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


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.

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
J Inflamm Res ; 14: 869-884, 2021.
Article in English | MEDLINE | ID: covidwho-1138640


Purpose: Coronil is a tri-herbal formulation containing extracts from Withania somnifera, Tinospora cordifolia, and Ocimum sanctum. Recently, it was shown that Coronil rescued humanized zebrafish from SARS-CoV-2 induced pathologies. Based on reported computational studies on the phytochemicals present in Coronil, it could be a potential inhibitor of SARS-CoV-2 entry into the host cell and associated cytokines' production. Methods: Through an ELISA-based biochemical assay, effects of Coronil on interaction between ACE-2 and different mutants of viral spike (S) protein, crucial for viral invasion of host cell, were evaluated. Additionally, using recombinant pseudoviruses having SARS-CoV-2 spike (S) protein in their envelopes and firefly luciferase reporter in their genomes, effects of Coronil on virus entry into human alveolar epithelial cells were evaluated through luciferase assay. UHPLC profiled Coronil also modulated S-protein mediated production of pro-inflammatory cytokines in A549 cells, like interleukin-6 (IL-6), interleukin-1ß (IL-1ß), and tumor necrosis factor-α (TNF-α), as evaluated through RT-qPCR and ELISA. Results: Coronil effectively inhibited the interaction of ACE-2 not only with the wild-type S protein (SWT) but also with its currently prevalent and more infectious variant (SD614G) and another mutant (SW436R) with significantly higher affinity toward ACE-2. Treatment with Coronil significantly reduced the increased levels of IL-6, IL-1ß, and TNF-α in A549 cells incubated with different S-protein variants in a dose-dependent manner. Likewise, it also prevented the SARS-CoV-2 S-protein pseudotyped vesicular stomatitis virus (VSVppSARS-2S) mediated cytokine response in these cells by reducing entry of pseudoviruses into host cells. Conclusion: Coronil prevented SARS-CoV-2 S-protein mediated viral entry into A549 cells by inhibiting spike protein-ACE-2 interactions. SARS-CoV-2 S protein induced inflammatory cytokine response in these cells was also moderated by Coronil.

AMB Express ; 10(1): 210, 2020 Dec 01.
Article in English | MEDLINE | ID: covidwho-951800


COVID-19 pandemic has almost made hand sanitization a ritual resulting in a steep increase in the frequency of hand sanitization and an unprecedented surge in demand for hand sanitizers. In fact, several governments had to ration hand sanitizers in the retail outlets and over the counter chemist shops. Additionally, Indian government has put a cap on the prices of hand sanitizers. Currently, large sections of global and Indian population are grappling under financial crises. Therefore, mandatory hand sanitization has made an unwelcoming, yet unavoidable addition to the already-hard-to-maintain-grocery-list. Here, we have compared the anti-microbial efficacy of Patanjali Hand Sanitizer (PHS), developed and marketed by Patanjali Ayurved Ltd. (an India-based food and herbal medicine company) with one of the topmost hand sanitizers currently used under clinical set-ups. PHS has anti-microbial efficacy comparable to that of the standard hand sanitizer. Besides, disc diffusion and time-dependent thumb print assays showed that PHS has longer retentivity on the applied surfaces, suggesting lesser consumption of the sanitizer and concomitant relaxation on the monthly grocery budget. Observed anti-bacterial potency of PHS is attributed to the disruption of bacterial cell membrane, as employed by alcohol-based hand sanitizers. A rough estimation revealed that PHS is ~ 4.3 times cost effective than the standard hand sanitizer used as the positive control in this study. Taken together, PHS is a suitable alternative for existing hand sanitizers available in the market that can relax the demand-supply strain and soften significantly the burden of monthly expenditure on hand sanitizers.