Virtual screening, ADME/T, and binding free energy analysis of anti-viral, anti-protease, and anti-infectious compounds against NSP10/NSP16 methyltransferase and main protease of SARS CoV-2

Dynamic Combinatorial Chemistry Unveils Nsp10 Inhibitors with Antiviral Potential Against SARS-CoV-2

The development of antiviral drugs against the Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) responsible for the recent Covid-19 pandemic is crucial, as treatment options remain limited and vaccination does not prevent (re)infection. Two relatively underexplored targets of this virus are the 3'-5' exoribonuclease (ExoN) and the 2'-O-methyltransferase (2'-O-MTase), both essential for viral viability. The non-structural proteins Nsp14 and Nsp16 exhibit enzymatic activities for ExoN and 2'-O-MTase, respectively, especially when in complex with their co-factor protein Nsp10. The study focuses on the use of target-directed dynamic combinatorial chemistry (tdDCC) to identify binders of Nsp10, aiming to disturb the protein-protein interactions (PPI) involving Nsp10-Nsp14, as well as Nsp10-Nsp16. We synthesised the hits and evaluated them to assess Nsp10 affinity, ExoN and 2'-O-MTase activities inhibition, and antiviral activity in hCoV-229E and SARS-CoV-2-infected whole-cell settings. This study reports a novel class of ExoN and/or 2'-O-MTase inhibitors exhibiting antiviral activity against coronaviruses.

Exploration of the link between COVID-19 and gastric cancer from the perspective of bioinformatics and systems biology

Background

Coronavirus disease 2019 (COVID-19), an infectious disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has caused a global pandemic. Gastric cancer (GC) poses a great threat to people's health, which is a high-risk factor for COVID-19. Previous studies have found some associations between GC and COVID-19, whereas the underlying molecular mechanisms are not well understood.

Methods

We employed bioinformatics and systems biology to explore these links between GC and COVID-19. Gene expression profiles of COVID-19 (GSE196822) and GC (GSE179252) were obtained from the Gene Expression Omnibus (GEO) database. After identifying the shared differentially expressed genes (DEGs) for GC and COVID-19, functional annotation, protein-protein interaction (PPI) network, hub genes, transcriptional regulatory networks and candidate drugs were analyzed.

Results

We identified 209 shared DEGs between COVID-19 and GC. Functional analyses highlighted immune-related pathways as key players in both diseases. Ten hub genes (CDK1, KIF20A, TPX2, UBE2C, HJURP, CENPA, PLK1, MKI67, IFI6, IFIT2) were identified. The transcription factor/gene and miRNA/gene interaction networks identified 38 transcription factors (TFs) and 234 miRNAs. More importantly, we identified ten potential therapeutic agents, including ciclopirox, resveratrol, etoposide, methotrexate, trifluridine, enterolactone, troglitazone, calcitriol, dasatinib and deferoxamine, some of which have been reported to improve and treat GC and COVID-19.

Conclusion

This research offer valuable insights into the molecular interplay between COVID-19 and GC, potentially guiding future therapeutic strategies.

Structural and functional insights into the 2'-O-methyltransferase of SARS-CoV-2

A unique feature of coronaviruses is their utilization of self-encoded nonstructural protein 16 (nsp16), 2'-O-methyltransferase (2'-O-MTase), to cap their RNAs through ribose 2'-O-methylation modification. This process is crucial for maintaining viral genome stability, facilitating efficient translation, and enabling immune escape. Despite considerable advances in the ultrastructure of SARS-CoV-2 nsp16/nsp10, insights into its molecular mechanism have so far been limited. In this study, we systematically characterized the 2'-O-MTase activity of nsp16 in SARS-CoV-2, focusing on its dependence on nsp10 stimulation. We observed cross-reactivity between nsp16 and nsp10 in various coronaviruses due to a conserved interaction interface. However, a single residue substitution (K58T) in SARS-CoV-2 nsp10 restricted the functional activation of MERS-CoV nsp16. Furthermore, the cofactor nsp10 effectively enhanced the binding of nsp16 to the substrate RNA and the methyl donor S-adenosyl-l-methionine (SAM). Mechanistically, His-80, Lys-93, and Gly-94 of nsp10 interacted with Asp-102, Ser-105, and Asp-106 of nsp16, respectively, thereby effectively stabilizing the SAM binding pocket. Lys-43 of nsp10 interacted with Lys-38 and Gly-39 of nsp16 to dynamically regulate the RNA binding pocket and facilitate precise binding of RNA to the nsp16/nsp10 complex. By assessing the conformational epitopes of nsp16/nsp10 complex, we further determined the critical residues involved in 2'-O-MTase activity. Additionally, we utilized an in vitro biochemical platform to screen potential inhibitors targeting 2'-O-MTase activity. Overall, our results significantly enhance the understanding of viral 2'-O methylation process and mechanism, providing valuable targets for antiviral drug development.

Role of multi-targeted bioactive natural molecules and their derivatives in the treatment of Alzheimer's disease: an insight into structure-activity relationship

Alzheimer's disease (AD) is a complex neurodegenerative disorder involving cognitive dysfunction like short-term memory and behavioral changes as the disease progresses due to other unaltered physiological factors. The solution for this problem is Multi-targeted Drugs (MTDs), which can affect multiple determinants to realize the multifunctional effects. Acetylcholinesterase (AChE) inhibitors donepezil, rivastigmine, galantamine, and N-methyl-D-aspartate (NMDA) receptor antagonist memantine are FDA-approved drugs used to treat AD symptomatically. The key objective of this review is to understand multitargeted bioactive natural molecules that could be considered as leads for further development as effective drugs for treating AD, along with understanding its pharmacology and structure-activity relationship (SAR). Understanding the molecular mechanism of the AD pathophysiology, the role of existing drugs, treatment of AD via amyloid beta (Aβ) plaque, and neurofibrillary tangle (NFT) inhibition by natural bioactive molecules were also discussed in the review. The current quest and recent advancements with natural bioactive compounds like physostigmine, resveratrol, curcumin, and catechins, along with the study of in silico SAR, were reported in the present study. This review summarises the structural properties required for bioactive natural molecules to show anti-Alzheimer's activity by emphasizing on SAR of several bioactive natural molecules targeting various AD pathologies, their key molecular interactions that are critical for target specificity, their role as multitargeted ligands, used with adjunctive therapy for AD followed by related US patents granted recently. This article highlights the significance of the structural features of natural bioactive molecules in the treatment of AD and establishes a connection between them.Communicated by Ramaswamy H. Sarma.

In silico studies of alkaloids and their derivatives against N-acetyltransferase EIS protein from Mycobacterium tuberculosis

Antibiotic resistance against Mycobacterium tuberculosis (M.tb.) has been a significant cause of death worldwide. The Enhanced intracellular survival (EIS) protein of the bacteria is an acetyltransferase that multiacetylates aminoglycoside antibiotics, preventing them from binding to the bacterial ribosome. To overcome the EIS-mediated antibiotics resistance of M.tb., we compiled 888 alkaloids and derivatives from five different databases and virtually screened them against the EIS receptor. The compound library was filtered down to 87 compounds, which underwent additional analysis and filtration. Moreover, the top 15 most prominent phytocompounds were obtained after the drug-likeness prediction and ADMET screening. Out of 15, nine compounds confirmed the maximum number of hydrogen bond interactions and reliable binding energies during molecular docking. Additionally, the Molecular dynamics (MD) simulation of nine compounds showed the three most stable complexes, further verified by re-docking with mutated protein. The density functional theory (DFT) calculation was performed to identify the HOMO-LUMO energy gaps of the selected three potential compounds. Finally, our selected top lead compounds i.e., Alkaloid AQC2 (PubChem85634496), Nobilisitine A (ChEbi68116), and N-methylcheilanthifoline (ChEbi140673) demonstrated more favourable outcomes when compared with reference compounds (i.e., 39b and 2i) in all parameters used in this study. Therefore, we anticipate that our findings will help to explore and develop natural compound therapy against multi and extensively drug-resistant strains of M.tb.Communicated by Ramaswamy H. Sarma.

Myricitrin from bayberry as a potential inhibitor of cathepsin-D: Prospects for squamous lung carcinoma prevention

Cathepsin-D (CATD) inhibitors' design and development drawn interest due to their potential therapeutic applications in managing different cancer types, including lung cancer. This study investigated myricitrin, a flavonol-3-O-rhamnoside, for its binding affinity to CATD. Molecular docking experiments revealed a strong binding affinity (-7.8 kcal/mol). Molecular dynamics (MD) simulation confirmed the complex's stability, while enzyme activity studies showed inhibitory concentration (IC50) of 35.14 ± 6.08 μM (in cell-free) and 16.00 ± 3.48 μM (in cell-based) test systems. Expression analysis indicated downregulation of CATD with a fold change of 1.35. Myricitrin demonstrated antiproliferative effects on NCIH-520 cells [IC50: 64.11 μM in Sulphorhodamine B (SRB), 24.44 μM in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)], but did not affect healthy CHANG cells. It also prolonged the G2/M phase (at 10 μM: 1.19-fold; at 100 μM: 1.13-fold) and increased sub-diploid population by 1.35-fold. Based on the analysis done using SwissADME program, it is predicted that myricitrin is not a cytochrome p450s (CYPs) inhibitor, followed the rule of Ghose and found not permeable to the blood-brain barrier (BBB) which suggests it as a safe molecule. In summary, the experimental findings may establish the foundation for myricitrin and its analogues to be used therapeutically in CATD-mediated lung cancer prevention.

Identifying inhibitors of NSP16-NSP10 of SARS-CoV-2 from large databases

The COVID-19 pandemic, which has already claimed millions of lives, continues to pose a serious threat to human health, requiring the development of new effective drugs. Non-structural proteins of SARS-CoV-2 play an important role in viral replication and infection. Among them, NSP16 (non-structured protein 16) and its cofactor NSP10 (non-structured protein 10) perform C2'-O methylation at the 5' end of the viral RNA, which promotes efficient virus replication. Therefore, the NSP16-NSP10 complex becomes an attractive target for drug development. Using a multi-step virtual screening protocol which includes Lipinski's rule, docking, steered molecular dynamics and umbrella sampling, we searched for potential inhibitors from the PubChem and anti-HIV databases. It has been shown that CID 135566620 compound from PubChem is the best candidate with an inhibition constant in the sub-μM range. The Van der Waals interaction was found to be more important than the electrostatic interaction in the binding affinity of this compound to NSP16-NSP10. Further in vitro and in vivo studies are needed to test the activity of the identified compound against COVID-19.Communicated by Ramaswamy H. Sarma.

Daphnetin, a Coumarin with Anticancer Potential against Human Melanoma: In Vitro Study of Its Effective Combination with Selected Cytostatic Drugs

(1) The treatment of metastatic or drug-resistant melanoma is still a significant therapeutic problem. The aim of this study was to evaluate the anticancer potential of daphnetin (7,8-dihydroxycoumarin) and its combinations with five different cytostatic drugs (mitoxantrone, docetaxel, vemurafenib, epirubicin and cisplatin). (2) The viability, proliferation and cytotoxicity of daphnetin against four human malignant melanoma cell lines were evaluated. The interactions were assessed using isobolographic analysis for the combinations of daphnetin with each of the five cytostatic drugs. (3) Daphnetin showed anticancer activity against malignant melanoma, with IC₅₀ values ranging from 40.48 ± 10.90 µM to 183.97 ± 18.82 µM, depending on the cell line. The combination of daphnetin with either vemurafenib or epirubicin showed an antagonistic interaction. Moreover, additive interactions were observed for the combinations of daphnetin with cisplatin and docetaxel. The most desirable synergistic interactions for human melanoma metastatic cell lines were observed for the combination of daphnetin with mitoxantrone. (4) The obtained results suggest that daphnetin should not be combined with vemurafenib or epirubicin in the treatment of malignant melanoma due to the abolition of their anticancer effects. The combination of daphnetin with mitoxantrone is beneficial in the treatment of metastatic melanoma due to their synergistic interaction.

Virtual screening, structure based pharmacophore mapping, and molecular simulation studies of pyrido[2,3-d]pyrimidines as selective thymidylate synthase inhibitors

Human thymidylate synthase is the rate-limiting enzyme in the de novo synthesis of 2'-deoxythymidine-5'-monophosphate. dUMP (pyrimidine) and folate binding site hTS inhibitors showed resistance in colorectal cancer (CRC). In the present study, we have performed virtual screening of the pyrido[2,3-d]pyrimidine database, followed by binding free energy calculations, and pharmacophore mapping to design novel pyrido[2,3-d]pyrimidine derivatives to stabilize inactive confirmation of hTS. A library of 42 molecules was designed. Based on the molecular docking studies, four ligands (T36, T39, T40, and T13) were identified to have better interactions and docking scores with the catalytic sites [dUMP (pyrimidine) and folate binding sites] of hTS protein than standard drug, raltitrexed. To validate efficacy of the designed molecules, we performed molecular dynamics simulation studies at 1000 ns with principal component analysis and binding free energy calculations on the hTS protein, also drug likeness properties of all hits were in acceptable range. Compounds T36, T39, T40, and T13 interacted with the catalytic amino acid (Cys195), an essential amino acid for anticancer activity. The designed molecules stabilized the inactive conformation of hTS, resulting in the inhibition of hTS. The designed compounds will undergo synthesis and biological evaluation, which may yield selective, less toxic, and highly potent hTS inhibitors.Communicated by Ramaswamy H. Sarma.

Methods in Drug Repurposing: Emphasis on COVID-19

Coronavirus disease 19 (COVID-19) is a pandemic situation caused by the SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), and dedicated medical research finding to cure the disease are rapidly evolving globally. SARS-Co- -2 is a highly mutating virus having various strains, till the reporting of this study, COVID-19 has 5 variants, i.e., Alfa, beta, gamma, delta, and omicron. A potential way for drug development is drug repurposing has got a lot of attention. Drug repurposing is the easiest and safest way to find out the drugs to cure COVID-19. Various new drugs have been discovered and are under clinical trial for the treatment of disease. Combinatorial treatments of COVID-19 patients give a very positive response in the treatment of SARS-CoV-2. The various vaccine already has been developed to produce antibodies against COVID-19. However, a large number of research studies have been done on COVID-19. This study is dedicated to research on COVID-19 therapy by the repurposing of existing drugs and methods used for the drug repurposing.<br>

Molecular docking and simulation studies of flavonoid compounds against PBP-2a of methicillin-resistant Staphylococcus aureus

Methicillin-Resistant Staphylococcus aureus (MRSA), a pathogenic bacterium that causes life-threatening outbreaks such as community-onset and nosocomial infections as emerging 'superbug'. Time and motion study of its virulent property developed resistance against most of the antibiotics such as Vancomycin. Thereby, to curb this problem entails the development of new therapeutic agents. Plant-derived antimicrobial agents have recently piqued people's interest, so in this research, 186 flavonoids compound selected to unmask the best candidates that can act as potent inhibitors against the Penicillin Binding Protein-2a (PBP-2a) of MRSA. Molecular docking performed using PyRx and GOLD suite to determine the binding affinities and interactions between the phytochemicals and the PBP-2a. The selected candidates strongly interact with the different amino acid residues. The 30 ns molecular dynamics (MD) simulations with five top-ranked compounds such as Naringin, Hesperidin, Neohesperidin, Didymin and Icariin validated the docking interactions. These findings are also strongly supported by root-mean-square deviation, root-mean-square fluctuation and the radius of gyration. ADME/T analysis demonstrates that these candidates appear to be safer inhibitors. Our findings point to natural flavonoids as a promising and readily available source of adjuvant antimicrobial therapy against resistant strains in the future.Communicated by Ramaswamy H. Sarma.

Novel Drug Design for Treatment of COVID-19: A Systematic Review of Preclinical Studies

Background

Since the beginning of the novel coronavirus (SARS-CoV-2) disease outbreak, there has been an increasing interest in discovering potential therapeutic agents for this disease. In this regard, we conducted a systematic review through an overview of drug development (in silico, in vitro, and in vivo) for treating COVID-19.

Methods

A systematic search was carried out in major databases including PubMed, Web of Science, Scopus, EMBASE, and Google Scholar from December 2019 to March 2021. A combination of the following terms was used: coronavirus, COVID-19, SARS-CoV-2, drug design, drug development, In silico, In vitro, and In vivo. A narrative synthesis was performed as a qualitative method for the data synthesis of each outcome measure.

Results

A total of 2168 articles were identified through searching databases. Finally, 315 studies (266 in silico, 34 in vitro, and 15 in vivo) were included. In studies with in silico approach, 98 article study repurposed drug and 91 studies evaluated herbal medicine on COVID-19. Among 260 drugs repurposed by the computational method, the best results were observed with saquinavir (n = 9), ritonavir (n = 8), and lopinavir (n = 6). Main protease (n = 154) following spike glycoprotein (n = 62) and other nonstructural protein of virus (n = 45) was among the most studied targets. Doxycycline, chlorpromazine, azithromycin, heparin, bepridil, and glycyrrhizic acid showed both in silico and in vitro inhibitory effects against SARS-CoV-2.

Conclusion

The preclinical studies of novel drug design for COVID-19 focused on main protease and spike glycoprotein as targets for antiviral development. From evaluated structures, saquinavir, ritonavir, eucalyptus, Tinospora cordifolia, aloe, green tea, curcumin, pyrazole, and triazole derivatives in in silico studies and doxycycline, chlorpromazine, and heparin from in vitro and human monoclonal antibodies from in vivo studies showed promised results regarding efficacy. It seems that due to the nature of COVID-19 disease, finding some drugs with multitarget antiviral actions and anti-inflammatory potential is valuable and some herbal medicines have this potential.

Withaniasomnifera phytochemicals possess SARS-CoV-2 RdRp and human TMPRSS2 protein binding potential

ABSTRACT

Coronavirus disease-19 (COVID-19) pandemic caused by severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) has infected approximately 26 million people and caused more than 6 million deaths globally. Spike (S)-protein on the outer surface of the virus uses human trans-membrane serine protease-2 (TMPRSS2) to gain entry into the cell. Recent reports indicate that human dipeptidyl peptidase-4 inhibitors (DPP4 or CD26) could also be utilized to check the S-protein mediated viral entry into COVID-19 patients. RNA dependent RNA polymerase (RdRp) is another key virulence protein of SARS-CoV-2 life cycle. The study aimed to identify the potential anti-SARS-CoV-2 inhibitors present in Withania somnifera (Solanaceae) using computer aided drug discovery approach. Molecular docking results showed that flavone glycoside, sugar alcohol, and flavonoid present in W. somnifera showed - 11.69, - 11.61, - 10.1, - 7.71 kcal/mole binding potential against S-protein, CD26, RdRp, and TMPRSS2 proteins. The major standard inhibitors of the targeted proteins (Sitagliptin, VE607, Camostat mesylate, and Remdesivir) showed the - 7.181, - 6.6, - 5.146, and - 7.56 kcal/mole binding potential. Furthermore, the lead phytochemicals and standard inhibitors bound and non-bound RdRp and TMPRSS2 proteins were subjected to molecular dynamics (MD) simulation to study the complex stability and change in protein conformation. The result showed energetically favorable and stable complex formation in terms of RMSD, RMSF, SASA, Rg, and hydrogen bond formation. Drug likeness and physiochemical properties of the test compounds exhibited satisfactory results. Taken together, the present study suggests the presence of potential anti-SARS-CoV-2 phytochemicals in W. somnifera that requires further validation in in vitro and in vivo studies.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s42535-022-00404-4.

Characterization of mutations modulating enhanced transmissibility of SARS-CoV-2 B.1.617+ (Delta) variant using In Silico tools

Since the beginning of the of SARS-CoV-2 (Covid-19) pandemic, variants of concern (VOC) have emerged taxing health systems worldwide. In October 2020, a new variant of SARS-CoV-2 (B.1.617+/Delta variant) emerged in India, triggering a deadly wave of Covid-19. Epidemiological data strongly suggests that B.1.617+ is more transmissible and previous reports have revealed that B.1.617+ has numerous mutations compared to wild type (WT), including several changes in the spike protein (SP). The main goal of this study was to use In Silico (computer simulation) techniques to examine mutations in the SP, specifically L452R and E484Q (part of the receptor binding domain (RBD) for human angiotensin-converting enzyme 2 (hACE2)) and P681R (upstream of the Furin cleavage motif), for effects in modulating the transmissibility of the B.1.617+ variant. Using computational models, the binding free energy (BFE) and H-bond lengths were calculated for SP-hACE2 and SP-Furin complexes. Comparison of the SP-hACE2 complex in the WT and B.1.617+ revealed both complexes have identical receptor-binding modes but the total BFE of B.1.617+ binding was more favorable for complex formation than WT, suggesting L452R and E484Q have a moderate impact on binding affinity. In contrast, the SP-Furin complex of B.1.617+ substantially lowered the BFE and revealed changes in molecular interactions compared to the WT complex, implying stronger complex formation between the variant and Furin. This study provides an insight into mutations that modulate transmissibility of the B.1.617+ variant, specifically the P681R mutation which appears to enhance transmissibility of the B.1.617+ variant by rendering it more receptive to Furin.

"In silico identification of ethoxy phthalimide pyrazole derivatives as IL-17A and IL-18 targeted gouty arthritis agents"

Two proinflammatory cytokines, IL17A and IL18, are observed to be elevated in the serum of gout patients and they play a crucial role in the development and worsening of inflammation, which has severe effects. In present study, we have combined molecular docking, molecular dynamics studies and MM-PBSA analysis to study the effectiveness of ethoxy phthalimide pyrazole derivatives (series 3a to 3e) as potential inhibitors against cytokines IL17A and IL18 as a druggable targets. The binding energy of the docked series ranges from -13.5 to -10.0 kcal/mol and extensively interacts with the amino acids in the active pocket of IL17A and IL18. Compound 3e had the lowest binding energy with IL17A at -12.6 kcal/mol compared to control allopurinol (3.32 kcal/mol). With IL18, compound 3a seems to have the lowest binding energy of -9.6 kcal/mol compared to control allopurinol (3.18 kcal/mol). In MD simulation studies, compound 3a forms a stable and energetically stabilized complex with the target protein. Depending on properties of the bound IL17A-3a and IL18-3a complexes was compared by means of MM-PBSA analysis. These derivatives can be used as a scaffold to develop promising IL17A and IL18 inhibitors to assess their potential for gouty arthritis and other related diseases.

Chemical biology and medicinal chemistry of RNA methyltransferases

RNA methyltransferases (MTases) are ubiquitous enzymes whose hitherto low profile in medicinal chemistry, contrasts with the surging interest in RNA methylation, the arguably most important aspect of the new field of epitranscriptomics. As MTases become validated as drug targets in all major fields of biomedicine, the development of small molecule compounds as tools and inhibitors is picking up considerable momentum, in academia as well as in biotech. Here we discuss the development of small molecules for two related aspects of chemical biology. Firstly, derivates of the ubiquitous cofactor S-adenosyl-l-methionine (SAM) are being developed as bioconjugation tools for targeted transfer of functional groups and labels to increasingly visible targets. Secondly, SAM-derived compounds are being investigated for their ability to act as inhibitors of RNA MTases. Drug development is moving from derivatives of cosubstrates towards higher generation compounds that may address allosteric sites in addition to the catalytic centre. Progress in assay development and screening techniques from medicinal chemistry have led to recent breakthroughs, e.g. in addressing human enzymes targeted for their role in cancer. Spurred by the current pandemic, new inhibitors against coronaviral MTases have emerged at a spectacular rate, including a repurposed drug which is now in clinical trial.

Identification of 1, 2, 4-Triazine and Its Derivatives Against Lanosterol 14-Demethylase (CYP51) Property of Candida albicans: Influence on the Development of New Antifungal Therapeutic Strategies

This research aims to find out whether the 1, 2, 4-triazine and its derivatives have antifungal effects and can protect humans from infection with Candida albicans. Molecular docking and molecular dynamic simulation are widely used in modern drug design to target a particular protein with a ligand. We are interested in using molecular docking and molecular dynamics modeling to investigate the interaction between the derivatives of 1, 2, 4-triazine with enzyme Lanosterol 14-demethylase (CYP51) of Candida albicans. The inhibition of Candida albicans CYP51 is the main goal of our research. The 1, 2, 4-triazine and its derivatives have been docked to the CYP51 enzyme, which is involved in Candida albicans Multidrug Drug Resistance (MDR). Autodock tools were used to identify the binding affinities of molecules against the target proteins. Compared to conventional fluconazole, the molecular docking results indicated that each drug has a high binding affinity for CYP51 proteins and forms unbound interactions and hydrogen bonds with their active residues and surrounding allosteric residues. The docking contacts were made using a 10 ns MD simulation with nine molecules. RMSD, RMSF, hydrogen bonds, and the Rg all confirm these conclusions. In addition, these compounds were expected to have a favorable pharmacological profile and low toxicity. The compounds are being offered as scaffolds for the development of new antifungal drugs and as candidates for future in vitro testing.

Molecular docking and dynamics approach to in silico drug repurposing for inflammatory bowels disease by targeting TNF alpha

Inflammatory bowel disease is a chronic disorder of the large intestine with the prevalence of approximately 400 cases in 100000, and it is rising day by day. However, several drugs like sulfasalazine (composed of sulfapyridine and 5-aminosalicylic acid or 5-ASA), corticosteroids, and immunosuppressants manage the disease. But there are no absolute treatments for the pain and inflammation of the disease. TNFα is an important target, and drugs like infliximab and adalimumab have pharmacological potency but with pronounced toxicity. So, we choose this major target TNFα for the virtual screening of US-FDA-approved drugs for its repurposing using the in silico method. The protein TNFα (PDB ID: 2AZ5) with small molecule inhibitor and the US-FDA-approved drug molecules (from Zinc database) were first imported and prepared using Protein Preparation Wizard and LigPrep, respectively, followed by molecular docking, ADMET analysis and prime MMGBSA. After that, the drugs were shortlisted according to dock score, ADMET parameters and MM GBSA dG binding score. After that, the shortlisted drug molecules were subjected to an induced-fit docking analysis. Two of the most promising molecules, ZINC000003830957 (Iopromide) and ZINC000003830635 (Deferoxamine), were chosen for molecular dynamics simulation. Finally, the bioisosteric replacement was used to improve the ADMET properties of these molecules. This research provides an idea for drug exploration and computational tools for drug discovery in treating inflammatory bowel disease.Communicated by Ramaswamy H. Sarma.

Molecular Docking and Dynamics Investigations for Identifying Potential Inhibitors of the 3-Chymotrypsin-like Protease of SARS-CoV-2: Repurposing of Approved Pyrimidonic Pharmaceuticals for COVID-19 Treatment

This study demonstrates the inhibitory effect of 42 pyrimidonic pharmaceuticals (PPs) on the 3-chymotrypsin-like protease of SARS-CoV-2 (3CL^pro) through molecular docking, molecular dynamics simulations, and free binding energies by means of molecular mechanics-Poisson Boltzmann surface area (MM-PBSA) and molecular mechanics-generalized Born surface area (MM-GBSA). Of these tested PPs, 11 drugs approved by the US Food and Drug Administration showed an excellent binding affinity to the catalytic residues of 3CL^pro of His41 and Cys145: uracil mustard, cytarabine, floxuridine, trifluridine, stavudine, lamivudine, zalcitabine, telbivudine, tipiracil, citicoline, and uridine triacetate. Their percentage of residues involved in binding at the active sites ranged from 56 to 100, and their binding affinities were in the range from -4.6 ± 0.14 to -7.0 ± 0.19 kcal/mol. The molecular dynamics as determined by a 200 ns simulation run of solvated docked complexes confirmed the stability of PP conformations that bound to the catalytic dyad and the active sites of 3CL^pro. The free energy of binding also demonstrates the stability of the PP-3CL^pro complexes. Citicoline and uridine triacetate showed free binding energies of -25.53 and -7.07 kcal/mol, respectively. Therefore, I recommend that they be repurposed for the fight against COVID-19, following proper experimental and clinical validation.

Discovery of SARS-CoV-2 Nsp14 and Nsp16 Methyltransferase Inhibitors by High-Throughput Virtual Screening

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) uses mRNA capping to evade the human immune system. The cap formation is performed by the SARS-CoV-2 mRNA cap methyltransferases (MTases) nsp14 and nsp16, which are emerging targets for the development of broad-spectrum antiviral agents. Here, we report results from high-throughput virtual screening against these two enzymes. The docking of seven million commercially available drug-like compounds and S-adenosylmethionine (SAM) co-substrate analogues against both MTases resulted in 80 virtual screening hits (39 against nsp14 and 41 against nsp16), which were purchased and tested using an enzymatic homogeneous time-resolved fluorescent energy transfer (HTRF) assay. Nine compounds showed micromolar inhibition activity (IC₅₀ < 200 μM). The selectivity of the identified inhibitors was evaluated by cross-checking their activity against human glycine N-methyltransferase. The majority of the compounds showed poor selectivity for a specific MTase, no cytotoxic effects, and rather poor cell permeability. Nevertheless, the identified compounds represent good starting points that have the potential to be developed into efficient viral MTase inhibitors.

Ligand-based quantitative structural assessments of SARS-CoV-2 3CLpro inhibitors: An analysis in light of structure-based multi-molecular modeling evidences

Due to COVID-19, the whole world is undergoing a devastating situation, but treatment with no such drug candidates still has been established exclusively. In that context, 69 diverse chemicals with potential SARS-CoV-2 3CL^pro inhibitory property were taken into consideration for building different internally and externally validated linear (SW-MLR and GA-MLR), non-linear (ANN and SVM) QSAR, and HQSAR models to identify important structural and physicochemical characters required for SARS-CoV-2 3CL^pro inhibition. Importantly, 2-oxopyrrolidinyl methyl and benzylester functions, and methylene (hydroxy) sulphonic acid warhead group, were crucial for retaining higher SARS-CoV-2 3CL^pro inhibition. These GA-MLR and HQSAR models were also applied to predict some already repurposed drugs. As per the GA-MLR model, curcumin, ribavirin, saquinavir, sepimostat, and remdesivir were found to be the potent ones, whereas according to the HQSAR model, lurasidone, saquinavir, lopinavir, elbasvir, and paritaprevir were the highly effective SARS-CoV-2 3CL^pro inhibitors. The binding modes of those repurposed drugs were also justified by the molecular docking, molecular dynamics (MD) simulation, and binding energy calculations conducted by several groups of researchers. This current work, therefore, may be able to find out important structural parameters to accelerate the COVID-19 drug discovery processes in the future.

A network representation approach for COVID-19 drug recommendation

The coronavirus disease 2019 (COVID-19) has outbreak since early December 2019, and COVID-19 has caused over 100 million cases and 2 million deaths around the world. After one year of the COVID-19 outbreak, there is no certain and approve medicine against it. Drug repositioning has become one line of scientific research that is being pursued to develop an effective drug. However, due to the lack of COVID-19 data, there is still no specific drug repositioning targeting the COVID-19. In this paper, we propose a framework for COVID-19 drug repositioning. This framework has several advantages that can be exploited: one is that a local graph aggregating representation is used across a heterogeneous network to address the data sparsity problem; another is the multi-hop neighbors of the heterogeneous graph are aggregated to recall as many COVID-19 potential drugs as possible. Our experimental results show that our COVDR framework performs significantly better than baseline methods, and the docking simulation verifies that our three potential drugs have the ability to against COVID-19 disease.

Computational approach towards the design of artemisinin-thymoquinone hybrids against main protease of SARS-COV-2

Background

The sanitary emergency installed in the world, generated by the pandemic of COVID-19, instigates the search for scientific strategies to mitigate the damage caused by the disease to different sectors of society. The disease caused by the coronavirus, SARS-CoV-2, reached 216 countries/territories, where about 199 million people were reported with the infection. Of these, more than 4 million died. In this sense, strategies involving the development of new antiviral molecules are extremely important. The main protease (Mpro) from SARS-CoV-2 is an important target, which has been widely studied for antiviral treatment. This work aims to perform a screening of pharmacodynamics and pharmacokinetics of synthetic hybrids from thymoquinone and artemisin (THY-ART) against COVID-19.

Results

Molecular docking studies indicated that hybrids of artemisinin and thymoquinone showed a relevant interaction with the active fraction of the enzyme Mpro, when compared to the reference drugs. Furthermore, hybrids show an improvement in the interaction of substances with the enzyme, mainly due to the higher frequency of interactions with the Thr199 residue. ADMET studies indicated that hybrids tend to permeate biological membranes, allowing good human intestinal absorption, with low partition to the central nervous system, potentiation for CYP-450 enzyme inhibitors, low risk of toxicity compared to commercially available drugs, considering mainly mutagenicity and cardiotoxicity, low capacity of hybrids to permeate the blood–brain barrier, high absorption and moderate permeability in Caco-2 cells. In addition, T1–T7 tend to have a better distribution of their available fractions to carry out diffusion and transport across cell membranes, as well as increase the energy of interaction with the SARS-CoV-2 target.

Conclusions

Hybrid products of artemisinin and thymoquinone have the potential to inhibit Mpro, with desirable pharmacokinetic and toxicity characteristics compared to commercially available drugs, being indicated for preclinical and subsequent clinical studies against SARS-CoV-2. Emphasizing the possibility of synergistic use with currently used drugs in order to increase half-life and generate a possible synergistic effect. This work represents an important step for the development of specific drugs against COVID-19.

Profile of Bacterial Infections in COVID-19 Patients: Antimicrobial Resistance in the Time of SARS-CoV-2

Simple Summary

Since the beginning of COVID-19 pandemic, no specific drugs have been available to treat the SARS-CoV-2 infection, therefore antibiotics have been often used both for prophylactic and therapeutic purposes. Their wide use, though, is known to contribute to the emergence of antimicrobial resistance. Aiming at evaluating the impact of the COVID-19 pandemic on the distribution and characteristics of bacterial infections, and on the frequency of antimicrobial resistance, we investigated the microbial strains identified through laboratory tests on clinical specimens from COVID-19 and non-COVID-19 patients accessing an Italian tertiary hospital over nearly one year. We highlighted that COVID+ patients bore a significantly higher number of bacterial species. Eight out of the 100 species identified were isolated exclusively from COVID+ and most of them are known to establish infections only in immunocompromised patients. Resistance to every tested antibiotic was seen in 8.3% of the isolates with a correlation with the positivity to COVID, but neither all COVID+ or COVID− isolates showed characteristic responses to the tested antibiotics. The predicted increase of antibiotic resistance is not observable yet, but the higher frequency of multi-resistant COVID+ isolates suggests that it is actually occurring, further calling for the definition of alternative treatments of COVID-19 infections.

Abstract

The global onset of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus infections happened suddenly, hence imposing a rapid definition of effective therapeutic approaches. Antibiotics were included among the prophylactic agents because of both the similarity between SARS-CoV-2 and atypical pneumonia symptoms, and the immune-modulating and anti-inflammatory properties of such drugs. Although, this approach could exacerbate the emergence of antimicrobial resistance. To evaluate the impact of the COVID-19 pandemic on the spread and characteristics of bacterial infections, as well as on the frequency of antimicrobial resistance, we investigated and compared clinical bacterial strains isolated in an Italian hospital from COVID-19 patients and non-COVID-19 patients during and before the COVID-19 outbreak. Data clearly indicate the impact of the COVID-19 pandemic on bacterial infections: not only some bacterial species were found in either COVID-19 positive or in COVID-19 negative patients, but isolates from COVID-19 patients also showed higher levels of antimicrobial resistance. Nevertheless, despite some bacterial species were isolated only before or over the pandemic, no differences were observed among the antimicrobial resistance levels. Overall, these results recapitulate the current situation of microbial infections and could also provide an overview of the impact of COVID-19 on bacterial pathogens spread and resistance.

Computational Identification of SARS-CoV-2 Inhibitor in Tinospora cordifolia, Cinnamomum zeylanicum and Myristica fragrans

A novel coronavirus disease (COVID-19), caused by SARS-CoV-2, has spread over more than 100 countries all over the world. The World Health Organization has recognized Coronavirus as a pandemic and finding an effective drug for this infectious disease is of high importance. In this study, we have explored the potent inhibitors of COVID-19 main protease from Tinospora cordifolia an Ayurvedic herb locally called as Amrita meaning ‘immortality’ and two other Ayurveda plants namely Cinnamomum zeylanicum and Myristica fragrans. Saponarin, a phytochemical present in Tinospora cordifolia showed a very promising result with the binding affinity of − 8.75 kcal/mol. Remdesivir and Favipiravir, the experimental drugs that are known to show inhibitory activity towards COVID-19 are used as a control. The Docking results were verified by the means of molecular dynamic analysis. This study suggests that Saponarin can be a potential inhibitor for the main protease of the COVID-19.

Peptide inhibitors against SARS-CoV-2 2'-O-methyltransferase involved in RNA capping: A computational approach

The COVID-19 pandemic is still evolving and is caused by SARS-CoV-2. The 2'-O-methyltransferase (nsp16) enzyme is crucial for maintaining the stability of viral RNA for effective translation of viral proteins and its life cycle. Another protein, nsp10, is important for enzymatic activity of nsp16. Any disturbance in the interaction between nsp16 and nsp10 may affect viral replication fidelity. Here, five peptide inhibitors, derived from nsp16, were designed and assessed for their effectiveness in binding to nsp10 using molecular dynamics simulation. The inhibitors were derived from the nsp10/nsp16 binding interface. Post-simulation analysis showed that inhibitors 2 and 5 were stable and bind to the nsp16 interacting region of nsp10 which could potentially prevent the interaction between the two proteins. The proposed peptides are useful starting points for the development of therapeutics to manage the spread of COVID-19.

What the dental practitioner needs to know about pharmaco-therapeutic modalities of COVID-19 treatment: A review

BACKGROUND/PURPOSE

Several pharmacotherapeutic methods have been used for the treatment of COVID-19 with varying degrees of success. No definitive treatment or vaccine has been officially approved to-date. This review aimed to highlight COVID-19 pharmacotherapeutic agents that are relevant to dental practice in terms of their clinical indications in COVID-19 and dental practice, as well as their adverse effects as they impact the dental patient.

MATERIAL AND METHODS

Systematic search was performed using the following keywords combinations: Pharmacotherapy AND COVID-19 OR Pharmacotherapy AND SARS-CoV-2 OR Treatment AND COVID-19. Studies were categorized according to the type of pharmacotherapy used. Pharmacotherapeutic agents were extracted and only those relevant to dental practice were included for review.

RESULTS

For analysis, a total of 79 clinical trials research articles were included that included COVID-19 pharmacotherapeutic agents relevant to dental practice. Those were analgesics (paracetamol; non-steroidal anti-inflammatory agents); antibiotics (azithromycin, doxycycline, metronidazole); antivirals (penciclovir); and immunomodulatory agents (hydroxychloroquine, corticosteroids). While some COVID-19 drugs are less relevant to dental practice, as antivirals and hydroxychloroquine, their association with long-term adverse effects requires adequate knowledge among dental practitioners.

CONCLUSION

Many of COVID-19 pharmacotherapeutic agents are used to treat oral diseases particularly orofacial pain and inflammatory conditions. Furthermore, some of these drugs may induce adverse effects that complicate dental treatment. Thorough knowledge of COVID-19 therapy and its dental implications is essential for dental practitioners, and is expected to contribute to a better understanding and effective utilization of these therapeutic agents.

The Role of Coronavirus RNA-Processing Enzymes in Innate Immune Evasion

Viral RNA sensing triggers innate antiviral responses in humans by stimulating signaling pathways that include crucial antiviral genes such as interferon. RNA viruses have evolved strategies to inhibit or escape these mechanisms. Coronaviruses use multiple enzymes to synthesize, modify, and process their genomic RNA and sub-genomic RNAs. These include Nsp15 and Nsp16, whose respective roles in RNA capping and dsRNA degradation play a crucial role in coronavirus escape from immune surveillance. Evolutionary studies on coronaviruses demonstrate that genome expansion in Nidoviruses was promoted by the emergence of Nsp14-ExoN activity and led to the acquisition of Nsp15- and Nsp16-RNA-processing activities. In this review, we discuss the main RNA-sensing mechanisms in humans as well as recent structural, functional, and evolutionary insights into coronavirus Nsp15 and Nsp16 with a view to potential antiviral strategies.

A Multidisciplinary Approach to Coronavirus Disease (COVID-19)

Since December 2019, humanity has faced an important global threat. Many studies have been published on the origin, structure, and mechanism of action of the SARS-CoV-2 virus and the treatment of its disease. The priority of scientists all over the world has been to direct their time to research this subject. In this review, we highlight chemical studies and therapeutic approaches to overcome COVID-19 with seven different sections. These sections are the structure and mechanism of action of SARS-CoV-2, immunotherapy and vaccine, computer-aided drug design, repurposing therapeutics for COVID-19, synthesis of new molecular structures against COVID-19, food safety/security and functional food components, and potential natural products against COVID-19. In this work, we aimed to screen all the newly synthesized compounds, repurposing chemicals covering antiviral, anti-inflammatory, antibacterial, antiparasitic, anticancer, antipsychotic, and antihistamine compounds against COVID-19. We also highlight computer-aided approaches to develop an anti-COVID-19 molecule. We explain that some phytochemicals and dietary supplements have been identified as antiviral bioproducts, which have almost been successfully tested against COVID-19. In addition, we present immunotherapy types, targets, immunotherapy and inflammation/mutations of the virus, immune response, and vaccine issues.

Mutation Signatures and In Silico Docking of Novel SARS-CoV-2 Variants of Concern

One year since the first severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was reported in China, several variants of concern (VOC) have appeared around the world, with some variants seeming to pose a greater thread to public health due to enhanced transmissibility or infectivity. This study provides a framework for molecular characterization of novel VOC and investigates the effect of mutations on the binding affinity of the receptor-binding domain (RBD) to human angiotensin-converting enzyme 2 (hACE2) using in silico approach. Notable nonsynonymous mutations in RBD of VOC include the E484K and K417N/T that can be seen in South African and Brazilian variants, and N501Y and D614G that can be seen in all VOC. Phylogenetic analyses demonstrated that although the UK-VOC and the BR-VOC fell in the clade GR, they have different mutation signatures, implying an independent evolutionary pathway. The same is true about SA-VOC and COH-VOC felling in clade GH, but different mutation signatures. Combining molecular interaction modeling and the free energy of binding (FEB) calculations for VOC, it can be assumed that the mutation N501Y has the highest binding affinity in RBD for all VOC, followed by E484K (only for BR-VOC), which favors the formation of a stable complex. However, mutations at the residue K417N/T are shown to reduce the binding affinity. Once vaccination has started, there will be selective pressure that would be in favor of the emergence of novel variants capable of escaping the immune system. Therefore, genomic surveillance should be enhanced to find and monitor new emerging SARS-CoV-2 variants before they become a public health concern.

Molecular Simulation-Based Investigation of Highly Potent Natural Products to Abrogate Formation of the nsp10-nsp16 Complex of SARS-CoV-2

The SARS-CoV-2 non-structural protein (nsp) nsp10–nsp16 complex is essential for the 2′-O-methylation of viral mRNA, a crucial step for evading the innate immune system, and it is an essential process in SARS-CoV-2 life cycle. Therefore, detecting molecules that can disrupt the nsp10–nsp16 interaction are prospective antiviral drugs. In this study, we screened the North African Natural Products database (NANPDB) for molecules that can interact with the nsp10 interface and disturb the nsp10–nsp16 complex formation. Following rigorous screening and validation steps, in addition to toxic side effects, drug interactions and a risk /benefit assessment, we identified four compounds (genkwanin-6-C-beta-glucopyranoside, paraliane diterpene, 4,5-di-p-trans-coumaroylquinic acid and citrinamide A) that showed the best binding affinity and most favourable interaction with nsp10 interface residues. To understand the conformational stability and dynamic features of nsp10 bound to the four selected compounds, we subjected each complex to 200 ns molecular dynamics simulations. We then calculated the free binding energies of compounds interacting with nsp10 structure using the molecular mechanics-generalised Born surface area (MMGBSA). Of the four compounds, genkwanin-6-C-beta-glucopyranoside demonstrated the most stable complex with nsp10, in addition to a tighter binding affinity of −37.4 ± 1.3 Kcal/mol. This potential to disrupt the nsp10–nsp16 interface interaction and inhibit it now sets the path for functional studies.

Bacterial ClpP Protease Is a Potential Target for Methyl Gallate

Methyl gallate (MG) is an effective microbicide with great potential application in the integrated management of plant diseases and an important potential drug for clinical application. However, its target remains unknown. This study conducted a transposon sequencing (Tn-seq) under MG treatment in plant pathogenic bacterium Ralstonia solanacearum. Tn-seq identified that the mutation of caseinolytic protease proteolytic subunit gene clpP significantly increased the resistance of R. solanacearum to MG, which was validated by the in-frame gene deletion. iTRAQ (isobaric tags for relative and absolute quantitation) proteomics analysis revealed that chemotaxis and flagella associated proteins were the major substrates degraded by ClpP under the tested condition. Moreover, sulfur metabolism-associated proteins were potential substrates of ClpP and were upregulated by MG treatment in wild-type R. solanacearum but not in clpP mutant. Furthermore, molecular docking confirmed the possible interaction between MG and ClpP. Collectively, this study revealed that MG might target bacterial ClpP, inhibit the activity of ClpP, and consequently disturb bacterial proteostasis, providing a theoretical basis for the application of MG.

Cheminformatics-Based Identification of Potential Novel Anti-SARS-CoV-2 Natural Compounds of African Origin

The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome virus 2 (SARS-CoV-2) has impacted negatively on public health and socioeconomic status, globally. Although, there are currently no specific drugs approved, several existing drugs are being repurposed, but their successful outcomes are not guaranteed. Therefore, the search for novel therapeutics remains a priority. We screened for inhibitors of the SARS-CoV-2 main protease and the receptor-binding domain of the spike protein from an integrated library of African natural products, compounds generated from machine learning studies and antiviral drugs using AutoDock Vina. The binding mechanisms between the compounds and the proteins were characterized using LigPlot+ and molecular dynamics simulations techniques. The biological activities of the hit compounds were also predicted using a Bayesian-based approach. Six potential bioactive molecules NANPDB2245, NANPDB2403, fusidic acid, ZINC000095486008, ZINC0000556656943 and ZINC001645993538 were identified, all of which had plausible binding mechanisms with both viral receptors. Molecular dynamics simulations, including molecular mechanics Poisson-Boltzmann surface area (MM/PBSA) computations revealed stable protein-ligand complexes with all the compounds having acceptable free binding energies <-15 kJ/mol with each receptor. NANPDB2245, NANPDB2403 and ZINC000095486008 were predicted as antivirals; ZINC000095486008 as a membrane permeability inhibitor; NANPDB2403 as a cell adhesion inhibitor and RNA-directed RNA polymerase inhibitor; and NANPDB2245 as a membrane integrity antagonist. Therefore, they have the potential to inhibit viral entry and replication. These drug-like molecules were predicted to possess attractive pharmacological profiles with negligible toxicity. Novel critical residues identified for both targets could aid in a better understanding of the binding mechanisms and design of fragment-based de novo inhibitors. The compounds are proposed as worthy of further in vitro assaying and as scaffolds for the development of novel SARS-CoV-2 therapeutic molecules.

Peptide modelling and screening against human ACE2 and spike glycoprotein RBD of SARS-CoV-2

Outbreak of Coronavirus Disease 2019 (COVID-19) has become a great challenge for scientific community globally. Virus enters cell through spike glycoprotein fusion with ACE2 (Angiotensin-Converting Enzyme 2) human receptor. Hence, spike glycoprotein of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a potential target for diagnostics, vaccines, and antibodies. Also, virus entry can be prevented by blocking ACE2 thus, ACE2 can be considered potential target for therapeutics. As being highly specific, safe and efficacious, peptides hold their place in therapeutics. In present study, we retrieved sequence of 70 peptides from Antiviral Peptide Database (AVPdb), modelled them using 3D structure predicting web tool and docked them with receptor binding domain (RBD) of spike protein and human host receptor ACE2 using peptide-protein docking. It was observed that peptides have more affinity towards ACE2 in comparison with spike RBD. Interestingly it was noticed that most of the peptides bind to RBM (residue binding motif) which is responsible for ACE2 binding at the interface of RBD while, for ACE2, peptides prefer to bind the core cavity rather than RBD binding interface. To further investigate how peptides at the interface of RBD or ACE2 alter the binding between RBD and ACE2, protein-protein docking of RBD and ACE2 with and without peptides was performed. Peptides, AVP0671 at RBD and AVP1244 at ACE2 interfaces significantly reduce the binding affinity and change the orientation of RBD and ACE2 binding. This finding suggests that peptides can be used as a drug to inhibit virus entry in cells to stop COVID-19 pandemic in the future after experimental evidences.

COVID-19: molecular targets, drug repurposing and new avenues for drug discovery

Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly contagious infection that may break the healthcare system of several countries. Here, we aimed at presenting a critical view of ongoing drug repurposing efforts for COVID-19 as well as discussing opportunities for development of new treatments based on current knowledge of the mechanism of infection and potential targets within. Finally, we also discuss patent protection issues, cost effectiveness and scalability of synthetic routes for some of the most studied repurposing candidates since these are key aspects to meet global demand for COVID-19 treatment.

In silico validation of coumarin derivatives as potential inhibitors against Main Protease, NSP10/NSP16-Methyltransferase, Phosphatase and Endoribonuclease of SARS CoV-2

Coronavirus Disease (COVID-19) is recently declared pandemic (WHO) caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). The virus was named Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), (Coronavirus Disease 2019). Currently, there is no specific drug for the therapy of COVID-19. So, there is a need to develop or find out the new drug from the existing to cure the COVID-19. Identification of a potent inhibitor of Methyltransferase, Endoribonuclease, Phosphatase and Main Protease enzymes of SARS CoV-2 by coumarin derivatives using insilico approach. The in silico studies were performed on maestro 12.0 software (Schrodinger LLC 2019, USA). Two thousand seven hundred fifty-five biologically active coumarin derivative was docked with above receptor proteins of SARS CoV-2. The molecular dynamic simulation of the top one ligand of respected proteins was performed. Top five ligands of each protein were taken for study. Coumarin derivatives actively interact with taken receptors and showed good docking results for Methyltransferase, Endoribonuclease, Phosphatase and Main Protease and top five compounds of each have docking score from –9.00 to –7.97, –8.42 to –6.80, –8.63 to –7.48 and –7.30 to –6.01 kcal/mol, respectively. The docked compounds were showed RMSD and binding stability of simulated ligands are show the potency of ligands against the SARS CoV-2. Our study provides information on drugs that may be a potent inhibitor of COVID-19 infection. Drug repurposing of the available drugs would be great help in the treatment of COVID-19 infection. The combination therapy of the finding may improve inhibitory activity.

Communicated by Ramaswamy H. Sarma

Highlights

Coronavirus Disease (COVID-19) is recently declared pandemic (WHO) caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2).

In silico virtual screening, docking, ADME, MM-GBSA and MD simulation analysis of coumarin derivatives against Methyltransferase (MTase), Endoribonuclease(endoU), ADP ribose Phosphatase and Main Protease enzyme of SARS CoV-2.

All the analysis was performed on Maestro 12.0 Schrodinger software against respective receptors.

Top five compounds of coumarin derivatives s docked at the active site of Methyltransferase (MTase), Endoribonuclease(endoU), ADP ribose Phosphatase and protease and top five compounds of each have docking score from –9.00 to –7.97, –8.42 to –6.80, –8.63 to –7.48 and –7.30 to –6.01 kcal/mol, respectively, of SARS CoV-2.

These compounds were used to analysis of binding free energy by using the Prime MM-GBSA module.

All the compounds showed drug-likeness properties.

MD simulation of Proteins and ligands showed binding stability and good RMSD, radius of gyration of protein, coulomb-SR and LJ-SR energy.