Antiviral Research Articles

A Retrospective Claims Data Analysis on the Burden of COVID-19-Related Hospitalization in Adults at High Risk for Severe Disease Progression in Germany.

Individuals at increased risk of severe coronavirus disease 2019 (COVID-19) progression have a higher probability of being hospitalized. Nirmatrelvir/ritonavir (NMV/r) is an antiviral drug aiming to prevent severe disease courses. Our study aimed to assess the resource utilization and costs of adults hospitalized for COVID-19 at high risk for severe disease progression. A retrospective study was conducted using German claims data. The presence of high-risk criteria was determined through recorded diagnoses, operations, procedures, and prescriptions. Individuals at high risk for severe COVID-19 progression, primarily hospitalized for COVID-19, required a recorded diagnosis for COVID-19 and additionally a diagnosis of sepsis, pulmonary embolism, acute respiratory failure, pneumonia, or a remdesivir prescription. Patients were grouped by eligibility for NMV/r treatment (eligible, eligible with restrictions, and not eligible). The outcomes of interest were reported for the timeframe of the last dominant virus variant available in the database, i.e., Delta (June 21, 2021 to December 31, 2021). Of approximately 3.7 million individuals continuously observable in the database, about 60% were identified as being at high risk for severe COVID-19 progression. Among high-risk individuals, 2938 patients were primarily hospitalized for COVID-19 between June 21, 2021, and December 31, 2021, two-thirds of which were suitable for NMV/r treatment (half without restrictions). Advanced age (86.3%) and cardiovascular conditions (83.9%) were the most prevalent of the predefined risk factors. Identified patients stayed, on average, 11.3 days in hospital, with inpatient mortality of 18.9%. These COVID-19-related hospitalizations resulted in mean healthcare costs of €8728. This study reflects the economic burden of hospitalized adult individuals with COVID-19 at high risk for severe disease progression from payer's perspective in Germany. Our findings highlight the need to prevent severe disease courses and associated hospitalizations to relieve healthcare systems regarding costs and resource allocation.

Effects of combined immunosuppressant and hepatitis B virus antiviral use on COVID-19 vaccination in recipients of living donor liver transplantation.

The global pandemic caused by the highly contagious SARS-CoV-2 virus led to the emergency approval of COVID-19 vaccines to reduce rising morbidity and mortality. However, limited research exists on evaluating the impact of these vaccines on immunocompromised individuals, such as recipients of living donor liver transplantation, highlighting the need for further studies to better understand their effectiveness in this specific population. From June 2021, we followed up on the effectiveness of the vaccine for patients taking immunosuppressive drugs after living-donor liver transplantation (LDLT). A total of 105 immunocompromised individuals participated, of which 50 patients with hepatitis B were taking antiviral drugs. Patients were assessed to analyze how the combination of immunosuppressive and antiviral drugs affected the efficacy of the BNT162b2, mRNA-1273, and ChAdOx1 nCoV-19 COVID-19 vaccines. Before and after the vaccinations, patients were monitored to establish differences between immunosuppressed patients and those additionally taking antiviral drugs. In immunocompromised patients taking antiviral drugs for hepatitis B, we confirmed that the effect of the COVID-19 vaccine was reduced when compared to immunocompromised patients. Interestingly, 23 patients (11 without and 12 additionally with hepatitis B drug administration) encountered breakthrough infections, and although there was a minor discrepancy in vaccine efficacy among the patients taking antiviral drugs for hepatitis B, it did not reach statistical significance. Additional COVID-19 vaccination is recommended for patients taking immunosuppressive drugs and hepatitis B antiviral drugs after LDLT.

Exploring Mycolactone—The Unique Causative Toxin of Buruli Ulcer: Biosynthetic, Synthetic Pathways, Biomarker for Diagnosis, and Therapeutic Potential

Mycolactone is a complex macrolide toxin produced by Mycobacterium ulcerans, the causative agent of Buruli ulcer. The aim of this paper is to review the chemistry, biosynthetic, and synthetic pathways of mycolactone A/B to help develop an understanding of the mode of action of these polyketides as well as their therapeutic potential. The synthetic work has largely been driven by the desire to afford researchers enough (≥100 mg) of the pure toxins for systematic biological studies toward understanding their very high biological activities. The review focuses on pioneering studies of Kishi which elaborate first-, second-, and third-generation approaches to the synthesis of mycolactones A/B. The three generations focused on the construction of the key intermediates required for the mycolactone synthesis. Synthesis of the first generation involves assignment of the relative and absolute stereochemistry of the mycolactones A and B. This was accomplished by employing a linear series of 17 chemical steps (1.3% overall yield) using the mycolactone core. The second generation significantly improved the first generation in three ways: (1) by optimizing the selection of protecting groups; (2) by removing needless protecting group adjustments; and (3) by enhancing the stereoselectivity and overall synthetic efficiency. Though the synthetic route to the mycolactone core was longer than the first generation, the overall yield was significantly higher (8.8%). The third-generation total synthesis was specifically aimed at an efficient, scalable, stereoselective, and shorter synthesis of mycolactone. The synthesis of the mycolactone core was achieved in 14 linear chemical steps with 19% overall yield. Furthermore, a modular synthetic approach where diverse analogues of mycolactone A/B were synthesized via a cascade of catalytic and/or asymmetric reactions as well as several Pd-catalyzed key steps coupled with hydroboration reactions were reviewed. In addition, the review discusses how mycolactone is employed in the diagnosis of Buruli ulcer with emphasis on detection methods of mass spectrometry, immunological assays, RNA aptamer techniques, and fluorescent-thin layer chromatography (f-TLC) methods as diagnostic tools. We examined studies of the structure–activity relationship (SAR) of various analogues of mycolactone. The paper highlights the multiple biological consequences associated with mycolactone such as skin ulceration, host immunomodulation, and analgesia. These effects are attributed to various proposed mechanisms of actions including Wiskott–Aldrich Syndrome protein (WASP)/neural Wiskott–Aldrich Syndrome protein (N-WASP) inhibition, Sec61 translocon inhibition, angiotensin II type 2 receptor (AT2R) inhibition, and inhibition of mTOR. The possible application of novel mycolactone analogues produced based on SAR investigations as therapeutic agents for the treatment of inflammatory disorders and inflammatory pain are discussed. Additionally, their therapeutic potential as anti-viral and anti-cancer agents have also been addressed.

Study anti-viral drugs for their efficiency against multiple SARS CoV-2 drug targets within molecular docking, molecular quantum similarity, and chemical reactivity indices frameworks

The study focused on drug discovery for COVID-19, emphasizing the challenges posed by the pandemic and the importance of understanding the virus’s biology. The research utilized molecular docking and quantum similarity analyses to explore potential ligands for SARS-CoV-2 RNA-dependent RNA polymerase. Docking Results Docking outcomes for various ligands, including Oseltamivir, Prochloraz, Valacyclovir, Baricitinib, Molnupiravir, Penciclovir, Famciclovir, Lamivudine, and Nitazoxanide, were presented. Interactions between ligands and specific residues in the RNA-dependent RNA polymerase were analyzed. Reactivity Descriptors Global parameters, such as electronic chemical potential, chemical hardness, global softness, and global electrophilicity, were computed for the ligands. For the local reactivity descriptors, the Fukui Functions were used. Fukui functions, representing electrophilic and nucleophilic sites, were calculated for selected ligands (Valacyclovir and Penciclovir). Nucleophilic character assignments for specific molecular regions were discussed, providing insights into potential charge-donating interactions. Results and Discussion Challenges in COVID-19 drug discovery, such as virus mutability, rapid evolution, and resource limitations, were summarized. Progress in vaccine development and the need for ongoing research to address variants and breakthrough cases were emphasized. Overlap Operator Analysis Higher MQSM between Lamivudine and Molnupiravir (0.5742) indicates structural and electronic similarity. Lowest MQSM between Oseltamivir and Prochloraz (0.2233) implies structural dissimilarity. Coulomb Operator Analysis Higher MQSM between Lamivudine and Molnupiravir (0.9178) suggests both structural and electronic similarity. Lowest MQSM between Baricitinib and Famciclovir (0.6001) indicates greater structural diversity. Measurements above 0.5 in Table 3 suggest electronic similarity, emphasizing the electronic aspects in molecular analysis. In this sense, it study employed a multi-faceted approach combining molecular docking, quantum similarity analyses, and chemical reactivity assessments to explore potential drug candidates for COVID-19. The findings provide valuable insights into ligand interactions, reactivity patterns, and the challenges associated with drug discovery in the context of the global pandemic.

Repurposing raltegravir for reducing inflammation and treating cancer: a bioinformatics analysis

Inflammation is a defensive mechanism that safeguards the human body against detrimental stimuli. Within this intricate process, ADAM17, a zinc-dependent metalloprotease, emerges as an indispensable element, fostering the activation of diverse inflammatory and growth factors within the organism. Nonetheless, ADAM17 malfunctions can augment the rate of growth, inflammatory factors, and subsequent damage. Thus, in this study, we examined and repurposed drugs to suppress the activity of ADAM17. To this end, we employed bioinformatics techniques such as molecular docking, molecular dynamics, and pharmacokinetic studies. Five FDA-approved drugs including Raltegravir, Conivaptan, Paclitaxel, Saquinavir, and Venetoclax with the ability to impede the activity of the ADAM17 metalloenzyme were identified. Moreover, these drugs did not include strong zinc-binding functional groups when verified by the ACE functional group finder. However, further in silico analysis has indicated that Raltegravir demonstrates a commendable interaction with the active site amino acids and exhibits the most favorable pharmacokinetic properties compared to others. Considering the results of bioinformatics tools, it can be concluded that Raltegravir as an antiviral drug could be repurposed to prevent severe inflammatory response and tumorigenesis resulting from ADAM17 malfunction.

Porcine ISG15 fused IFN-λ3 as a novel antiviral agent for treating porcine reproductive and respiratory syndrome virus infection in vivo.

IFN-λs hold promise as therapeutic candidates against mutable respiratory viruses, but their efficacy against porcine reproductive and respiratory syndrome virus (PRRSV) remains unclear. In this study, we expressed a recombinant fusion protein consisting of porcine ISG15 linked porcine IFN-λ3 (ISG15-IFN-λ3) via a rigid protein linker in Escherichia coli (E. coli). In vitro experiments demonstrated that treatment of porcine alveolar macrophage (PAM)-derived CRL-2843 cells with ISG15-IFN-λ3 induced upregulation of several Interferon-stimulated Genes (ISGs) proteins, including ISG15, ISG56, and HERC5. CRL-2843 cells pretreated with ISG15-IFN-λ3 exhibited heightened resistance to Newcastle disease virus infection, while PRRSV-permissive cells treated with ISG15-IFN-λ3 before and during PRRSV exposure showed significantly inhibited PRRSV replication as well. In animal experiments, at 21 days post-infection, ISG15-IFN-λ3-treated piglets displayed milder lung tissue pathology and significantly reduced serum PRRSV-RNA, indicating enhanced viral clearance and faster recovery. Additionally, PAMs collected from ISG15-IFN-λ3-treated piglets showed significantly reduced mRNA expression of representative cytokines, chemokines, suggesting that ISG15-IFN-λ3 treatment may mitigate pneumonia severity by reducing the levels of these inflammatory mediators. These findings indicate that recombinant ISG15-IFN-λ3 expressed in E. coli may serve as a novel, effective, and affordable agent for treating severe PRRSV infection in piglets, potentially benefiting the pork industry.

A novel microRNA promotes coxsackievirus B4 infection of pancreatic β cells.

The epidemiological association of coxsackievirus B infection with type 1 diabetes suggests that therapeutic strategies that reduce viral load could delay or prevent disease onset. Moreover, recent studies suggest that treatment with antiviral agents against coxsackievirus B may help preserve insulin levels in type 1 diabetic patients. In the current study, we performed small RNA-sequencing to show that infection of immortalized trophoblast cells with coxsackievirus caused differential regulation of several miRNAs. One of these, hsa-miR-AMC1, was similarly upregulated in human pancreatic β cells infected with coxsackievirus B4. Moreover, treatment of β cells with non-cytotoxic concentrations of an antagomir that targets hsa-miR-AMC1 led to decreased CVB4 infection, suggesting a positive feedback loop wherein this microRNA further promotes viral infection. Interestingly, some predicted target genes of hsa-miR-AMC1 are shared with hsa-miR-184, a microRNA that is known to suppress genes that regulate insulin production in pancreatic β cells. Consistently, treatment of coxsackievirus B4-infected β cells with the hsa-miR-AMC1 antagomir was associated with a trend toward increased insulin production. Taken together, our findings implicate novel hsa-miR-AMC1 as a potential early biomarker of coxsackievirus B4-induced type 1 diabetes and suggest that inhibiting hsa-miR-AMC1 may provide therapeutic benefit to type 1 diabetes patients. Our findings also support the use of trophoblast cells as a model for identifying microRNAs that might be useful diagnostic markers or therapeutic targets for coxsackievirus B-induced type 1 diabetes.

Interaction Between the Matrix Protein and the Polymerase Complex of Respiratory Syncytial Virus

The global burden of respiratory syncytial virus (RSV) and severe associated disease is prodigious. RSV-specific vaccines have been launched recently but there is no antiviral medicine commercially available. RSV polymerase (L) protein is one of the promising antiviral targets, along with fusion and nucleocapsid proteins. During medicinal chemistry campaigns, two potent L-protein inhibitors (PC786 and PC751) were identified. Both compounds inhibited the RSV A/B-induced cytopathic effect in HEp-2 cells equally, but PC786 was more potent than PC751 in bronchial epithelial cells. Repeated treatment with escalating concentrations on RSV A2-infected HEp-2 cells revealed both inhibitors led to a Y1631H mutation in the L protein, but only PC786 induced a mutation in the M protein (V153A). By L protein fragment and M protein binding analysis, we showed that the M protein interacts with the 1392–1735 amino acid region of the L protein, where PC786 potentially binds. In addition, PC786 treatment or PC786-induced mutant RSV was found to increase M-protein nuclear localisation later in infection, concomitant with delayed fusion protein localisation at the budding viral filaments. As M protein is known to play a key role in virus assembly and budding late in infection, our data suggests that disrupting the interaction between the M and L proteins could provide a novel target for antiviral development.

Discovery of New 1,2,4-Triazole/1,3,4-Oxadiazole-Decorated Quinolinones as Agrochemical Alternatives for Controlling Viral Infection by Inhibiting the Viral Replication and Self-Assembly Process.

Tobacco mosaic virus (TMV), a representative plant virus, is widely known and causes severe crop losses worldwide. In order to ensure the demand for crop and food security, the exploration of novel antiviral agents with outstanding activity and unique mechanisms of action is necessary. Herein, 40 new azole-quinolinone molecules were elaborately designed and systematically evaluated for their anti-TMV activity. Notably, compound A21 had significant therapeutic activity against TMV (EC50 value = 200 μg/mL), which was superior to commercial ningnanmycin (280 μg/mL). Studies on the anti-TMV mechanism showed that compound A21 could suppress the expression level of important TMV genes and affect the assembly of TMV viral particles by disrupting the self-assembly process of TMV coat protein (TMV-CP). In-depth antiviral behaviors were verified by molecular docking, fluorescence titration analysis, and TMV assembly assays, suggesting that compound A21 strongly interacted with TMV coat protein through various interactions. Overall, this promising work discloses a new paradigm for the exploitation of 2-quinolinone-based virucidal agents for hindering plant viral infection through triggering versatile antiviral behavior.

Therapeutic Drug Monitoring of Nirmatrelvir/Ritonavir (Paxlovid) in Patients Treated for COVID-19: Results from a Prospective Multicenter Observational Study

Background: Paxlovid is a combination of the antiviral agents nirmatrelvir and ritonavir indicated for the oral treatment of high-risk, symptomatic patients with coronavirus disease 2019 (COVID-19). As real-world data on the plasma concentrations of nirmatrelvir/ritonavir (Paxlovid) are limited, the aim of this study was to investigate nirmatrelvir/ritonavir plasma trough levels in a clinical setting using therapeutic drug monitoring. Methods: A prospective, noninterventional, multicenter, observational clinical study was conducted in which the plasma trough levels of nirmatrelvir/ritonavir were simultaneously determined by using liquid chromatography tandem mass spectrometry in patients with symptomatic COVID-19. The blood samples were collected on days 1, 3, and 5 after the first full-dose day (day 0), and patient data such as sex, height, weight, renal function, liver enzymes, and concomitant (co-) medications were obtained to describe the plasma levels with respect to potential influencing factors. Results: A total of 46 blood samples from 21 patients were analyzed. The geometric mean Cmin was 4997 ng/mL for nirmatrelvir and 529.4 ng/mL for ritonavir. The plasma concentrations covered a wide range, the highest being observed in patients with advanced age and renally excreted comedications. Patients older than 65 years had a significantly higher risk of achieving excessive plasma trough concentrations above 8840 ng/mL for nirmatrelvir and 1440 ng/mL for ritonavir compared with younger patients (odds ratio 11.2, 95% confidence interval 1.04–120.4). Conclusions: The plasma trough concentrations of nirmatrelvir and ritonavir in patients treated for symptomatic COVID-19 were higher than the reference values of 2210 ng/mL for nirmatrelvir and 360 ng/mL for ritonavir stated in the product characteristics. Advanced age and renally eliminated comedication were identified as possible influencing factors that warrant further investigation.

Comprehensive analysis of the first complete mitogenome and plastome of a traditional Chinese medicine Viola diffusa

BackgroundViola diffusa is used in the formulation of various Traditional Chinese Medicines (TCMs), including antiviral, antimicrobial, antitussive, and anti-inflammatory drugs, due to its richness in flavonoids and triterpenoids. The biosynthesis of these compounds is largely mediated by cytochrome P450 enzymes, which are primarily located in the membranes of mitochondria and the endoplasmic reticulum.ResultsThis study presents the complete assembly of the mitogenome and plastome of Viola diffusa. The circular mitogenome spans 474,721 bp with a GC content of 44.17% and encodes 36 unique protein-coding genes, 21 tRNA, and 3 rRNA. Except for the RSCU values of 1 observed for the start codon (AUG) and tryptophan (UGG), the mitochondrial protein-coding genes exhibited a codon usage bias, with most estimates deviating from 1, similar to patterns observed in closely related species. Analysis of repetitive sequences in the mitogenome demonstrated potential homologous recombination mediated by these repeats. Sequence transfer analysis revealed 24 homologous sequences shared between the mitogenome and plastome, including nine full-length genes. Collinearity was observed among Viola diffusa species within the other members of Malpighiales order, indicated by the presence of homologous fragments. The length and arrangement of collinear blocks varied, and the mitogenome exhibited a high frequency of gene rearrangement.ConclusionsWe present the first complete assembly of the mitogenome and plastome of Viola diffusa, highlighting its implications for pharmacological, evolutionary, and taxonomic studies. Our research underscores the multifaceted importance of comprehensive mitogenome analysis.

Synergistic potential of lopinavir and azole combinational therapy against clinically important Aspergillus species.

Aspergillus fumigatus is a widely distributed pathogen responsible for severe infections, particularly in immunocompromised individuals. Triazoles are the primary treatments options for Aspergillus infections; however, the emergence of acquired resistance to this antifungal class is becoming a growing concern. In this study, we investigated the potential of the antiviral drug, lopinavir (LPV) to restore the susceptibility of A. fumigatus strains to a set of azoles, while also reducing the required azole dosage for treatment of susceptible isolates. The combination of LPV with either itraconazole (ITC) or posaconazole (POS) demonstrated potent synergistic interactions against 16 out of 23 (~70%) and 21 out of 23 (~91%) A. fumigatus isolates, respectively. Moreover, the combination showed synergistic activity against other clinically important Aspergillus species, including A. niger, A. flavus, and A. brasiliensis. The fractional inhibitory concentration index (FICI) for the combinations ranged from 0.18 to 0.313 for ITC and 0.091 to 0.313 for POS, indicating strong synergistic effects. Further investigation revealed that efflux pump inhibition contributed to the synergy observed between azole and LPV. Morphological examination of the fungal cells subjected to this combinational therapy at sub-inhibitory doses showed the presence of carbohydrate granules/patches. The identification of LPV as a promising adjunct therapy holds promise for addressing the emerging challenge of azole resistance in Aspergillus species and improving treatment outcomes for patients.

Berberine promotes K48-linked polyubiquitination of HNF4α, leading to the inhibition of HBV replication.

The current antiviral agents for the treatment of chronic infection with hepatitis B virus (HBV) do not completely remove covalently closed circular DNA (cccDNA) and integrated viral DNA fragments from patients. Berberine is an isoquinoline alkaloid extracted from various plants and has been reported to inhibit the replication of various types of DNA. In this study, we tested the effects of berberine and its derivatives on HBV infection. Berberine inhibited viral core promoter activity at the highest level among the compounds tested and suppressed HBV production and cccDNA synthesis in primary human hepatocytes and HBV-infected HepG2-NTCP cells at an EC50 value of 3.6 μM and a CC50 value of over 240.0 μM. Compared with other viral promoter activities, berberine treatment potently downregulated core promoter activity and reduced protein levels, but not RNA levels, of hepatic nuclear factor 4α (HNF4α), which primarily enhances enhancer II/core promoter activity. Furthermore, berberine treatment enhanced K48-linked, but not K63-linked, polyubiquitination and subsequent proteasome-dependent degradation of HNF4α. These results suggest that berberine enhances the polyubiquitination- and proteasome-dependent degradation of HNF4α and then inhibits HBV replication via the suppression of core promoter activity. The development of antiviral agents based on berberine may contribute to the amelioration of HBV-related disorders, regardless of the presence of residual cccDNA or integrated viral DNA fragments.

Monitoring of Hepatitis E Virus Infection and Replication by Functional Tagging of the ORF2 Protein

Background and AimsHepatitis E virus (HEV) infection is a leading cause of acute hepatitis worldwide. Understanding of the mechanisms underlying productive HEV infection remains incomplete and would benefit from technological advances improving current model systems. MethodsWe exploited transposon-mediated random insertion and selection of viable clones to identify sites in the HEV ORF2 protein, corresponding to the viral capsid, allowing the insertion of reporter sequences in a functional context. ResultsShort sequence insertions (5 aa) were tolerated at four distinct sites in the C-terminal region of ORF2 protein, without significantly affecting viral capsid expression and subcellular localization as well as virus production. Full-length HEV genomes harboring larger sequence insertions such as an HA epitope tag, a highly sensitive miniaturized luciferase reporter (HiBiT) or a split GFP at these sites conserved their ability to produce infectious virus, while with about 1-log decrease in viral titers. Findings were confirmed in two different HEV genotype 3. In addition, we demonstrate that HiBiT-tagged HEV, offering rapid and several-log amplitude detection, can be used for the evaluation of antiviral drugs and neutralizing antibodies. ConclusionsWe describe a convenient, quantitative and potentially scalable system for the monitoring of HEV infection and replication in tissue culture. Impact And ImplicationsHepatitis E virus (HEV) infection is one of the most frequent causes of acute hepatitis and jaundice worldwide. As treatment options are limited and a vaccine is not universally available, the development of molecular tools to facilitate the identification of new therapeutic strategies is crucial. Based on a screening approach to identify viable insertion sites in the viral genome, we describe a versatile system for preparing recombinant viruses harboring split-reporter tags, i.e. luciferase and GFP. Proof-of-concept experiments revealed that convenient and quantitative monitoring of viral infection and replication is possible with this system, allowing to evaluate antiviral drugs and neutralizing antibodies.

Computer-aided Design of Wide-spectrum Coronavirus Helicase NSP13 Cage Inhibitors: A Molecular Modelling Approach.

The coronavirus helicase NSP13 plays a critical role in its life cycle. The found NSP13 inhibitors have been tested only in vitro but they definitely have the potential to become antiviral drugs. Thus, the search for NSP13 inhibitors is of great importance. The goal of the present work was to develop a general approach to the design of ligands of coronaviral NSP13 helicase and to propose on its basis potential inhibitors. The structure of the NSP13 protein was refined by molecular dynamics and the cavity, responsible for RNA binding, was chosen as the inhibitor binding site. The potential inhibitor structures were identified by molecular docking and their binding was verified by molecular dynamics simulation. A number of potential NSP13 inhibitors were identified and the binding modes and probable mechanism of action of potential inhibitors was clarified. Using the molecular dynamics and molecular docking techniques, we have refined the structure of the coronavirus NSP13 helicase, a number of potential inhibitors, containing cage fragment were proposed and their probable mechanism of action was clarified. The proposed approach is also suitable for the design of ligands interacting with other viral helicases.

Antiviral Medications: Unravelling their Significance in Context to COVID-19

Abstract: Viruses represent a significant health menace due to their rapid transmissibility and potential to cause worldwide pandemics, resulting in substantial loss of human life. Antiviral agents play a pivotal role in mitigating the impact of viral infections. Nonetheless, treating viral infections is a multifaceted process due to the inherent characteristics of viruses, such as their capacity to undergo mutations and rapid evolution. Consequently, the effectiveness of current antiviral therapies can be impeded. This review encompasses the diverse manners in which viruses, emphasizing COVID-19, affect the human body and elucidates the challenges encountered in formulating efficacious antiviral treatments. Moreover, the limitations of conventional antiviral therapies are underscored. Additionally, a comprehensive compendium of 41 antiviral drugs is presented, detailing their mechanisms of action and routes of administration. Subsequently, the discussion includes 9 drugs repurposed for treating COVID-19, delineating their primary use as well as any accompanying side effects. In conclusion, while antiviral drugs remain pivotal in the battle against viral infections, the obstacles associated with their development and usage warrant careful consideration. Ongoing research is imperative to devise more potent and less toxic antiviral interventions against COVID-19 infection.

Garlic Peel-based Carbon Quantum Dots as a Sustainable Alternative for the Sensitive and Green Spectrofluorometric Quantification of Molnupiravir in Pharmaceutical Capsules

Searching for natural alternatives to replace environmentally harmful chemical reagents in analysis is just as crucial as finding easily accessible analytical tools. To reinforce these concepts, this study proposes a simple spectrofluorometric approach using natural carbon quantum dots (n-CQDs) as fluorescence probes for sensitive and environmentally friendly measurement of molnupiravir, an antiviral drug that was initially developed for influenza and has demonstrated potential efficacy against COVID-19. n-CQDs were synthesized using garlic peels (GP), a waste material, via a microwave-assisted method. n-CQDs have a characteristic broad absorbance and narrow emission spectrum, making it easier to analyze several targets. The GP-based n-CQDs showed maximum excitation/emission at 265/347 nm with an acceptable quantum yield. After reaction with molnupiravir, the produced n-CQDs demonstrated unique features to determine the tested analyte. Different factors influencing the synthesis of n-CQDs and their interaction with the studied drug, molnupiravir, were investigated and optimized. Using GP-based n-QCDs as fluorescent probe for measuring molnupiravir by FL, a green analytical approach based on the probes' fluorescence quenching was developed (GP- n-CQDs -QN-FL). The method demonstrated good linearity from 0.5 to 30 μg/mL and detection/quantitation limits of 0.19/0.5 μg/mL. Validation studies confirmed accuracy (98-102% recovery), precision (<2% RSD), robustness and selectivity. Various assessment indexes have been utilized to assess the environmental friendliness and suitability aspects of the suggested approach in comparison to other existing techniques. Furthermore, n-CQDs were successfully employed for the precise analysis of molnupiravir in its pharmaceutical capsules. The comprehensive results proved that the method can be deemed eco-friendly and feasible more than the other techniques for its intended purpose for molnupiravir determination in pharmaceutical dosage forms with an average recovery 101.17%.

Negative regulation of SREBP-1/FAS signalling molecules activates the RIG-1/TBK1-mediated IFN-I pathway to inhibit BVDV replication.

For many viruses, controlling the process of infection is largely dependent on the enzymes of the fatty acid synthesis (FAS) pathway. An appealing therapeutic target in antiviral research is fatty acid synthetase (FASN), a crucial enzyme in the FAS pathway. Bovine viral diarrhea, caused by the Bovine viral diarrhea virus (BVDV), is a significant viral infectious disease posing a substantial threat to global animal husbandry. Our study revealed that BVDV infection not only upregulates the expression of FAS-related enzymes in BT cells and the blood, liver, and spleen of mice but also markedly enhances the accumulation of lipid droplets, free fatty acids, and triglycerides. The FAS pathway plays a pivotal role throughout the entire BVDV replication cycle. Additionally, administration of the FASN inhibitor C75 and Acetyl CoA carboxylase-1 (ACC-1) inhibitor TOFA significantly reduced the viral content in both serum and organs of BVDV-infected mice, exhibiting inhibitory effects across diverse viral strains. Intriguingly, We found that RIG-1/TBK1-mediated IFN-I signaling inhibits SREBP-1/FAS and reduces BVDV replication. Conversely, targeting a few essential enzymes of SREBP-1/FAS also activates IFN-I signaling. More importantly, FASN inhibitor led to heightened expression of ISGs in mouse spleens by activating the RIG-1/TBK-1 pathway. These findings highlight that FASN inhibitors inhibit BVDV replication through the activation of the RIG-1/TBK-1 pathway to induce ISGs, and offering a novel therapeutic approach for combating BVDV. Thus, it is crucial to negatively regulate SREBP-1/FAS signaling molecules in order to create novel antiviral drugs that are safe, effective, and broad-spectrum.

Exploring bifunctional molecules for anti-SARS-CoV-2 and anti-inflammatory activity through structure-based virtual screening, SAR investigation, and biological evaluation.

As new variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continue to emerge, they raise increasing concerns about the efficacy of neutralizing antibodies and vaccines. This situation underscores the urgent need for specific drugs against the coronavirus disease 2019 (COVID-19). Given that COVID-19 is particularly associated with substantial inflammation, the development of novel, effective antiviral and anti-inflammatory agents represents a promising research direction. In this study, we virtually screened a library consisting of 2900 anti-inflammatory small molecules for their inhibitory effects on the 3-chymotrypsin-like protease (3CLpro) of SARS-CoV-2 and selected 23 promising candidates for further testing using a fluorescence resonance energy transfer (FRET) assay. The results indicated that Gnetol had the most potent inhibitory effect against SARS-CoV-2 3CLpro. Further structural modifications led to the identification of compounds 38 and 39, which displayed superior inhibitory activity. Compound 39 showed good selectivity for host proteases. Subsequently, Gnetol and its structural analogs, which demonstrated SARS-CoV-2 3CLpro inhibitory activity, were tested for their anti-inflammatory effects. Among these, Piceatannol and compound 39 exhibited enhanced anti-inflammatory effects, with compound 39 alone showing the most potent antiviral and anti-inflammatory activity. Thus, our study has explored a new research strategy for discovering antiviral and anti-inflammatory bifunctional molecules. The discovery of Gnetol and its structural analogs has provided new lead candidates for the development of COVID-19 therapeutics.

Two Birds with One Stone: Drug Regime Targets Viral Pathogenesis Phases and COVID-19 ARDS at the Same Time.

Severe COVID-19 or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a kind of viral pneumonia induced by infection with the coronavirus that causes ARDS. It involves symptoms that are a combination of viral pneumonia and ARDS. Antiviral or immunosuppressive medicines are used to treat many COVID-19 patients. Several drugs are now undergoing clinical studies in order to see if they can be repurposed in the future. In this study, in silico biomarker-targeted methodologies, such as target/ molecule virtual screening by docking technique and drug repositioning strategy, as well as data mining approach and meta-analysis of investigational data, were used. In silico findings of used combination of drug repurposing and high-throughput docking methods presented acetaminophen, ursodiol, and β-carotene as a three-drug therapy regimen to treat ARDS induced by viral pneumonia in addition to inducing direct antiviral effects against COVID-19 viral infection. In the current study, drug repurposing and high throughput docking methods have been employed to develop combination drug regimens as multiple-molecule drugs for the therapy of COVID-19 and ARDS based on a multiple-target therapy strategy. This approach offers a promising avenue for the treatment of COVID-19 and ARDS, and highlights the potential benefits of drug repurposing in the fight against the current pandemic.