral, anti-tumor, anti-inflammatory, anticonvulsant, antinephritis and hepatoprotective activities. They have also been known to have anti-coronaviral property by interfering the early stage of viral replication including absorption and penetration of the virus. Thus, the present study was undertaken to screen and evaluate the potency of different Saikosaponins against different sets of SARS-CoV-2 binding protein via computational molecular docking simulations. Docking was carried out on a Glide module of Schrodinger Maestro 2018-1 MM Share Version on NSP15 (PDB ID: 6W01) and Prefusion 2019-nCoV spike glycoprotein (PDB ID: 6VSB) from SARS-CoV-2. From the binding energy and interaction studies, the Saikosaponins U and V showed the best affinity towards both the proteins suggesting them to be future research molecule as they mark the desire interaction with NSP15, which is responsible for replication of RNA and also with 2019-nCoV spike glycoprotein which manage the connection with ACE2.

COVID-19 has ravaged the world and is the greatest of pandemics in modern human history, in the absence of treatment or vaccine, the mortality and morbidity rates are very high. The present investigation identifies potential leads from the plant Withania somnifera (Indian ginseng), a well-known antiviral, immunomodulatory, anti-inflammatory and a potent antioxidant plant, using molecular docking and dynamics studies. Two different protein targets of SARS-CoV-2 namely NSP15 endoribonuclease and receptor binding domain of prefusion spike protein from SARS-CoV-2 were targeted. Molecular docking studies suggested Withanoside X and Quercetin glucoside from W. somnifera have favorable interactions at the binding site of selected proteins, that is, 6W01 and 6M0J. The top-ranked phytochemicals from docking studies, subjected to 100 ns molecular dynamics (MD) suggested Withanoside X with the highest binding free energy (DG bind ¼ À89.42 kcal/mol) as the most promising inhibitor. During MD studies, the molecule optimizes its conformation for better fitting with the receptor active site justifying the high binding affinity. Based on proven therapeutic, that is, immunomodulatory, antioxidant and anti-inflammatory roles and plausible potential against n-CoV-2 proteins, Indian ginseng could be one of the alternatives as an antiviral agent in the treatment of COVID 19. HIGHLIGHTSWithania somnifera has antiviral potential. Phytochemicals of Ashwagandha showed promising in silico docking and molecular dynamics results.

COVID-19 has ravaged the world and is the greatest of pandemics in human history, in the absence of treatment or vaccine the mortality and morbidity rates are very high. The present investigation was undertaken to screen and identify the potent leads from the Indian Ayurvedic herb, Asparagus racemosus (Willd.) against SARS-CoV-2 using molecular docking and dynamics studies. The docking analysis was performed on the Glide module of Schr€ odinger suite on two different proteins from SARS-CoV-2 viz. NSP15 Endoribonuclease and spike receptor-binding domain. Asparoside-C, Asparoside-D and Asparoside -F were found to be most effective against both the proteins as confirmed through their docking score and affinity. Further, the 100 ns molecular dynamics study also confirmed the potential of these compounds from reasonably lower root mean square deviations and better stabilization of Asparoside-C and Asparoside-F in spike receptor-binding domain and NSP15 Endoribonuclease respectively. MM-GBSA based binding free energy calculations also suggest the most favourable binding affinities of Asparoside-C and Asparoside-F with binding energies of À62.61 and À55.19 Kcal/mol respectively with spike receptor-binding domain and NSP15 Endoribonuclease. HIGHLIGHTSAsparagus racemosus have antiviral potential Phytochemicals of Shatavari showed promising in-silico docking and MD results Asparaoside-C and Asparoside-F has good binding with target proteins Asparagus racemosus holds promise as SARS-COV-2 (S) and (N) proteins inhibitor

Traditionally, Withania somnifera is widely used as an immune booster, anti-viral, and for multiple medicinal purposes. The present study investigated the withanolides as an immune booster and antiviral agents against the coronavirus-19. Withanolides from Withania somnifera were retrieved from the open-source database, their targets were predicted using DIGEP-Pred, and the protein-protein interaction was evaluated. The drug-likeness score and intestinal absorptivity of each compound were also predicted. The network of compounds, proteins, and modulated pathways was constructed using Cytoscape, and docking was performed using autodock4.0, and selected protein-ligand complexes were subjected to 100 ns Molecular Dynamics simulations. The molecular dynamics trajectories were subjected to free energy calculation by the MM-GBSA method. Withanolide_Q was predicted to modulate the highest number of proteins, showed human intestinal absorption, and was predicted for the highest drug-likeness score. Similarly, combined network interaction identified Withanolide_Q to target the highest number of proteins; RAC1 was majorly targeted, and fluid shear stress and atherosclerosis associated pathway were chiefly regulated. Similarly, Withanolide_D and Withanolide_G were predicted to have a better binding affinity with PLpro, Withanolide_M with 3CLpro, and Withanolide_M with spike protein based on binding energy and number of hydrogen bond interactions. MD studies suggested Withanoside_I with the highest binding free energy (DG bind -31.56 kcal/mol) as the most promising inhibitor. Among multiple withanolides from W. somnifera, Withanolide_D, Withanolide_G, Withanolide_M, and Withanolide_Q were predicted as the lead hits based on drug-likeness score, modulated proteins, and docking score to boost the immune system and inhibit the COVID-19 infection, which could primarily act against COVID-19. HIGHLIGHTSWithanolides are immunity boosters. Withanolides are a group of bio-actives with potential anti-viral properties. Withanolide_G, Withanolide_I, and Withanolide_M from Withania somnifera showed the highest binding affinity with PLpro, 3CLpro, and spike protein, respectively. Withanolides from Withania somnifera holds promising anti-viral efficacy against COVID-19.

Bioflavonoids are the largest group of plant-derived polyphenolic compounds with diverse biological potential and have also been proven efficacious in the treatment of Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS). The present investigation validates molecular docking, simulation, and MM-PBSA studies of fifteen bioactive bioflavonoids derived from plants as a plausible potential antiviral in the treatment of COVID-19. Molecular docking studies for 15 flavonoids on the three SARS CoV-2 proteins, non-structural protein-15 Endoribonuclease (NSP15), the receptor-binding domain of spike protein (RBD of S protein), and main protease (M pro /3CL pro ) were performed and selected protein-ligand complexes were subjected to Molecular Dynamics simulations. The molecular dynamics trajectories were subjected to free energy calculation by the MM-PBSA method. All flavonoids were further assessed for their effectiveness as adjuvant therapy by network pharmacology analysis on the target proteins. The network pharmacology analysis suggests the involvement of selected bioflavonoids in the modulation of multiple signaling pathways like p53, FoxO, MAPK, Wnt, Rap1, TNF, adipocytokine, and leukocyte transendothelial migration which plays a significant role in immunomodulation, minimizing the oxidative stress and inflammation. Molecular docking and molecular dynamics simulation studies illustrated the potential of glycyrrhizic acid, amentoflavone, and mulberroside in inhibiting key SARS-CoV-2 proteins and these results could be exploited further in designing future ligands from natural sources.