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Dengue virus (DENV) infection poses a global health threat, leading to severe conditions with the potential for critical outcomes. Currently, there are no specific drugs available whereas the vaccine does not offer comprehensive protection across all DENV serotypes. Therefore, the development of potential antiviral agents is necessary to reduce the severity risk and interrupt the transmission circuit. The search for effective antiviral agents against DENV has predominantly focused on natural resources, particularly those demonstrating diverse biological activities and high safety profiles. Cyanobacteria and algae including Leptolyngbya sp., Spirulina sp., Chlorella sp., and Sargassum spp., which are prevalent species in Thailand, have been reported for their diverse biological activities and high safety profiles. However, their anti-DENV activity has not been documented. In this study, the screening assay was performed to compare the antiviral activity against DENV of crude polysaccharide and ethanolic extracts derived from 4 species of cyanobacteria and algae in Vero cells. Polysaccharide extracts from Sargassum spp. were the most effective in inhibiting DENV-2 infection under co-infection conditions, where the virus was exposed to the extract at the time of infection. Treatment of the extract significantly reduced the ability of DENV to bind to the host cells to 47.87 ± 3.88 % while treatment upon virus binding step had no antiviral effect suggesting the underlaying mechanism of the extract on interfering virus binding step. Fucoidan, a key bioactive substance in Sargassum polysaccharide, showed to reduce DENV-2 infection to 26.59 ± 5.01 %, 20.46 ± 6.58 % under the co-infection condition in Vero and A549 cells, respectively. In accompanied with Sargassum polysaccharide, fucoidan disturbed the virus binding to the host cells. These findings warrant further development and exploration of the Sargassum-derived polysaccharide, fucoidan, as a promising candidate for combating DENV infections., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Dengue, caused by dengue virus (DENV), is now endemic in nearly 100 countries and infection incidence is reported in another 30 countries. Yearly an estimated 400 million cases and 2200 deaths are reported. Effective vaccines against DENV are limited and there has been significant focus on the development of effective antiviral against the disease. The World Health Organization has initiated research programs to prioritize the development and optimization of antiviral agents against several viruses including Flaviviridae. A significant effort has been taken by the researchers to develop effective antivirals against DENV. Several potential small-molecule inhibitors like efavirenz, tipranavir and dasabuvir have been tested against envelope and non-structural proteins of DENV, and are in clinical trials around the world. We recently developed one small molecule, namely 7D, targeting the host PF4-CXCR3 axis. 7D inhibited all 4 serotypes of DENV in vitro and specifically DENV2 infection in two different mice models. Although the development of dengue vaccines remains a high priority, antibody cross reactivity among the serotypes and resulting antibody-dependent enhancement (ADE) of infection are major concerns that have limited the development of effective vaccine against DENV. Therefore, there has been a significant emphasis on the development of antiviral drugs against dengue. This review article describes the rescue effects of some of the small molecule inhibitors to viral/host factors associated with DENV pathogenesis., (© 2024 The Author(s).)

Traditional medicine offers a wide range of application for in silico study techniques. This drug research and development strategy is embryonic in the West African context, particularly in Burkina Faso, which is increasingly faced with emerging diseases such as dengue fever. Circulation of the 4 serotypes of this virus has been documented in the country. This study aims to evaluate the therapeutic potential of phytocompounds contained in the West African pharmacopoeia against dengue virus NS2B/NS3 protein, using computational methods integrating several software packages and databases. Based on a literature review, we identified 191 molecules from 30 plants known for their antiviral effects. Five met the inclusion criteria for molecular docking: patulin from calotropis procera, resiniferonol from Euphorbia poissonii, Securinol A from Flueggea virosa, Shikimic acid and Methyl gallate from Terminalia macroptera. The best binding scores were observed between resiniferonol and the serotypes 1, 2 and 4 NS2B/NS3 protease, with binding energies of -7.4 Kcal/mol, -6.8 Kcal/mol and -7.3 Kcal/mol respectively; while the NS2B/NS3 protease of serotype 3 had the best affinity for securinol A (-7 Kcal/mol). This study points the way to further research in computer aided drug design field and calls for multidisciplinary collaboration to promote West African medicinal plants against health challenges.

Zika virus (ZIKV) is a re-emerging mosquito-borne flavivirus that has been associated with congenital neurological defects in fetuses born to infected mothers. At present, no vaccine or antiviral therapy is available to combat this devastating disease. Repurposing drugs that target essential host factors exploited by viruses is an attractive therapeutic approach. Here, we screened a panel of clinically approved small-molecule kinase inhibitors for their antiviral effects against a clinical isolate of ZIKV and thoroughly characterized their mechanisms of action. We found that the Raf kinase inhibitors Dabrafenib and Regorafenib potently impair the replication of ZIKV, but not that of its close relative dengue virus. Time-of-addition experiments showed that both inhibitors target ZIKV infection at post-entry steps. We found that Dabrafenib, but not Regorafenib, interfered with ZIKV genome replication by impairing both negative- and positive-strand RNA synthesis. Regorafenib, on the other hand, altered steady-state viral protein levels, viral egress, and blocked NS1 secretion. We also observed Regorafenib-induced ER fragmentation in ZIKV-infected cells, which might contribute to its antiviral effects. Because these inhibitors target different steps of the ZIKV infection cycle, their use in combination therapy may amplify their antiviral effects which could be further explored for future therapeutic strategies against ZIKV and possibly other flaviviruses., Importance: There is an urgent need to develop effective therapeutics against re-emerging arboviruses associated with neurological disorders like Zika virus (ZIKV). We identified two FDA-approved kinase inhibitors, Dabrafenib and Regorafenib, as potent inhibitors of contemporary ZIKV strains at distinct stages of infection despite overlapping host targets. Both inhibitors reduced viral titers by ~1 to 2 log 10 (~10-fold to 100-fold) with minimal cytotoxicity. Furthermore, we show that Dabrafenib inhibits ZIKV RNA replication whereas Regorafenib inhibits ZIKV translation and egress. Regorafenib has the added benefit of limiting NS1 secretion, which contributes to the pathogenesis and disease progression of several flaviviruses. Because these inhibitors affect distinct post-entry steps of ZIKV infection, their therapeutic potential may be amplified by combination therapy and likely does not require prophylactic administration. This study provides further insight into ZIKV-host interactions and has implications for the development of novel antivirals against ZIKV and possibly other flaviviruses., Competing Interests: The authors declare no conflicts of interest.

Dengue, caused by the dengue virus (DENV), is a global health threat transmitted by Aedes mosquitoes, resulting in 400 million cases annually. The disease ranges from mild to severe, with potential progression to hemorrhagic dengue. Current research is focused on natural antivirals due to challenges in vector control. This study evaluates the antiviral potential of peptides derived from the microalgae Phaeodactylum tricornutum , known for its bioactive compounds. Microalgae were cultivated under controlled conditions, followed by protein extraction and hydrolysis to produce four peptide fractions. These fractions were assessed for cytotoxicity via the MTT assay and antiviral activity against DENV serotype 2 using flow cytometry and plaque formation assays. The 10-30 kDa peptide fraction, at 150 and 300 μg/mL concentrations, demonstrated no cytotoxicity and significantly reduced the percentage of infected cells and viral titers. These findings suggest that peptides derived from Phaeodactylum tricornutum exhibit promising antiviral activity against dengue virus serotype 2, potentially contributing to developing new therapeutic approaches for dengue.

Ethnopharmacological Relevance: Dengue is one of the most prevalent mosquito-borne viral infections. Moreover, due to the absence of appropriate curative and preventive measures against it, the mortality rate is increasing alarmingly. However, remarkable docking and clinical advances have been achieved with plant-based natural and conventional therapeutics. Tinospora cordifolia is one of the highly explored panaceas at the local level for its effective anti-dengue formulations., Aim of the Study: The present article aims for critical assessment of the data available on the anti-dengue therapeutic use of T. cordifolia. Efforts have also been made on the clinical and in-silico anti-dengue efficacy of this plant. The phytochemistry and the antiviral machinery of the plant are also emphasized., Materials and Methods: The present article is the outcome of the literature survey on the anti-dengue effect of T. cordifolia. A literature survey was conducted from 2011 to 2024 using different databases with appropriate keywords., Results: The present study confirms the anti-dengue potential of T. cordifolia. The plant can suppress the initiation of 'cytokine storm', vascular leakage and inhibition of various structural and NS proteins to exert its anti-dengue potential. Berberine and magnoflorine phytocompounds were highly explored for their anti-dengue potential., Conclusions: The present study concluded that T. cordifolia serves as an effective therapeutic agent for treating dengue. Further in-silico and clinical studies are needed so that stable, safe and efficacious anti-dengue drug can be developed. Besides, a precise antiviral mechanism of T. cordifolia against DENV infection is still needed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Macrocyclization of acyclic compounds is a powerful strategy for improving inhibitor potency and selectivity. Here we have optimized 2-aminopyrimidine-based macrocycles to use these compounds as chemical tools for the ephrin kinase family. Starting with a promiscuous macrocyclic inhibitor, 6 , we performed a structure-guided activity relationship and selectivity study using a panel of over 100 kinases. The crystal structure of EPHA2 in complex with the developed macrocycle 23 provided a basis for further optimization by specifically targeting the back pocket, resulting in compound 55 , a potent inhibitor of EPHA2/A4 and GAK. Subsequent front-pocket derivatization resulted in an interesting in cellulo selectivity profile, favoring EPHA4 over the other ephrin receptor kinase family members. The dual EPHA2/A4 and GAK inhibitor 55 prevented dengue virus infection of Huh7 liver cells. However, further investigations are needed to determine whether this was a compound-specific effect or target-related.

Infections with Flaviviridae viruses, such as hepatitis C (HCV), dengue (DENV), and yellow fever (YFV) viruses, are major public health problems worldwide. In the case of HCV, treatment is associated with drug resistance and high costs, while there is no clinically approved therapy for DENV and YFV. Consequently, there is still a need for new chemotherapies with alternative modes of action. We have previously identified novel 2-hydroxypyrazino[1,2- a ]indole-1,3(2 H ,4 H )-diones as metal-chelating inhibitors targeting HCV RNA replication. Here, by utilizing a structure-based approach, we rationally designed a second series of compounds by introducing various substituents at the indole core structure and at the imidic nitrogen, to improve specificity against the RNA-dependent RNA polymerase (RdRp). The resulting derivatives were evaluated for their potency against HCV genotype 1b, DENV2, and YFV-17D using stable replicon cell lines. The most favorable substitution was nitro at position 6 of the indole ring (compound 36 ), conferring EC 50 1.6 μM against HCV 1b and 2.57 μΜ against HCV 1a, with a high selectivity index. Compound 52 , carrying the acetohydroxamic acid functionality (-CH 2 CONHOH) on the imidic nitrogen, and compound 78 , the methyl-substituted molecule at the position 4 indolediketopiperazine counterpart, were the most effective against DENV and YFV, respectively. Interestingly, compound 36 had a high genetic barrier to resistance and only one resistance mutation was detected, T181I in NS5B, suggesting that the compound target HCV RdRp is in accordance with our predicted model.

The increasing emergence and re-emergence of RNA virus outbreaks underlines the urgent need to develop effective antivirals. RNA interference (RNAi) is a sequence-specific gene silencing mechanism that is triggered by small interfering RNAs (siRNAs) or short hairpin RNAs (shRNAs), which exhibits significant promise for antiviral therapy. AGO2-dependent shRNA (agshRNA) generates a single-stranded guide RNA and presents significant advantages over traditional siRNA and shRNA. In this study, we applied a logistic regression algorithm to a previously published chemically siRNA efficacy dataset and built a machine learning-based model with high predictive power. Using this model, we designed siRNA sequences targeting diverse RNA viruses, including human enterovirus A71 (EV71), Zika virus (ZIKV), dengue virus 2 (DENV2), mouse hepatitis virus (MHV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and transformed them into agshRNAs. We validated the performance of our agshRNA design by evaluating antiviral efficacies of agshRNAs in cells infected with different viruses. Using the agshRNA targeting EV71 as an example, we showed that the anti-EV71 effect of agshRNA was more potent compared with the corresponding siRNA and shRNA. Moreover, the antiviral effect of agshRNA is dependent on AGO2-processed guide RNA, which can load into the RNA-induced silencing complex (RISC). We also confirmed the antiviral effect of agshRNA in vivo. Together, this work develops a novel antiviral strategy that combines machine learning-based algorithm with agshRNA design to custom design antiviral agshRNAs with high efficiency., Competing Interests: Conflict of interest Professor Xi Zhou is an editorial board member for Virologica Sinica and were not involved in the editorial review or the decision to publish this article. The authors declare that they have no conflict of interest., (Copyright © 2024 The Authors. Publishing services by Elsevier B.V. All rights reserved.)

The quest to identify antiviral drug candidates for dengue and rabies viral diseases is a great challenge for the researchers. While different research is being conducted on the repurposed drugs against these two viruses, no drug compound has gained success in treating them. Therefore, in this study, 3, 4-dihydroxy complexes have been virtually designed to investigate their antiviral properties and analyze their efficiency in interaction with the concerned viral diseases. DFT calculations are carried out to study the electronic and thermodynamic properties to understand the stability and reactivity of the reported compounds. These compounds were subjected to molecular docking studies to understand the binding interactions with NS5 Dengue virus mRNA 2'-O-methyltransferase and phosphoprotein C-terminal domain of Rabies virus. MD simulation, hydrogen bond analysis, and MM/PBSA were performed at 100 ns to support the obtained docking results.Communicated by Ramaswamy H. Sarma.

DENV-2 strain is the most fatal and infectious of the five dengue virus serotypes. The non-structural protein NS1 encoded by its genome is the most significant protein required for viral pathogenesis and replication inside the host body. Thus, targeting the NS1 protein and designing an inhibitor to limit its stability and secretion is a propitious attempt in our fight against dengue. Four novel inhibitors are designed to target the conserved cysteine residues (C55, C313, C316, and C329) and glycosylation sites (N130 and N207) of the NS1 protein in an attempt to halt the spread of the dengue infection in the host body altogether. Numerous computer-aided drug designing techniques including molecular docking, molecular dynamics simulation, virtual screening, principal component analysis, and dynamic cross-correlation matrix were employed to determine the structural and functional activity of the NS1-inhibitor complexes. From our analysis, it was evident that the extent of structural and atomic level fluctuations of the ligand-bound protein exhibited a declining trend in contrast to unbound protein which was prominently noticeable through the RMSD, RMSF, R g , and SASA graphs. The ADMET analysis of the four ligands revealed a promising pharmacokinetics and pharmacodynamic profile, along with good bioavailability and toxicity properties. The proposed drugs when bound to the targeted cavities resulted in stable conformations in comparison to their unbound state, implying they have good affinity promising effective drug action. Thus, they can be tested in vitro and used as potential anti-dengue drugs.Communicated by Ramaswamy H. Sarma.

Dengue is a major global health threat, and there are no approved antiviral agents. Prior research using Cas13 only demonstrated dengue mitigation in vitro. Here we demonstrate that systemic delivery of mRNA-encoded Cas13a and guide RNAs formulated in lipid nanoparticles can be used to treat dengue virus (DENV) 2 and 3 in mice. First, we identified guides against DENV 2 and 3 that demonstrated in vitro efficacy. Next, we confirmed that Cas13 enzymatic activity is necessary for DENV 2 or DENV 3 mitigation in vitro. Last, we show that a single dose of lipid-nanoparticle-formulated mRNA-encoded Cas13a and guide RNA, administered 1 day post-infection, promotes survival of all infected animals and serum viral titre decreases on days 2 and 3 post-infection after lethal challenge in mice. Off-target analysis in mice using RNA sequencing showed no collateral cleavage. Overall, these data demonstrate the potential of mRNA-encoded Cas13 as a pan-DENV drug., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Viruses have developed sophisticated strategies to control metabolic activity of infected cells in order to supply replication machinery with energy and metabolites. Dengue virus (DENV), a mosquito-borne flavivirus responsible for dengue fever, is no exception. Previous reports have documented DENV interactions with metabolic pathways and shown in particular that glycolysis is increased in DENV-infected cells. However, underlying molecular mechanisms are still poorly characterized and dependence of DENV on this pathway has not been investigated in details yet. Here, we identified an interaction between the non-structural protein 3 (NS3) of DENV and glucokinase regulator protein (GCKR), a host protein that inhibits the liver-specific hexokinase GCK. NS3 expression was found to increase glucose consumption and lactate secretion in hepatic cell line expressing GCK. Interestingly, we observed that GCKR interaction with GCK decreases DENV replication, indicating the dependence of DENV to GCK activity and supporting the role of NS3 as an inhibitor of GCKR function. Accordingly, in the same cells, DENV replication both induces and depends on glycolysis. By targeting NAD(H) biosynthesis with the antimetabolite 6-Amino-Nicotinamide (6-AN), we decreased cellular glycolytic activity and inhibited DENV replication in hepatic cells. Infection of primary organotypic liver cultures (OLiC) from hamsters was also inhibited by 6-AN. Altogether, our results show that DENV has evolved strategies to control glycolysis in the liver, which could account for hepatic dysfunctions associated to infection. Besides, our findings suggest that lowering intracellular availability of NAD(H) could be a valuable therapeutic strategy to control glycolysis and inhibit DENV replication in the liver., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Tanreqing injection (TRQ) has been employed in clinical practice as a treatment for dengue fever (DF). Nevertheless, the precise pharmacological mechanism underlying its efficacy remains elusive., Method: Network pharmacology, molecular docking, transcriptome sequencing, and experimental evaluation were employed to analyze and study the inhibitory potential of TRQ against dengue virus (DENV)., Result: We found that TRQ inhibited the replication of DENV in human umbilical vein endothelial cells, Huh-7 cells, and Hep3B cells. In addition, TRQ prolonged the survival duration of AG129 mice infected with DF, decreased the viral load in serum and organs, and alleviated organ damage. Subsequently, ultra-high-performance liquid chromatography-tandem mass spectrometry analysis of TRQ was performed to identify 314 targets associated with 36 active compounds present in TRQ. Integration of multiple databases yielded 47 DF-related genes. Then, 15 hub targets of TRQ in DF were determined by calculating the network topology parameters (Degree). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses revealed that these pathways were primarily enriched in the processes of cytokine activation and leukocyte cross-endothelial migration, with significant enrichment of cell adhesion molecules. Molecular docking revealed favorable binding affinity between TRQ's key active compounds and the predicted hub targets. Transcriptome sequencing results showed TRQ's ability to restore the expression of vascular cell adhesion molecule-1 (VCAM-1) post-DENV infection. Finally, TRQ was found to modulate the immune status by regulating the nuclear factor kappa-B (NF-κB)- intercellular cell adhesion molecule-1 (ICAM-1)/VCAM-1 axis, as well as reduce immune cell alterations, inflammatory factor secretion, vascular permeability, and bleeding tendencies induced by DENV infection., Conclusion: Our research suggests that TRQ exerts therapeutic effects on DF by regulating the NF-κB-ICAM-1/VCAM-1 axis., Competing Interests: Declaration of competing interest The authors declared no conflict of interest., (Copyright © 2024. Published by Elsevier GmbH.)

Objective: To investigate the effect of type 2 dengue virus (DENV-2) infection on autophagy in human umbilical vein endothelial cells (HUVECs) and the mechanism mediating the inhibitory effect of baicalin against DENV-2 infection., Methods: Cultured HUVECs with DENV-2 infection were treated with different concentrations of baicalin, and the changes in autophagy of the cells were detected using transmission electron microscopy. Lyso Tracker Red staining was used to examine pH changes in the lysosomes of the cells, and the expressions of ATG5, beclin-1, LC3, P62, STX17, SNAP29, VAMP8, and PI3K/AKT signaling pathway-related proteins were detected by Western blotting. DENV-2 replication in the cells were evaluated using RT-qPCR. The differentially expressed proteins in DENV-2-infected HUVECs were identified by proteomics screening., Results: Treatment with baicalin did not significantly affect the viability of cultured HUVECs. Proteomic studies suggested that the PI3K-AKT pathway played an important role in mediating cell injury induced by DENV-2 infection. The results of RT-qPCR demonstrated that baicalin dose-dependently inhibited DENV-2 replication in HUVECs and produced the strongest inhibitory effect at the concentration of 50 μg/mL. Transmission electron microscopy, Lyso Tracker Red staining, RT-qPCR, and Western blotting all showed significant inhibitory effect of baicalin on DENV-2-induced autophagy in HUVECs. DENV-2 infection of HUVECs caused increased cellular expressions of LC3 and P62 proteins, which were significantly lowered by treatment with LY294002 (a PI3K inhibitor)., Conclusion: Baicalin inhibits DENV-2 replication in HUVECs and suppresses DENV-2-induced cell autophagy by inhibiting the PI3K/AKT signaling pathway.

Dengue fever represents a significant medical and socio-economic burden in (sub)tropical regions, yet antivirals for treatment or prophylaxis are lacking. JNJ-A07 was described as highly active against the different genotypes within each serotype of the disease-causing dengue virus (DENV). Based on clustering of resistance mutations it has been assumed to target DENV non-structural protein 4B (NS4B). Using a photoaffinity labeling compound with high structural similarity to JNJ-A07, here we demonstrate binding to NS4B and its precursor NS4A-2K-NS4B. Consistently, we report recruitment of the compound to intracellular sites enriched for these proteins. We further specify the mechanism-of-action of JNJ-A07, which has virtually no effect on viral polyprotein cleavage, but targets the interaction between the NS2B/NS3 protease/helicase complex and the NS4A-2K-NS4B cleavage intermediate. This interaction is functionally linked to de novo formation of vesicle packets (VPs), the sites of DENV RNA replication. JNJ-A07 blocks VPs biogenesis with little effect on established ones. A similar mechanism-of-action was found for another NS4B inhibitor, NITD-688. In summary, we unravel the antiviral mechanism of these NS4B-targeting molecules and show how DENV employs a short-lived cleavage intermediate to carry out an early step of the viral life cycle., (© 2024. The Author(s).)

Background: Dengue fever has become a significant worldwide health concern, because of its high morbidity rate and the potential for an increase in mortality rates due to lack of adequate treatment. There is an immediate need for the development of effective medication for dengue fever., Methods: Homology modeling of dengue virus (DENV) non-structural 4B (NS4B) protein was performed by SWISS-MODEL to predict the 3D structure of the protein. Structure validation was conducted using PROSA, PROCHECK, Ramachandran plot, and VERIFY-3D. MOE software was used to find out the in-Silico inhibitory potential of the five triterpenoids against the DENV-NS4B protein., Results: The SWISS-MODEL was employed to predict the three-dimensional protein structure of the NS4B protein. Through molecular docking, it was found that the chosen triterpenoid NS4B protein had a high binding affinity interaction. It was observed that the NS4B protein binding energy for 15-oxoursolic acid, betulinic acid, ursolic acid, lupeol, and 3-o-acetylursolic acid were - 7.18, - 7.02, - 5.71, - 6.67 and - 8.00 kcal/mol, respectively., Conclusions: NS4B protein could be a promising target which showed good interaction with tested triterpenoids which can be developed as a potential antiviral drug for controlling dengue virus pathogenesis by inhibiting viral replication. However, further investigations are necessary to validate and confirm their efficacy., (© 2024. The Author(s).)

Zika virus (ZIKV) is one of the mosquito-borne flaviviruses that exhibits a unique tropism to nervous systems and is associated with Guillain-Barre syndrome and congenital Zika syndrome (CZS). Dengue virus (DENV) and yellow fever virus (YFV), the other two mosquito-borne flaviviruses, have also been circulating for a long time and cause severe diseases, such as dengue hemorrhagic fever and yellow fever, respectively. However, there are no safe and effective antiviral drugs approved for the treatment of infections or coinfections of these flaviviruses. Here, we found that zafirlukast, a pregnancy-safe leukotriene receptor antagonist, exhibited potent antiviral activity against infections of ZIKV strains from different lineages in different cell lines, as well as against infections of DENV-2 and YFV 17D. Mechanistic studies demonstrated that zafirlukast directly and irreversibly inactivated these flaviviruses by disrupting the integrity of the virions, leading to the loss of viral infectivity, hence inhibiting the entry step of virus infection. Considering its efficacy against flaviviruses, its safety for pregnant women, and its neuroprotective effect, zafirlukast is a promising candidate for prophylaxis and treatment of infections or coinfections of ZIKV, DENV, and YFV, even in pregnant women., Competing Interests: The authors declare no conflict of interest.

RNA-dependent RNA polymerase (RdRp) is considered a potential drug target for dengue virus (DENV) inhibition and has attracted attention in antiviral drug discovery. Here, we screened 121 natural compounds from Litsea cubeba against DENV RdRp using various approaches of computer-based drug discovery. Notably, we identified four potential compounds (Ushinsunine, Cassameridine, (+)-Epiexcelsin, (-)-Phanostenine) with good binding scores and allosteric interactions with the target protein. Moreover, molecular dynamics simulation studies were done to check the conformational stability of the complexes under given conditions. Additionally, we performed post-simulation analysis to find the stability of potential drugs in the target protein. The findings suggest Litsea cubeba -derived phytomolecules as a therapeutic solution to control DENV infection.Communicated by Ramaswamy H. Sarma.

Dengue virus is a mosquito-borne pathogen that causes a variety of illnesses ranging from mild fever to severe and fatal dengue haemorrhagic fever or dengue shock syndrome. One of the major clinical manifestations of severe dengue infection is thrombocytopenia. The dengue non-structural protein 1 (NS1) is the primary protein that stimulates immune cells via toll-like receptor 4 (TLR4), induces platelets, and promotes aggregation, which could result in thrombocytopenia. The leaf extracts of Carica papaya seem to have therapeutic benefits in managing thrombocytopenia associated with dengue. The present study focuses on understanding the underlying mechanism of the use of papaya leaf extracts in treating thrombocytopenia. We have identified 124 phytocompounds that are present in the papaya leaf extract. The pharmacokinetics, molecular docking, binding free energy calculations, and molecular dynamic simulations were performed to investigate the drug-like properties, binding affinities, and interaction of phytocompounds with NS1 protein as well as the interactions of NS1 with TLR4. Three phytocompounds were found to bind with the ASN130, a crucial amino acid residue in the active site of the NS1 protein. Thus, we conclude that Rutin, Myricetin 3-rhamnoside, or Kaempferol 3-(2''-rhamnosylrutinoside) may serve as promising molecules by ameliorating thrombocytopenia in dengue-infected patients by interfering the interaction of NS1 with TLR4. These molecules can serve as drugs in the management of dengue-associated thrombocytopenia after verifying their effectiveness and assessing the drug potency, through additional in-vitro assays.Communicated by Ramaswamy H. Sarma.

Arboviruses such as chikungunya virus (CHIKV) and dengue virus (DENV) collectively afflict millions of individuals worldwide particularly in endemic countries like India, leading to substantial morbidity and mortality. With the lack of effective vaccines for both CHIKV and DENV in India, the search for antiviral compounds becomes paramount to control these viral infections. In line with this, our investigation was focused on screening natural compounds for their potential antiviral activity against CHIKV and DENV. Using different assays, including plaque assay, immunofluorescence, and reverse transcription-quantitative real-time PCR (qRT-PCR), out of 109 natural compounds tested, we confirmed lycorine's in vitro antiviral activity against CHIKV and DENV at low micromolar concentrations in different cell types. Time of addition assays indicated that lycorine does not impede viral entry. Additionally, qRT-PCR results along with time of addition assay suggested that lycorine interferes with the synthesis of negative strand viral RNA. Molecular docking analysis was done to understand the mode of inhibition of viral replication. The results revealed that the most likely binding site with the highest binding affinity of lycorine, was at the palm and finger domains, in the vicinity of the catalytic site of CHIKV and DENV RNA-dependent RNA polymerase (RdRp). Collectively, our data underscores the potential of lycorine to be developed as a direct acting inhibitor for DENV and CHIKV, addressing the critical need of requirement of an antiviral in regions where these viruses pose significant public health threats., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Dengue virus (DENV2) is the cause of dengue disease and a worldwide health problem. DENV2 replicates in the host cell using polyproteins such as NS3 protease in conjugation with NS2B cofactor, making NS3 protease a promising antiviral drug-target. This study investigated the efficacy of 'Niloticin' against NS2B/NS3-protease. In silico and in vitro analyses were performed which included interaction of niloticin with NS2B/NS3-protease, protein stability and flexibility, mutation effect, betweenness centrality of residues and analysis of cytotoxicity, protein expression and WNV NS3-protease activity. Similar like acyclovir, niloticin forms strong H-bonds and hydrophobic interactions with residues LEU149, ASN152, LYS74, GLY148 and ALA164. The stability of the niloticin-NS2B/NS3-protease complex was found to be stable compared to the apo NS2B/NS3-protease in structural deviation, PCA, compactness and FEL analysis. The IC 50 value of niloticin was 0.14 μM in BHK cells based on in vitro cytotoxicity analysis and showed significant activity at 2.5 μM in a concentration-dependent manner. Western blotting and qRT-PCR analyses showed that niloticin reduced DENV2 protein transcription in a dose-dependent manner. Besides, niloticin confirmed the inhibition of NS3-protease by the SensoLyte 440 WNV protease detection kit. These promising results suggest that niloticin could be an effective antiviral drug against DENV2 and other flaviviruses., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest regarding the publication of this article., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Finding an effective therapy against diseases caused by flaviviruses remains a challenge. Here, we present a protocol to test Food and Drug Administration-approved drugs that inhibit host nuclear protein import, promoting a reduction of dengue infection. We describe steps for analyzing the drug effect on nuclear import inhibition of cellular and viral proteins by confocal microscopy or western blotting. We then describe procedures for measuring the antiviral drug effects on virus-infected cells by flow cytometry and testing drug efficacy in dengue-infected AG129 mice by survival assays. For complete details on the use and execution of this protocol, please refer to Palacios-Rápalo et al. 1 ., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Viral genetic diversity presents significant challenges in developing antivirals with broad-spectrum activity and high barriers to resistance. Here we report development of proteolysis targeting chimeras (PROTACs) targeting the dengue virus envelope (E) protein through coupling of known E fusion inhibitors to ligands of the CRL4 CRBN E3 ubiquitin ligase. The resulting small molecules block viral entry through inhibition of E-mediated membrane fusion and interfere with viral particle production by depleting intracellular E in infected Huh 7.5 cells. This activity is retained in the presence of point mutations previously shown to confer partial resistance to the parental inhibitors due to decreased inhibitor-binding. The E PROTACs also exhibit broadened spectrum of activity compared to the parental E inhibitors against a panel of mosquito-borne flaviviruses. These findings encourage further exploration of targeted protein degradation as a differentiated and potentially advantageous modality for development of broad-spectrum direct-acting antivirals., (© 2024. The Author(s).)

Dengue virus (DENV), mainly transmitted by Aedes aegypti mosquitoes, is the most prevalent arbovirus worldwide, representing a public health problem in tropical and subtropical countries. In these areas, antibiotic consumption rises which may impact both mosquito microbiota and dengue transmission. Here, we assessed how the ingestion by Ae. aegypti of therapeutic concentrations of amoxicillin-clavulanic Acid association (Amox/Clav), a broad-spectrum antibiotic used to treat febrile symptoms worldwide, impacted its microbiota. We also evaluated whether simultaneous ingestion of antibiotic and DENV impacted Ae. aegypti ability to transmit this virus. We found that Amox/Clav ingestion impacted microbiota composition in Ae. aegypti and we confirmed such impact in field-collected mosquitoes. Furthermore, we observed that Amox/Clav ingestion enhanced DENV dissemination and transmission by this mosquito at 21 days post-DENV exposure. These findings increase our understanding of factors linked to human hosts that may influence dengue transmission dynamics in regions with mass-drug administration programs., (© 2024. The Author(s).)

Dengue virus (DENV) infection is a public health concern in several countries and is associated with severe diseases, such as dengue hemorrhagic fever and dengue shock syndrome. DENVs are transmitted to humans via the bites of infected Aedes mosquitoes, and no antiviral therapeutics are currently available. In this work, we aimed to identify antiviral drugs against DENV type 2 (DENV2) infections and selected pimecrolimus as a potential antiviral drug candidate. Pimecrolimus significantly inhibited DENV2-mediated cell death and replication in vitro. We also confirmed a decrease in the number of plaques formed as well as in the envelope protein levels of DENV2. The time-of-addition and course experiments revealed that pimecrolimus inhibited DENV2 infection during the early stages of the virus replication cycle. In an experimental mouse model, orally administered pimecrolimus alleviated body weight loss and lethality caused by DENV2 infection, which we used as readouts of the drug's antiviral potency. Furthermore, pimecrolimus significantly inhibited the DENV2 load and ameliorated focal necrosis in the liver and spleen. Taken together, our in vitro and in vivo findings suggest that pimecrolimus is a promising antiviral drug candidate for the treatment of DENV2 infection., (© 2024. The Author(s).)

Dengue virus is a single positive-strand RNA virus that is composed of three structural proteins including capsid, envelope, and precursor membrane while seven non-structural proteins (NS1, NS2A, NS2B, NS3A, NS3B, NS4, and NS5). Dengue is a viral infection caused by the dengue virus (DENV). DENV infections are asymptomatic or produce only mild illness. However, DENV can occasionally cause more severe cases and even death. There is no specific treatment for dengue virus infections. Therapeutic peptides have several important advantages over proteins or antibodies: they are small in size, easy to synthesize, and have the ability to penetrate the cell membranes. They also have high activity, specificity, affinity, and less toxicity. Based on the known peptide inhibitor, the current study designs peptide inhibitors for dengue virus envelope protein using an alanine and residue scanning technique. By replacing I21 with Q21, L14 with H14, and V28 with K28, the binding affinity of the peptide inhibitors was increased. The newly designed peptide inhibitors with single residue mutation improved the binding affinity of the peptide inhibitors. The inhibitory capability of the new promising peptide inhibitors was further confirmed by the utilization of MD simulation and free binding energy calculations. The molecular dynamics simulation demonstrated that the newly engineered peptide inhibitors exhibited greater stability compared to the wild-type peptide inhibitors. According to the binding free energies MM(GB)SA of these developed peptides, the first peptide inhibitor was the most effective against the dengue virus envelope protein. All peptide derivatives had higher binding affinities for the envelope protein and have the potential to treat dengue virus-associated infections. In this study, new peptide inhibitors were developed for the dengue virus envelope protein based on the already reported peptide inhibitor., (© 2024. The Author(s).)

Vector-borne diseases, constituting over 17 % of infectious diseases, are caused by parasites, viruses, and bacteria, and their prevalence is shaped by environmental and social factors. Dengue virus (DENV) and Zika virus (ZIKV), some of the most prevalent infectious agents of this type of diseases, are transmitted by mosquitoes belonging to the genus Aedes. The highest prevalence is observed in tropical regions, inhabited by around 3 billion people. DENV infects millions of people annually and constitutes an additional sanitary challenge due to the circulation of four serotypes, which has complicated vaccine development. ZIKV causes large outbreaks globally and its infection is known to lead to severe neurological diseases, including microcephaly in newborns. Besides, not only mosquito control programs have proved to be not totally effective, but also, no antiviral drugs have been developed so far. The envelope protein (E) is a major component of DENV and ZIKV virion surface. This protein plays a key role during the virus cell entry, constituting an attractive target for the development of antiviral drugs. Our previous studies have identified two pyrimidine analogs (3e and 3h) as inhibitors; however, their activity was found to be hindered by their low water solubility. In this study, we performed a low-throughput antiviral screening, revealing compound 16a as a potent DENV-2 and ZIKV inhibitor (EC 50  = 1.4 μM and 2.4 μM, respectively). This work was aimed at designing molecules with improved selectivity and pharmacokinetic properties, thus advancing the antiviral efficacy of compounds for potential therapeutic use., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Background: The first dengue outbreak in Sao Tome and Principe was reported in 2022. Entomological investigations were undertaken to establish the typology of Aedes larval habitats, the distribution of Ae. aegypti and Ae. albopictus, the related entomological risk and the susceptibility profile of Ae. aegypti to insecticides, to provide evidence to inform the outbreak response., Methodology/principal Findings: Entomological surveys were performed in all seven health districts of Sao Tome and Principe during the dry and rainy seasons in 2022. WHO tube and synergist assays using piperonyl butoxide (PBO) and diethyl maleate (DEM) were carried out, together with genotyping of F1534C/V1016I/V410L mutations in Ae. aegypti. Aedes aegypti and Ae. albopictus were found in all seven health districts of the country with high abundance of Ae. aegypti in the most urbanised district, Agua Grande. Both Aedes species bred mainly in used tyres, discarded tanks and water storage containers. In both survey periods, the Breteau (BI > 50), house (HI > 35%) and container (CI > 20%) indices were higher than the thresholds established by WHO to indicate high potential risk of dengue transmission. The Ae. aegypti sampled were susceptible to all insecticides tested except dichlorodiphenyltrichloroethane (DDT) (9.2% mortality, resistant), bendiocarb (61.4% mortality, resistant) and alpha-cypermethrin (97% mortality, probable resistant). A full recovery was observed in Ae. aegypti resistant to bendiocarb after pre-exposure to synergist PBO. Only one Ae. aegypti specimen was found carrying F1534C mutation., Conclusions/significance: These findings revealed a high potential risk for dengue transmission throughout the year, with the bulk of larval breeding occurring in used tyres, water storage and discarded containers. Most of the insecticides tested remain effective to control Aedes vectors in Sao Tome, except DDT and bendiocarb. These data underline the importance of raising community awareness and implementing routine dengue vector control strategies to prevent further outbreaks in Sao Tome and Principe, and elsewhere in the subregion., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Kamgang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Brucea javanica, a valued traditional medicinal plant in Malaysia, known for its fever-treating properties yet remains underexplored for its potential antiviral properties against dengue. This study aims to simultaneously identify chemical classes and metabolites within B. javanica using molecular networking (MN), by Global Natural Product Social (GNPS), and SIRIUS in silico annotation. Liquid chromatography-mass spectrometry (LC-MS 2) -based MN explores chemical diversity across four plant parts (leaves, roots, fruits, and stem bark), revealing diverse metabolites such as tryptophan-derived alkaloids, terpenoids, and octadecadenoids. Simultaneous LC-MS 2 and MN analyses reveal a discriminative capacity for individual plant components, with roots accumulating tryptophan alkaloids, fruits concentrating quassinoids, leaves containing fusidanes, and stem bark primarily characterised by simple indoles. Subsequently, extracts were evaluated for dengue antiviral activity using adenosine triphosphate (ATP) and plaque assays, indicates potent efficacy in the dichloromethane (DCM) extract from roots (EC 50  = 0.3 μg/mL, SI = 10). Molecular docking analysis of two major compounds; canthin-6-one (264) and 1-hydroxy-11-methoxycanthin-6-one (275) showed potential binding interactions with active sites of NS5 RNA-dependent RNA polymerase (RdRp) of dengue virus (DENV) protein. Subsequent in vitro evaluation revealed compounds 264 and 275 had a promising dengue antiviral activity with SI value of 63 and 1.85. These identified metabolites emerge as potential candidates for further evaluation in dengue antiviral activities., Competing Interests: Declaration of competing interest The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Approximately 3.9 billion individuals are vulnerable to dengue infection, a prevalent cause of tropical diseases worldwide. Currently, no drugs are available for preventing or treating Flavivirus diseases, including Dengue, West Nile, and the more recent Zika virus. The highly conserved Flavivirus NS2B-NS3 protease, crucial for viral replication, is a promising therapeutic target. This study employed in-silico methodologies to identify novel and potentially effective anti-dengue small molecules. A pharmacophore model was constructed using an experimentally validated NS2B-NS3 inhibitor, with the Gunner Henry score confirming the model's validity. The Natural Product Activity and Species Source (NPASS) database was screened using the validated pharmacophore model, yielding a total of 60 hits against the NS2B-NS3 protease. Furthermore, the docking finding reveals that our newly identified compounds from the NPASS database have enhanced binding affinities and established significant interactions with allosteric residues of the target protein. MD simulation and post-MD analysis further validated this finding. The free binding energy was computed in terms of MM-GBSA analysis, with the total binding energy for compound 1 (-57.3 ± 2.8 and - 52.9 ± 1.9 replica 1 and 2) indicating a stronger binding affinity for the target protein. Overall, this computational study identified these compounds as potential hit molecules, and these findings can open up a new avenue to explore and develop inhibitors against Dengue virus infection., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Background: Dengue and chikungunya, caused by dengue virus (DENV) and chikungunya virus (CHIKV) respectively, are the most common arthropod-borne viral diseases worldwide, for which there are no FDA-approved antivirals or effective vaccines. Arctigenin, a phenylpropanoid lignan from the seeds of Arctium lappa L. is known for its anti-inflammatory, anti-cancer, antibacterial, and immunomodulatory properties. Arctigenin's antimicrobial and immunomodulatory capabilities make it a promising candidate for investigating its potential as an anti-DENV and anti-CHIKV agent., Purpose: The aim of the study was to explore the anti-DENV and anti-CHIKV effects of arctigenin and identify the possible mechanisms of action., Methods: The anti-DENV or anti-CHIKV effects of arctigenin was assessed using various in vitro and in silico approaches. Vero CCL-81 cells were infected with DENV or CHIKV and treated with arctigenin at different concentrations, temperature, and time points to ascertain the effect of the compound on virus entry or replication. In silico molecular docking was performed to identify the interactions of the compound with viral proteins., Results: Arctigenin had no effects on DENV. Various time- and temperature-dependent assays revealed that arctigenin significantly reduced CHIKV RNA copy number and infectious virus particles and affected viral entry. Entry bypass assay revealed that arctigenin inhibited the initial steps of viral replication. In silico docking results revealed the high binding affinity of the compound with the E1 protein and the nsp3 macrodomain of CHIKV., Conclusion: This study demonstrates the in-vitro anti-CHIKV potential of arctigenin and suggests that the compound might affect CHIKV entry and replication. Further preclinical and clinical studies are needed to identify its safety and efficacy as an anti-CHIKV drug., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest, (Copyright © 2024 Elsevier GmbH. All rights reserved.)

Zoonotic diseases are major public health concerns and undeniable threats to human health. Among Zoonotic diseases, zoonotic viruses and prions are much more difficult to eradicate, as they result in higher infections and mortality rates. Several investigations have shown curcumin, the active ingredient of turmeric, to have wide spectrum properties such as anti-microbial, anti-vascular, anti-inflammatory, anti-tumor, anti-neoplastic, anti-oxidant, and immune system modulator properties. In the present study, we performed a comprehensive review of existing in silico, in vitro, and in vivo evidence on the antiviral (54 important zoonotic viruses) and anti-prion properties of curcumin and curcuminoids in PubMed, Google Scholar, Science Direct, Scopus, and Web of Science databases. Database searches yielded 13,380 results, out of which 216 studies were eligible according to inclusion criteria. Of 216 studies, 135 (62.5%), 24 (11.1%), and 19 (8.8%) were conducted on the effect of curcumin and curcuminoids against SARS-CoV-2, Influenza A virus, and dengue virus, respectively. This review suggests curcumin and curcuminoids as promising therapeutic agents against a wide range of viral zoonoses by targeting different proteins and signaling pathways., (© 2024 John Wiley & Sons Ltd.)

Global warming and climate change have made dengue disease a global health issue. More than 50 % of the world's population is at danger of dengue virus (DENV) infection, according to the World Health Organization (WHO). Therefore, a clinically approved dengue fever vaccination and effective treatment are needed. Peptide medication development is new pharmaceutical research. Here we intend to recognize the structural features inhibiting the DENV NS2B/NS3 serine protease for a series of peptide-hybrid inhibitors (R 1 -R 2 -Lys-R 3 -NH 2 ) by the 3D-QSAR technique. Comparative molecular field analysis (q 2  = 0.613, r 2  = 0.938, r 2 pred  = 0.820) and comparative molecular similarity indices analysis (q 2  = 0.640, r 2  = 0.928, r 2 pred  = 0.693) were established, revealing minor, electropositive, H-bond acceptor groups at the R 1 position, minor, electropositive, H-bond donor groups at the R 2 position, and bulky, hydrophobic groups at the R 3 position for higher inhibitory activity. Docking studies revealed extensive H-bond and hydrophobic interactions in the binding of tripeptide analogues to the NS2B/NS3 protease. This study provides an insight into the key structural features for the design of peptide-based inhibitors of DENV NS2B/NS3 protease., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Dengue virus (DENV) infection can lead to severe outcomes through a virus-induced cytokine storm, resulting in vascular leakage and inflammation. An effective treatment strategy should target both virus replication and cytokine storm. This study identified Kaempferia galanga L. (KG) extract as exhibiting anti-DENV activity. The major bioactive compound, ethyl-p-methoxycinnamate (EPMC), significantly reduced DENV-2 infection, virion production, and viral protein synthesis in HepG2 and A549 cells, with half-maximal effective concentration (EC 50 ) values of 22.58 µM and 6.17 µM, and impressive selectivity indexes (SIs) of 32.40 and 173.44, respectively. EPMC demonstrated efficacy against all four DENV serotypes, targeting the replication phase of the virus life cycle. Importantly, EPMC reduced DENV-2-induced cytokines (IL-6 and TNF-α) and chemokines (RANTES and IP-10), as confirmed by immunofluorescence and immunoblot analyses, indicating inhibition of NF-κB activation. EPMC's role in preventing excessive inflammatory responses suggests it as a potential candidate for dengue treatment. Absorption, distribution, metabolism, excretion, and toxicity (ADMET) and drug-likeness for EPMC were predicted using SwissADME and ProTox II servers, showing good drug-like properties without toxicity. These findings highlight KG extract and EPMC as promising candidates for future anti-dengue therapeutics, offering a dual-action approach by inhibiting virus replication and mitigating inflammatory reactions., (© 2024. The Author(s).)

In the global pandemic scenario, dengue and zika viruses (DENV and ZIKV, respectively), both mosquito-borne members of the flaviviridae family, represent a serious health problem, and considering the absence of specific antiviral drugs and available vaccines, there is a dire need to identify new targets to treat these types of viral infections. Within this drug discovery process, the protease NS2B/NS3 is considered the primary target for the development of novel anti-flavivirus drugs. The NS2B/NS3 is a serine protease that has a dual function both in the viral replication process and in the elusion of the innate immunity. To date, two main classes of NS2B/NS3 of DENV and ZIKV protease inhibitors have been discovered: those that bind to the orthosteric site and those that act at the allosteric site. Therefore, this perspective article aims to discuss the main features of the use of the most potent NS2B/NS3 inhibitors and their impact at the social level.

Background Objectives: Peptides isolated from different sources of plants have the advantages of specificity, lower toxicity, and increased therapeutic effects; hence, it is necessary to search for newer antivirals from plant sources for the treatment of dengue viral infections., Methods: In silico screening of selected plant peptides against the non-structural protein 1, NS3 protease domain (NS2B-NS3Pro) with the cofactor and ATPase/helicase domain (NS3 helicase domain/NS3hel) of dengue virus was performed. The physicochemical characteristics of the peptides were calculated using Protparam tools, and the allergenicity and toxicity profiles were assessed using allergenFP and ToxinPred, respectively., Results: Among the tested compounds, Ginkbilobin demonstrated higher binding energy against three tested nonstructural protein targets. Kalata B8 demonstrated maximum binding energy against NSP-1 and NSP-2, whereas Circulin A acted against the NSP3 protein of dengue virus., Interpretation Conclusion: The three compounds identified by in silico screening can be tested in vitro, which could act as potential leads as they are involved in hampering the replication of the dengue virus by interacting with the three prime non-structural proteins., (Copyright © 2024 Copyright: © 2024 Journal of Vector Borne Diseases.)

Background: Dengue infection can trigger an immunological response that results in an inflammatory reaction, which acts as a defensive mechanism to protect the host. Dengue infection leads to an elevation in the release of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6). These three cytokines have been shown to correlate with the development of thrombocytopenia and plasma leakage, which is related to the severity of the disease., Aim: This study aims to investigate the effect of faloak ( Sterculia quadrifida R. Br) stem bark on TNF-α, IL-1β, and IL-6 levels in Wistar rats infected with dengue, specifically DENV-3., Methods: A group of 27 male Wistar rats ( Rattus norvegicus ) aged 2-3 months and weighting 200-300 g were divided into three distinct groups: healthy, dengue, and treatment (dengue infection and extract) groups. The rats in both the dengue and treatment groups were administered an injection of DENV-3 with a titer of 105 pfu at a dosage of 0.8 cc via the intraperitoneal route. The propagation of DENV-3 was initiated using C6/36 cells, and it underwent four passages. The extract was administered orally via a nasogastric tube at a dosage of 1,500 mg/kg body weight once daily for 7 days. The healthy group underwent blood sampling on the first day, whereas the dengue and therapy groups underwent blood sampling on the fifth and eighth, respectively., Results: Compared with the healthy group, TNF-α levels in the dengue and treatment groups showed significant differences on day 5 post-infection. The post hoc analysis revealed a statistically significant difference between the dengue-treatment and dengue-healthy groups. The IL-1β levels in the dengue and healthy groups significantly differed on days 5 and 8 post-infection compared to the healthy group. The treatment group had less of a decrease in IL-6 levels on days 5 and 8 than the dengue group. However, no statistically significant differences were observed., Conclusion: The stem bark of S. quadrifida shows potential as an anti-inflammatory agent in dengue infections, particularly in its ability to decrease levels of TNF-α and IL-1β., Competing Interests: There is no conflict of interest in this study.

Dengue fever is a mosquito-borne disease that claims the lives of millions of people around the world. A number of factors like disease's non-specific symptoms, increased viral mutation, growing antiviral drug resistance due to reduced susceptibility, unavailability of an effective vaccine for dengue, weak immunity against the virus, and many more are involved. Dengue belongs to the Flaviviridae family of viruses. The two species of the vector transmitting dengue are Aedes aegypti and Aedes albopictus, with the former one being dominant. Serotypes 2 of dengue fever are spread to the human body and cause severe illness. Recently, dengue has imposed an aggressive effect synergistically with the COVID-19 pandemic. As a result, we concentrated our efforts on finding a potential therapeutic. For this, we chose natural compounds to fight dengue fever, which is currently regarded as successful among many drug therapies. Following this, we started the in silico experiment with 922 plant extracts as lead compounds to fight serotype 2. In this study, we used SwissADME for analyzing ligand drug-likeness, pkCSM for designing an ADMET profile, Autodock vina 4.2 and Swissdock tools for molecular docking, and finally Desmond for molecular dynamics simulation. Ultimately 45 were found effective against the 2'O methyltransferase protein of serotype 2. CHEMBL376820 was found as possible therapeutic candidates for inhibiting methyltransferase protein in this thorough analysis. Nevertheless, more in vitro and in vivo research are required to substantiate their potential therapeutic efficacy., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Viral infections continue to increase morbidity and mortality severely. The flavivirus genus has fifty different species, including the dengue, Zika, and West Nile viruses that can infect 40% of individuals globally, who reside in at least a hundred different countries. Dengue, one of the oldest and most dangerous human infections, was initially documented by the Chinese Medical Encyclopedia in the Jin period. It was referred to as "water poison," connected to flying insects, i.e., Aedes aegypti and Aedes albopictus . DENV causes some medical expressions like dengue hemorrhagic fever, acute febrile illness, and dengue shock syndrome., Objective: According to the World Health Organization report of 2012, 2500 million people are in danger of contracting dengue fever worldwide. According to a recent study, 96 million of the 390 million dengue infections yearly show some clinical or subclinical severity. There is no antiviral drug or vaccine to treat this severe infection. It can be controlled by getting enough rest, drinking plenty of water, and using painkillers. The first dengue vaccine created by Sanofi, called Dengvaxia, was previously approved by the USFDA in 2019. All four serotypes of the DENV1-4 have shown re-infection in vaccine recipients. However, the usage of Dengvaxia has been constrained by its adverse effects., Conclusion: Different classes of compounds have been reported against DENV, such as nitrogen-containing heterocycles (i.e., imidazole, pyridine, triazoles quinazolines, quinoline, and indole), oxygen-containing heterocycles (i.e., coumarins), and some are mixed heterocyclic compounds of S, N (thiazole, benzothiazine, and thiazolidinediones), and N, O (i.e., oxadiazole). There have been reports of computationally designed compounds to impede the molecular functions of specific structural and non-structural proteins as potential therapeutic targets. This review summarized the current progress in developing dengue protease inhibitors., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Dengue is a major health threat and the number of symptomatic infections caused by the four dengue serotypes is estimated to be 96 million 1 with annually around 10,000 deaths 2 . However, no antiviral drugs are available for the treatment or prophylaxis of dengue. We recently described the interaction between non-structural proteins NS3 and NS4B as a promising target for the development of pan-serotype dengue virus (DENV) inhibitors 3 . Here we present JNJ-1802-a highly potent DENV inhibitor that blocks the NS3-NS4B interaction within the viral replication complex. JNJ-1802 exerts picomolar to low nanomolar in vitro antiviral activity, a high barrier to resistance and potent in vivo efficacy in mice against infection with any of the four DENV serotypes. Finally, we demonstrate that the small-molecule inhibitor JNJ-1802 is highly effective against viral infection with DENV-1 or DENV-2 in non-human primates. JNJ-1802 has successfully completed a phase I first-in-human clinical study in healthy volunteers and was found to be safe and well tolerated 4 . These findings support the further clinical development of JNJ-1802, a first-in-class antiviral agent against dengue, which is now progressing in clinical studies for the prevention and treatment of dengue., (© 2023. The Author(s).)

Background: Dengue caused by dengue virus (DENV) spreads rapidly around the world. However, there are no worldwide licensed vaccines or specific antivirals to combat DENV infection. Quassinoids are the most characteristic components of Eurycoma longifolia, which have been reported to display a variety of biological activities. However, whether quassinoids exert anti-DENV activities remains unknown., Purpose: To test the quassinoids of E. longifolia for their activity against DENV and to clarify the potential mechanisms., Methods: The quassinoids from E. longifolia were isolated by chromatography techniques, and their chemical structures were elucidated by spectroscopic analysis. The anti-DENV activities of quassinoids on baby hamster kidney cells BHK-21 were determined by lactate dehydrogenase (LDH) assay. The synthesis of progeny virus was measured by plaque assay. The expression levels of envelope protein (E) and non-structural protein 1 (NS1) were evaluated by qRT-PCR, Western blot and immunofluorescence assays. Molecular docking was used to screen the potential targets of the most active quassinoid against DENV-2, and surface plasmon resonance analysis was employed to confirm the direct binding between the most active quassinoid and potential target., Results: Twenty-four quassinoids, including three new quassinoids (1 - 3), were isolated from the ethanol extract of E. longifolia. Quassinoids 4, 5, 9, 11, 12, 15, 16, 17, 19 and 20 significantly reduced the LDH release at the stages of viral binding and entry or intracellular replication. Among them, 19 (6α-hydroxyeurycomalactone, 6α-HEL) exhibited the best anti-DENV-2 activities with an EC 50 value of 0.39 ± 0.02 μM. Further experiments suggested that 6α-HEL remarkably inhibited progeny virus synthesis and mRNA and protein expression levels of E and NS1 of DENV-2. Time-of-drug-addition assay suggested that 6α-HEL inhibited intracellular replication of DENV-2 at an early stage. Moreover, 6α-HEL was shown to interact with NS5-RdRp domain at a binding affinity of -8.15 kcal/mol. SPR assay further verified 6α-HEL bound to RdRp protein with an equilibrium dissociation constant of 1.49 × 10 -7  M., Conclusion: Ten quassinoids from E. longifolia showed anti-DENV activities at processes of virus binding and entry or intracellular replication. The most active quassinoid 6α-HEL exerts the anti-DENV-2 activities at intracellular replication stage by directly targeting the NS5-RdRp protein. These results suggest that 6α-HEL could be a promising candidate for the treatment of DENV-2 infection., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier GmbH.)

Dengue virus (DENV) infection has increased worldwide, with over 400 million infections annually, and has become a serious public health concern. Several drug candidates, new and repurposed, have failed to meet the primary efficacy endpoints. We have recently shown that Aqueous Extract of the stem of Cocculus hirsutus (AQCH) was effective in vitro and in vivo against DENV and was safe in humans. We now report that an active ingredient of AQCH, Sinococuline, protects against the antibody-mediated secondary-DENV infection in the AG129 mouse model. DENV infection markers were assessed, viz. serum viremia and vital organs pathologies-viral load, proinflammatory cytokines and intestinal vascular leakage. The treatment with Sinococuline at 2.0 mg/kg/day; BID (twice a day), was the most effective in protecting the severely DENV-infected AG129 mice. Also, this dose effectively reduced serum viremia and tissue-viral load and inhibited the elevated expression levels of proinflammatory cytokines (TNF-α and IL-6) in several vital organs. Based on these findings, it could be explored further for pre-clinical and clinical developments for the treatment of dengue., (© 2023. The Author(s).)

We synthesised and screened 18 aromatic derivatives of guanylhydrazones and oximes aromatic for their capacity to bind to dengue virus capsid protein (DENVC). The intended therapeutic target was the hydrophobic cleft of DENVC, which is a region responsible for its anchoring in lipid droplets in the infected cells. The inhibition of this process completely suppresses virus infectivity. Using NMR, we describe five compounds able to bind to the α1-α2 interface in the hydrophobic cleft. Saturation transfer difference experiments showed that the aromatic protons of the ligands are important for the interaction with DENVC. Fluorescence binding isotherms indicated that the selected compounds bind at micromolar affinities, possibly leading to binding-induced conformational changes. NMR-derived docking calculations of ligands showed that they position similarly in the hydrophobic cleft. Cytotoxicity experiments and calculations of in silico drug properties suggest that these compounds may be promising candidates in the search for antivirals targeting DENVC.

Dengue fever is a mosquito-borne viral disease that has become a serious health issue across the globe. It is caused by a virus of the Flaviviridae family, and it comprises five different serotypes (DENV-1 to DENV-5). As there is no specific medicine or effective vaccine for controlling dengue fever, there is an urgent need to develop potential inhibitors against it. Traditionally, various natural products have been used to manage dengue fever and its co-morbid conditions. A detailed analysis of these plants revealed the presence of various chromene derivatives as the major phytochemicals. Inspired by these observations, authors have critically analyzed the anti-dengue virus potential of various 4 H chromene derivatives. Further, in silico, in vitro, and in vivo reports of these scaffolds against the dengue virus are detailed in the present manuscript. These analogues exerted their activity by interfering with various stages of viral entry, assembly, and replications. Moreover, these analogues mainly target envelope protein, NS2B-NS3 protease, and NS5 RNA-dependent RNA polymerase, etc. Overall, chromene-containing analogues exerted a potent activity against the dengue virus and the present review will be helpful for the further exploration of these scaffolds for the development of novel antiviral drug candidates.

Dengue virus (DENV) is a danger to more than 400 million people in the world, and there is no specific treatment. Thus, there is an urgent need to develop an effective method to combat this pathology. NS2B/NS3 protease is an important biological target due it being necessary for viral replication and the fact that it promotes the spread of the infection. Thus, this study aimed to design DENV NS2B/NS3pro allosteric inhibitors from a matrix compound. The search was conducted using the Swiss Similarity tool. The compounds were subjected to molecular docking calculations, molecular dynamics simulations (MD) and free energy calculations. The molecular docking results showed that two compounds, ZINC000001680989 and ZINC000001679427, were promising and performed important hydrogen interactions with the Asn152, Leu149 and Ala164 residues, showing the same interactions obtained in the literature. In the MD, the results indicated that five residues, Lys74, Leu76, Asn152, Leu149 and Ala166, contribute to the stability of the ligand at the allosteric site for all of the simulated systems. Hydrophobic, electrostatic and van der Waals interactions had significant effects on binding affinity. Physicochemical properties, lipophilicity, water solubility, pharmacokinetics, druglikeness and medicinal chemistry were evaluated for four compounds that were more promising, showed negative indices for the potential penetration of the Blood Brain Barrier and expressed high human intestinal absorption, indicating a low risk of central nervous system depression or drowsiness as the the side effects. The compound ZINC000006694490 exhibited an alert with a plausible level of toxicity for the purine base chemical moiety, indicating hepatotoxicity and chromosome damage in vivo in mouse, rat and human organisms. All of the compounds selected in this study showed a synthetic accessibility (SA) score lower than 4, suggesting the ease of new syntheses. The results corroborate with other studies in the literature, and the computational approach used here can contribute to the discovery of new and potent anti-dengue agents.

Dengue is an important arboviral infectious disease for which there is currently no specific cure. We report gemini-like (geminoid) alkylated amphiphilic peptides containing lysines in combination with glycines or alanines (C 15 H 31 C(O)-Lys-(Gly or Ala) n Lys-NHC 16 H 33 , shorthand notation C 16 -KX n K-C 16 with X = A or G, and n = 0-2). The representatives with 1 or 2 Ala inhibit dengue protease and human furin, two serine proteases involved in dengue virus infection that have peptides with cationic amino acids as their preferred substrates, with IC 50 values in the lower µM range. The geminoid C 16 -KAK-C 16 combined inhibition of DENV2 protease (IC 50 2.3 µM) with efficacy against replication of wildtype DENV2 in LLC-MK2 cells (EC 50 4.1 µM) and an absence of toxicity. We conclude that the lysine-based geminoids have activity against dengue virus infection, which is based on their inhibition of the proteases involved in viral replication and are therefore promising leads to further developing antiviral therapeutics, not limited to dengue.

Dengue is an arthropod-borne acute febrile illness caused by Dengue Virus (DENV), a member of Flaviviridae . Severity of the infection ranges from mild self-limiting illness to severe life-threatening hemorrhagic fever (DHF) and dengue shock syndrome (DSS). To date, there is no specific antiviral therapy established to treat the infection. The current study reports the epidemiology of DENV infections and potential inhibitors of DENV 'E' protein. Among the various serotypes, DENV-2 serotype was observed more frequently, followed by DENV-4, DENV-1, and DENV-3. New variants of existing genotypes were observed in DENV-1, 2, and 4 serotypes. Predominantly, the severe form of dengue was attributable to DENV-2 infections, and the incidence was more common in males and pediatric populations. Both the incidence and the disease severity were more common among the residents of non-urban environments. Due to the predominantly self-limiting nature of primary dengue infection and folk medicine practices of non-urban populations, we observed a greater number of secondary dengue cases than primary dengue cases. Hemorrhagic manifestations were more in secondary dengue in particularly in the pediatric group. Through different computational methods, ligands RGBLD1, RGBLD2, RGBLD3, and RGBLD4 are proposed as potential inhibitors in silico against DENV-1, -2, -3, and -4 serotypes.

Zika virus (ZIKV) is a member of the Flaviviridae family that can cause neurological disorders and congenital malformations. The NS2B-NS3 viral serine protease is an attractive target for the development of new antiviral agents against ZIKV. We report here a SAR study on a series of substrate-like linear tripeptides that inhibit in a non-covalent manner the NS2B-NS3 protease. Optimization of the residues at positions P1, P2, P3 and of the N-terminal and C-terminal portions of the tripeptide allowed the identification of inhibitors with sub-micromolar potency with phenylglycine as arginine-mimicking group and benzylamide as C-terminal fragment. Further SAR exploration and application of these structural changes to a series of peptides having a 4-substituted phenylglycine residue at the P1 position led to potent compounds showing double digit nanomolar inhibition of the Zika protease (IC 50  = 30 nM) with high selectivity against trypsin-like proteases and the proteases of other flavivirus, such as Dengue 2 virus (DEN2V) and West Nile virus (WNV)., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

We previously showed that 5-ethynyl-(1-β-D-ribofuranosyl)imidazole-4-carboxamide (1; EICAR) is a potent anti-dengue virus (DENV) compound but is cytotoxic to some cell lines, while its 4-thio derivative, 5-ethynyl-(4-thio-1-β-D-ribofuranosyl)imidazole-4-carboxamide (2; 4'-thioEICAR), has less cytotoxicity but also less anti-DENV activity. Based on the hypothesis that the lower anti-DENV activity of 2 is due to reduced susceptibility to phosphorylation by cellular kinase(s), we investigated whether a monophosphate prodrug of 2 can improve its activity. Here, we first prepared two types of prodrug of 1, which revealed that the S-acyl-2-thioethyl (SATE) prodrug had stronger anti-DENV activity than the aryloxyphosphoramidate (so-called ProTide) prodrug. Based on these findings, we next prepared the SATE prodrug of 4'-thioEICAR 18. As expected, the resulting 18 showed potent anti-DENV activity, which was comparable to that of 1; however, its cytotoxicity was also increased relative to 2. Our findings suggest that prodrugs of 4'-thioribonucleoside derivatives such as EICAR (1) represent an effective approach to developing potent biologically active compounds; however, the balance between antiviral activity and cytotoxicity remains to be addressed.