Antiviral activitiy of curcumin, demethoxycurcumin, bisdemethoxycurcumin and cyclocurcumin compounds of Curcuma longa against NSP3 on SARS-CoV-2

SARS-CoV-2 genome encodes two large polyproteins (pp), pp1a and pp1ab which are cleaved and transformed into a mature form by a protease, non-structural protein 3 (NSP3). NSP3 is encoded by open reading frame (ORF) 1a/b. Curcuma longa (C. longa) or turmeric has been documented to have antiviral effects. The aim of this study was to assess the viral activities of C. longa against SARS-CoV-2 focusing on its potency to inhibit viral replication by targeting NSP3. PubChem databases were used to obtain the metabolic profile of C. longa. The compound's interaction with nucleocapsid was analyzed using molecular docking with Molegro Virtual Docker. Bioinformatics analysis based on rerank score presents all compounds of C. longa have higher binding affinity than the native ligand with cyclocurcumin as the lowest score (-128.38 kcal/mol). This anti-viral activity was hypothesized from the similarity of hydrogen bonds with amino acid residues Ser 128 and Asn 40 as key residues present in Ribavirin. This study reveals that C. longa is the potential to be developed as an antiviral agent through replication inhibition in SARS-CoV-2 targeting its replication mediated by NSP3.

Computational Screening of Inhibitory Compounds for SARS-Cov-2 3CL Protease with a Database Consisting of Approved and Investigational Chemicals.

Computational screening is one of the fundamental techniques in drug discovery. Each compound in a chemical database is bound to the target protein in virtual, and candidate compounds are selected from the binding scores. In this work, we carried out combinational computation of docking simulation to generate binding poses and molecular mechanics calculation to estimate binding scores. The coronavirus infectious disease has spread worldwide, and effective chemotherapy is strongly required. The viral 3-chymotrypsin-like (3CL) protease is a good target of low molecular-weight inhibitors. Hence, computational screening was performed to search for inhibitory compounds acting on the 3CL protease. As a preliminary assessment of the performance of this approach, we used 51 compounds for which inhibitory activity had already been confirmed. Docking simulations and molecular mechanics calculations were performed to evaluate binding scores. The preliminary evaluation suggested that our approach successfully selected the inhibitory compounds identified by the experiments. The same approach was applied to 8820 compounds in a database consisting of approved and investigational chemicals. Hence, docking simulations, molecular mechanics calculations, and re-evaluation of binding scores including solvation effects were performed, and the top 200 poses were selected as candidates for experimental assays. Consequently, 25 compounds were chosen for in vitro measurement of the enzymatic inhibitory activity. From the enzymatic assay, 5 compounds were identified to have inhibitory activities against the 3CL protease. The present work demonstrated the feasibility of a combination of docking simulation and molecular mechanics calculation for practical use in computational virtual screening.

Studying the Predictive Effects of Bacterial Carotenoids in the Treatment of Endometriosis Using Virtual Screening Methods

Background: Endometriosis is a chronic inflammatory disease defined as the presence of endometrial tissue outside the uterus, which causes pelvic pain and infertility. Cytokines appear to play vital roles in the development and progression of endometriosis and associated infertility. Tumor necrosis factoralpha (TNF-alpha) is a multifunctional pro-inflammatory cytokine, responsible for autoimmune and inflammatory disorders. TNF- alpha plays an important role in endometrial physiology as well as during early implantation. In addition, this cytokine has a considerable pathophysiological function in diseases such as menorrhagia, endometriosis, or infertility due to its regulatory impact on proliferation, differentiation, and angiogenesis in the human endometrium. In women with endometriosis, TNF-alpha levels increases in peritoneal fluid and serum significantly. In the present study, we focused on finding novel small molecules that can directly block TNFalpha- hTNFR1 (human TNF receptor 1) interaction. Method(s): In this regard, TNF-alpha inhibiting capacity of natural carotenoids was investigated in terms of blocking TNF-alpha-hTNFR1 interaction with the help of a combination of in silico approaches, based on virtual screening, molecular docking, and molecular dynamics (MD) simulation. Result(s): A total of 125 carotenoids were selected out of 1204 natural molecules, based on their pharmacokinetics properties, and they all met Lipinski's rule of five. Among them, sorgomol, strigol, and orobanchol had the most favorable DELTAG with the best pharmacokinetics properties and were selected for MD simulation studies, which explored the complex stability and the impact of ligands on protein conformation. It was shown that sorgomol formed the most hydrogen bonds, resulting in the highest binding energy with the lowest RMSD and RMSF. Conclusion(s): Our results showed that sorgomol was the most appropriate candidate as a TNF-alpha inhibitor. In conclusion, the present study could serve to expand possibilities to develop new therapeutic small molecules against TNF-alpha which plays an important role in the inflammation of endometriosis.

In silico screening of chalcones and their derivatives as potential inhibitors of spike proteins and ACE2 enzymes for SARS-CoV-2 treatment

The COVID-19 pandemic causing acute respiratory syndrome is a significant public health problem. Drugs that can treat this disease are currently a high priority. The SARS-CoV-2 spike protein and human ACE2 enzyme receptor, which both play important roles in virus entry into the host cell, are promising therapeutic targets for inhibiting viral infection. This research evaluates the potential of chalcone compounds to inhibit the spike proteins and ACE2 enzymes through molecular docking in silico approaches. Based on the ChemFaces database, we collected 92 chalcone compounds. These compounds were further docked to target the active sites of spike protein and human ACE2. After comparing the binding energies of the 92 compounds to artemisinin, ribavirin, and lopinavir, which have inhibitory activity to these protein targets of SARS-CoV-2, we chose 20 out of the 92 compounds that had a higher ability to inhibit the protein targets than the reference inhibitors. Next, five phytochemical compounds with the best binding energy were selected, which included flavanomarein, sarcandrone B, sarcandrone A, calyxin H, and sieboldin. Then, Lipinski's 5 rule was used to evaluate the druglike properties of these compounds. Predictive ADME/tox filtering tests were also applied to the top docked compounds. The results suggest that sarcandrone B has good pharmacokinetic properties, which should be further explored as an anti-SARS-CoV-2. To confirm these findings, experimental studies are recommended.

Potential Health Survey of Traditional Spices & Herbs in Prevention and Treatment of COVID-19: A Review

The coronavirus (COVID-19) is a global public health pandemic disease emerged from the novel strain of the coronavirus 2 (SARS-CoV-2) that caused severe acute respiratory syndrome. It is the most significant respiratory illness that has affected the world since World War II. Currently, there is no globally approved drug for the treatment of pandemic COVID-19 except for some recently approved vaccines. Instead, various non-specific treatment options are being utilized by different countries. While some of these are effective, there is a lack of well-documented studies on the impact of traditional medicines on the management of SARS-CoV-2 in vitro and in silico. For thousands of years, traditional healers have been using various herbs and spices products and dietary plants to treat various diseases. This review aims to provide information on the use of traditional spices & herbs in COVID-19 protection and treatment and present the main characteristics of these products and their potential antiviral actions. Various databases were searched for articles related to the use of various herbs for the treatment of viral infections. Many of these studies show that various plant compounds can be utilized for the treatment of viral infections. This study aims to summarize the common used of herbal products and dietary supplements with potent bioactive compounds in treatment or prevent of COVID-19.

Efficacy evaluation of quercetin and its analogues on the main protease enzyme of the COVID-19 using molecular docking studies

Introduction: COVID-19 is an acute respiratory infectious disease caused by the SARS-CoV-2 virus. There is an urgent need to discover antiviral drugs for better performance against new strains of coronaviruses (CoVs) due to the rapid spread of the disease despite scientific advances in vaccine development. This study aimed to evaluate the efficacy of quercetin and its analogues on the COVID-19 Mpro enzyme. Material & Methods: In this descriptive-analytical study, the three-dimensional structures of quercetin analogues (20 compounds), standard drugs (ritonavir and lopinavir), and the COVID-19 Mpro enzyme were obtained from PubChem and PDB databases for bioinformatics study, respectively. Molecular docking studies of the compounds on theMpro were performed using MOE-2014 software. Afterward, the physicochemical properties and biological activity of the compounds were predicted using Swiss ADME, PASS, and Swiss Target Prediction software. Findings: The findings of the present study showed that the most important bonds involved in drug-receptor binding are hydrogen, hydrophobic, and - interaction bonds. The best docking results were obtained for Baicalein, Genistein, Naringenin, and Quercetin compounds with strong binding energy (-12.83 to -13.54 kcal/mol), compared to ritonavir and lopinavir. These compounds have a greater tendency to bind to the catalytic amino acids His41 and Cys145 and other key amino acids of the active site of the COVID-19 Mpro enzyme. Discussion & Conclusion: Based on the results of bioinformatics studies, quercetin analogues had more effective inhibition than standard chemical drugs due to their suitable placement in the active site of the main protease enzyme of COVID-19 and can be good candidates for in vitro and in vivo studies.

The Suggestion of a Drug for COVID-19 with Molecular Docking

Background and objectives: This study aimed to study the interaction between the severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) spike protein complex and seven drugs that inhibit the angiotensin-converting enzyme 2. Methods: Plots of protein-ligand interaction were obtained using the LigPlot software. In addition, binding energies in kcal/mol, hydrophobic interactions, and hydrogen bonds were determined. Autodock software v.1.5.6 and AutoDock Vina were used for the analysis of molecular docking processes. Results: The only structure that interacted with the SARS‑CoV‑2 spike protein was anakinra. Conclusion: Anakinra was the only drug that interacted with the SARS‑CoV‑2 spike protein. This could be further investigated for finding a temporary alternative medicine for the treatment of coronavirus disease 2019. [ABSTRACT FROM AUTHOR] Copyright of Medical Laboratory Journal is the property of Golestan University of Medical Sciences, Deputy of Research & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Studies towards investigation of Naphthoquinone-based scaffold with crystal structure as lead for SARS-CoV-19 management.

In this work, 1-(4-bromophenyl)-2a,8a-dihydrocyclobuta[b]naphthalene-3,8­dione (1-(4-BP)DHCBN-3,8-D) has been characterized by single crystal X-ray to get it's crystal structure with R(all data) - R1 = 0.0569, wR2 = 0.0824, 13C and 1HNMR, as well as UV-Vis and IR spectroscopy. Quantum chemical calculations via DFT were used to predict the compound structural, electronic, and vibrational properties. The molecular geometry of 1-(4-BP)DHCBN-3,8-Dwas optimized utilizing the B3LYP functional at the 6-311++G(d,p) level of theory. The Infrared spectrum has been recorded in the range of 4000-550 cm-1. The Potential Energy Distribution (PED) assignments of the vibrational modes were used to determine the geometrical dimensions, energies, and wavenumbers, and to assign basic vibrations. The UV-Vis spectra of the titled compound were recorded in the range of 200-800 nm in ACN and DMSO solvents. Additionally, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy gap and electronic transitions were determined using TD-DFT calculations, which also simulate the UV-Vis absorption spectrum. Natural Bond Orbital (NBO) analysis can be used to investigate electronic interactions and transfer reactions between donor and acceptor molecules. Temperature-dependent thermodynamic properties were also calculated. To identify the interactions in the crystal structure, Hirshfeld Surface Analysis was also assessed. The Molecular Electrostatic Potential (MEP) and Fukui functions were used to determine the nucleophilic and electrophilic sites. Additionally, the biological activities of 1-(4-BP)DHCBN-3,8-D were done using molecular docking. These results demonstrate a significant therapeutic potential for 1-(4-BP)DHCBN-3,8-D in the management of Covid-19 disorders. Molecular Dynamics Simulation was used to look at the stability of biomolecules.

Ligand-based discovery of coronavirus main protease inhibitors using MACAW molecular embeddings

Ligand-based drug design methods are thought to require large experimental datasets to become useful for virtual screening. In this work, we propose a computational strategy to design novel inhibitors of coronavirus main protease, M(pro). The pipeline integrates publicly available screening and binding affinity data in a two-stage machine-learning model using the recent MACAW embeddings. Once trained, the model can be deployed to rapidly screen large libraries of molecules in silico. Several hundred thousand compounds were virtually screened and 10 of them were selected for experimental testing. From these 10 compounds, 8 showed a clear inhibitory effect on recombinant M(pro), with half-maximal inhibitory concentration values (IC(50)) in the range 0.18-18.82 μM. Cellular assays were also conducted to evaluate cytotoxic, haemolytic, and antiviral properties. A promising lead compound against coronavirus M(pro) was identified with dose-dependent inhibition of virus infectivity and minimal toxicity on human MRC-5 cells.

Computational approaches to define poncirin from Magnolia champaka leaves as a novel multi-target inhibitor of SARS-CoV-2.

Phytochemical-based drug discovery against the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has been the focus of the current scenario. In this context, we aimed to perform the phytochemical profiling of Magnolia champaka, an evergreen tree from the Magnoliaceae family, in order to perform a virtual screening of its phytoconstituents against different biological targets of SARS-CoV-2. The phytochemicals identified from the ethanol extract of M. champaka leaves using liquid chromatography-mass spectroscopy (LC-MS) technique were screened against SARS-CoV-2 spike glycoprotein (PDB ID: 6M0J), main protease/Mpro (PDB ID: 6LU7), and papain-like protease/PLpro (PDB ID: 7CMD) through computational tools. The experimentation design included molecular docking simulation, molecular dynamics simulation, and binding free energy calculations. Through molecular docking simulation, we identified poncirin as a common potential inhibitor of all the above-mentioned target proteins. In addition, molecular dynamics simulations, binding free energy calculations, and PCA analysis also supported the outcomes of the virtual screening. By the virtue of all the in silico results obtained, poncirin could be taken for in vitro and in vivo studies in near future.Communicated by Ramaswamy H. Sarma.

Structure-based virtual screening and molecular docking of drugs against the SARS-CoV-2 spike protein-ACE2 receptor complex

The agent responsible for the COVID-19 pandemic was the newly discovered coronavirus SARS-CoV-2. A trimeric spike protein on the SARS-CoV-2 virion binds to the ACE2 receptor on host cells. In this study we performed a structure-based virtual screening and molecular docking of existing drugs against a high-resolution structure of the SARS-CoV-2 spike protein-ACE2 receptor complex. The 2.5-A crystal structure of the C-terminal domain of the SARS-CoV-2 spike protein (residues 319-541) in complex with human ACE2 (SARS-CoV-2-S-CTD/hACE2) (PDB ID: 6LZG) was used as the target for screening 4,374 FDA-approved drugs from the ZINC15 database using PyRx software. Molecular docking was performed using BIO VIA Discovery Studio Visualizer. The top twenty highest affinity drugs had binding energies of -7.0 to -8.8 kcal/mol. The highest affinity drug was the selective vasopressin V2-receptor antagonist Tolvaptan, for which molecular docking identified drug-amino acid residue interactions with ACE2. Other drugs displaying binding energies better than -8.0 kcal/mol were Nizoral, Amaryl, Accolate, Sorafenib, Glipizide and Azelastine. The predicted interactions of these highest affinity drugs with residues in ACE2 were at positions that could disrupt the spike protein-ACE2 complex, so these drugs have the potential to be repurposed as inhibitors of the SARS-CoV-2 virus.

Systematic structure guided clustering of chemical lead compounds targeting RdRp of SARS-CoV-2

BACKGROUND: To combat the global health issue caused by SARS-CoV2, scientists are attempting various therapeutic approaches towards drug discovery including computational biology and drug-repurposing. Recent studies have highlighted the conserved nature of RNA-dependent RNA polymerase (RdRp) of coronaviruses affecting human, bat and animals. In this study attempts have been made to identify the potential inhibitors of RdRp by utilizing molecular docking and MD simulation studies. METHOD(S): Systematic structure-based screening of chemical compounds from public libraries was performed to identify the potential lead molecules inhibiting RdRp. This structure driven clustering of compounds is based on decision tree model generated by combining two properties: 1) shape descriptors;and 2) critical number of multiple bonds. The enabled screening of potential chemical compounds was subjected to molecular docking followed by molecular dynamics simulation studies. RESULT(S): The results revealed that the stability of protein-drug complex structure was in the order of RdRp-Oxoglaucine >RdRp-Flutroline >RdRp-Brucine complex. CONCLUSION(S): This study identifies Oxoglaucine, Brucine and Flutroline as prospective inhibiting agents of SARS-CoV-2 RdRp and further warrants for experimental validation. Copyright © 2022 EDIZIONI MINERVA MEDICA.

Searching for potential inhibitors of SARS-COV-2 main protease using supervised learning and perturbation calculations.

Inhibiting the biological activity of SARS-CoV-2 Mpro can prevent viral replication. In this context, a hybrid approach using knowledge- and physics-based methods was proposed to characterize potential inhibitors for SARS-CoV-2 Mpro. Initially, supervised machine learning (ML) models were trained to predict a ligand-binding affinity of ca. 2 million compounds with the correlation on a test set of R = 0.748 ± 0.044 . Atomistic simulations were then used to refine the outcome of the ML model. Using LIE/FEP calculations, nine compounds from the top 100 ML inhibitors were suggested to bind well to the protease with the domination of van der Waals interactions. Furthermore, the binding affinity of these compounds is also higher than that of nirmatrelvir, which was recently approved by the US FDA to treat COVID-19. In addition, the ligands altered the catalytic triad Cys145 - His41 - Asp187, possibly disturbing the biological activity of SARS-CoV-2.

Multi Epitope-Based Vaccine Design for Protection Against Mycobacterium tuberculosis and SARS-CoV-2 Coinfection.

Background: A prophylactic and immunotherapeutic vaccine for Mycobacterium tuberculosis (MTB) and SARS-CoV-2 coinfection needs to be developed for a proactive and effective therapeutic approach. Therefore, this study aims to use immunoinformatics to design a multi-epitope vaccine for protection against MTB and SARS-CoV-2 coinfection. Methods: The bioinformatic techniques were used to screen and construct potential epitopes from outer membrane protein A Rv0899 of MTB and spike glycoprotein of SARS-CoV-2 for B and T cells. The antigenicity, allergenicity, and several physiochemical properties of the developed multi-epitope vaccination were then evaluated. Additionally, molecular docking and normal mode analysis (NMA) were utilized in evaluating the vaccine's immunogenicity and complex stability. Results: Selected proteins and predicted epitopes suggest that the vaccine prediction can be helpful in the protection against both SARS-CoV-2 and MTB coinfection. Through docking molecular and NMA, the vaccine-TLR4 protein interaction was predicted to be efficient with a high level of IgG, T-helper cells, T-cytotoxic cells, andIFN-γ. Conclusion: This epitope-based vaccine is a potentially attractive tool for SARS-CoV-2 and MTB coinfection vaccine development.

Synthesis, characterization, theoretical study and molecular docking studies of some new cobalt(II), chromium(II) and nickel (II) complexes

Three transition metal complexes with general formula [M(L)(2)] (Co = (1), Cr = (2) and Ni = (3)), were synthesized by treating CoCl2/CrCl3 center dot 6H(2)O/NiCl2 center dot 6H(2)O with an ONS-donor Schiff base ligand (HL) derived from the condensation of 3,5-Diiodosalicylaldehyde and 4,4-Dimethyl-3-thiosemicarbazide. The geometry around the centre metal ions was octahedral as revealed by the data collection from spectroscopic studies. The newly synthesized compounds were fully characterized by various physicochemical and spectroscopic methods. DFT calculations were performed on the compounds to get a structure-property relationship. Some global reactivity descriptors like chemical potential (mu), electronegativity (chi), hardness (eta) and electrophilicity index (omega) were also evaluated using DFT method. The ADMET prediction analyses have been explored. Molecular dynamics simulations were also studied. Besides this, to find a potential inhibitor for anti-SARS-CoV-2, metal complexes are also assessed through molecular docking and 3-D visualizations of intermolecular interactions against main protease (M-pro) of SARS-CoV-2 (PDB ID: 7JKV). The molecular docking calculations of the complex (1) into the main protease of SARS-CoV-2 virus (PDB ID: 7JKV) revealed the binding energy of -7.2 kcal/mol with an inhibition constant of 2.529 mu M at inhibition binding site of receptor protein. Complex (2) with SARS-CoV-2 resulted in the binding energy of -7.8 kcal/mol and the inhibition constant of 5.231 mu M. Similarly, complex (3) with SARS-CoV-2 (PDB ID: 7JKV) exhibited the binding energy and the inhibition constant of -7.5 kcal/mol and 3.585 mu M respectively at inhibition binding site of receptor protein. Overall, in silico studies explored the potential role of metal complexes, which would offer new drug candidates against SARS-CoV-2.

An in silico study on inhibitability of Baloxavir marboxil, Baricitinib, Galidesivir, Nitazoxanide, and Oseltamivir against SARS-CoV-2

Baloxavir marboxil (D1), Baricitinib (D2), Galidesivir (D3), Nitazoxanide (D4), and Oseltamivir (D5) are well-known performing broad-spectrum activity against a variety of viruses, thus holding high potentiality towards SARS-CoV-2. Quantum properties were examined using density functional theory (DFT). The inhibitability of the drugs towards Angiotensin-converting enzyme 2 (ACE2) and SARS-CoV-2 main protease (6LU7) was evaluated by molecular docking simulation, while their bio-compatibility was justified by physicochemical properties obtained from QSARIS-based analysis in reference to Lipinski's rule of five. Quantum analysis suggests that the compounds are highly favourable for intermolecular interaction towards protein structures. Given ligand-ACE2 systems, the inhibitory effectiveness follows the order D3-ACE2?>?D4-ACE2?>?D2-ACE2?>?D5-ACE2?>?D1-ACE2;and the corresponding order for ligand-6LU7 systems is D2-6LU7?>?D4-6LU7?>?D3-6LU7?>?D5-6LU7?>?D1-6LU7. Galidesivir is predicted as the most effective inhibitor towards both targeted protein structures (DSaverage -13.1 kcal.mol-1) and the most bio-compatible molecule (Mass 264.9 amu;LogP -0.9;Polarisability 26.8 Å3). The theoretical screening suggests all drugs, especially Galidesivir (D3), promising for treatment of SARS-CoV-2 infection and encourages in-related clinical trials.

Integrated bioinformatics-cheminformatics approach toward locating pseudo-potential antiviral marine alkaloids against SARS-CoV-2-Mpro.

The emergence of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) with the most contagious variants, alpha (B.1.1.7), beta (B.1.351), delta (B.1.617.2), and Omicron (B.1.1.529) has continuously added a higher number of morbidity and mortality, globally. The present integrated bioinformatics-cheminformatics approach was employed to locate potent antiviral marine alkaloids that could be used against SARS-CoV-2. Initially, 57 antiviral marine alkaloids and two repurposing drugs were selected from an extensive literature review. Then, the putative target enzyme SARS-CoV-2 main protease (SARS-CoV-2-Mpro) was retrieved from the protein data bank and carried out a virtual screening-cum-molecular docking study with all candidates using PyRx 0.8 and AutoDock 4.2 software. Further, the molecular dynamics (MD) simulation of the two most potential alkaloids and a drug docking complex at 100 ns (with two ligand topology files from PRODRG and ATB server, separately), the molecular mechanics/Poisson-Boltzmann surface area (MM/PBSA) free energy, and contributions of entropy were investigated. Then, the physicochemical-toxicity-pharmacokinetics-drug-likeness profiles, the frontier molecular orbitals energies (highest occupied molecular orbital, lowest unoccupied molecular orbital, and ΔE), and structural-activity relationship were assessed and analyzed. Based on binding energy, 8-hydroxymanzamine (-10.5 kcal/mol) and manzamine A (-10.1 kcal/mol) from all alkaloids with darunavir (-7.9 kcal/mol) and lopinavir (-7.4 kcal/mol) against SARS-CoV-2-Mpro were recorded. The MD simulation (RMSD, RMSF, Rg, H-bond, MM/PBSA binding energy) illustrated that the 8-hydroxymanzamine exhibits a static thermodynamic feature than the other two complexes. The predicted physicochemical, toxicity, pharmacokinetics, and drug-likeness profiles also revealed that the 8-hydroxymanzamine could be used as a potential lead candidate individually and/or synergistically with darunavir or lopinavir to combat SARS-CoV-2 infection after some pharmacological validation.

Abiraterone Acetate Attenuates SARS-CoV-2 Replication by Interfering with the Structural Nucleocapsid Protein.

The drug repurposing strategy has been applied to the development of emergency COVID-19 therapeutic medicines. Current drug repurposing approaches have been directed against RNA polymerases and viral proteases. Recently, we found that the inhibition of the interaction between the SARS-CoV-2 structural nucleocapsid (N) and spike (S) proteins decreased viral replication. In this study, drug repurposing candidates were screened by in silico molecular docking simulation with the SARS-CoV-2 structural N protein. In the ChEMBL database, 1994 FDA-approved drugs were selected for the in silico virtual screening against the N terminal domain (NTD) of the SARS-CoV-2 N protein. The tyrosine 109 residue in the NTD of the N protein was used as the center of the ligand binding grid for the docking simulation. In plaque forming assays performed with SARS-CoV-2 infected Vero E6 cells, atovaquone, abiraterone acetate, and digoxin exhibited a tendency to reduce the size of the viral plagues without affecting the plaque numbers. Abiraterone acetate significantly decreased the accumulation of viral particles in the cell culture supernatants in a concentration-dependent manner. In addition, abiraterone acetate significantly decreased the production of N protein and S protein in the SARS-CoV-2-infected Vero E6 cells. In conclusion, abiraterone acetate has therapeutic potential to inhibit the viral replication of SARS-CoV-2.

Prediction of COVID-19 manipulation by selective ACE inhibitory compounds of Potentilla reptant root: In silico study and ADMET profile.

In the novel SARS-CoV-2 (COVID-19) as a global emergency event, the main reason of the cardiac injury from COVID-19 is angiotensin-converting enzyme 2 (ACE2) targeting in SARS-CoV-2 infection. The inhibition of ACE2 induces an increase in the angiotensin II (Ang II) and the angiotensin II receptor type 1 (AT1R) leading to impaired cardiac function or cardiac inflammatory responses. The ethyl acetate fraction of Potentilla reptans L. root can rescue heart dysfunction, oxidative stress, cardiac arrhythmias and apoptosis. Therefore, isolated components of P. reptans evaluated to identify natural anti-SARS-CoV-2 agents via molecular docking. In silico molecular docking study were carried out using the Auto Dock software on the isolated compounds of Potentilla reptans root. The protein targets of selective ACE and others obtained from Protein Data Bank (PDB). The best binding pose between amino acid residues involved in active site of the targets and compounds was discovered via molecular docking. Furthermore, ADMET properties of the compounds were evaluated. The triterpenoids of P. reptans showed more ACE inhibitory potential than catechin in both domains. They were selective on the nACE domain, especially compound 5. Also, the compound 5 & 6 had the highest binding affinity toward active site of nACE, cACE, AT1R, ACE2, and TNF-α receptors. Meanwhile, compound 3 showed more activity to inhibit TXA2. Drug likeness and ADMET analysis showed that the compounds passed the criteria of drug likeness and Lipinski rules. The current study depicted that P. reptans root showed cardioprotective effect in COVID-19 infection and manipulation of angiotensin II-induced side effects.

Unique Mode of Antiviral Action of a Marine Alkaloid against Ebola Virus and SARS-CoV-2.

Lamellarin α 20-sulfate is a cell-impenetrable marine alkaloid that can suppress infection that is mediated by the envelope glycoprotein of human immunodeficiency virus type 1. We explored the antiviral action and mechanisms of this alkaloid against emerging enveloped RNA viruses that use endocytosis for infection. The alkaloid inhibited the infection of retroviral vectors that had been pseudotyped with the envelope glycoprotein of Ebola virus and SARS-CoV-2. The antiviral effects of lamellarin were independent of the retrovirus Gag-Pol proteins. Interestingly, although heparin and dextran sulfate suppressed the cell attachment of vector particles, lamellarin did not. In silico structural analyses of the trimeric glycoprotein of the Ebola virus disclosed that the principal lamellarin-binding site is confined to a previously unappreciated cavity near the NPC1-binding site and fusion loop, whereas those for heparin and dextran sulfate were dispersed across the attachment and fusion subunits of the glycoproteins. Notably, lamellarin binding to this cavity was augmented under conditions where the pH was 5.0. These results suggest that the final action of the alkaloid against Ebola virus is specific to events following endocytosis, possibly during conformational glycoprotein changes in the acidic environment of endosomes. Our findings highlight the unique biological and physicochemical features of lamellarin α 20-sulfate and should lead to the further use of broadly reactive antivirals to explore the structural mechanisms of virus replication.