Antiviral Molecules Research Articles

Impact of new cyclooxygenase 2 inhibitors on human cytomegalovirus replication in vitro.

Human cytomegalovirus (HCMV) is involved in complications on immunocompromised patients. Current therapeutics are associated with several drawbacks, such as nephrotoxicity. As HCMV infection affects inflammation pathways, especially prostaglandin E2 (PGE2) production via cyclooxygenase 2 enzyme (COX-2), we designed 2'-hydroxychalcone compounds to inhibit human cytomegalovirus. We first selected the most efficient new synthetic chalcones for their effect against COX-2-catalyzed PGE2. Among the selected compounds, we assessed the antiviral efficacy against different HCMV strains, such as the laboratory strain AD169 and clinical strains (naïve or multi-resistant to conventional drugs) and toxicity on human cells. The most efficient and less toxic compound (chalcone 7) was tested against HCMV in combination with other antiviral molecules: artesunate (ART), baicalein (BAI), maribavir (MBV), ganciclovir (GCV), and quercetin (QUER) using Compusyn software. Association of chalcone 7 with MBV and BAI is synergistic, antagonistic with QUER, and additive with GCV and ART. These results provide a promising search path for potential bitherapies against HCMV.

Impact of direct acting antivirals (DAA) on neurologic disorders in chronic hepatitis C.

Neurologic and neuropsychiatric manifestations sometimes provide the first evidence of an unknown HCV infection. These conditions develop with a variable ranging of morbidity, including: "brain fog," fatigue, subtle cognitive and attention impairment, but also with more severe complications or acute presentation, like encephalomyelitis, encephalopathy, stroke and peripheral nerves involvement. We performed a systematic literature search on PubMed, Cochrane Library and Web of Science databases for articles only in English language, that assessed the relationship between "DAA treatment and neurologic disorders" and after the attainment of SVR in full reports of cases that received the DAA schedule from January 2015 to December 2019. The following terms were used: "chronic Hepatitis C," "HCV," "DAA," "direct-acting antiviral," "SVR," "sustained virologic response," peripheral neuropathy" and "neurologic diseases or disorders." HCV infection does not only involve the liver, causing cirrhosis and hepatocellular carcinoma (HCC), but also induces extrahepatic manifestations (EHM), mainly due to a complex immune disease, that damage small and medium vessels, called "mixed cryoglobulinemic vasculitis" (MCV). This kind of mechanism generates most of the HCV-induced neurological damages. Since 2015, the availability of direct-acting antiviral (DAA) oral molecules interfering with HCV replication has completely revolutionized therapeutic options and the target population, which now includes patients aged 12 to 80 years and with advanced liver disease. Relevant was the highlighted DAA effectiveness by achievement of a sustained virologic response (SVR) in about 95% of cases, showing a great tolerability. This favorable effect has arisen in a wide category of patients infected by HCV, including subjects with cirrhosis and complications and/or with EHM, who showed a significant improvement of their symptoms and the disease regression. In this concise review, we examine the clinical outcomes after the introduction of the DAA for the treatment of chronic hepatitis C (CHC), focusing on the neurologic disorders and concluding that there is a strong amelioration of neurologic conditions in several cases, particularly, after attaining the viral eradication with a favorable course in most treated cases.

Identifying the natural compound Catechin from tropical mangrove plants as a potential lead candidate against 3CLpro from SARS-CoV-2: An integrated in silico approach

SARS-CoV-2, a member of beta coronaviruses, is a single-stranded, positive-sense RNA virus responsible for the COVID-19 pandemic. With global fatalities of the pandemic exceeding 4.57 million, it becomes crucial to identify effective therapeutics against the virus. A protease, 3CLpro, is responsible for the proteolysis of viral polypeptides into functional proteins, which is essential for viral pathogenesis. This indispensable activity of 3CLpro makes it an attractive target for inhibition studies. The current study aimed to identify potential lead molecules against 3CLpro of SARS-CoV-2 using a manually curated in-house library of antiviral compounds from mangrove plants. This study employed the structure-based virtual screening technique to evaluate an in-house library of antiviral compounds against 3CLpro of SARS-CoV-2. The library was comprised of thirty-three experimentally proven antiviral molecules extracted from different species of tropical mangrove plants. The molecules in the library were virtually screened using AutoDock Vina, and subsequently, the top five promising 3CLpro-ligand complexes along with 3CLpro-N3 (control molecule) complex were subjected to MD simulations to comprehend their dynamic behaviour and structural stabilities. Finally, the MM/PBSA approach was used to calculate the binding free energies of 3CLpro complexes. Among all the studied compounds, Catechin achieved the most significant binding free energy (−40.3 ± 3.1 kcal/mol), and was closest to the control molecule (−42.8 ± 5.1 kcal/mol), and its complex with 3CLpro exhibited the highest structural stability. Through extensive computational investigations, we propose Catechin as a potential therapeutic agent against SARS-CoV-2. Communicated by Ramaswamy H. Sarma

Computational approach towards the design of artemisinin\u2013thymoquinone hybrids against main protease of SARS-COV-2

BackgroundThe 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.ResultsMolecular 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.ConclusionsHybrid 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.

Identification of antiviral molecules against West‐Nile virus by an approach combining cell imaging and equine neural cells derived from induced‐pluripotent stem cells

Identification of antiviral molecules against West‐Nile virus by an approach combining cell imaging and equine neural cells derived from induced‐pluripotent stem cells

Synthesis and Biological Evaluation of Honokiol Derivatives Bearing 3-((5-phenyl-1,3,4-oxadiazol-2-yl)methyl)oxazol-2(3H)-ones as Potential Viral Entry Inhibitors against SARS-CoV-2.

The 2019 coronavirus disease (COVID-19) caused by SARS-CoV-2 virus infection has posed a serious danger to global health and the economy. However, SARS-CoV-2 medications that are specific and effective are still being developed. Honokiol is a bioactive component from Magnoliae officinalis Cortex with damp-drying effect. To develop new potent antiviral molecules, a series of novel honokiol analogues were synthesized by introducing various 3-((5-phenyl-1,3,4-oxadiazol-2-yl)methyl)oxazol-2(3H)-ones to its molecule. In a SARS-CoV-2 pseudovirus model, all honokiol derivatives were examined for their antiviral entry activities. As a result, 6a and 6p demonstrated antiviral entry effect with IC50 values of 29.23 and 9.82 µM, respectively. However, the parental honokiol had a very weak antiviral activity with an IC50 value more than 50 µM. A biolayer interfero-metry (BLI) binding assay and molecular docking study revealed that 6p binds to human ACE2 protein with higher binding affinity and lower binding energy than the parental honokiol. A competitive ELISA assay confirmed the inhibitory effect of 6p on SARS-CoV-2 spike RBD’s binding with ACE2. Importantly, 6a and 6p (TC50 > 100 μM) also had higher biological safety for host cells than honokiol (TC50 of 48.23 μM). This research may contribute to the discovery of potential viral entrance inhibitors for the SARS-CoV-2 virus, although 6p’s antiviral efficacy needs to be validated on SARS-CoV-2 viral strains in a biosafety level 3 facility.

High-Throughput NanoBiT-Based Screening for Inhibitors of HIV-1 Vpu and Host BST-2 Protein Interaction.

Bone marrow stromal cell antigen 2 (BST-2), also known as CD317 or tetherin, has been identified as a host restriction factor that suppresses the release of enveloped viruses from host cells by physically tethering viral particles to the cell surface; however, this host defense can be subverted by multiple viruses. For example, human immunodeficiency virus (HIV)-1 encodes a specific accessory protein, viral protein U (Vpu), to counteract BST-2 by binding to it and directing its lysosomal degradation. Thus, blocking the interaction between Vpu and BST-2 will provide a promising strategy for anti-HIV therapy. Here, we report a NanoLuc Binary Technology (NanoBiT)-based high-throughput screening assay to detect inhibitors that disrupt the Vpu-BST-2 interaction. Out of more than 1000 compounds screened, four inhibitors were identified with strong activity at nontoxic concentrations. In subsequent cell-based BST-2 degradation assays, inhibitor Y-39983 HCl restored the cell-surface and total cellular level of BST-2 in the presence of Vpu. Furthermore, the Vpu-mediated enhancement of pesudotyped viral particle production was inhibited by Y-39983 HCl. Our findings indicate that our newly developed assay can be used for the discovery of potential antiviral molecules with novel mechanisms of action.

Molecular modelling of coat protein of the Groundnut bud necrosis tospovirus and its binding with Squalene as an antiviral agent: In vitro and in silico docking investigations

Bud blight disease caused by groundnut bud necrosis virus (GBNV) is a serious constraint in the cultivation of agricultural crops such as legumes, tomato, chilies, potato, cotton etc. Owing to the significant damage caused by GBNV, an attempt was made to identify suitable organic antiviral agents through molecular modelling of the nucleocapsid Coat Protein of GBNV; molecular docking and molecular dynamics that disclosed the interaction of the ligands viz., Squalene and Ganoderic acid-A with coat protein of GBNV. Invitro inhibitory effect of Squalene and Ganoderic acid-A was examined in comparison with different concentrations, against GBNV in cowpea plants under glasshouse condition. The different concentrations of Squalene (50, 100, 150, 250 and 500 ppm) tested in vitro resulted in reduction of lesion numbers (1.69 cm2) as well as reduced virus titre in co-inoculation spray. The present study suggests the antiviral activity of Squalene by effectively fitting into binding site of coat protein of GBNV with favourable hydrophilic as well as strong hydrophobic interactions thereby challenging and blocking the binding of viral replication RNA with coat protein and propagation. The present organic antiviral molecules will be helpful in development of suitable eco-friendly formulations to mitigate GBNV infection disease in plants.

Antiviral therapeutics directed against RNA dependent RNA polymerases from positive-sense viruses

Viruses with positive-sense single stranded RNA (+ssRNA) genomes are responsible for different diseases and represent a global health problem. In addition to developing new vaccines that protect against severe illness on infection, it is imperative to identify new antiviral molecules to treat infected patients. The genome of these RNA viruses generally codes for an enzyme with RNA dependent RNA polymerase (RdRP) activity. This molecule is centrally involved in the duplication of the RNA genome. Inhibition of this enzyme by small molecules will prevent duplication of the RNA genome and thus reduce the viral titer. An overview of the different therapeutic strategies used to inhibit RdRPs from +ssRNA viruses is provided, along with an analysis of these enzymes to highlight new binding sites for inhibitors.

Folic acid enhances proinflammatory and antiviral molecular pathways in chicken B-lymphocytes infected with a mild infectious bursal disease virus

ABSTRACT 1. This study evaluated the effect of folic acid (FA) supplementation on the proinflammatory and antiviral molecular pathways of B-lymphocytes infected with a modified live IBDV (ST-12) mild vaccine strain during a timed post-infection analysis. 2. A chicken B-lymphocytes (DT-40) cell line was cultured in triplicate at a concentration of 5 × 105 cells per well in 24-well plates; and was divided into three groups: 1: No virus, FA; 2: Virus, no FA; 3: Virus + FA at a concentration of 3.96 mM. The experiment was repeated three times. 3. Cells in groups 2 and 3 were infected with a modified live IBDV (ST-12) mild vaccine strain at one multiplicity of infection (MOI: 1). After 1 hour of virus adsorption, samples were collected at 0, 3, 6, 12, 24 and 36 hours post-infection (hpi). 4. The modified live IBDV (ST-12) mild vaccine strain triggered a B-lymphocyte specific immune response associated with the upregulation of genes involved in virus recognition (Igß), virus sensing (TLR-2, TLR-3, TLR-4 and MDA5), signal transduction and regulation (TRIF, MyD88 and IRF7), and the antiviral effector molecules (IFN-α, OAS, PKR, and viperin). 5. FA supplementation modulated IBDV replication and regulated the proinflammatory and antiviral downstream molecular pathways. 6. In conclusion, the low virulent pathotype serotype I modified live IBDV (ST-12) mild vaccine strain was able to trigger and mount an immune response in chicken B-lymphocytes without affecting B-cell viability. FA supplementation modulated B lymphocytes response and improved their innate immune proinflammatory and antiviral response molecular pathways.

Bioactive molecules from plants: a prospective approach to combat SARS-CoV-2

The emergence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) or 2019 Novel Coronavirus (2019-nCoV) has put the entire globe into unrest, primarily due to unavailability of specific drug against the viral proteins. In the last two decades the world has withstood many contagious disease crashes. SARS-CoV-2 has put the world and the mankind in danger. It is spreading unstoppably all over the world. The virus is evolving and thus the pathogenicity of SARS-CoV-2 strains has been different and making it difficult to develop a broad-spectrum anti-viral molecule that would be effective against all the SARS-CoV-2 variants. This imperative situation demands development of molecules for effective treatment against SARS-CoV-2. The phytomolecules or the bioactive molecules of plants could be a great alternative to combat SARS-CoV-2. The bioactive molecules with their antiviral properties and the secondary metabolites may effectively deactivate the functioning of viral proteins. The structural configuration of 2019-nCoV proteins and genomic information are available, thus contributing immensely for fast molecular docking studies and hence, enables screening of numerous accessible phytomolecules. In the current study, we have essentially highlighted common phytomolecules against the known viral proteins and described the mode of action of few plant-derived molecules which have the potential to suppress the activity of the viral proteins.Graphic abstract

In Silico Analysis of Drug Repurposing Strategy for the Identification of Potential NS3 Helicase Inhibitors Against Zika Virus

Background: Ancestral recapitulation of the Zika virus from Uganda, Africa, an epidemic in American territories since 2015, was reported by CDC, 2016. To date, there is no specific vaccine or drug for the Zika virus. Objective: The study aims to identify the potential inhibitors that have the capability to be effective against Zika virus. Natural and FDA-approved anti-viral drug molecules are utilized through the drug repurposing approach to screen the lead compounds. Method: Molecular docking approach was utilized to screen the best hit compounds. The identified compounds were further evaluated through binding free energy calculations and physiochemical properties. Density functional theory calculations were calculated for the best hit compounds to observe the structural properties and electrophilic/nucleophilic attack at the quantum level. Furthermore, molecular dynamic simulation studies provide insight into structural stability and conformational analysis of the protein and ligand molecules. Result: Non-covalent interactions observed between the molecules are Gly199, Lys200, Thr201, Arg202, Asn417, Glu231, Glu286, and Arg459. Telaprevir, a Hepatitis C virus (NS3/4 protease) inhibitor, and Curcuma Longa, a natural drug, are found to be more potent druggable candidates among the screened leads for the Zika virus. Conclusion: The results of the study suggest Telaprevir and Curcuma Longa to be considered as the lead agents for experimental studies on Zika virus. The outcome of the study may provide much knowledge in designing anti-zika drugs in the future.

LC-ESI-QTOF-MS/MS Analysis, Cytotoxic, Antiviral, Antioxidant, and Enzyme Inhibitory Properties of Four Extracts of Geranium pyrenaicum Burm. f.: A Good Gift from the Natural Treasure.

This study focused on the biological evaluation and chemical characterization of Geranium pyrenaicum Burm. f. Different solvent extracts (hexane, ethyl acetate, methanol, and water extracts) were prepared. The phytochemical profile, antioxidant, and enzyme inhibitory activity were investigated. Cytotoxicity was assessed using VERO, FaDu, HeLa and RKO cells. The antiviral activity was carried out against HSV-1 (Herpes simplex virus 1) propagated in VERO cell line. The aqueous extract, possessing high phenolic content (170.50 mg gallic acid equivalent/g extract), showed the highest reducing capacity (613.27 and 364.10 mg Trolox equivalent/g extract, for cupric reducing antioxidant capacity and ferric reducing antioxidant power, respectively), radical scavenging potential (469.82 mg Trolox equivalent/g extract, against 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), metal chelating ability (52.39 mg ethylenediaminetetraacetic acid equivalent/g extract) and total antioxidant capacity (3.15 mmol Trolox equivalent/g extract). Liquid chromatography-electrospray ionization-quadrupole time-of-flight-mass spectrometry (LC-ESI-QTOF-MS/MS) alloved to tentatively identify a total of 56 compounds in the extracts, including ellagitannins, gallic acid and galloyl derivatives amongst others. The ethyl acetate extracts substantially depressed cholinesterase enzymes (4.49 and 12.26 mg galantamine equivalent/g extract against AChE and BChE, respectively) and α-amylase enzyme (1.04 mmol acarbose equivalent/g extract). On the other hand, the methanolic extract inhibited tyrosinase (121.42 mg kojic acid equivalent/g extract) and α-glucosidase (2.39 mmol acarbose equivalent/g extract) activities. The highest selectivity towards all cancer cell lines (SI 4.5–10.8) was observed with aqueous extract with the FaDu cells being the most sensitive (CC50 40.22 µg/mL). It can be concluded that the presence of certain bioactive antiviral molecules may be related to the high anti HSV-1 activity of the methanolic extract. This work has generated vital scientific data on this medicinal plant, which is a prospective candidate for the creation of innovative phyto-pharmaceuticals.

Antiviral peptides against the main protease of SARS-CoV-2: A molecular docking and dynamics study.

The recent coronavirus outbreak has changed the world’s economy and health sectors due to the high mortality and transmission rates. Because the development of new effective vaccines or treatments against the virus can take time, an urgent need exists for the rapid development and design of new drug candidates to combat this pathogen. Here, we obtained antiviral peptides obtained from the data repository of antimicrobial peptides (DRAMP) and screened their predicted tertiary structures for the ability to inhibit the main protease of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using multiple combinatorial docking programs, including PatchDock, FireDock, and ClusPro. The four best peptides, DRAMP00877, DRAMP02333, DRAMP02669, and DRAMP03804, had binding energies of −1125.3, −1084.5, −1005.2, and −924.2 Kcal/mol, respectively, as determined using ClusPro, and binding energies of −55.37, −50.96, −49.25, −54.81 Kcal/mol, respectively, as determined using FireDock, which were better binding energy values than observed for other peptide molecules. These peptides were found to bind with the active cavity of the SARS-CoV-2 main protease; at Glu166, Cys145, Asn142, Phe140, and Met165, in addition to the substrate-binding sites, Domain 2 and Domain 3, whereas fewer interactions were observed with Domain 1. The docking studies were further confirmed by a molecular dynamics simulation study, in which several descriptors, including the root-mean-square difference (RMSD), root-mean-square fluctuation (RMSF), solvent-accessible surface area (SASA), radius of gyration (Rg), and hydrogen bond formation, confirmed the stable nature of the peptide–main protease complexes. Toxicity and allergenicity studies confirmed the non-allergenic nature of the peptides. This present study suggests that these identified antiviral peptide molecules might inhibit the main protease of SARS-CoV-2, although further wet-lab experiments remain necessary to verify these findings.

The Antiviral Molecule 5-Pyridoxolactone Identified Post BmNPV Infection of the Silkworm, Bombyx mori

Bombyx mori nucleopolyhedrovirus (BmNPV) is a pathogen that causes great economic losses in sericulture. Many genes play a role in viral infection of silkworms, but silkworm metabolism in response to BmNPV infection is unknown. We studied BmE cells infected with BmNPV. We performed liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS)-based non-targeted metabolomics analysis of the cytosolic extract and identified 36, 76, 138, 101, 189, and 166 different molecules at 3, 6, 12, 24, 48, and 72 h post BmNPV infection (hpi) compared with 0 hpi. Compounds representing different areas of metabolism were increased in cells post BmNPV infection. These areas included purine metabolism, aminoacyl−tRNA biosynthesis, and ABC transporters. Glycerophosphocholine (GPC), 2-hydroxyadenine (2-OH-Ade), gamma-glutamylcysteine (γ-Glu-Cys), hydroxytolbutamide, and 5-pyridoxolactone glycerophosphocholine were continuously upregulated in BmE cells post BmNPV infection by heat map analysis. Only 5-pyridoxolactone was found to strongly inhibit the proliferation of BmNPV when it was used to treat BmE cells. Fewer infected cells were detected and the level of BmNPV DNA decreased with increasing 5-pyridoxolactone in a dose-dependent manner. The expression of BmNPV genes ie1, helicase, GP64, and VP39 in BmE cells treated with 5-pyridoxolactone were strongly inhibited in the BmNPV infection stage. This suggested that 5-pyridoxolactone may suppress the entry of BmNPV. The data in this study characterize the metabolism changes in BmNPV-infected cells. Further analysis of 5-pyridoxolactone, which is a robust antiviral molecule, may increase our understanding of antiviral immunity.

Therapeutic potential of phytoconstituents of edible fruits in combating emerging viral infections.

Plant‐derived bioactive molecules display potential antiviral activity against various viral targets including mode of viral entry and its replication in host cells. Considering the challenges and search for antiviral agents, this review provides substantiated data on chemical constituents of edible fruits with promising antiviral activity. The bioactive constituents like naringenin, mangiferin, α‐mangostin, geraniin, punicalagin, and lectins of edible fruits exhibit antiviral effect by inhibiting viral replication against IFV, DENV, polio, CHIKV, Zika, HIV, HSV, HBV, HCV, and SARS‐CoV. The significance of edible fruit phytochemicals to block the virulence of various deadly viruses through their inhibitory action against the entry and replication of viral genetic makeup and proteins are discussed. In view of the antiviral property of active constituents of edible fruits which can strengthen the immune system and reduce oxidative stress, they are suggested to be diet supplements to combat various viral diseases including COVID‐19.Practical applicationsConsidering the increasing threat of COVID‐19, it is suggested to examine the therapeutic efficacy of existing antiviral molecules of edible fruits which may provide prophylactic and adjuvant therapy with their potential antioxidant, anti‐inflammatory, and immune‐modulatory effects. Several active molecules like geraniin, naringenin, (2R,4R)‐1,2,4‐trihydroxyheptadec‐16‐one, betacyanins, mangiferin, punicalagin, isomangiferin, procyanidin B2, quercetin, marmelide, jacalin lectin, banana lectin, and α‐mangostin isolated from various edible fruits have showed promising antiviral properties against different pathogenic viruses. Especially flavonoid compounds extracted from edible fruits possess potential antiviral activity against a wide array of viruses like HIV‐1, HSV‐1 and 2, HCV, INF, dengue, yellow fever, NSV, and Zika virus infection. Hence taking such fruits or edible fruits and their constituents/compounds as dietary supplements could deliver adequate plasma levels in the body to optimize the cell and tissue levels and could lead to possible benefits for the preventive measures for this pandemic COVID‐19 situation.

Exploring Phytochemicals of Traditional Medicinal Plants Exhibiting Inhibitory Activity Against Main Protease, Spike Glycoprotein, RNA-dependent RNA Polymerase and Non-Structural Proteins of SARS-CoV-2 Through Virtual Screening.

Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) being a causative agent for global pandemic disease nCOVID’19, has acquired much scientific attention for the development of effective vaccines and drugs. Several attempts have been made to explore repurposing existing drugs known for their anti-viral activities, and test the traditional herbal medicines known for their health benefiting and immune-boosting activity against SARS-CoV-2. In this study, efforts were made to examine the potential of 605 phytochemicals from 37 plant species (of which 14 plants were endemic to India) and 139 antiviral molecules (Pubchem and Drug bank) in inhibiting SARS-CoV-2 multiple protein targets through a virtual screening approach. Results of our experiments revealed that SARS-CoV-2 MPro shared significant disimilarities against SARS-CoV MPro and MERS-CoV MPro indicating the need for discovering novel drugs. This study has screened the phytochemical cyanin (Zingiber officinale) which may exhibit broad-spectrum inhibitory activity against main proteases of SARS-CoV-2, SARS-CoV and MERS-CoV with binding energies of (−) 8.3 kcal/mol (−) 8.2 kcal/mol and (−) 7.7 kcal/mol respectively. Amentoflavone, agathisflavone, catechin-7-o-gallate and chlorogenin were shown to exhibit multi-target inhibitory activity. Further, Mangifera indica, Anacardium occidentale, Vitex negundo, Solanum nigrum, Pedalium murex, Terminalia chebula, Azadirachta indica, Cissus quadrangularis, Clerodendrum serratum and Ocimum basilicumaree reported as potential sources of phytochemicals for combating nCOVID’19. More interestingly, this study has highlighted the anti-viral properties of the traditional herbal formulation “Kabasura kudineer” recommended by AYUSH, a unit of Government of India. Short listed phytochemicals could be used as leads for future drug design and development. Genomic analysis of identified herbal plants will help in unraveling molecular complexity of therapeutic and anti-viral properties which proffer lot of chance in the pharmaceutical field for researchers to scout new drugs in drug discovery.

SARS-CoV-2 Infection Remodels the Phenotype and Promotes Angiogenesis of Primary Human Lung Endothelial Cells.

SARS-CoV-2-associated acute respiratory distress syndrome (ARDS) and acute lung injury are life-threatening manifestations of severe viral infection. The pathogenic mechanisms that lead to respiratory complications, such as endothelialitis, intussusceptive angiogenesis, and vascular leakage remain unclear. In this study, by using an immunofluorescence assay and in situ RNA-hybridization, we demonstrate the capability of SARS-CoV-2 to infect human primary lung microvascular endothelial cells (HL-mECs) in the absence of cytopathic effects and release of infectious particles. Preliminary data point to the role of integrins in SARS-CoV-2 entry into HL-mECs in the absence of detectable ACE2 expression. Following infection, HL-mECs were found to release a plethora of pro-inflammatory and pro-angiogenic molecules, as assessed by microarray analyses. This conditioned microenvironment stimulated HL-mECs to acquire an angiogenic phenotype. Proteome analysis confirmed a remodeling of SARS-CoV-2-infected HL-mECs to inflammatory and angiogenic responses and highlighted the expression of antiviral molecules as annexin A6 and MX1. These results support the hypothesis of a direct role of SARS-CoV-2-infected HL-mECs in sustaining vascular dysfunction during the early phases of infection. The construction of virus-host interactomes will be instrumental to identify potential therapeutic targets for COVID-19 aimed to inhibit HL-mEC-sustained inflammation and angiogenesis upon SARS-CoV-2 infection.

In silico screening of phytopolyphenolics for the identification of bioactive compounds as novel protease inhibitors effective against SARS-CoV-2

Due to the unavailability specific drugs or vaccines (FDA approved) that can cure COVID-19, the development of potent antiviral drug candidates/therapeutic molecules against COVID-19 is urgently required. This study was aimed at in silico screening and study of polyphenolic phytochemical compounds in a rational way by virtual screening, molecular docking and molecular dynamics studies against SARS-CoV-2 main protease (Mpro) and papain-like protease (PLpro) enzymes. The objective of the study was to identify plant-derived polyphenolic compounds and/or flavonoid molecules as possible antiviral agents with protease inhibitory potential against SARS-CoV-2. In this study, we report plant-derived polyphenolic compounds (including flavonoids) as novel protease inhibitors against SARS-CoV-2. From virtual docking and molecular docking study, 31 polyphenolic compounds were identified as active antiviral molecules possessing well-defined binding affinity with acceptable ADMET, toxicity and lead-like or drug-like properties. Six polyphenolic compounds, namely, enterodiol, taxifolin, eriodictyol, leucopelargonidin, morin and myricetin were found to exhibit remarkable binding affinities against the proteases with taxifolin and morin exhibiting the highest binding affinity toward Mpro and PLpro respectively. Molecular dynamics simulation studies of these compounds in complex with the proteases showed that the binding of the compounds is characterized by structural perturbations of the proteases suggesting their antiviral activities. These compounds can therefore be investigated further by in vivo and in vitro techniques to assess their potential efficacy against SARS-CoV-2 and thus serve as the starting point for the development of potent antiviral agents against the deadly COVID-19. Communicated by Ramaswamy H. Sarma

Chemical Synthesis of the Antiviral Nucleotide Analogue ddhCTP.

3'-Deoxy-3',4'-didehydro-cytidine triphosphate (ddhCTP) is a novel antiviral molecule produced by the enzyme viperin as part of the innate immune response. ddhCTP has been shown to act as an obligate chain terminator of flavivirus and SARS-CoV-2 RNA-dependent RNA polymerases; however, further biophysical studies have been precluded by limited access to this promising antiviral. Herein, we report a robust and scalable synthesis of ddhCTP as well as the mono- and diphosphates ddhCMP and ddhCDP, respectively. Identification of a 2'-silyl ether protection strategy enabled selective synthesis and facile purification of the 5'-triphosphate, culminating in the preparation of ddhCTP on a gram scale.