Antiviral Research Articles

Human bronchopulmonary disposition and plasma pharmacokinetics of oral bemnifosbuvir (AT-527), an experimental guanosine nucleotide prodrug for COVID-19.

Bemnifosbuvir (AT-527) is a novel oral guanosine nucleotide antiviral drug for the treatment of persons with COVID-19. Direct assessment of drug disposition in the lungs, via bronchoalveolar lavage, is necessary to ensure antiviral drug levels at the primary site of SARS-CoV-2 infection are achieved. This Phase 1 study in healthy subjects aimed to assess the bronchopulmonary pharmacokinetics, safety and tolerability of repeated doses of bemnifosbuvir. A total of 24 subjects were assigned to receive bemnifosbuvir twice daily at doses of 275, 550 or 825 mg for up to 3.5 days. AT-511, the free base of bemnifosbuvir, was largely eliminated from the plasma within 6 h post dose in all dosing groups. Antiviral drug levels of bemnifosbuvir were consistently achieved in the lungs with bemnifosbuvir 550 mg twice daily. The mean level of the guanosine nucleoside metabolite AT-273, the surrogate of the active triphosphate metabolite of the drug, measured in the epithelial lining fluid of the lungs was 0.62 µM at 4-5 h post dose. This exceeded the target in vitro 90% effective concentration (EC90) of 0.5 µM for antiviral drug exposure against SARS-CoV-2 replication in human airway epithelial cells. Bemnifosbuvir was well tolerated across all doses tested, and most treatment-emergent adverse events reported were mild in severity and resolved. The favourable pharmacokinetics and safety profile of bemnifosbuvir demonstrates its potential as an oral antiviral treatment for COVID-19, with 550 mg bemnifosbuvir twice daily currently under further clinical evaluation in persons with COVID-19.

DeepAVP-TPPred: identification of antiviral peptides using transformed image-based localized descriptors and binary tree growth algorithm.

Despite the extensive manufacturing of antiviral drugs and vaccination, viral infections continue to be a major human ailment. Antiviral peptides (AVPs) have emerged as potential candidates in the pursuit of novel antiviral drugs. These peptides show vigorous antiviral activity against a diverse range of viruses by targeting different phases of the viral life cycle. Therefore, the accurate prediction of AVPs is an essential yet challenging task. Lately, many machine learning-based approaches have developed for this purpose; however, their limited capabilities in terms of feature engineering, accuracy, and generalization make these methods restricted. In the present study, we aim to develop an efficient machine learning-based approach for the identification of AVPs, referred to as DeepAVP-TPPred, to address the aforementioned problems. First, we extract two new transformed feature sets using our designed image-based feature extraction algorithms and integrate them with an evolutionary information-based feature. Next, these feature sets were optimized using a novel feature selection approach called binary tree growth (BTG) Algorithm. Finally, the optimal feature space from the training dataset was fed to the Deep neural network (DNN) to build the final classification model. The proposed model DeepAVP-TPPred was tested using stringent 5-fold cross-validation and two independent dataset testing methods, which achieved the maximum performance and showed an enhanced efficiency over existing predictors in terms of both accuracy and generalization capabilities. https://github.com/MateeullahKhan/DeepAVP-TPPred. Supplementary data are available at Bioinformatics online.

In vitro study of HPV18-positive cervical cancer HeLa cells based on CRISPR/Cas13a system.

The E6 protein is a known oncogene in cervical cancer and plays a key role in the development and progression of cervical cancer by reducing the expression level of the tumor suppressor protein P53 and ultimately leading to enhanced cell proliferation and reduced apoptosis. Therefore, antiviral agents that inhibit the expression of E6 oncoprotein are expected to be potential therapies for human cervical cancer. Here we developed CRISPR/Cas13a: crRNA dual plasmid system and demonstrated that CRISPR/Cas13a could effectively and specifically knock down human papillomavirus 18 E6 mRNA, downregulate the expression level of E6 protein, and restore the expression of the tumor suppressor gene P53 protein, thereby inhibiting the growth of cervical cancer cells and increasing their apoptosis, the E6-2, E6-3, and E6-5 groups resulted in apoptosis rates of 25.4%, 22.4%, and 22.2% in HeLa cells. Moreover, CRISPR/Cas13a enhances the proliferation inhibition and apoptosis induction of cisplatin in cervical cancer HeLa cells. The CRISPR/Cas13a system targeting HPV E6 mRNA may be a promising therapeutic approach for the treatment of human papillomavirus-associated cervical cancer.

The clinical outcomes and effectiveness of antiviral agents among underweight patients with COVID-19

ABSTRACT Objectives This study investigated the outcomes ofunderweight patients with COVID-19 and the effectiveness of antiviral agents inthis population. Methods A retrospective cohort study using theTriNetX research network wasconducted. Propensity score matching (PSM) was employed to balance the firstcohort involving COVID-19 patients with underweight and normal-weight. In thesecond cohort, underweight patients receiving antiviral agents and untreatedindividuals were matched using PSM. The primary outcome was a composite ofall-cause hospitalization and death during the 7–30-day follow-up period. Results After PSM, the first cohort including eachgroup of 13,502 patients with balanced baseline characteristics were identifiedfor comparing the outcome of patients with underweight and normal weight. The underweightgroup had a higher risk of the composite primary outcome than those with normalweight (hazard ratio [HR], 1.251; 95% confidence interval [CI], 1.132–1.382). The second cohort included each 884 underweight patients withand without receiving antivirals.Compared with untreated patients,those receiving antiviral treatment had a lower risk of composite primaryoutcomes (HR, 0.426; 95% CI, 0.278–0.653). Conclusion Underweight status may be associated with ahigher risk of all-cause hospitalization and death in patients with COVID-19.Among underweight patients, antiviral agents demonstrated clinically beneficial effects.

Carnosic Acid Inhibits Herpes Simplex Virus Replication by Suppressing Cellular ATP Synthesis

Acquiring resistance against antiviral drugs is a significant problem in antimicrobial therapy. In order to identify novel antiviral compounds, the antiviral activity of eight plants indigenous to the southern region of Hungary against herpes simplex virus-2 (HSV-2) was investigated. The plant extracts and the plant compound carnosic acid were tested for their effectiveness on both the extracellular and intracellular forms of HSV-2 on Vero and HeLa cells. HSV-2 replication was measured by a direct quantitative PCR (qPCR). Among the tested plant extracts, Salvia rosmarinus (S. rosmarinus) exhibited a 90.46% reduction in HSV-2 replication at the 0.47 μg/mL concentration. Carnosic acid, a major antimicrobial compound found in rosemary, also demonstrated a significant dose-dependent inhibition of both extracellular and intracellular forms of HSV-2. The 90% inhibitory concentration (IC90) of carnosic acid was between 25 and 6.25 μg/mL. Proteomics and high-resolution respirometry showed that carnosic acid suppressed key ATP synthesis pathways such as glycolysis, citrate cycle, and oxidative phosphorylation. Inhibition of oxidative phosphorylation also suppressed HSV-2 replication up to 39.94-fold. These results indicate that the antiviral action of carnosic acid includes the inhibition of ATP generation by suppressing key energy production pathways. Carnosic acid holds promise as a potential novel antiviral agent against HSV-2.

Covalent Polymer-RNA Conjugates for Potent Activation of the RIG-I Pathway.

RNA ligands of retinoic acid-inducible gene I (RIG-I) are a promising class of oligonucleotide therapeutics with broad potential as antiviral agents, vaccine adjuvants, and cancer immunotherapies. However, their translation has been limited by major drug delivery barriers, including poor cellular uptake, nuclease degradation, and an inability to access the cytosol where RIG-I is localized. Here this challenge is addressed by engineering nanoparticles that harness covalent conjugation of 5'-triphospate RNA (3pRNA) to endosome-destabilizing polymers. Compared to 3pRNA loaded into analogous nanoparticles via electrostatic interactions, it is found that covalent conjugation of 3pRNA improves loading efficiency, enhances immunostimulatory activity, protects against nuclease degradation, and improves serum stability. Additionally, it is found that 3pRNA could be conjugated via either a disulfide or thioether linkage, but that the latter is only permissible if conjugated distal to the 5'-triphosphate group. Finally, administration of 3pRNA-polymer conjugates to mice significantly increases type-I interferon levels relative to analogous carriers that use electrostatic 3pRNA loading. Collectively, these studies have yielded a next-generation polymeric carrier for in vivo delivery of 3pRNA, while also elucidating new chemical design principles for covalent conjugation of 3pRNA with potential to inform the further development of therapeutics and delivery technologies for pharmacological activation of RIG-I.

Antiviral Activities of Heparan Sulfate Mimetic RAFT Polymers Against Mosquito-borne Viruses.

Mosquito-borne viruses are a major worldwide health problem associated with high morbidity and mortality rates and significant impacts on national healthcare budgets. The development of antiviral drugs for both the treatment and prophylaxis of these diseases is thus of considerable importance. To address the need for therapeutics with antiviral activity, a library of heparan sulfate mimetic polymers was screened against dengue virus (DENV), Yellow fever virus (YFV), Zika virus (ZIKV), and Ross River virus (RRV). The polymers were prepared by RAFT polymerization of various acidic monomers with a target MW of 20 kDa (average Mn ∼ 27 kDa by GPC). Among the polymers, poly(SS), a homopolymer of sodium styrenesulfonate, was identified as a broad spectrum antiviral with activity against all the tested viruses and particularly potent inhibition of YFV (IC50 = 310 pM). Our results further uncovered that poly(SS) exhibited a robust inhibition of ZIKV infection in both mosquito and human cell lines, which points out the potential functions of poly(SS) in preventing mosquito-borne viruses associated diseases by blocking viral transmission in their mosquito vectors and mitigating viral infection in patients.

Safety, tolerability, and pharmacokinetics of the novel RdRp inhibitor SHEN26 against SARS-CoV-2: a randomized, placebo-controlled, double-blind phase I study in healthy subjects

ABSTRACT Background SHEN26, an oral broad-spectrum antiviral drug, possesses potent preclinical activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has a favorable safety profile. Methods We report safety, tolerability, and pharmacokinetic data from a randomized, double-blind, placebo-controlled phase I study of SHEN26. Eighty-six healthy subjects were enrolled in the three studies: a single ascending-dose study (SAD), a multiple ascending-dose study (MAD), and a food-effect study (FE). Results In the SAD trial, the maximum observed plasma concentration (Cmax) and area under the curve (AUC) of the SHEN26 rapid metabolite SHEN26-69-0 increased approximately dose-proportionally in the 50–400 mg fasting dose range. In the 800 mg dose group, standard meals increased the Cmax and AUC of SHEN26-69-0. In the MAD trial, the accumulation ratios of Cmax and AUC indicated slight accumulation upon repeated SHEN26 dosing. In the FE trial, a high-fat meal prolonged the time to maximum plasma concentration (Tmax) and increased the Cmax and AUC of SHEN26-69-0 compared with fasting administration. Most treatment-related adverse events were mild and resolved without treatment. Conclusion SHEN26 demonstrated satisfactory safety and tolerability in healthy subjects, which supports the continued study of SHEN26 against SARS-CoV-2. Trial Registration The trial is registered in ClinicalTrials.gov (CT. gov identifier: NCT05504746).

Purification of living environments using photocatalysts: inactivation of microorganisms and decomposition of allergens.

Many emerging and re-emerging infectious diseases are prevalent, and the number of patients with allergies is increasing. Therefore, the importance of purifying the living environment is increasing. Photocatalysts undergo extreme redox reactions and decompose organic matter upon exposure to the excitation light. In contrast to ultraviolet light and disinfectants, which are standard methods for inactivating viruses and eliminating microorganisms, photocatalysts can decompose toxic substances, such as endotoxins and allergens, rendering them harmless to the human body. Photocatalysts have attracted significant attention as potential antiviral and antimicrobial agents. This review outlines the antiviral, antimicrobial, and anti-allergenic effects of photocatalysts. Especially, we have discussed the inactivation of SARS-CoV-2 in liquids and aerosols, elimination of Legionella pneumophila in liquids, decomposition of its endotoxin, decomposition of cat and dog allergens, and elimination of their allergenicity using photocatalysts. Furthermore, we discuss future perspectives on how photocatalysts can purify living environments, and how photocatalytic technology can be applied to companion animals and the livestock industry.

АНАЛИЗ КЛИНИЧЕСКОГО СЛУЧАЯ ВУЛЬГАРНОЙ ПУЗЫРЧАТКИ, АССОЦИИРОВАННОЙ С ХРОНИЧЕСКОЙ ВЭБ-ИНФЕКЦИЕЙ (ГЛОССИТА, ОБУСЛОВЛЕННОГО ВЭБ)

Background. One of the autoimmune diseases is pemphigus, a chronic malignantly occurring autoimmune dermatosis accompanied by the development of blisters on the skin and mucous membranes. Isolated lesions of the SOPR occur in 10–20% of cases, complicating differential diagnosis. Numerous studies have proven the role of herpes virus infection as an aggravating factor in the course of true acantholytic pemphigus. The aim of the study was to determine the features of the clinical course of vulgar pemphigus against the background of reactivation of chronic EBV infection (glossitis caused by EBV). The clinical case of a patient with a diagnosis of “Vulgar pemphigus. Glossitis caused by the Epstein-Barr virus”. The anamnesis of the disease was carefully collected, a clinical and laboratory examination was performed with a cytological examination of a smear taken from a LITTER, a general blood test with an expanded leukocyte formula, C-reactive protein. In order to diagnose the viral load, PCR diagnostics was performed on the DNA of the herpes virus 1, 2, 4, 5 types in saliva, on the DNA of EBV in the blood, quantitatively. Specific antibodies of Ig classes M and G to EBV were determined by the ELISA method. Results. Due to the lifelong persistence of EBV in the structures of the oral cavity, its reactivation leads not only to chronic pastoral infection and the local development of the corresponding glossitis, but also, first of all, to a decrease in the level of local immunity. This fact aggravates the course of pemphigus, shortens the period of absence of relapse. The appointment of antiviral therapy at the first visit allowed to stabilize the symptoms caused by EBV, which led to positive dynamics in the course of pemphigus against the background of average dosages of prednisone in a shorter time. Conclusions. With clinical and laboratory confirmation of chronic EBV infection (glossitis caused by EBV), it is recommended to include antiviral and immunocorrective drugs, systemically and topically, in the complex treatment of pemphigus erythematosus.

Exploring the Communication, Information, and Education Strategies of the Indonesian FDA for COVID-19 Vaccine Development

The COVID-19 pandemic has become a complicated problem faced by the world. The absence of specific antiviral drugs or vaccines at the beginning of the outbreak made the public health approach the primary strategy for preventing the spread of COVID-19. The lack of transparency at the start of the COVID-19 outbreak also led to public misinformation. WHO called it an infodemic, an excess of information, whether true or not, making it difficult for people to determine valid references. In Indonesia, misinformation on health matters is not a new difficulty and is in the top rank along with socio-political. The government utilizes social media to provide information to the citizens. Social media itself has a vital role in the infodemic as a medium for disseminating information, whether credible or not. The Indonesian FDA plays an essential role in conducting education through social media. This study aims to map the elements forming citizens' engagement in Indonesian FDA social media use, especially in disseminating information about the COVID-19 vaccine. This study uses a regression method with citizens' engagement (calculated from the number of likes and comments) as the dependent variable. Three independent variables form citizen engagement elements: media richness, content production, and content type defined by the government. The sentiment toward government Instagram posts was measured by analyzing citizens' comments using the dataset from InSet Semantic Lexicon. Based on negative binomial regression results, data obtained that the framework developed in this research was statistically significant in observing the phenomenon. Media richness and content production significantly affect citizens' engagement. On the other hand, original and informative content encourages more citizen engagement. Generally, public sentiment on Indonesian FDA Instagram content, both head office and regional offices, tends to be more positive than negative.

Impurity Study of Tecovirimat

This article delineates the systematic identification, synthesis, and impurity control methods used during the manufacturing process development of tecovirimat, an antiviral drug that treats monkeypox. Critical impurities were synthesized, and their chemical structure was confirmed through NMR analysis, GC, and HPLC mass spectrometry. The results established a thorough approach to identify, address, and control impurities to produce high-quality tecovirimat drug substance in accordance with International Conference on Harmonization (ICH)-compliant standards. This study is the first of its kind to evaluate both process and genotoxic impurities in tecovirimat, demonstrating effective control measures during commercial sample investigations and scaling up to a 60-kilogram batch size. The findings highlight the importance of critical impurity characterization and control in pharmaceutical development and production to ensure the safety and efficacy of the final product.

Novel insights into the host cell glycan binding profile of human metapneumovirus.

Numerous viruses have been found to exploit glycoconjugates expressed on human cells as their initial attachment factor for viral entry and infection. The virus-cell glycointeractome, when characterized, may serve as a template for antiviral drug design. Heparan sulfate proteoglycans extensively decorate the human cell surface and were previously described as a primary receptor for human metapneumovirus (HMPV). After respiratory syncytial virus, HMPV is the second most prevalent respiratory pathogen causing respiratory tract infection in young children. To date, there is neither vaccine nor drug available to prevent or treat HMPV infection. Using a multidisciplinary approach, we report for the first time the glycointeractome of the HMPV fusion (F) protein, a viral surface glycoprotein that is essential for target-cell recognition, attachment, and entry. Our glycan microarray and surface plasmon resonance results suggest that Galβ1-3/4GlcNAc moieties that may be sialylated or fucosylated are readily recognized by HMPV F. The bound motifs are highly similar to the N-linked and O-linked glycans primarily expressed on the human lung epithelium. We demonstrate that the identified glycans have the potential to compete with the cellular receptors used for HMPV entry and consequently block HMPV infection. We found that lacto-N-neotetraose demonstrated the strongest HMPV binding inhibition in a cell infection assay. Our current findings offer an encouraging and novel avenue for the design of anti-HMPV drug candidates using oligosaccharide templates.IMPORTANCEAll cells are decorated with a dense coat of sugars that makes a sugar code. Many respiratory viruses exploit this sugar code by binding to these sugars to cause infection. Human metapneumovirus is a leading cause for acute respiratory tract infections. Despite its medical importance, there is no vaccine or antiviral drug available to prevent or treat human metapneumovirus infection. This study investigates how human metapneumovirus binds to sugars in order to more efficiently infect the human host. We found that human metapneumovirus binds to a diverse range of sugars and demonstrated that these sugars can ultimately block viral infection. Understanding how viruses can take advantage of the sugar code on our cells could identify new intervention and treatment strategies to combat viral disease.

Development in the Inhibition of Dengue Proteases as Drug Targets.

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. 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 US-FDA 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. 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.

Therapeutic Intervention of Serine Protease Inhibitors against Hepatitis C Virus.

Hepatitis C virus (HCV) is a globally prevalent and hazardous disorder that is responsible for inducing several persistent and potentially fatal liver diseases. Current treatment strategies offer limited efficacy, often accompanied by severe and debilitating adverse effects. Consequently, there is an urgent and compelling need to develop novel therapeutic interventions that can provide maximum efficacy in combating HCV while minimizing the burden of adverse effects on patients. One promising target against HCV is the NS3-4A serine protease, a complex composed of two HCV-encoded proteins. This non-covalent heterodimer is crucial in the viral life cycle and has become a primary focus for therapeutic interventions. Although peginterferon, combined with ribavirin, is commonly employed for HCV treatment, its efficacy is hampered by significant adverse effects that can profoundly impact patients' quality of life. In recent years, the development of direct-acting antiviral agents (DAAs) has emerged as a breakthrough in HCV therapy. These agents exhibit remarkable potency against the virus and have demonstrated fewer adverse effects when combined with other DAAs. However, it is important to note that there is a potential for developing resistance to DAAs due to alterations in the amino acid position of the NS3-4A protease. This emphasizes the need for ongoing research to identify strategies that can minimize the emergence of resistance and ensure long-term effectiveness. While the combination of DAAs holds promise for HCV treatment, it is crucial to consider the possibility of drug-drug interactions. These interactions may occur when different DAAs are used concurrently, potentially compromising their therapeutic efficacy. Therefore, carefully evaluating and monitoring potential drug interactions are vital to optimize treatment outcomes. In the pursuit of novel therapeutic interventions for HCV, the field of computational biology and bioinformatics has emerged as a valuable tool. These advanced technologies and methodologies enable the development and design of new drugs and therapeutic agents that exhibit maximum efficacy, reduced risk of resistance, and minimal adverse effects. By leveraging computational approaches, researchers can efficiently screen and optimize potential candidates, accelerating the discovery and development of highly effective treatments for HCV, treatments.

Pharmacological activation of TLR7 exerts inhibition on the replication of EV-D68 in respiratory cells.

The globally reemerging respiratory pathogen enterovirus D68 (EV-D68) is implicated in outbreaks of severe respiratory illness and associated with acute flaccid myelitis. However, there remains a lack of effective treatments for EV-D68 infection. In this work, we found that the host Toll-like receptor 7 (TLR7) proteins, which function as powerful innate immune sensors, were selectively elevated in expression in response to EV-D68 infection. Subsequently, we investigated the impact of Vesatolimod (GS-9620), a Toll-like receptor 7 agonist, on EV-D68 replication. Our findings revealed that EV-D68 infection resulted in increased mRNA levels of TLR7. Treatment with Vesatolimod significantly inhibited EV-D68 replication [half maximal effective concentration (EC50) = 0.1427 µM] without inducing significant cytotoxicity at virucidal concentrations. Although Vesatolimod exhibited limited impact on EV-D68 attachment, it suppressed RNA replication and viral protein synthesis after virus entry. Vesatolimod broadly inhibited the replication of circulating isolated strains of EV-D68. Furthermore, our findings demonstrated that treatment with Vesatolimod conferred resistance to both respiratory and neural cells against EV-D68 infection. Overall, these results present a promising strategy for drug development by pharmacologically activating TLR7 to initiate an antiviral state in EV-D68-infected cells selectively.IMPORTANCEConventional strategies for antiviral drug development primarily focus on directly targeting viral proteases or key components, as well as host proteins involved in viral replication. In this study, based on our intriguing discovery that enterovirus D68 (EV-D68) infection specifically upregulates the expression of immune sensor Toll-like receptor 7 (TLR7) protein, which is either absent or expressed at low levels in respiratory cells, we propose a potential antiviral approach utilizing TLR7 agonists to activate EV-D68-infected cells into an anti-viral defense state. Notably, our findings demonstrate that pharmacological activation of TLR7 effectively suppresses EV-D68 replication in respiratory tract cells through a TLR7/MyD88-dependent mechanism. This study not only presents a promising drug candidate and target against EV-D68 dissemination but also highlights the potential to exploit unique alterations in cellular innate immune responses induced by viral infections, selectively inducing a defensive state in infected cells while safeguarding uninfected normal cells from potential adverse effects associated with therapeutic interventions.

Marine Fungi of the Genera Aspergillus and Penicillium: A Promising Reservoir of Chemical Diversity for Developing Anti-Viral Drug Candidates

Marine Fungi of the Genera Aspergillus and Penicillium: A Promising Reservoir of Chemical Diversity for Developing Anti-Viral Drug Candidates

The Terminase Complex of Each Human Herpesvirus.

The human herpesviruses (HHVs) are classified into the following three subfamilies: Alphaherpesvirinae, Betaherpesvirinae, and Gammaherpesvirinae. These HHVs have distinct pathological features, while containing a highly conserved viral replication pathway. Among HHVs, the basic viral particle structure and the sequential processes of viral replication are nearly identical. In particular, the capsid formation mechanism has been proposed to be highly similar among herpesviruses, because the viral capsid-organizing proteins are highly conserved at the structural and functional levels. Herpesviruses form capsids containing the viral genome in the nucleus of infected cells during the lytic phase, and release infectious virus (i.e., virions) to the cell exterior. In the capsid formation process, a single-unit-length viral genome is encapsidated into a preformed capsid. The single-unit-length viral genome is produced by cleavage from a viral genome precursor in which multiple unit-length viral genomes are tandemly linked. This encapsidation and cleavage is carried out by the terminase complex, which is composed of viral proteins. Since the terminase complex-mediated encapsidation and cleavage is a virus-specific mechanism that does not exist in humans, it may be an excellent inhibitory target for anti-viral drugs with high virus specificity. This review provides an overview of the functions of the terminase complexes of HHVs.

Electrochemical Investigations and Molecular Docking Analysis to Evaluate the Molnupiravir-Calf Thymus dsDNA Interaction

Molnupiravir (MLP) is an important antiviral drug recommended for the treatment of COVID-19. In order to design new pharmaceuticals, exploring drug and DNA interaction is crucial. This study aimed to determine the interaction of MLP with calf thymus double-stranded DNA (ct-dsDNA) by electrochemical methods. Investigation of these interactions was carried out using the differential pulse voltammetry technique (DPV) on the biosensor surface and in-solution studies. Changes in ct-dsDNA between deoxyguanosine (dGuo) and deoxyadenosine (dAdo) oxidation signals were examined before and after the interaction. It was found that MLP interacts significantly with bases of ct-dsDNA dAdo. Limits of detection and quantification for MLP-ct-dsDNA interaction were calculated as 2.93 and 9.67 μM in the linear range of 10–200 μM, respectively, based on dAdo’s decreasing peak current. To calculate the binding constant of MLP and ct-dsDNA, cyclic voltammetry was used, and it was found to be 8.6 × 104 M. As for molecular docking techniques, the binding energy of MLP with DNA is −8.1 kcal mol−1, and this binding occurred by a combination of strong conventional hydrogen bonding to both adenine and guanine base pair edges, which indicates the interaction of MLP with DNA.

An eco-friendly and cost-effective HPTLC method for quantification of COVID-19 antiviral drug and co-administered medications in spiked human plasma

The coronavirus-2 has led to a global pandemic of COVID-19 with an outbreak of severe acute respiratory syndrome leading to worldwide quarantine measures and a rise in death rates. The objective of this study is to propose a green, sensitive, and selective densitometric method to simultaneously quantify remdesivir (REM) in the presence of the co-administered drug linezolid (LNZ) and rivaroxaban (RIV) in spiked human plasma. TLC silica gel aluminum plates 60 F254 were used as the stationary phase, and the mobile phase was composed of dichloromethane (DCM): acetone (8.5:1.5, v/v) with densitometric detection at 254 nm. Well-resolved peaks have been observed with retardation factors (Rf) of 0.23, 0.53, and 0.72 for REM, LNZ, and RIV, respectively. A validation study was conducted according to ICH Q2 (R1) Guidelines. The method was rectilinear over the concentration ranges of 0.2–5.5 μg/band, 0.2–4.5 μg/band and 0.1–3.0 μg/band for REM, LNZ and RIV, respectively. The sensitivities of REM, LIN, and RIV were outstanding, with quantitation limits of 128.8, 50.5, and 55.8 ng/band, respectively. The approach has shown outstanding recoveries ranging from 98.3 to 101.2% when applied to pharmaceutical formulations and spiked human plasma. The method’s greenness was assessed using Analytical Eco-scale, GAPI, and AGREE metrics.