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1.
Chin Herb Med ; 13(3): 359-369, 2021 Jul.
Article in English | MEDLINE | ID: covidwho-1283985

ABSTRACT

OBJECTIVE: To identify the safe and effective natural inhibitors of spike glycoprotein and main protease 3CLpro using potential natural antiviral compounds which are studied under various animal models and viral cell lines. METHODS: First, compounds were retrieved from the PubChem database and predicted for their druggability using the MolSoft web server, and compounds having drug-like property were predicted for major adverse drug reactions like cardiotoxicity, hepatotoxicity, arrhythmia, myocardial infarction, and nephrotoxicity using ADVERpred. Docking of nontoxic antiviral compounds with spike glycoprotein and main protease 3CLpro was performed using AutoDock vina by PyRx 0.8 version. The stability of compound-protein interactions was checked by molecular dynamic (MD) simulation using Schrodinger Desmond software. RESULTS: Based on the druggable and nontoxic profile, nine compounds were selected. Among them, Withanone from Withania somnifera showed the highest binding affinity and best fit at active sites 1 of spike glycoprotein (glycosylation site) and main protease 3CLpro via interacting with active site amino acid residues before and after MD simulation at 50 ns. Withanone, which may reduce the glycosylation of SARS-CoV-2 via interacting with Asn343 and inhibit viral replication. CONCLUSION: The current study reports Withanone as a non-toxic antiviral against SARS-CoV-2 and serve as a potential lead hit for further experimental validation.

2.
Drug Des Devel Ther ; 15: 1111-1133, 2021.
Article in English | MEDLINE | ID: covidwho-1150609

ABSTRACT

PURPOSE: SARS-CoV-2 engages human ACE2 through its spike (S) protein receptor binding domain (RBD) to enter the host cell. Recent computational studies have reported that withanone and withaferin A, phytochemicals found in Withania somnifera, target viral main protease (MPro) and host transmembrane TMPRSS2, and glucose related protein 78 (GRP78), respectively, implicating their potential as viral entry inhibitors. Absence of specific treatment against SARS-CoV-2 infection has encouraged exploration of phytochemicals as potential antivirals. AIM: This study aimed at in silico exploration, along with in vitro and in vivo validation of antiviral efficacy of the phytochemical withanone. METHODS: Through molecular docking, molecular dynamic (MD) simulation and electrostatic energy calculation the plausible biochemical interactions between withanone and the ACE2-RBD complex were investigated. These in silico observations were biochemically validated by ELISA-based assays. Withanone-enriched extract from W. somnifera was tested for its ability to ameliorate clinically relevant pathological features, modelled in humanized zebrafish through SARS-CoV-2 recombinant spike (S) protein induction. RESULTS: Withanone bound efficiently at the interacting interface of the ACE2-RBD complex and destabilized it energetically. The electrostatic component of binding free energies of the complex was significantly decreased. The two intrachain salt bridge interactions (K31-E35) and the interchain long-range ion-pair (K31-E484), at the ACE2-RBD interface were completely abolished by withanone, in the 50 ns simulation. In vitro binding assay experimentally validated that withanone efficiently inhibited (IC50=0.33 ng/mL) the interaction between ACE2 and RBD, in a dose-dependent manner. A withanone-enriched extract, without any co-extracted withaferin A, was prepared from W. somnifera leaves. This enriched extract was found to be efficient in ameliorating human-like pathological responses induced in humanized zebrafish by SARS-CoV-2 recombinant spike (S) protein. CONCLUSION: In conclusion, this study provided experimental validation for computational insight into the potential of withanone as a potent inhibitor of SARS-CoV-2 coronavirus entry into the host cells.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Antiviral Agents/pharmacology , COVID-19/drug therapy , SARS-CoV-2/drug effects , Spike Glycoprotein, Coronavirus/metabolism , Withania , Withanolides/pharmacology , A549 Cells , Animals , Antiviral Agents/chemistry , Antiviral Agents/isolation & purification , COVID-19/enzymology , COVID-19/virology , Disease Models, Animal , Female , Host-Pathogen Interactions , Humans , Male , Molecular Docking Simulation , Molecular Dynamics Simulation , Protein Interaction Domains and Motifs , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/chemistry , Static Electricity , Structure-Activity Relationship , Virus Internalization/drug effects , Withania/chemistry , Withanolides/chemistry , Withanolides/isolation & purification , Zebrafish
3.
J Biomol Struct Dyn ; 40(1): 1-13, 2022 01.
Article in English | MEDLINE | ID: covidwho-436584

ABSTRACT

Coronavirus disease 2019 (COVID-19) initiated in December 2019 in Wuhan, China and became pandemic causing high fatality and disrupted normal life calling world almost to a halt. Causative agent is a novel coronavirus called Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2/2019-nCoV). While new line of drug/vaccine development has been initiated world-wide, in the current scenario of high infected numbers, severity of the disease and high morbidity, repurposing of the existing drugs is heavily explored. Here, we used a homology-based structural model of transmembrane protease serine 2 (TMPRSS2), a cell surface receptor, required for entry of virus to the target host cell. Using the strengths of molecular docking and molecular dynamics simulations, we examined the binding potential of Withaferin-A (Wi-A), Withanone (Wi-N) and caffeic acid phenethyl ester to TPMRSS2 in comparison to its known inhibitor, Camostat mesylate. We found that both Wi-A and Wi-N could bind and stably interact at the catalytic site of TMPRSS2. Wi-N showed stronger interactions with TMPRSS2 catalytic residues than Wi-A and was also able to induce changes in its allosteric site. Furthermore, we investigated the effect of Wi-N on TMPRSS2 expression in MCF7 cells and found remarkable downregulation of TMPRSS2 mRNA in treated cells predicting dual action of Wi-N to block SARS-CoV-2 entry into the host cells. Since the natural compounds are easily available/affordable, they may even offer a timely therapeutic/preventive value for the management of SARS-CoV-2 pandemic. We also report that Wi-A/Wi-N content varies in different parts of Ashwagandha and warrants careful attention for their use.Communicated by Ramaswamy H. Sarma.


Subject(s)
SARS-CoV-2 , Serine Proteinase Inhibitors/pharmacology , Virus Internalization/drug effects , Withanolides/pharmacology , Binding Sites , COVID-19 , Humans , MCF-7 Cells , Molecular Docking Simulation , Plant Extracts/chemistry , Serine , Serine Endopeptidases/genetics
4.
J Biomol Struct Dyn ; 39(11): 3842-3854, 2021 07.
Article in English | MEDLINE | ID: covidwho-324383

ABSTRACT

The recent novel coronavirus, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2/2019-nCoV) has caused a large number of deaths around the globe. There is an urgent need to understand this new virus and develop prophylactic and therapeutic drugs. Since drug development is an expensive, intense and time-consuming path, timely repurposing of the existing drugs is often explored wherein the research avenues including genomics, bioinformatics, molecular modeling approaches offer valuable strengths. Here, we have examined the binding potential of Withaferin-A (Wi-A), Withanone (Wi-N) (active withanolides of Ashwagandha) and Caffeic Acid Phenethyl Ester (CAPE, bioactive ingredient of propolis) to a highly conserved protein, Mpro of SARS-CoV-2. We found that Wi-N and CAPE, but not Wi-A, bind to the substrate-binding pocket of SARS-CoV-2 Mpro with efficacy and binding energies equivalent to an already claimed N3 protease inhibitor. Similar to N3 inhibitor, Wi-N and CAPE were interacting with the highly conserved residues of the proteases of coronaviruses. The binding stability of these molecules was further analyzed using molecular dynamics simulations. The binding free energies calculated using MM/GBSA for N3 inhibitor, CAPE and Wi-N were also comparable. Data presented here predicted that these natural compounds may possess the potential to inhibit the functional activity of SARS-CoV-2 protease (an essential protein for virus survival), and hence (i) may connect to save time and cost required for designing/development, and initial screening for anti-COVID drugs, (ii) may offer some therapeutic value for the management of novel fatal coronavirus disease, (iii) warrants prioritized further validation in the laboratory and clinical tests.Communicated by Ramaswamy H. Sarma.


Subject(s)
COVID-19 , SARS-CoV-2 , Caffeic Acids , Humans , Molecular Docking Simulation , Peptide Hydrolases , Phenylethyl Alcohol/analogs & derivatives , Protease Inhibitors/pharmacology , Withanolides
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