Antiviral Research Articles

Elucidation of the Pharmacological Development and Action Mechanism of Remdesivir and Paxlovid in Combatting COVID-19

COVID-19, the disease identified in 2019 as coronavirus disease, stems from an infection by severe acute respiratory syndrome coronavirus 2, or SARS-CoV-2, which possesses a single-stranded RNA genome. Since the onset of the pandemic attributed to COVID-19, a variety of vaccines and antiviral medications have received approval from international regulatory bodies. Two notable antiviral agents, remdesivir and paxlovid, serve as treatments for viral infections. Initially developed to combat Ebola, remdesivir has also demonstrated efficacy against a broad spectrum of coronaviruses (CoV). It is a nucleoside analogue and functions by being incorporated into the RNA chain of the virus and thus induce the early termination of RNA synthesis. Paxlovid comprises two pharmacological agents, nirmatrelvir and ritonavir. The mechanism of nirmatrelvir involves the specific targeting and inhibition of the viral protease’s active site, thereby impeding the viral replication process. By inhibiting the cytochrome CYP3A4 enzyme which metabolites nirmatrelvir, ritonavir acts as a pharmacokinetic enhancer in this combination. The initial section of this review provides a comprehensive analysis of SARS-CoV-2, detailing the mechanisms of its pathogenesis and the subsequent immune responses elicited by the body. Then this article generalizes the history of development, the structure, and the mode of action of remdesivir and paxlovid.

A structural snapshot of the multiple working states of the Mpox virus helicase-primase D5.

The Mpox virus (or Monkeypox virus, MPXV) uses its own encoded proteins to form a replication machine that replicates the viral genome in the host cell cytoplasm, making this machinery a key target for antiviral drug design. The D5 (also known as the OPG117 or E5) protein, a bi-functional helicase-primase enzyme, is crucial in the MPXV replication machinery and genome uncoating process. Recently, cryo-electron microscopy (cryo-EM) structures of D5 in multiple states have been determined. These structures have elucidated the full trajectory of the MPXV D5 helicase-primase as it moves along single-stranded DNA, providing unprecedented advancements in the molecular dynamics and unwinding mechanism. This structural snapshot describes the structural features of the D5 protein and dissects the broader implications of its pivotal role in MPXV replication.

Induced Native Phage Cocktails for Multi-microbial Activation Syndrome in Treatment-Resistant Illnesses.

The global population is plagued by chronic illnesses of many types due to, in part, the activation of virulence of many latent microbes leading to chronic multi-system illness, stimulating the new term, multi-microbial activation syndrome (MMAS). Treatment-resistant infections across the entire microbial spectrum are now largely untreatable using the previously successful pharmaceutical and natural medicine options. The heavy-handed methods of long-term chemotherapeutic antibiotics, antifungals, and antiviral drugs, whose adverse effects could be worse than the original illness, are presently essentially useless in the long run, as microbes have developed rapid adaptive mutations, becoming drug-resistant. The introduction of induced native phage therapy opened a completely new treatment category that has the potential to complement or replace aggressive drug therapies of many classes. Since its introduction, many advancements have been made to the technology. The most recent development in this new treatment genre is the ability to formulate induced native phage cocktails that use a wide spectrum of induction signatures within the formulation to stimulate various types of beneficial phages already living within the phageome of the body, to target a wide range of pathogenic microbes and associated advantageous physiological targets. The ability to address the MMAS commonly seen in various chronic illnesses simultaneously within the same formulation enables greater clinical outcomes without harm to the microbiome or to the tissues and systems of the body.

Human cellular restriction factors that target SARS-CoV-2 replication

Millions of people have died and a worldwide economic catastrophe has been brought on by the coronavirus disease 2019 (COVID-19) pandemic. Infections caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may presently be treated with less than 10 antiviral drugs such as Remdesivir. The need for medical intervention due to sickness has led to unprecedented research efforts to study the biology of coronaviruses. Additionally, there is a strong likelihood that coronaviruses will cause pandemics in the future. All viruses cannot replicate optimally due to host restriction factors. Given that they are genetically more stable than viral targets and may be shared by similar viruses, these antiviral host factors provide appealing targets for antiviral treatment. The identification of antiviral host factors that are a component of human innate immunity and that prevent the completion of the SARS-CoV-2 life cycle has been made possible by the deployment of several “omics” technologies. In this review, we provide an overview of the antiviral host factors that limit the replication of SARS-CoV-2 in this, which were mostly discovered using functional genetic and interactome screening. Important cellular mechanisms for the SARS-CoV-2 life cycle are covered. Finally, we highlight host restriction factors that could be targeted by clinically approved molecules and the induction of these factors as potential antiviral therapies for COVID-19.

Asiatic acid inhibits HBV cccDNA transcription by promoting HBx degradation

BackgroundHepatitis B virus (HBV) infection is a persistent global public health problem, and curing for chronic hepatitis B (CHB) through the application of existing antiviral drugs is beset by numerous challenges. The viral protein HBx is a critical regulatory factor in the life cycle of HBV. Targeting HBx is a promising possibility for the development of novel therapeutic strategies.MethodsThe Nano-Glo® HiBiT Lysis Detection System was used to screen the herbal monomer compound library for compounds that inhibit HBx expression. Western blotting was used to examine proteins expression. Southern blotting or Northern blotting were used to detect HBV DNA or HBV RNA. ELISA was performed to detect the HBsAg level. The effect of asiatic acid on HBV in vivo was investigated by using recombinant cccDNA mouse model.ResultsAsiatic acid, an extract of Centella asiatica, significantly reduced the HBx level. Mechanistic studies demonstrated that asiatic acid may promote the degradation of HBx in an autophagy pathway-dependent manner. Subsequently, asiatic acid was found to reduce the amount of HBx bound to covalently closed circular DNA (cccDNA) microchromosomes, and repressive chromatin modifications then occurred, ultimately inhibiting cccDNA transcriptional activity. Moreover, in HBV-infected cells and a mouse model of persistent HBV infection, asiatic acid exhibited potent anti-HBV activity, as evidenced by decreased levels of HBV RNAs, HBV DNA and HBsAg.ConclusionsAsiatic acid was identified as a compound that targets HBx, revealing its potential for application as an anti-HBV agent.

Phaleria macrocarpa Fruit Protein Aqueous Extract Affects Viral Entry, Virucidal Activity, and Progeny Release

Presence of acyclovir (ACV) resistant virus posed a major problem in treating virus infection. Alternative treatment with the ability to encounter infection of acyclovir-resistant virus is thus needed and possibly with a different mode of action from ACV. Hence, this study evaluates the antiviral effect of Phaleria macrocarpa (Scheff.) Boerl fruit protein aqueous extract (PMFPAE) against three different strains of human herpesvirus type-1 (HHV-1) including a clinical strain, a less pathogenic strain (KOS-1), and acyclovir (ACV) resistant mutant (UKM-1). PMFPAE displayed antiviral activity towards all the HHV-1 strains when post-treated with high selective indices (SIs) of 80.6, 50, and 35, respectively. Plaque reduction percentages were reduced in attachment and penetration assays following treatment with PMFPAE indicating the ability to deactivate the early phases of the HHV-1 replication cycle. The virucidal activity was also noted following treatment of the virus with PMFPAE and this is supported by damages to the virus envelope as observed by transmission electron microscopy (TEM). Incubation of virus-treated cells with PMFPAE for 24 hr, reduced progeny release in a dose-dependent manner. The study confirms the antiviral mode of action of P. macrocarpa fruit against HHV-1 strains and the ACV-mutant strain includes inhibition during virus entry represented as the early stages of viral replication, virucidal activity, and interfering with progeny release. PMFPAE mode of action is hence different from ACV and worthy for the development of future antiviral drugs.

Chemokine CCL2 and its receptor CCR2 in different age groups of patients with COVID-19

BackgroundDespite the development of various antiviral drugs, most of them are not effective in the treatment of coronavirus disease 2019 (COVID-19) as a hyperinflammatory disorder. Chemokine (C-C motif) ligand 2 (CCL2) is one of the critical CC chemokines involved in the pathogenesis and severity of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. This study aimed to investigate the expression of CCL2 and CC chemokine receptor 2 (CCR2) in COVID-19 patients.MethodsPeripheral blood samples were collected from 60 confirmed COVID-19 patients and 60 age-matched healthy subjects. The ages of the subjects were categorized as follows: up to 20 years, 20 to 40 years, 40 to 60 years, and more than 60 years. CCL2 serum levels were measured using the enzyme-linked immunosorbent assay (ELISA). CCR2 gene expression in peripheral blood mononuclear cells (PBMCs) was measured employing real-time polymerase chain reaction (PCR).ResultsIn all age groups, CCL2 serum levels were significantly elevated in patients compared to healthy controls (P < 0.0001). CCL2 levels were higher in severe patients than in moderate patients. Moreover, CCR2 expression by PBMCs was higher in patients compared to control subjects. However, a significant difference between patients and controls over 60 years of age was identified (P = 0.0353). There was no significant difference in CCR2 expression between moderate and severe COVID-19 patients.ConclusionsTaken together, the findings demonstrate that CCL2 and CCR2 are upregulated in COVID-19 patients at protein and mRNA levels, respectively. Therefore, the CCL2/CCR2 axis may be a potential therapeutic target in order to improve patient outcomes.

Eco-Friendly and Low-Cost Synthesis of Transparent Antiviral- and Antibacterial-Coated Films Based on Cu2O and MIL-53(Al).

This research presents the development of an innovative antimicrobial coating consisting of cuprous oxide (Cu2O) integrated with the metal-organic framework MIL-53(Al) through an eco-friendly and low-cost synthesis method that employs glucose as a reducing agent under mild conditions. The microstructural properties of the composite materials were characterized by using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The antibacterial efficacy of the Cu2O-MIL-53(Al) (CuM) composite was assessed against Escherichia coli and Staphylococcus aureus, achieving a reduction efficacy of 99.99% with 5% copper incorporated into the MIL-53(Al) framework within a contact time of 24 h. The incorporation of CuM into a macromolecular host matrix of polyurethane-carboxymethylcellulose (CuM/PUD-CMC), applied as a coating on a low-cost plastic film, produced a transparent film with 87.10% transparency. This coating demonstrated a 99.99% reduction in E. coli and S. aureus populations within a contact time of 24 h. The CuM/PUD-CMC coating demonstrated substantial antiviral efficacy, achieving inactivation rates of 99.35% for Human Coronavirus 229E, 99.40% for Influenza A virus, and 97.76% for Enterovirus 71 within a contact time of 5 min. The CuM nanoparticles exhibited low toxicity toward zebrafish while effectively eradicating bacteria and inactivating viruses. The proposed low-cost material and coating method demonstrate significant potential as a broad-spectrum antimicrobial and antiviral agent, highlighting its suitability for various applications in biomedical and healthcare formulations.

The precipitate structure of copper-based antibacterial and antiviral agents enhances their longevity for kitchen use

The transmission of bacteria through cooking surfaces, the handles of hot plates, and cookware that is not cleaned frequently can pose a problem. In this study, a copper ion-based mixed solution (CBMS) containing only inorganic ions with controlled acidity was assessed as a new antibacterial and antiviral agent. We analysed the structure of the precipitates, and various deposits measuring a few micrometres were observed on the substrates. We have defined these deposits as strongly bonded scaly copper dispersion (SBSCD) structures.The antibacterial copper component of the liquid agent changed over time after application; this mechanism appears to be responsible for the maintenance of antibacterial performance.CBMS demonstrates high safety for the human body and can be applied to stainless steel materials used in kitchens and tables. It exhibits a sustained antibacterial effect over time, and its antibacterial properties can be continuously maintained.

Antiviral Peptide-Generative Pre-Trained Transformer (AVP-GPT): A Deep Learning-Powered Model for Antiviral Peptide Design with High-Throughput Discovery and Exceptional Potency

Traditional antiviral peptide (AVP) discovery is a time-consuming and expensive process. This study introduces AVP-GPT, a novel deep learning method utilizing transformer-based language models and multimodal architectures specifically designed for AVP design. AVP-GPT demonstrated exceptional efficiency, generating 10,000 unique peptides and identifying potential AVPs within two days on a GPU system. Pre-trained on a respiratory syncytial virus (RSV) dataset, AVP-GPT successfully adapted to influenza A virus (INFVA) and other respiratory viruses. Compared to state-of-the-art models like LSTM and SVM, AVP-GPT achieved significantly lower perplexity (2.09 vs. 16.13) and higher AUC (0.90 vs. 0.82), indicating superior peptide sequence prediction and AVP classification. AVP-GPT generated a diverse set of peptides with excellent novelty and identified candidates with remarkably higher antiviral success rates than conventional design methods. Notably, AVP-GPT generated novel peptides against RSV and INFVA with exceptional potency, including four peptides exhibiting EC50 values around 0.02 uM—the strongest anti-RSV activity reported to date. These findings highlight AVP-GPT’s potential to revolutionize AVP discovery and development, accelerating the creation of novel antiviral drugs. Future studies could explore the application of AVP-GPT to other viral targets and investigate alternative AVP design strategies.

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.

Adapted Milwaukee protocol for rabies treatment in a Brazilian indigenous child: case report

BackgroundThis case report describes the treatment of a 12-year-old indigenous Brazilian girl from the Maxakali group with rabies using the adapted Milwaukee Protocol.Case presentationThe patient suffered a superficial bat bite on her right elbow, reported on April 5, 2022. Despite receiving immunoglobulin, a vaccine, and antiviral medications such as amantadine and sapropterin, the patient succumbed to the disease 25 days after hospital admission. The report highlights the inherent challenges in treating rabies due to the virus’s neurotropic nature and the difficulties in delivering antiviral drugs to the central nervous system. The case underscores the need for early antiviral intervention and calls for more studies to validate and improve treatment protocols for rabies in vulnerable populations, particularly those with genetic and immunological susceptibilities like the Maxakali indigenous group.ConclusionThe findings suggest that while the Milwaukee Protocol offers some hope, significant obstacles remain in achieving successful outcomes in rabies cases.

Oseltamivir phosphate (Tamiflu) alters neurobehavior of zebrafish larvae by inducing mitochondrial dysfunction

Antiviral drugs are widely used, yet their potential risks during early development, particularly within the central nervous system, remain contentious. Oseltamivir phosphate (OSE), a commonly prescribed antiviral, is increasingly detected in various environments. However, its toxicity to organisms and the underlying mechanisms are not well understood. In this study, we employed the zebrafish model to evaluate the developmental neurotoxic effects of OSE at environmentally and therapeutically relevant doses, through high-throughput behavioral analysis, in vivo two-photon imaging, transcriptomic sequencing, pharmacological intervention, and biochemical and molecular assays. Our results indicated that OSE exposure increased heart rate and induced pericardial edema in zebrafish larvae. Additionally, OSE-exposed larvae exhibited hyperactive behavior, impaired social interactions, and reduced habitual learning capacity. Although OSE at our selected levels did not significantly affect neuron count in the brain, it activated neuroinflammatory responses, altered blood vessel morphology, modulated neurotransmitter levels and the expression of neurodevelopment-related genes. Transcriptomic analysis revealed upregulation of mitochondria-related genes associated with oxidative phosphorylation. Further assessments of mitochondrial function demonstrated altered activities of respiratory chain complexes, reduced mitochondrial membrane potential (MMP), and decreased ATP content. Notably, co-treatment with mitochondrial protectants acetyl-l-carnitine-hydrochloride (ALC) or nicotinamide riboside (NR) effectively mitigated OSE-induced neurobehavioral disorders. These findings suggest that overuse of OSE can pose neurodevelopmental risks for both humans and animals, potentially attributable to mitochondrial dysfunction.

Predictors of treatment outcomes for Hepatitis C infection in a nationwide elimination program in Iceland: The treatment as prevention for Hepatitis C (TraP HepC) study

BackgroundLimited data exists about treatment outcomes in nationwide hepatitis C virus (HCV) elimination programs where injection drug use (IDU) is the main mode of transmission. In 2016 Iceland initiated the HCV elimination program known as Treatment as Prevention for Hepatitis C (TraP HepC). Factors associated with HCV cure in this population are examined. MethodsUnrestricted access was offered to direct acting antiviral agents (DAAs). Testing and harm reduction was scaled up and re-treatments were offered for those who did not attain cure. Cure rates for the first 36 months were assessed and factors associated with failure to achieve cure analysed using multivariable logistic regression. ResultsTreatment was initiated for 718; 705 consented for the study. Median age was 44 years (IQR 35–56), history of IDU reported by 593 (84.1 %), recent IDU by 234 (33.2 %); 48 (6.8 %) were homeless. Of 705 patients, 635 achieved cure (90.1 %) during the first treatment. A total of 70 (9.9 %) patients initiated two or more treatments, resulting in 673 participants cured (95.5 %). By multivariable analysis, homelessness was the only statistically significant independent factor associated with not achieving cure (OR 2.67, 95 % CI 1.32–5.41) after first treatment attempt. ConclusionBy reengagement in care and prompt retreatment when needed, a cure rate of 95.5 % was achieved. Unstable housing, a potentially actionable factor is associated with poor outcome.

A fast solid-phase microextraction scheme for in vivo monitoring of bio-accumulation and bio-transformation of arbidol in living plants

Large quantity of the antiviral drug arbidol is used for resisting virus infection like the Corona Virus Disease 2019 and influenza, resulting in unanticipated environmental pollution. Herein, to investigate the environmental risks of the unanticipated arbidol contamination, a novel in vivo sampling probe was developed based on a bromo-substituted porous organic polymer (Br-POP) and then adopted for tracking the bio-accumulation and bio-transformation of arbidol in living plants by coupling with a nano-electrospray ionization fourier-transform ion cyclotron resonance mass spectrometry (Nano-ESI-FT-ICR-MS) method. The established method showed good extraction performance towards arbidol with limit of detection (LOD) of 0.48 ng g−1, and relative standard deviation (RSD) of single-and multiple- probe of 2.2 and 14 %. Owing to the interactions between the Br-POP and the target analytes, as well as the fast analysis process of Nano-ESI-FT-ICR-MS, <6 min was cost for total sampling and analysis duration, achieving hourly tracking of arbidol and its metabolites in this work. During 21-d in vivo tracking, the concentration of arbidol in living plant stems increased rapidly within 6 h and peaked at 413.93 ± 47.09 ng g−1. Meanwhile, it was found that dissolved organic matters (DOM) had significant effect on arbidol behaviors in living plants, resulting in a decrease of the maximum concentration of arbidol in plant stems (152.70 ± 42.44 ng g−1) and the change of dominant metabolite of arbidol that the S-oxidation rather than N-demethylation product of arbidol was dominant with DOM participation. Additionally, the plant root secretion was found to be significantly altered by arbidol exposure. To summarized, the combination of in vivo SPME and the FT-ICR-MS analysis provide new and important information regarding arbidol contamination and related alternation of plant root metabolism.

Artemisia campestris L. as a promising source of potential antiviral drugs for SARS-CoV-2: Docking and dynamic simulation studies

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been considered as global public health security threats. Due to its rapid spread, high mortality rate and unavailability of treatment, we need to find a potent drug against SARS-CoV-2. Natural products are useful agents for the discovery of new potential drugs to combat coronavirus. Artemisia campestris, an aromatic plant widely used in traditional medicine, particularly in southern region of Algeria, is recognized for its essential oils and phenolics compounds possessing a wide range of biological activities. This study selected sixty-nine compounds from this plant to determine their binding interactions with the SARS-CoV-2 main protease (Mpro) and receptor-binding domain of the spike (S-RBD) protein, by using computational methods. Rutin, isoquercetin, and quercetin-3-O-glucuronide were shown to be the most potent inhibitors for Mpro and S-RBD with docking scores and Ki values ranging from -16.06 to -10.67 Kcal/mol and 0.005 to 30.01 nM, respectively. Evaluation of ADMET pharmacokinetic properties and the drug likeness in silico revealed that only 3,5-dicaffeoylquinic acid, 3–4–5-tricaffeoylquinic acid, isorhamnetin-3-O-glucoside, and rubescensin A could be more effective drugs against COVID-19. Molecular dynamics (MD) simulations (100 ns) and MM-GBSA calculations confirmed the stability of ligand-protein complexes via hydrogen bonding interactions with crucial residues. The analysis of structural parameters (RMSD, RMSF, H-bonds, Rg, and SASA) indicates that 3,4,5-tricaffeoylquinic acid and rubescensin A compounds have good stability and significant binding affinity with the Mpro and S-RBD protein. Taken together, our findings confirm that Artemisia campestris as a plausible source of anti-SARS-COV-2 phytochemicals and suggest that may play important role in this activity.

Mitochondrial resilience and antioxidant defence against HIV-1: unveiling the power of Asparagus racemosus extracts and Shatavarin IV

Asparagusracemosus (AR), an Ayurvedic botanical, possesses various biological characteristics, yet its impact on HIV-1 replication remains to be elucidated. This study aimed to investigate the inhibitory effects of AR root extracts and its principal bioactive molecule, Shatavarin IV (Shatavarin), on HIV-1 replication and their role in mitigating mitochondrial dysfunction during HIV-1 infection, utilizing both in vitro and in silico methodologies. The cytotoxicity of the extracts was evaluated using MTT and ATPlite assays. In vitro anti-HIV-1 activity was assessed in TZM-bl cells against X4 and R5 subtypes, and confirmed in peripheral blood mononuclear cells using HIV-1 p24 antigen capture ELISA and viral copy number assessment. Mechanistic insights were obtained through enzymatic assays targeting HIV-1 Integrase, Protease and Reverse Transcriptase. Shatavarin’s activity was also validated via viral copy number and p24 antigen capture assays, along with molecular interaction studies against key HIV-1 replication enzymes. HIV-1 induced mitochondrial dysfunction was evaluated by detecting mitochondrial reactive oxygen species (ROS), calcium accumulation, mitochondrial potential, and caspase activity within the infected cells. Non-cytotoxic concentrations of both aqueous and hydroalcoholic extracts derived from Asparagus racemosus roots displayed dose-dependent inhibition of HIV-1 replication. Notably, the hydroalcoholic extract exhibited superior Reverse Transcriptase activity, complemented by moderate activity observed in the Protease assay. Molecular interaction studies revealed that Shatavarin IV, the key bioactive constituent of AR, formed hydrogen bonds within the active binding pocket site residues crucial for HIV replication enzyme catalysis, suggesting its potential in attenuating HIV-1 infection. Mitochondrial dysfunction induced by HIV-1 infection, marked by increased oxidative stress, mitochondrial calcium overload, loss of mitochondrial membrane potential, and elevated caspase activity, was effectively mitigated by treatment with AR extracts and Shatavarin IV. These findings underscore the potential of AR extracts and Shatavarin IV as antiviral agents, while enhancing mitochondrial function during HIV-1 infection. In conclusion, Asparagus racemosus extracts, particularly Shatavarin IV, demonstrate promising inhibitory effects against HIV-1 replication while concurrently ameliorating mitochondrial dysfunction induced by the virus. These findings suggest the therapeutic potential of AR extracts and Shatavarin in combating HIV-1 infection and improving mitochondrial health.

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.

Virtual screening of antiviral peptides as novel blockers of human papillomavirus 16

Human papillomaviruses (HPVs) contribute to 5% of cancers, yet there is a lack of specific antiviral agents targeting HPV infection. Antiviral peptides (AVPs) present a promising alternative to conventional therapeutics. This study aims to explore the use of AVPs against the HPV16 E6 oncoprotein through virtual screening. The potential binding pocket of the E6 oncoprotein was determined, and using the antimicrobial CAMPR4 database 18 AVPs were shortlisted. These AVPs were then docked to the E6 oncoprotein using the HawkDock server, followed by dynamic simulation. Among the AVPs tested, AVP18, AVP10, and AVP7 demon­strated the highest inhibitory potential against the E6 oncoprotein. AVP18 exhibited more non-bonded contacts, hydrogen bonds, and electrostatic forces. Dynamics simulation confirmed the stability of the complexes formed by these top AVPs with E6. This research suggests that AVP7, AVP10, and AVP18 are promising lead candidates for blocking HPV16 by inhibiting the E6 oncoprotein. Keywords: antiviral peptides, docking, dynamics simulation, E6 oncoprotein, human papillomavirus

Phylogenetic Characterization of Novel Reassortant 2.3.4.4b H5N8 Highly Pathogenic Avian Influenza Viruses Isolated from Domestic Ducks in Egypt During the Winter Season 2021–2022

Avian influenza (AI) is an extremely contagious viral disease of domestic and wild birds that can spread rapidly among bird populations, inducing serious economic losses in the poultry industry. During the winter season 2021–2022, we isolated seventeen highly pathogenic avian influenza (HPAI) H5N8 viruses from outbreaks involving ducks in Egypt, occurring in both backyard and farm settings. The aim of this study was to pinpoint genetic key substitutions (KSs) that could heighten the risk of a human pandemic by influencing the virus’s virulence, replication ability, host specificity, susceptibility to drugs, or transmissibility. To understand their evolution, origin, and potential risks for a human pandemic, whole-genome sequencing and phylogenetic analysis were conducted. Our analysis identified numerous distinctive mutations in the Egyptian H5N8 viruses, suggesting potential enhancements in virulence, resistance to antiviral drugs, and facilitation of transmission in mammals. In this study, at least five genotypes within one genome constellation of H5N8 viruses were identified, raising concerns about the potential emergence of novel viruses with altered characteristics through reassortment between different genotypes and distinct groups. These findings underscore the role of ducks in the virus’s evolutionary process and emphasize the urgent need for enhanced biosecurity measures in domestic duck farms to mitigate pandemic risk.