Antiviral Compounds Research Articles

Cannabinoid-Inspired Inhibitors of the SARS-CoV-2 Coronavirus 2′-O-Methyltransferase (2′-O-MTase) Non-Structural Protein (Nsp10–16)

The design and synthesis of antiviral compounds were guided by computationally predicted data against highly conserved non-structural proteins (Nsps) of the SARS-CoV-2 coronavirus. Chromenephenylmethanone-1 (CPM-1), a novel biphenylpyran (BPP), was selected from a unique natural product library based on in silico docking scores to coronavirus Nsps with high specificity to the methyltransferase protein (2′-O-MTase, Nsp10–16), which is responsible for viral mRNA maturation and host innate immune response evasion. To target the 2′-O-MTase, CPM-1, along with intermediate BPP regioisomers, tetrahydrophenylmethanones (TPMs), were synthesized and structurally validated via nuclear magnetic resonance (NMR) data and DP4+ structure probability analyses. To investigate the activity of these BPPs, the following in vitro assays were conducted: SARS-CoV-2 inhibition, biochemical target validation, mutagenicity, and cytotoxicity. CPM-1 possessed notable activity against SARS-CoV-2 with 98.9% inhibition at 10 µM and an EC50 of 7.65 µM, as well as inhibition of SARS-CoV-2’s 2′-O-MTase (expressed and purified) with an IC50 of 1.5 ± 0.2 µM. In addition, CPM-1 revealed no cytotoxicity (CC50 of >100 µM) or mutagenicity (no frameshift or base-pair mutations). This study demonstrates the potential of computational modeling for the discovery of natural product prototypes followed by the design and synthesis of drug leads to inhibit the SARS-CoV-2 2′-O-MTase.

Structural and free energy landscape analysis for the discovery of antiviral compounds targeting the cap-binding domain of influenza polymerase PB2

Influenza poses a significant threat to global health, with the ability to cause severe epidemics and pandemics. The polymerase basic protein 2 (PB2) of the influenza virus plays a crucial role in the viral replication process, making the CAP-binding domain of PB2 an attractive target for antiviral drug development. This study aimed to identify and evaluate potential inhibitors of the influenza polymerase PB2 CAP-binding domain using computational drug discovery methods. We employed a comprehensive computational approach involving virtual screening, molecular docking, and 500 ns molecular dynamics (MD) simulations. Compounds were selected from the Diverse lib database and assessed for their binding affinity and stability in interaction with the PB2 CAP-binding domain. The study utilized the generalized amber force field (GAFF) for MD simulations to further evaluate the dynamic behaviour and stability of the interactions. Among the screened compounds, compounds 1, 3, and 4 showed promising binding affinities. Compound 4 demonstrated the highest binding stability and the most favourable free energy profile, indicating strong and consistent interaction with the target domain. Compound 3 displayed moderate stability with dynamic conformational changes, while Compound 1 maintained robust interactions throughout the simulations. Comparative analyses of these compounds against a control compound highlighted their potential efficacy. Compound 4 emerged as the most promising inhibitor, with substantial stability and strong binding affinity to the PB2 CAP-binding domain. These findings suggest that compound 4, along with compounds 1 and 3, holds the potential for further development into effective antiviral agents against influenza. Future studies should focus on experimental validation of these compounds and exploration of resistance mechanisms to enhance their therapeutic utility.

Antiviral Potential of Chiococca alba (L.) Hitchc. Plant Extracts Against Chikungunya and Mayaro Viruses

Chikungunya and Mayaro fevers are viral infectious diseases characterized by fever and arthralgia, for which there are currently no effective vaccines or treatments. The urgent need for novel antiviral agents against Chikungunya virus (CHIKV) and Mayaro virus (MAYV) has led to interest in plant-based compounds that can disrupt the viral replication cycle. Chiococca alba (L.) Hitchc., a Neotropical plant traditionally used by Yucatec Maya healers as an antipyretic and antirheumatic, may hold potential as a source of antiviral agents. This study aimed to evaluate the antiviral potential of C. alba methanolic extracts (CAH21 and CAH24) against CHIKV and MAYV through preliminary in vitro and in silico analyses. The cytotoxicity of two methanolic extracts from C. alba roots was assessed in Vero cells using the neutral red assay, and their viral activity was determined via plaque assay post-treatment. Given the observed antiviral effects, we used computational predictions to explore interactions between the multifunctional nsP2 proteases and secondary metabolites identified in C. alba extracts. The metabolites were identified using high-performance liquid chromatography (HPLC) and gas chromatography–mass spectrometry (GC-MS). Phytochemical analysis revealed the presence of flavonoids, coumarins, and phenolic acids in the C. alba extracts. In vitro assays demonstrated that both extracts inhibited over 70% of activity against CHIKV and MAYV at a concentration of 60 µg/mL. In silico predictions suggested that the flavonoids naringin and vitexin had the highest affinity for the nsP2 proteases of CHIKV and MAYV, indicating their potential as viral inhibitors. Our findings revealed that C. alba extract represents a promising source of novel antiviral compounds.

In Silico evaluation of the anti-influenza potential of Streptomyces bioactive compounds

Influenza, a highly contagious respiratory viral disease characterized by its short incubation period and severe symptoms, is treatable with antiviral drugs targeting viremia. Among new antiviral agents, Actinobacteria, particularly from the Streptomyces genus, are notable for their ability to produce potent antiviral compounds. This study evaluates the antiviral potential of Streptomyces sp. KSF 103, isolated from Kuala Sat, Jerantut, Pahang, against the Influenza A virus (IAV). Using molecular docking tools such as AutoDock Vina and PyMOL, the interactions of four compounds – hypoxanthine, vitamin D, purine, and aminocaproic acid – were analyzed against IAV proteins. Vitamin D exhibited the highest binding affinity against H3N2’s M2 (−9.6 kcal/mol) and HA (−9.2 kcal/mol) proteins. Additionally, RMSD dynamics parameters indicated that the best-scoring complexes are predicted to be satisfactorily stable under physiological settings. These findings suggest that Streptomyces sp. KSF 103 could be a promising source for developing new antiviral treatments against influenza.

Design, In Silico, and In vitro Evaluation of Polymer-Based Drug Conjugates Incorporated with Derivative of Cinnamic Acid, Zidovudine, and 4-Aminosalicylic Acid against Pseudo-HIV-1.

The incorporation of anti-HIV drugs into polymer to form polymer-drug conjugates has been reported to result in improved therapeutic activity. Zidovudine, an anti-HIV drug, was explored alone and in combination with known drug molecules using polyamidoaminebased carriers. Polymer-drug conjugates incorporated with zidovudine, cinnamic acid, and 4-aminosalicylic acid were prepared and evaluated for their potential efficacy in vitro against pseudo- HIV-1. Aqueous Michael addition polymerization reaction was employed to prepare the conjugates. The conjugates were incorporated with zidovudine, cinnamic acid, and 4-aminosalicylic acid. They were characterized by SEM/EDX, XRD, FTIR, NMR, LC-MS, particle size analysis, in vitro analysis, computational studies, and in silico toxicity predictions. The conjugates displayed spherically shaped morphology. The in vitro findings showed that polymer-drug conjugates, T15 and T16, with a single drug were effective against pseudo- HIV-1 at high concentrations of 111.11 and 333.33 μg/mL, respectively. The molecular docking studies confirmed the in vitro results. The Swiss ADME, ProTox-II, and GUSAR (General Unrestricted Structure-Activity Relationships) revealed that these compounds are promising antiviral compounds. The prepared polymer-drug conjugates with a single drug showed promising effects against the Pseudo-HIV-1, and the conjugates displayed features that make them potential anti- HIV therapeutics that require further studies.

Evaluation of the antiviral activity of different extracts of Gliricidia sepium and Xylopia aethiopica on enteroviruses isolated in Côte d'Ivoire

Objective : The emergence of viral infections has highlighted the need for new antiviral molecules. This study is part of an exploration into finding new antiviral compounds from medicinal plants used in traditional pharmacopoeia in Côte d'Ivoire. The aim is to determine which of the extracts from Gliricidia sepium leaves and Xylopia aethiopica fruits (hydroalcoholic, hexane/water, ethyl acetate/water, aqueous) exhibits the best antiviral activity. Methodology: The cytotoxicity of each partition P1 (hydroalcoholic), P2 (hexane/water), P3 (ethyl acetate/water), P4 (aqueous) of Gliricidia sepium leaves and P1' (hydroalcoholic), P2' (hexane/water), P3' (ethyl acetate/water), P4' (aqueous) of Xylopia aethiopica fruits is determined on RD cells. The antiviral activity of these partitions was then evaluated against a type 1 enterovirus. Results: The hexane-water partition showed high antiviral activity against type 1 enterovirus, with an inhibition of 65.78±9.21% at a concentration of 1 μg/mL for Gliricidia sepium leaves, compared to a non-significant inhibition of 86.84±5.26% at 31.25 μg/mL for Xylopia aethiopica fruits. Additionally, the aqueous partition of Gliricidia sepium induced an inhibition of 50±0.01% at a concentration of 1.95 μg/mL. Conclusion: Hexane-water and aqueous partitions of Gliricidia sepium showed́ potent antiviral activitý against enterovirus 1 than those of Xylopia. aethiopica. Keywords: plant partition, RD cells, enterovirus type 1.

Oxoammonium salts exert antiviral effects against coronavirus via denaturation of their spike proteins

Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV2) infection has forced social changes worldwide. Development of potent antiviral agents is necessary to prevent future pandemics. Titanium oxide, a photocatalyst, is a long-acting antiviral agent; however, its effects are weakened in the dark. Therefore, new antiviral substances that can be used in the dark are needed. Two types of nitroxyl radicals, 2,2,6,6-tetramethylpiperidine N-oxyl (TEMPO) and 2-azaadamantane N-oxyl (AZADO), are commonly used as oxidation catalysts utilizing oxygen in the air as the terminal oxidant. Therefore, in this study, we aimed to evaluate the potential of these radicals as antiviral compounds with sustained activity even in the dark. We evaluated the antiviral effects of oxoammonium salts corresponding to TEMPO and AZADO (TEMPO-Oxo and AZADO-Oxo, respectively), which are the active forms of nitroxyl radicals in oxidation reactions. TEMPO-Oxo and AZADO-Oxo inhibited the binding of SARS-CoV2 spike protein receptor-binding domain (S-RBD) to angiotensin-converting enzyme 2. Notably, AZADO-Oxo exhibited a 10-fold stronger inhibitory effect than TEMPO-Oxo. TEMPO-Oxo and AZADO-Oxo also denatured S-RBD; however, effects of AZADO-Oxo were 10-fold stronger than those of TEMPO-Oxo and did not change in the dark. Some S-RBD peptides treated with AZADO-Oxo were cleaved at the N-terminal side of tyrosine residues. TEMPO-Oxo and AZADO-Oxo exhibited concentration-dependent antiviral effects against feline coronavirus. In conclusion, active forms of the nitroxyl radicals, TEMPO-Oxo and AZADO-Oxo, exerted antiviral effects by denaturing S-RBD, regardless of the presence or absence of light, suggesting their potential as novel antiviral agents.

A critical review on the active anti-viral metabolites of bioprospecting traditionally used plant species from semi-arid regions of the subcontinent.

Plants are crucial medicinal resources, with 80 % of people relying on them for primary healthcare. The search for natural antiviral compounds is increasing, especially in semi-arid ecosystems where abiotic stress promotes the production of beneficial secondary metabolites. This review highlights semi-arid plants with the potential as functional foods to combat viral diseases and other illnesses. Literature was searched in databases like ScienceDirect to gather information on novel compounds from stress-tolerant semi-arid plant species. These compounds have potential uses in treating viral infections and other health issues such as diabetes and high blood pressure. The review screened 61 semi-arid plants known for their antiviral metabolites. Eight plants were identified with novel antiviral compounds. Key metabolites include agathisflavone, pectic arabinogalactan, azadirachtin, aloin, aloe-emodin, aloesaponarin I, allicin, terpenoids, chlorogenic acids, curcumin, chromones, β-sitosterol, lupeol, oleuropein, carissol, β-amyrin, and ∆-9-tetrahydrocannabinol. Stress-tolerant semi-arid plants are significant sources of metabolites for treating infectious diseases and boosting immune systems. Further research on these metabolites in animal models is needed to verify their efficacy for treating human diseases during endemic and pandemic outbreaks, such as COVID-19.

In silico study of lactoferrin as an anticancer, anti-viral, and anti-bacterial bioactive compound and disease diagnostic marker.

Studying the interaction of proteins and genes by current computational methods is effective in new drug design. Considering the special role of lactoferrin (Lf) identifying its action mechanism is a new gate to the targeted treatment of some diseases. This study aimed to investigate the molecular interaction of Lf with virus spike, the bacterial cell binding receptor, and the proteins involved in apoptosis by in silico research. The docking results showed that the amino acids involved in the interaction between the spike virus of COVID-19 with the ACE2 receptor were similar to the amino acids in the interaction between the virus spike and Lf, and the binding between Lf and the viral spike was more inclined. The N-terminus of Lf interacted with the N-terminus region of the CD14, which contains the binding sites of bacterial lipopolysaccharide to the cell. Lf can compete for binding with bacterial lipopolysaccharides. The results related to the docking of TP53, BAX, and BAK1 gene promoters and Lf showed that Lf with one or more amino acids that are responsible for binding to DNA interacted with TP53 and BAX genes with higher binding affinity. In all protein and protein-gene interactions, the N-lobe region of Lf, which is its functional region, is involved in these interactions, and the anticancer, antibacterial, and antiviral, roles of Lf are related to this region. Lf is important as a medicinal supplement for treating COVID-19 and cancer.

Bioactives from marine resources as natural health products: A review.

The oceans are a rich source of a myriad of structurally different and unique natural products that are mainly found in invertebrates with potential applications in different disciplines. Microbial infection and cancer are the leading causes of death worldwide. Discovery of new sources of therapy for microbial infections is an urgent requirement due to the emergence of pathogenic microorganisms that are resistant to existing therapies. Marine bioactives have demonstrated to be promising sources for the discovery and development of novel antimicrobial and anticancer compounds. Several marine compounds are confirmed to have antibacterial effects and most marine-based antifungal compounds are cytotoxic. Numerous antitumor marine natural products, derived mainly from sponges or molluscs, and also bryozoans and cyanobacteria, exhibit potent antimitotic activity. In addition, marine biodiversity offers some possible leads or new drugs to treat human immunodeficiency virus (HIV). A majority of marine derived drugs are currently in clinical trials or under preclinical evaluation. Furthermore, marine-based drugs, approved by the US Food and Drug Administration (FDA) are available in the market. This review summarizes the sources, mechanisms of action and potential utilization of marine natural products such as peptides, alkaloids, polyketides, polyphenols, terpenoids and sterols as antifungal, antibacterial, antiviral, and anticancer compounds. Significance Statement Utilization of marine bioactives as natural health products leads to crucial advancement in providing dietary supplements, nutraceuticals, functional foods and pharmaceuticals. Their myriad of application promotes health and plays a role in disease risk reduction. Therapeutic potential of potent compounds from marine organisms and use of their bioactives have promising medicinal value for preventing ailments and advancing pharmaceutical and nutraceutical industries. Their utilization benefits human health globally and contributes to the conservation of marine ecosystem in a transformative / sustainable approach.

Antiviral activity of the water extract and ethanol extract of Sorbus commixta against influenza A virus in vitro

Although vaccines and antivirals are currently available, influenza virus infections continually present major threats to human health. Due to genetic diversity and variability of influenza viruses, the development of new antiviral agents against the virus remains as a considerable challenge. In this study, we evaluated the antiviral activity of the water extract and ethanol extract of Sorbus commixta Hedl. (SCH), widely used as a medical herb, against influenza A viruses and identified molecular mechanisms for the antiviral activity. The water extract and ethanol extract of SCH demonstrated virucidal activity against influenza A virus at the noncytotoxic concentrations. In addition, cytopathic effect reduction assay and GFP fluorescence image analysis suggest that SCH extracts have inhibitory activity on multiple stages during influenza virus life cycle. Mechanisms studies showed that SCH extracts inhibited the biological functions of influenza viral surface hemagglutinin and neuraminidase proteins that play critical roles in the viral entry and release steps. SCH extracts not only prevented the receptor binding of influenza viral HA to the cellular receptors but also inhibited the HA-mediated membrane fusion. In addition, SCH extracts suppressed the enzyme activity of the viral neuraminidase. The results together suggest that SCH extracts contain antiviral natural compounds that inhibit multiple influenza viral proteins including the viral surface proteins. Our findings suggest that SCH extracts could be promising resources for the development of novel antiviral agents against influenza A viruses.

Identification of steroidal cardenolides from Calotropis procera as novel HIV-1 PR inhibitors: A molecular docking & molecular dynamics simulation study.

Background & objectives Despite advancements in antiretroviral therapy, drug-resistant strains of HIV (human immunodeficiency virus) remain a global health concern. Natural compounds from medicinal plants offer a promising avenue for developing new HIV-1 PR (protease) inhibitors. This study aimed to explore the potential of compounds derived from Calotropis procera, a medicinal plant, as inhibitors of HIV-1 PR. Methods This in silico study utilized natural compound information and the crystal structure of HIV-1 PR. Molecular docking of 17 steroidal cardenolides from Calotropis procera against HIV-1 PR was performed using AutoDock 4.2 to identify compounds with higher antiviral potential. A dynamic simulation study was performed to provide insights into the stability, binding dynamics, and potential efficacy of the top potential antiviral compound as an HIV-1 therapeutic. Results We found that all tested cardenolides had higher binding affinities than Amprenavir, indicating their potential as potent HIV-1 PR inhibitors. Voruscharin and uscharidin displayed the strongest interactions, forming hydrogen bonds and hydrophobic interactions with HIV-1 PR. Voruscharin showed improved stability with lower RMSD (Root Mean Square Deviation) values and reduced fluctuations in binding site residues but increased flexibility in certain regions. The radius of gyration analysis confirmed a stable binding pose between HIV-1 PR and Voruscharin. Interpretation & conclusions These findings suggest that Calotropis procera could potentially be a source of compounds for developing novel HIV-1 PR inhibitors, contributing to the efforts to combat HIV. Further studies and clinical trials are needed to evaluate the safety and efficacy of these compounds as potential drug candidates for the treatment of HIV-1 infection.

N-alkylation of amines for the synthesis of potential antiviral agents: A structural modification approach

The threat of emerging viral outbreaks has increased the need for fast and effective development of therapeutics against emerging pathogens. One approach is to modify the structure of existing therapeutic agents to achieve the desired antiviral properties. Here, we attempted to synthesize a new antiviral compound by modifying the structure of chloroquine using the N-alkylation of the primary amine (N1,N1-diethylpentane-1,4-diamine) that is used in chloroquine synthesis. Chloroquine is commonly used to treat malaria. Like chloroquine, chloroquine is used for treating conditions such as rheumatoid arthritis, lupus, and malaria. For instance, in malaria treatment, it targets and inhibits the growth of the malaria parasite, aiding in its elimination from the body. The synthesized compounds MP1, C1, and TT1 were further tested in vitro against the B.1 lineage of SARS-CoV-2. One of the compounds, MP1, demonstrated minor effectiveness, with an IC50 of XX at only a high concentration (at a concentration of 60 μM) and decreased both the number of SARS-CoV-2 copies and the amount of infectious virus. Although the synthesized compounds failed to markedly inhibit SARS-CoV-2, this could be a pontial mechanism for manipulating the drug structure against other pathogens. MP1, TT1, C1, and chloroquine diphosphate were used as ligands for molecular docking to determine the principal interactions between these compounds and the active site of the protein downloaded from the Protein Data Bank (PDB ID: 6lzg). Finally, ADMET assays were performed on the synthesized compounds to determine their pharmacokinetics and bioavailability.

Large-scale deep learning identifies the antiviral potential of PKI-179 and MTI-31 against coronaviruses

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has led to the global pandemic of Coronavirus Disease (2019) (COVID-19), underscoring the urgency for effective antiviral drugs. Despite the development of different vaccination strategies, the search for specific antiviral compounds remains crucial. Here, we combine machine learning (ML) techniques with in vitro validation to efficiently identify potential antiviral compounds. We overcome the limited amount of SARS-CoV-2 data available for ML using various techniques, supplemented with data from diverse biomedical assays, which enables end-to-end training of a deep neural network architecture. We use its predictions to identify and prioritize compounds for in vitro testing. Two top-hit compounds, PKI-179 and MTI-31, originally identified as Pi3K-mTORC1/2 pathway inhibitors, exhibit significant antiviral activity against SARS-CoV-2 at low micromolar doses. Notably, both compounds outperform the well-known mTOR inhibitor rapamycin. Furthermore, PKI-179 and MTI-31 demonstrate broad-spectrum antiviral activity against SARS-CoV-2 variants of concern and other coronaviruses. In a physiologically relevant model, both compounds show antiviral effects in primary human airway epithelial (HAE) cultures derived from healthy donors cultured in an air-liquid interface (ALI). This study highlights the potential of ML combined with in vitro testing to expedite drug discovery, emphasizing the adaptability of AI-driven approaches across different viruses, thereby contributing to pandemic preparedness.

Advances in the Search for SARS-CoV-2 Mpro and PLpro Inhibitors.

SARS-CoV-2 is a spherical, positive-sense, single-stranded RNA virus with a large genome, responsible for encoding both structural proteins, vital for the viral particle's architecture, and non-structural proteins, critical for the virus's replication cycle. Among the non-structural proteins, two cysteine proteases emerge as promising molecular targets for the design of new antiviral compounds. The main protease (Mpro) is a homodimeric enzyme that plays a pivotal role in the formation of the viral replication-transcription complex, associated with the papain-like protease (PLpro), a cysteine protease that modulates host immune signaling by reversing post-translational modifications of ubiquitin and interferon-stimulated gene 15 (ISG15) in host cells. Due to the importance of these molecular targets for the design and development of novel anti-SARS-CoV-2 drugs, the purpose of this review is to address aspects related to the structure, mechanism of action and strategies for the design of inhibitors capable of targeting the Mpro and PLpro. Examples of covalent and non-covalent inhibitors that are currently being evaluated in preclinical and clinical studies or already approved for therapy will be also discussed to show the advances in medicinal chemistry in the search for new molecules to treat COVID-19.

Chlorine Dioxide: Antiviral That Reduces the Spread of ToBRFV in Tomato (Solanum lycopersicum L.) Plants.

Tomato brown rugose fruit virus (ToBRFV), being a mechanically transmitted disease, is usually difficult to control; therefore, an effective alternative to reduce transmission and replication in the crop is by spraying with chlorine dioxide (ClO2) during routine crop management. In this research, the efficacy of chlorine dioxide (ClO2) for ToBRFV management in a greenhouse and open field was determined. The phytotoxicity of ClO2 and its effective concentration against ToBRFV in Nicotiana longiflora plants were evaluated. Subsequently, the effect of ClO2 on ToBRFV was evaluated in tomato plants grown in an open field. Finally, the effectiveness of ClO2 on plants inoculated with ToBRFV under greenhouse conditions was evaluated and the number of necrotic local lesions (NLLs) was quantified. The results revealed that ClO2 at 760 mg L-1 did not show phytotoxicity and reduced the number of NLLs in N. longiflora plants. It also decreased ToBRFV transmission and replication in field- and greenhouse-grown tomato plants, improving agronomic parameters. ClO2 reduced replication in plants inoculated with different amounts of ToBRFV inoculum in a greenhouse. N. longiflora leaves expressed lower numbers of NLLs when inoculated with ClO2-treated tomato plant extracts. Finally, the results demonstrate that ClO2 represents an effective management alternative when used by direct application to plants. To our knowledge, this is the first study where the use of an antiviral compound is carried out under field and greenhouse conditions.

Bioprospection for antiviral compounds from selected medicinal plants against RNA polymerase of rotavirus A using molecular modelling and density functional theory

Rotavirus A (RVA) infection remains a significant global health challenge, especially in developing countries, causing severe dehydrating diarrhoea in children under five years of age. Despite the availability of four World Health Organization (WHO) pre-qualified vaccines, their availability, particularly in low-income countries, pose significant challenges. Currently, there are no specific anti-rotaviral medications hence, the urgency to develop novel therapeutics against rotavirus infection. Thus, this study explored the potential of secondary metabolites of Spondias mombin, Macaranga barteri and Dicerocaryum eriocarpum as novel inhibitors of the RNA-dependent RNA polymerase (VP1) of rotavirus A using computational techniques. Pharmacokinetics parameters were adopted to screen the top 20 metabolites with high affinity for the target, initially identified through a docking study. Furthermore, the ability of the resulting compounds to modulate the investigated target was assessed using molecular dynamics (MD) simulation, while density functional theory (DFT) calculations were conducted to predict the molecular properties of the top-ranked compounds. Except for ellagic acid hexoside (-33.14 kcal/mol), all the leads had higher binding free energy values relative to sofosbuvir (-36.58 kcal/mol) following a 120 ns MD simulation. Overall, the resulting complexes with the lead compounds demonstrated acceptable stability, reduced flexibility and compactness, with spiraeoside (-51.02 kcal/mol) displaying more favourable thermodynamics metrics, albeit with a lesser binding free energy relative to chrysoeriol 7-glucuronide (-58.36 kcal/mol). The binding free energy and thermodynamic parameters of the top-hit compounds could be attributed to their respective bond interactions and molecular orbital properties except chrysoeriol 7-glucuronide, with a need for additional structural adjustment to enhance its thermodynamic properties. Thus, these findings indicate the potential modulatory ability of the lead compounds against the VP1 protein of RVA, underscoring the importance of further in vitro and in vivo studies to validate the predicted activity, and ongoing efforts are being made to pursue this line of investigation.

Punicalagin Inhibits African Swine Fever Virus Replication by Targeting Early Viral Stages and Modulating Inflammatory Pathways.

African swine fever (ASF), caused by the African swine fever virus (ASFV), has resulted in significant losses in the global pig industry. Considering the absence of effective vaccines, developing drugs against ASFV may be a crucial strategy for its prevention and control in the future. In this study, punicalagin, a polyphenolic substance extracted from pomegranate peel, was found to significantly inhibit ASFV replication in MA-104, PK-15, WSL, and 3D4/21 cells by screening an antiviral compound library containing 536 compounds. Time-of-addition studies demonstrated that punicalagin acted on early viral replication stages, impinging on viral attachment and internalization. Meanwhile, punicalagin could directly inactivate the virus according to virucidal assay. RT-qPCR and Western blot results indicated that punicalagin modulated the NF-κB/STAT3/NLRP3 inflammasome signaling pathway and reduced the levels of inflammatory mediators induced by ASFV. In conclusion, this study reveals the anti-ASFV activity of punicalagin and the mechanism of action, which may have great potential for developing effective drugs against ASFV.

In Silico Evaluation of HIV Protease and RNA Polymerase Inhibitors as Potential COVID-19 Therapeutics.

The COVID-19 coronavirus, also known as the acute respiratory syndrome coronavirus, emerged as a significant global health concern. First identified in Wuhan, China, in December 2019, the virus rapidly spread to over 187 countries due to its high transmissibility. Until an effective treatment or vaccine is developed, preventive measures remain the only mandatory strategy to curb person-to-person transmission. The study aimed to explore potential therapeutic options for COVID-19 by repurposing existing drugs. Specifically, the objective was to evaluate a library of clinically approved or investigational antiviral compounds through docking studies to identify candidates with high binding affinity to COVID-19 proteins. The study employed molecular docking techniques using the Maestro interface (Schrodinger Suite, LLC, NY) to assess the interaction of selected compounds with various COVID-19 protein targets. A total of 15 compounds were analyzed for their binding potential to multiple forms of the virus's proteins. The docking studies revealed that several compounds, particularly HIV protease inhibitors and RNA-dependent RNA polymerase inhibitors, demonstrated strong binding affinities to key COVID-19 enzymes. These interactions suggest their potential as therapeutic candidates for COVID-19 treatment. The findings from this drug repurposing study highlight the potential of certain existing antiviral agents in the treatment of COVID-19. The identified compounds could serve as promising candidates for further investigation in the ongoing battle against the coronavirus pandemic.

A mini review of antiviral compounds against dengue virus

A mini review of antiviral compounds against dengue virus