Current Antivirals and Novel Botanical Molecules Interfering With Herpes Simplex Virus Infection

Selenization of Small Molecule Drugs: A New Player on the Board

There is an urgent need to develop safer and more effective modalities for the treatment of a wide range of pathologies due to the increasing rates of drug resistance, undesired side effects, poor clinical outcomes, etc. Throughout the years, selenium (Se) has attracted a great deal of attention due to its important role in human health. Besides, a growing body of work has unveiled that the inclusion of Se motifs into a great number of molecules is a promising strategy for obtaining novel therapeutic agents. In the current Perspective, we have gathered the most recent literature related to the incorporation of different Se moieties into the scaffolds of a wide range of known drugs and their feasible pharmaceutical applications. In addition, we highlight different representative examples as well as provide our perspective on Se drugs and the possible future directions, promises, opportunities, and challenges of this ground-breaking area of research.

In Vitro Effect of 9,9'-Norharmane Dimer against Herpes Simplex Viruses

Herpes simplex virus (HSV) infections are highly widespread among humans, producing symptoms ranging from ulcerative lesions to severe diseases such as blindness and life-threatening encephalitis. At present, there are no vaccines available, and some existing antiviral treatments can be ineffective or lead to adverse effects. As a result, there is a need for new anti-HSV drugs. In this report, the in vitro anti-HSV effect of 9,9'-norharmane dimer (nHo-dimer), which belongs to the β-carboline (βC) alkaloid family, was evaluated. The dimer exhibited no virucidal properties and did not impede either the attachment or penetration steps of viral particles. The antiviral effect was only exerted under the constant presence of the dimer in the incubation media, and the mechanism of action was found to involve later events of virus infection. Analysis of fluorescence lifetime imaging data showed that the nHo-dimer internalized well into the cells when present in the extracellular incubation medium, with a preferential accumulation into perinuclear organelles including mitochondria. After washing the host cells with fresh medium free of nHo-dimer, the signal decreased, suggesting the partial release of the compound from the cells. This agrees with the observation that the antiviral effect is solely manifested when the alkaloid is consistently present in the incubation media.

Targeted delivery of herpes simplex virus glycoprotein D to CD169+ macrophages using ganglioside liposomes alleviates herpes simplex keratitis in mice

Herpes simplex keratitis (HSK) is a common blinding corneal disease caused by herpes simplex virus type 1 (HSV-1) infection. Antiviral drugs and corticosteroids haven't shown adequate therapeutic efficacy. During the early stage of HSV-1 infection, macrophages serve as the first line of defense. In particular, CD169+ macrophages play an important role in phagocytosis and antigen presentation. Therefore, we constructed GM-gD-lip, a ganglioside GM1 liposome vaccine encapsulating HSV-1 glycoprotein D and targeting CD169+ macrophages. After subconjunctival injection of the vaccine, we evaluated the survival rate and ocular surface lesions of the HSK mice, as well as the virus levels in the tear fluid, corneas, and trigeminal ganglia. We discovered that GM-gD-lip reduced HSV-1 viral load and alleviated the clinical severity of HSK. The GM-gD-lip also increased the number of corneal infiltrating macrophages, especially CD169+ macrophages, and polarized them toward M1. Furthermore, the number of dendritic cells (DCs) and CD8+ T cells in the ocular draining lymph nodes was significantly increased. These findings demonstrated that GM-gD-lip polarized CD169+ macrophages toward M1 to eliminate the virus while cross-presenting antigens to CD8+ T cells via DCs to activate adaptive immunity, ultimately attenuating the severity of HSK. The use of GM-gD-lip as an immunotherapeutic method for the treatment of HSK has significant implications.

Incorporation of Cordia glabrata (Mart.) A.DC. extract in microemulsions and their potential antioxidant, photoprotective and virucidal activities

Abstract Extracts of species from the Cordia genus have been reported with potential biological activities, such as antioxidant, antimicrobial, antiviral, and antiparasitic. The aim of this study was to develop microemulsions containing ethanolic extracts of C. glabrata leaves and to evaluate their stability and biological activities. The five developed microemulsions presented physicochemical stability and presented Newtonian behavior when submitted to rheological analysis. The diameter values of the globules ranged between 225.74 and 273.33 nm and the zeta potential of the formulations remained between -22.40 and -25.08. All phenolic acids of the extract, quantified by HPLC, showed consistency after being microemulsified. The EC50 values for the antioxidant activity by the DPPH scavenging method ranged between 38.13 and 45.54 µgmL-1, and between 34.46 and 39.60 mM for the ABTS+ scavenging method. The virucidal activity presented a CV50 <0.195 µgmL-1 and a selectivity index greater than 20. The photoprotection results ranged between 2.14 to 2.84. The study revealed stable microemulsions and potentiation of the antioxidant effect in the microemulsified extracts.

The Cooperation of IL-29 and PLGA Nanoparticles Improves the Protective Immunity of the gD-1 DNA Vaccine Against Herpes Simplex Virus Type 1 in Mice

In clinical practice, the low immunogenicity and low stability of the DNA plasmid vaccine candidates are two significant shortcomings in their application against infectious diseases. To overcome these two disadvantages, the plasmid expressing IL-29 (pIL-29) as a genetic adjuvant and polylactic-co-glycolic acid (PLGA) as a non-viral delivery system were used, respectively. In this study, the pIL-29 encapsulated in PLGA nanoparticles (nanoIL-29) and the pgD1 encapsulated in PLGA nanoparticles (nanoVac) were simultaneously applied to boost immunologic responses against HSV-1. We generated spherical nanoparticles with encapsulation efficiency of 75 ± 5% and sustained the release of plasmids from them. Then, Balb/c mice were subcutaneously immunized twice with nanoVac+nanoIL-29, Vac+IL-29, nanoVac, Vac, nanoIL-29, and/or IL-29 in addition to negative and positive control groups. Cellular immunity was evaluated via lymphocyte proliferation assay, cytotoxicity test, and IFN-γ, IL-4, and IL-2 measurements. Mice were also challenged with 50X LD50 of HSV-1. The nanoVac+nanoIL-29 candidate vaccine efficiently enhances CTL and Th1-immune responses and increases the survival rates by 100% in mice vaccinated by co-administration of nanoVac and nanoIL-29 against the HSV-1 challenge. The newly proposed vaccine is worth studying in further clinical trials, because it could effectively improve cellular immune responses and protected mice against HSV-1.

Vector-Transmitted Flaviviruses: An Antiviral Molecules Overview

Flaviviruses cause numerous pathologies in humans across a broad clinical spectrum with potentially severe clinical manifestations, including hemorrhagic and neurological disorders. Among human flaviviruses, some viral proteins show high conservation and are good candidates as targets for drug design. From an epidemiological point of view, flaviviruses cause more than 400 million cases of infection worldwide each year. In particular, the Yellow Fever, dengue, West Nile, and Zika viruses have high morbidity and mortality-about an estimated 20,000 deaths per year. As they depend on human vectors, they have expanded their geographical range in recent years due to altered climatic and social conditions. Despite these epidemiological and clinical premises, there are limited antiviral treatments for these infections. In this review, we describe the major compounds that are currently under evaluation for the treatment of flavivirus infections and the challenges faced during clinical trials, outlining their mechanisms of action in order to present an overview of ongoing studies. According to our review, the absence of approved antivirals for flaviviruses led to in vitro and in vivo experiments aimed at identifying compounds that can interfere with one or more viral cycle steps. Still, the currently unavailability of approved antivirals poses a significant public health issue.

AMPK protects endothelial cells against HSV-1 replication via inhibition of mTORC1 and ACC1

Herpes simplex virus type 1 (HSV-1) is a widespread contagious pathogen, mostly causing mild symptoms on the mucosal entry side. However, systemic distribution, in particular upon reactivation of the virus in immunocompromised patients, may trigger an innate immune response and induce damage of organs. In these conditions, HSV-1 may infect vascular endothelial cells, but little is known about the regulation of HSV-1 replication and possible defense mechanisms in these cells. The current study addresses the question of whether the host cell protein AMP-activated protein kinase (AMPK), an important metabolic sensor, can control HSV-1 replication in endothelial cells. We show that downregulation of the catalytic subunits AMPKα1 and/or AMPKα2 increased HSV-1 replication as monitored by TCID50 titrations, while a potent AMPK agonist, MK-8722, strongly inhibited it. MK-8722 induced a persistent phosphorylation of the AMPK downstream targets acetyl-CoA carboxylase (ACC) and the rapamycin-sensitive adaptor protein of mTOR (Raptor) and, related to this, impairment of ACC1-mediated lipid synthesis and the mechanistic target of the rapamycin complex-1 (mTORC1) pathway. Since blockade of mTOR by Torin-2 as well as downregulation of ACC1 by siRNA also decreased HSV-1 replication, MK-8722 is likely to exert its anti-viral effect via mTORC1 and ACC1 inhibition. Importantly, MK-8722 was able to reduce virus replication even when added after HSV-1. Together, our data highlight the importance of endothelial cells as host cells for HSV-1 replication upon systemic infection and identify AMPK, a metabolic host cell protein, as a potential target for antiviral strategies against HSV-1 infection and its severe consequences. IMPORTANCE Herpes simplex virus type 1 (HSV-1) is a common pathogen that causes blisters or cold sores in humans. It remains latent in infected individuals and can be reactivated multiple times. In adverse conditions, for instance, in immunocompromised patients, HSV-1 can lead to serious complications such as encephalitis, meningitis, or blindness. In these situations, infection of endothelial cells lining the surface of blood vessels may contribute to the manifestation of disease. Here, we describe the role of AMP-activated protein kinase (AMPK), a potent regulator of cellular energy metabolism, in HSV-1 replication in endothelial cells. While downregulation of AMPK potentiates HSV-1 replication, pharmacological AMPK activation inhibits it by limiting the availability of required host cell macromolecules such as proteins or fatty acids. These data highlight the role of metabolic host cell proteins as antiviral targets and reveal activation of endothelial AMPK as a potential strategy to protect from severe consequences of HSV-1 infection.

Topical formulations containing Trichilia catigua extract as therapeutic options for a genital and an acyclovir-resistant strain of herpes recurrent infection

Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) infect, respectively, 67% and 13% of the world population, most commonly causing mild symptoms, such as blisters/ulcers. However, severe conditions such as keratitis, encephalitis, and systemic infections may occur, generally associated with the patient's immunological condition. Although Acyclovir® (ACV) and its analogs are the reference drugs for herpetic infections, the number of ACV-resistant HSV infections is growing exponentially. Therefore, new natural products' bioactive compounds have been studied to develop novel effective anti-herpetics. Trichilia catigua is a plant widely used in traditional medicine, including the treatment of skin diseases and sexual infections. In our study, 16 extracts from the bark of T. catigua, obtained with different solvents and their combinations, were evaluated against HSV-1 AR and HSV-2, respectively, ACV resistance and genital strains in vitro. The extracts with the highest selectivity index were used to prepare new topical anti-herpetic formulations and confirmed in vivo. Two new topical formulations were suggested to treat cutaneous and genital herpetic recurrent lesions. The cytotoxicity and antiviral activity were tested using the MTT method. The cytotoxic (CC50) and inhibitory (IC50) concentrations of 50% and the selectivity index (SI: CC50/IC50) were determined. Tc12, Tc13, and Tc16 were added to the formulations. Infected BALB/c mice were treated for 8 days, and the severity of the herpetic lesions was analyzed daily. All CEs showed a CC50 value ranging from 143 to 400 µg/mL, except for Tc3 and Tc10. Tc12, Tc13, and Tc16 showed the best SI in the 0 h, virucidal, and adsorption inhibition assays. In the in vivo test against HSV-1 AR, the infected animals treated with creams were statistically different from the infected non-treated animals and similar to ACV-treated mice. In HSV-2-infected genitalia, similar effects were found for Tc13 and Tc16 gels. The present study demonstrated that extracts from the bark of T. catigua, traditionally used in folk medicine, are a valuable source of active compounds with anti-herpetic activity. The extracts showed a virucidal mechanism of action and prevented the initial stages of viral replication. The cutaneous and genital infections were strongly inhibited by the Tc12, Tc13, and Tc16 extracts. New topical therapeutic alternatives using Trichilia catigua extracts are suggested for patients infected with ACV-resistant strains of HSV.

Detailed pharmacokinetic characterization of advanced topical acyclovir formulations with IVPT and in vivo Open Flow Microperfusion

Successful treatment of herpes simplex viruses is currently limited by a lack of effective topical drugs. Commonly used topical acyclovir products only reduce the duration of lesions by a few days. Optimizing topical formulations to achieve an enhanced acyclovir solubility and penetration could increase the efficacy of topically applied acyclovir, but new formulations need to show reliable acyclovir delivery into at least the epidermis/dermis and need to provide sustained acyclovir release for extended time periods. The aim of this study was to compare pharmacokinetic data from in vitro permeation testing (IVPT) and preclinical dermal open flow microperfusion (dOFM) experiments regarding the penetration behavior of different acyclovir formulations relative to the reference product Zovirax® 5% cream. Four test formulations that delivered the best penetration data in IVPT were further tested using continuous dOFM in vivo dermal sampling. The use of dOFM identified one of the four tested formulations to perform significantly better than the other three tested formulations and the reference product. In vivo dOFM data showed differences in the dermal acyclovir concentration that had not been detected by using IVPT. Improved acyclovir delivery to the dermis was likely achieved by the new formulation that uses a much lower drug load compared to the reference product. This optimized formulation was able to achieve a dermal concentration similar to oral application and can thus provide the opportunity of more efficacious topical HSV-1 treatment with less side effects than oral systemic treatment.

Herpes Simplex Virus, Human Papillomavirus, and Cervical Cancer: Overview, Relationship, and Treatment Implications

There is a significant body of research examining the role of human papillomavirus (HPV) in the pathogenesis of cervical cancer, with a particular emphasis on the oncogenic proteins E5, E6, and E7. What is less well explored, however, is the relationship between cervical cancer and herpes simplex virus (HSV). To date, studies examining the role of HSV in cervical cancer pathogenesis have yielded mixed results. While several experiments have determined that HPV/HSV-2 coinfection results in a higher risk of developing cervical cancer, others have questioned the validity of this association. However, clarifying the potential role of HSV in the pathogenesis of cervical cancer may have significant implications for both the prevention and treatment of this disease. Should this relationship be clarified, treating and preventing HSV could open another avenue with which to prevent cervical cancer. The importance of this is highlighted by the fact that, despite the creation of an effective vaccine against HPV, cervical cancer still impacts 604,000 women and is responsible for 342,000 deaths annually. This review provides an overview of HSV and HPV infections and then delves into the possible links between HPV, HSV, and cervical cancer. It concludes with a summary of preventive measures against and recent treatment advances in cervical cancer.

Antiviral activity of red algae phycocolloids against herpes simplex virus type 2 in vitro

Herpes simplex virus type 2 (HSV-2) is a human infectious agent with significant impact on public health due to its high prevalence in the population and its ability to elicit a wide range of diseases, from mild to severe. Although several antiviral drugs, such as acyclovir, are currently available to treat HSV-2-related clinical manifestations, their effectiveness is poor. Therefore, the identification and development of new antiviral drugs against HSV-2 is necessary. Seaweeds are attractive candidates for such purposes because they are a vast source of natural products due to their highly diverse compounds, many with demonstrated biological activity. In this study, we evaluated the in vitro antiviral potential of red algae extracts obtained from Agarophyton chilense, Mazzaella laminarioides, Porphyridium cruentum, and Porphyridium purpureum against HSV-2. The phycocolloids agar and carrageenan obtained from the macroalgae dry biomass of A. chilense and M. laminarioides and the exopolysaccharides from P. cruentum and P. purpureum were evaluated. The cytotoxicity of these extracts and the surpluses obtained in the extraction process of the agar and carrageenans were evaluated in human epithelial cells (HeLa cells) in addition to their antiviral activity against HSV-2, which were used to calculate selectivity indexes (SIs). Several compounds displayed antiviral activity against HSV-2, but carrageenans were not considered as a potential antiviral therapeutic agent when compared to the other algae extracts with a SI of 23.3. Future assays in vivo models for HSV-2 infection should reveal the therapeutic potential of these algae compounds as new antivirals against this virus.

Antiherpetic Activity of Taurisolo®, a Grape Pomace Polyphenolic Extract

Herpes simplex virus (HSV) is widespread in the population, causing oral or genital ulcers and, rarely, severe complications such as encephalitis, keratitis, and neonatal herpes. Current available anti-HSV drugs are acyclovir and its derivatives, although long-term therapy with these agents can lead to drug resistance. Thus, the discovery of novel antiherpetic compounds merits additional studies. In recent decades, much scientific effort has been invested in the discovery of new synthetic or natural compounds with promising antiviral properties. In our study, we tested the antiviral potential of a novel polyphenol-based nutraceutical formulation (named Taurisolo^®) consisting of a water polyphenol extract of grape pomace. The evaluation of the antiviral activity was carried out by using HSV-1 and HSV-2 in plaque assay experiments to understand the mechanism of action of the extract. Results were confirmed by real-time PCR, transmission electron microscope (TEM), and fluorescence microscope. Taurisolo^® was able to block the viral infection by acting on cells when added together with the virus and also when the virus was pretreated with the extract, demonstrating an inhibitory activity directed to the early phases of HSV-1 and HSV-2 infection. Altogether, these data evidence for the first time the potential use of Taurisolo^® as a topical formulation for both preventing and healing herpes lesions.

In Vitro Antiviral Effect and Potential Neuroprotection of Salvadora persica L. Stem Bark Extract against Lipopolysaccharides-Induced Neuroinflammation in Mice: LC-ESI-MS/MS Analysis of the Methanol Extract

Neuroinflammation is a serious immunomodulatory complex disorder that causes neurological and somatic ailments. The treatment of brain inflammation with new drugs derived from natural sources is a significant therapeutic goal. Utilizing LC-ESI-MS/MS analysis, the active constituents of Salvadora persica extract (SPE) were identified tentatively as exerting antioxidant and anti-inflammatory effects in natural medicine. Herein, we determined the antiviral potential of SPE against herpes simplex virus type 2 (HSV-2) using the plaque assay. HSV-2 is a neurotropic virus that can cause neurological diseases. SPE exhibited promising antiviral potential with a half-maximal cytotoxic concentration (CC50) of 185.960 ± 0.1 µg/mL and a half-maximal inhibitory concentration (IC50) of 8.946 ± 0.02 µg/mL. The in vivo study of the SPE impact against lipopolysaccharide (LPS)-induced neuroinflammation was performed using 42 mice divided into seven groups. All groups were administered LPS (0.25 mg/kg) intraperitoneally, except for the normal and SPE groups 1 and 2. Groups 5, 6, and 7 received 100, 200, and 300 mg/kg SPE. It was revealed that SPE inhibited acetylcholinesterase in the brain. It increased superoxide dismutase and catalase while decreasing malondialdehyde, which explains its antioxidative stress activity. SPE downregulated the gene expression of the inducible nitric oxide synthase, as well as the apoptotic markers (caspase-3 and c-Jun). In addition, it decreased the expression of the proinflammatory cytokines (interleukin-6 and tumor necrosis factor-alpha). Mice administered SPE (300 mg/kg) with LPS exhibited normal neurons in the cerebral cortices, hippocampus pyramidal layer, and cerebellum, as determined by the histopathological analysis. Therefore, using S. persica to prevent and treat neurodegeneration could be a promising new therapeutic strategy to be explored.

COMPARATIVE EFFICACY OF ANTIVIRAL AGENTS FOR PREVENTION AND MANAGEMENT OF HERPES LABIALIS: A SYSTEMATIC REVIEW AND NETWORK META-ANALYSIS

OBJECTIVE

To compare the relative efficacy and safety of antiviral agents used in the prevention and management of herpes labialis through a network meta-analysis of clinical trials.

METHODS

A systematic search was performed in Ovid Medline PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Scopus and Clinicaltrials.gov for randomized controlled trials (RCTs) reporting a comparison of antiviral agents in the management and prevention of herpes labialis in healthy/immunocompetent adults. The data extracted from the selected RCTs were assessed and a network meta-analysis (NMA) was performed. The interventions were ranked according to the surface under the cumulative ranking (SUCRA).

RESULTS

A total of 52 articles were included for qualitative synthesis and for the quantitative part, 26 articles were analyzed for the primary treatment outcome and 7 studies were analyzed for the primary prevention outcome. The combination therapy of oral valacyclovir and topical clobetasol was the best ranked with a mean reduction in healing time of -3.50 (95% CI -5.22 to -1.78) followed by vidarabine monophosphate of -3.22 (95% CI -4.59 to -1.85). No significant inconsistencies, heterogeneity, and publication bias were reported for TTH outcome analysis. For primary prevention outcomes, only 7 RCTs fulfilled the inclusion criteria, and none of the interventions was shown to be superior to each other. The absence of adverse events was reported by 16 studies, whereas other studies reported mild side effects only.

CONCLUSION

NMA highlighted that several agents were effective in the management of herpes labialis among which the combination of oral valacyclovir with topical clobetasol therapy was the most effective in reducing the time to heal. However, further studies are required to determine which intervention is the most effective in preventing the recurrence of herpes labialis.

A Comprehensive Overview of Epidemiology, Pathogenesis and the Management of Herpes Labialis

Herpes labialis remains exceedingly prevalent and is one of the most common human viral infections throughout the world. Recurrent herpes labialis evolves from the initial viral infection by herpes simplex virus type 1 (HSV-1) which subsequently presents with or without symptoms. Reactivation of this virus is triggered by psychosocial factors such as stress, febrile environment, ultraviolet light susceptibility, or specific dietary inadequacy. This virus infection is also characterized by uninterrupted transitions between chronic-latent and acute-recurrent phases, allowing the virus to opportunistically avoid immunity and warrant the transmission to other vulnerable hosts simultaneously. This review comprehensively evaluates the current evidence on epidemiology, pathogenesis, transmission modes, clinical manifestations, and current management options of herpes labialis infections.

Complete and Prolonged Inhibition of Herpes Simplex Virus Type 1 Infection In Vitro by CRISPR/Cas9 and CRISPR/CasX Systems

Almost all people become infected with herpes viruses, including herpes simplex virus type 1 (HSV-1), during their lifetime. Typically, these viruses persist in a latent form that is resistant to all available antiviral medications. Under certain conditions, such as immunosuppression, the latent forms reactivate and cause disease. Moreover, strains of herpesviruses that are drug-resistant have rapidly emerged. Therefore, it is important to develop alternative methods capable of eradicating herpesvirus infections. One promising direction is the development of CRISPR/Cas systems for the therapy of herpesvirus infections. We aimed to design a CRISPR/Cas system for relatively effective long-term and safe control of HSV-1 infection. Here, we show that plasmids encoding the CRISPR/Cas9 system from Streptococcus pyogenes with a single sgRNA targeting the UL30 gene can completely suppress HSV-1 infection of the Vero cell line within 6 days and provide substantial protection within 9 days. For the first time, we show that CRISPR/CasX from Deltaproteobacteria with a single guide RNA against UL30 almost completely suppresses HSV-1 infection of the Vero cell line for 3 days and provides substantial protection for 6 days. We also found that the Cas9 protein without sgRNAs attenuates HSV-1 infection. Our results show that the developed CRISPR/Cas systems are promising therapeutic approaches to control HSV-1 infections.

Efficacy of Lazolex® Gel in the Treatment of Herpes Simplex Mucocutaneous Infections and the Prevention of Recurrences: A Pilot Study

Background. Previous in vitro and in vivo studies indicated that walnut extract has a therapeutic effect on herpes simplex infections. This study aimed to evaluate the efficacy and tolerance of Lazolex® Gel (Iveriapharma, Tbilisi, Georgia), an emollient gel to treat mucocutaneous lesions caused by herpes simplex virus. Methods. A single-center, single-arm, open-label, phase II clinical trial was conducted with 30 patients divided into two groups: 15 patients with herpes simplex virus type 1 (HSV-1) infections and 15 with herpes simplex virus type 2 (HSV-2). All received topical treatment with Lazolex® Gel four times a day for 10 days. The efficacy and tolerance of the treatment were evaluated on day 10 and day 20 of the study. Recurrence rates were also evaluated both prior to treatment with Lazolex® and over a 4-year follow-up period subsequent to treatment. Results. The median effective time to resolution of symptoms (itching, burning, and pain) was 1.97 days in the HSV-1 group and 3.11 days in the HSV-2 group. The median effective time for vesicles and erosion to disappear was 3.64 days in the HSV-1 group and 3.88 days for the HSV-2 group. Finally, the median effective time for inflammatory signs to disappear was 5.70 and 4.32 days, respectively. Following treatment with Lazolex® Gel, the frequency of outbreaks decreased from a median of 2.00 and 1.00 times per year in the HSV-1 and HSV-2 cohorts to 0.25 and 0.00 ( $p=0.001$ and $p=0.003$ ), respectively. Conclusions. Topical treatment with Lazolex® Gel applied to lesions four times a day for 10 days was shown to be effective and safe in the treatment of herpes simplex mucocutaneous infections and dramatically reduced the rate of recurrence. Clinical trial was approved by Drug Agency of Ministry of Labour, Health and Social Affairs of Georgia, registration # DA Nº CT-000032, date of approval 01.10.2007.

Viral Infection and Antiviral Treatments in Ocular Pathologies

Ocular viral infections are common and widespread globally. These infectious diseases are a major cause of acute red eyes and vision loss. The eye and its nearby tissues can be infected by several viral agents, causing infections with a short course and limited ocular implications or a long clinical progression and serious consequences for the function and structure of the ocular region. Several surveillance studies underline the increased emergence of drug resistance among pathogenic viral strains, limiting treatment options for these infections. Currently, in the event of resistant infections, topical or systemic corticosteroids are useful in the management of associated immune reactions in the eye, which contribute to ocular dysfunction. Many cases of viral eye infections are misdiagnosed as being of bacterial origin. In these cases, therapy begins late and is not targeted at the actual cause of the infection, often leading to severe ocular compromises, such as corneal infiltrates, conjunctival scarring, and reduced visual acuity. The present study aims at a better understanding of the viral pathogens that cause eye infections, along with the treatment options available.

Host factors associated with either VP16 or VP16-induced complex differentially affect HSV-1 lytic infection

Herpes simplex virus type 1 (HSV-1) is an important human pathogen with neurotropism. Following lytic infection in mucosal or skin epithelium, life-long latency is established mainly in sensory neurons, which can periodically reactivate by stress, leading to recurrent disease and virus transmission. During the virus's productive infection, the tegument protein VP16, a component of HSV-1 virion, is physically associated with two cellular factors, host cell factor-1 (HCF-1), and POU domain protein Oct-1, to construct the VP16-induced complex, which is essential to stimulate immediate early (IE)-gene transcription as well as initiate the lytic programme. Apart from HCF-1 and Oct-1, VP16 also associates with a series of other host factors, making a VP16-induced regulatory switch to either activate or inactivate virus gene transcription. In addition, VP16 has effects on distinct signalling pathways via binding to various host molecules that are essentially related to innate immune responses, RNA polymerases, molecular chaperones, and virus infection-induced host shutoff. VP16 also functionally compensates for given host factors, such as PPAR-γ and ß-catenin. In this review, we provide an overview of the updated insights on the interplay between VP16 and the host factors that coordinate virus infection.

Infectious Esophagitis in Children

Infectious esophagitis is the third most common cause of esophagitis after gastroesophageal reflux disease and eosinophilic esophagitis (EoE) and should always be considered in the differential of patients with dysphagia and odynophagia. The most common organisms causing disease are candida, Herpes simplex virus (HSV) and cytomegalovirus (CMV). It is well recognized that an impaired local or systemic immune system is a risk factor for disease; however, esophageal dysmotility and disruptions in esophageal homeostasis and the esophageal milieu are likely to represent additional risk factors in disease pathogenesis.

Superior antiviral activity of IFNβ in genital HSV-1 infection

Type I interferons (IFNs) present the first line of defense against viral infections, providing antiviral, immunomodulatory and antiproliferative effects. The type I IFN family contains 12 IFNα subtypes and IFNβ, and although they share the same receptor, they are classified as non-redundant, capable to induce a variety of different IFN-stimulated genes. However, the biological impact of individual subtypes remains controversial. Recent data propose a subtype-specificity of type I IFNs revealing unique effector functions for different viruses and thus expanding the implications for IFNα-based antiviral immunotherapies. Despite extensive research, drug-resistant infections with herpes simplex virus type 1 (HSV-1), which is the common agent of recurrent orogenital lesions, are still lacking a protective or curing therapeutic. However, due to the risk of generalized infections in immunocompromised hosts as well as the increasing incidence of resistance to conventional antiherpetic agents, HSV infections raise major health concerns. Based on their pleiotropic effector functions, the application of type I IFNs represents a promising approach to inhibit HSV-1 replication, to improve host immunity and to further elucidate their qualitative differences. Here, selective IFNα subtypes and IFNβ were evaluated for their therapeutic potential in genital HSV-1 infections. Respective in vivo studies in mice revealed subtype-specific differences in the reduction of local viral loads. IFNβ had the strongest antiviral efficacy against genital HSV-1 infection in mice, whereas IFNα1, IFNα4, and IFNα11 had no impact on viral loads. Based on flow cytometric analyses of underlying immune responses at local and peripheral sites, these differences could be further assigned to specific modulations of the antiviral immunity early during HSV-1 infection. IFNβ led to enhanced systemic cytokine secretion and elevated cytotoxic responses, which negatively correlated with viral loads in the vaginal tract. These data provide further insights into the diversity of type I IFN effector functions and their impact on the immunological control of HSV-1 infections.

Bioprocess development for biosurfactant production by Natrialba sp. M6 with effective direct virucidal and anti-replicative potential against HCV and HSV

Halophilic archaea is considered an promising natural source of many important metabolites. This study focused on one of the surface-active biomolecules named biosurfactants produced by haloarchaeon Natrialba sp. M6. The production trend was optimized and the product was partially purified and identified using GC-Mass spectrometry. Sequential optimization approaches, Plackett-Burman (PB) and Box-Behnken Designs (BBD) were applied to maximize the biosurfactants production from M6 strain by using 14 factors; pH, NaCl, agitation and glycerol; the most significant factors that influenced the biosurfactant production were used for Response Surface Methodology (RSM). The final optimal production conditions were agitation (150 rpm), glycerol (3%), NaCl (20.8%), pH (12) and cultivation temperature (37°C). GC-Mass spectrometry for the recovered extract revealed the presence of a diverse group of bipolar nature, hydrophobic hydrocarbon chain and charged function group. The majority of these compounds are fatty acids. Based on results of GC-MS, compositional analysis content and Zetasizer, it was proposed that the extracted biosurfactant produced by haloarchaeon Natrialba sp. M6 could be a cationic lipoprotein. The antiviral activity of such biosurfactant was investigated against hepatitis C (HCV) and herpes simplex (HSV1) viruses at its maximum safe doses (20 μg/mL and 8 μg/mL, respectively). Its mode of antiviral action was declared to be primarily via deactivating viral envelopes thus preventing viral entry. Moreover, this biosurfactant inhibited RNA polymerase- and DNA polymerase-mediated viral replication at IC₅₀ of 2.28 and 4.39 μg/mL, respectively also. Molecular docking studies showed that surfactin resided well and was bound to the specified motif with low and accepted binding energies (ΔG = - 5.629, - 6.997 kcal/mol) respectively. Therefore, such biosurfactant could be presented as a natural safe and effective novel antiviral agent.

Herpesvirus-Associated Encephalitis: an Update

Purpose of Review

Recent Findings

Summary

In vitro evaluation of antiviral activity of Shouchella clausii probiotic strain and bacterial supernatant against herpes simplex virus type 1

Herpes simplex virus-1 (HSV-1) is an important human neurotropic virus infecting 70% of the world population. Due to the emergence of viral resistance via mutations in HSV-1 genes and some of the adverse effects of antiviral compounds, there is a growing need for safe, novel, and effective therapeutic and preventive strategies. The aim of the present study was to investigate for the first time the potential antiviral activity of Shouchella clausii probiotic strain and bacterial supernatant against HSV-1. The MTT assay was used to determine the possible cytotoxicity of the S. clausii and bacterial supernatant. Vero cells were treated by S. clausii, bacterial supernatant, and HSV-1 under pre-treatment (incubation of Vero cells with S. clausii then HSV-1 inoculation), pre-incubation (mixture of co-incubated HSV-1/S. clausii added to Vero cell), competition (adding HSV-1 and S. clausii into Vero cells simultaneously) and post-treatment (Vero cells inoculated with HSV-1 then incubated with S. clausii) assays. Viral titer reduction (TCID₅₀) and viral DNA relative quantification by real-time PCR were measured in each experimental condition. The results indicated that S. clausii and its supernatant had the greatest inhibitory activity toward HSV-1 in pre-treatment assay. The HSV-1 titer treated with S. clausii, and bacterial supernatant was 3.6 and 2.2 Log₁₀TCID₅₀/mL lower compared to the control (7.66 Log₁₀TCID₅₀/mL). Results showed an antiviral effect of S. clausii and its supernatant. S. clausii could be considered as a novel inhibitor for HSV-1 infection.

Review of Drug Therapy for Peripheral Facial Nerve Regeneration That Can Be Used in Actual Clinical Practice

Although facial nerve palsy is not a life-threatening disease, facial asymmetry affects interpersonal relationships, causes psychological stress, and devastates human life. The treatment and rehabilitation of facial paralysis has many socio-economic costs. Therefore, in cases of facial paralysis, it is necessary to identify the cause and provide the best treatment. However, until now, complete recovery has been difficult regardless of the treatment used in cases of complete paralysis of unknown cause and cutting injury of the facial nerve due to disease or accident. Therefore, this article aims to contribute to the future treatment of facial paralysis by reviewing studies on drugs that aid in nerve regeneration after peripheral nerve damage.

Antiviral and Virucidal Properties of Essential Oils and Isolated Compounds - A Scientific Approach

Essential oils and isolated essential oil compounds are known to exert various pharmacological effects, such as antibacterial, antifungal, antiviral, anti-inflammatory, anti-immunomodulatory, antioxidant, and wound healing effects. Based on selected articles, this review deals with the potential antiviral and virucidal activities of essential oils and essential oil compounds together with their mechanism of action as well as in silico studies involving viral and host cell-specific target molecules that are indispensable for virus cell adsorption, penetration, and replication. The reported in vitro and in vivo studies highlight the baseline data about the latest findings of essential oils and essential oil compounds antiviral and virucidal effects on enveloped and non-enveloped viruses, taking into account available biochemical and molecular biological tests. The results of many in vitro studies revealed that several essential oils and essential oil compounds from different medicinal and aromatic plants are potent antiviral and virucidal agents that inhibit viral progeny by blocking different steps of the viral infection/replication cycle of DNA and RNA viruses in various host cell lines. Studies in mice infected with viruses causing respiratory diseases showed that different essential oils and essential oil compounds were able to prolong the life of infected animals, reduce virus titers in brain and lung tissues, and significantly inhibit the synthesis of proinflammatory cytokines and chemokines. In addition, some in vitro studies on hydrophilic nano-delivery systems encapsulating essential oils/essential oil compounds exhibited a promising way to improve the chemical stability and enhance the water solubility, bioavailabilty, and antiviral efficacy of essential oils and essential oil compounds.

Finding a chink in the armor: Update, limitations, and challenges toward successful antivirals against flaviviruses

Flaviviruses have caused large epidemics and ongoing outbreaks for centuries. They are now distributed in every continent infecting up to millions of people annually and may emerge to cause future epidemics. Some of the viruses from this group cause severe illnesses ranging from hemorrhagic to neurological manifestations. Despite decades of research, there are currently no approved antiviral drugs against flaviviruses, urging for new strategies and antiviral targets. In recent years, integrated omics data-based drug repurposing paired with novel drug validation methodologies and appropriate animal models has substantially aided in the discovery of new antiviral medicines. Here, we aim to review the latest progress in the development of both new and repurposed (i) direct-acting antivirals; (ii) host-targeting antivirals; and (iii) multitarget antivirals against flaviviruses, which have been evaluated both in vitro and in vivo, with an emphasis on their targets and mechanisms. The search yielded 37 compounds that have been evaluated for their efficacy against flaviviruses in animal models; 20 of them are repurposed drugs, and the majority of them exhibit broad-spectrum antiviral activity. The review also highlighted the major limitations and challenges faced in the current in vitro and in vivo evaluations that hamper the development of successful antiviral drugs for flaviviruses. We provided an analysis of what can be learned from some of the approved antiviral drugs as well as drugs that failed clinical trials. Potent in vitro and in vivo antiviral efficacy alone does not warrant successful antiviral drugs; current gaps in studies need to be addressed to improve efficacy and safety in clinical trials.

Cannabidiol and Terpene Formulation Reducing SARS-CoV-2 Infectivity Tackling a Therapeutic Strategy

In late 2019, COVID-19 emerged in Wuhan, China. Currently, it is an ongoing global health threat stressing the need for therapeutic compounds. Linking the virus life cycle and its interaction with cell receptors and internal cellular machinery is key to developing therapies based on the control of infectivity and inflammation. In this framework, we evaluate the combination of cannabidiol (CBD), as an anti-inflammatory molecule, and terpenes, by their anti-microbiological properties, in reducing SARS-CoV-2 infectivity. Our group settled six formulations combining CBD and terpenes purified from Cannabis sativa L, Origanum vulgare, and Thymus mastichina. The formulations were analyzed by HPLC and GC-MS and evaluated for virucide and antiviral potential by in vitro studies in alveolar basal epithelial, colon, kidney, and keratinocyte human cell lines.

Conclusions and Impact

We demonstrate the virucide effectiveness of CBD and terpene-based formulations. F2TC reduces the infectivity by 17%, 24%, and 99% for CaCo-2, HaCat, and A549, respectively, and F1TC by 43%, 37%, and 29% for Hek293T, HaCaT, and Caco-2, respectively. To the best of our knowledge, this is the first approach that tackles the combination of CBD with a specific group of terpenes against SARS-CoV-2 in different cell lines. The differential effectiveness of formulations according to the cell line can be relevant to understanding the pattern of virus infectivity and the host inflammation response, and lead to new therapeutic strategies.

Pharmacological Inhibition of IRE-1 Alpha Activity in Herpes Simplex Virus Type 1 and Type 2-Infected Dendritic Cells Enhances T Cell Activation

Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) infections are life-long and highly prevalent in the human population. These viruses persist in the host, eliciting either symptomatic or asymptomatic infections that may occur sporadically or in a recurrent manner through viral reactivations. Clinical manifestations due to symptomatic infection may be mild such as orofacial lesions, but may also translate into more severe diseases, such as ocular infections that may lead to blindness and life-threatening encephalitis. A key feature of herpes simplex viruses (HSVs) is that they have evolved molecular determinants that hamper numerous components of the host’s antiviral innate and adaptive immune system. Importantly, HSVs infect and negatively modulate the function of dendritic cells (DCs), by inhibiting their T cell-activating capacity and eliciting their apoptosis after infection. Previously, we reported that HSV-2 activates the splicing of the mRNA of XBP1, which is related to the activity of the unfolded protein response (UPR) factor Inositol-Requiring Enzyme 1 alpha (IRE-1α). Here, we sought to evaluate if the activation of the IRE-1α pathway in DCs upon HSV infection may be related to impaired DC function after infection with HSV-1 or HSV-2. Interestingly, the pharmacological inhibition of the endonuclease activity of IRE-1α in HSV-1- and HSV-2-infected DCs significantly reduced apoptosis in these cells and enhanced their capacity to migrate to lymph nodes and activate virus-specific CD4⁺ and CD8⁺ T cells. These findings suggest that the activation of the IRE-1α-dependent UPR pathway in HSV-infected DCs may play a significant role in the negative effects that these viruses exert over these cells and that the modulation of this signaling pathway may be relevant for enhancing the function of DCs upon infection with HSVs.

Sulfated Polysaccharides from Seaweed Strandings as Renewable Source for Potential Antivirals against Herpes simplex Virus 1

Herpes simplex virus 1 (HSV-1) remains a prominent health concern widespread all over the world. The increasing genital infections by HSV-1 that might facilitate acquisition and transmission of HIV-1, the cumulative evidence that HSV-1 promotes neurodegenerative disorders, and the emergence of drug resistance signify the need for new antiviral agents. In this study, the in vitro anti-herpetic activity of sulfated polysaccharides (SPs) extracted by enzyme or hot water from seaweeds collected in France and Mexico from stranding events, were evaluated. The anti-herpetic activity evaluation of the semi-refined-polysaccharides (sr-SPs) and different ion exchange purified fractions showed a wide range of antiviral activity. Among them, the sr-SPs from the Rhodophyta Halymenia floresii showed stronger activity EC₅₀ 0.68 μg/mL with SI 1470, without cytotoxicity. Further, the antiviral activity of the sr-SPs evaluated at different treatment schemes showed a high EC₅₀ of 0.38 μg/mL during the viral adsorption assays when the polysaccharide and the virus were added simultaneously, whilst the protection on Vero cell during the post-infection assay was effective up to 1 h. The chemical composition, FTIR and ¹H NMR spectroscopic, and molecular weights of the sr-SPs from H. floresii were determined and discussed based on the anti-herpetic activity. The potential utilization of seaweed stranding as a source of antiviral compounds is addressed.

JieZe-1 Alleviates HSV-2 Infection-Induced Genital Herpes in Balb/c Mice by Inhibiting Cell Apoptosis via Inducing Autophagy

Objectives: Genital herpes (GH) is a common sexually transmitted disease mainly caused by herpes simplex virus 2 (HSV-2). JieZe-1 (JZ-1) is an in-hospital prescription that has been used in Tongji Hospital for many years to treat various lower female genital tract infectious diseases. Our previous study showed that JZ-1 can protect against HSV-2 infection in vitro by inducing autophagy. However, whether JZ-1 can protect against HSV-2 infection in vivo, and the underlying mechanisms involved still remain unclear. Therefore, this study was designed to address above questions. Methods: 8-week-old female balb/c mice were injected intravaginally with HSV-2 to establish GH model. The symptom score, body weight, and histological examination were recorded to assess the animal model of HSV-2 infected and the therapeutic effect of JZ-1. Inflammatory response was determined by detecting inflammatory cells infiltration and local cytokines levels. After then, under autophagy inhibitor chloroquine application, we measured the levels of cell apoptosis and autophagy and investigated the relationship between enhanced autophagy and cell apoptosis. Next, the classic PI3K/Akt/mTOR axis was examined, and in vitro experiment was carried out for further verification. Results: Our results showed that JZ-1 administration significantly reduces symptom score, increases weight gain and alleviates histological damage in HSV-2 infection-induced GH in balb/c mice. JZ-1 administration obviously ameliorates inflammatory responses with reduced T-lymphocytes, T helper cells, macrophages and neutrophils infiltration, and local IL-1β, IL-6, TNF-α and CCL2 levels. HSV-2 infection leads to massive cell apoptosis, which was also restored by JZ-1. Meanwhile, we found that HSV-2 infection blocks autophagic flux in vivo and JZ-1 administration induces autophagy. After chloroquine application, it was observed that the inhibition of autophagy is strongly associated with increased cell apoptosis, whereas the promotion of autophagy remarkedly decreases apoptosis. These results suggested that JZ-1 inhibits cell apoptosis in GH by inducing autophagy, which was further supported in later in vitro experiment. Additionally, PI3K/Akt/mTOR signaling pathway was also downregulated by JZ-1 administration. Conclusion: Our data demonstrated that JZ-1 can alleviate HSV-2 infection-induced GH in balb/c mice by inhibiting cell apoptosis via inducing autophagy, and the underlying mechanisms may be associated with the inhibition of PI3K/Akt/mTOR pathway.

Natural Products and Their Derivatives against Human Herpesvirus Infection

Herpesviruses establish long-term latent infection for the life of the host and are known to cause numerous diseases. The prevalence of viral infection is significantly increased and causes a worldwide challenge in terms of health issues due to drug resistance. Prolonged treatment with conventional antiviral drugs is more likely to develop drug-resistant strains due to mutations of thymidine nucleoside kinase or DNA polymerase. Hence, the development of alternative treatments is clearly required. Natural products and their derivatives have played a significant role in treating herpesvirus infection rather than nucleoside analogs in drug-resistant strains with minimal undesirable effects and different mechanisms of action. Numerous plants, animals, fungi, and bacteria-derived compounds have been proved to be efficient and safe for treating human herpesvirus infection. This review covers the natural antiherpetic agents with the chemical structural class of alkaloids, flavonoids, terpenoids, polyphenols, anthraquinones, anthracyclines, and miscellaneous compounds, and their antiviral mechanisms have been summarized. This review would be helpful to get a better grasp of anti-herpesvirus activity of natural products and their derivatives, and to evaluate the feasibility of natural compounds as an alternative therapy against herpesvirus infections in humans.

Local Immune Control of Latent Herpes Simplex Virus Type 1 in Ganglia of Mice and Man

Herpes simplex virus type 1 (HSV-1) is a prevalent human pathogen. HSV-1 genomes persist in trigeminal ganglia neuronal nuclei as chromatinized episomes, while epithelial cells are typically killed by lytic infection. Fluctuations in anti-viral responses, broadly defined, may underlay periodic reactivations. The ganglionic immune response to HSV-1 infection includes cell-intrinsic responses in neurons, innate sensing by several cell types, and the infiltration and persistence of antigen-specific T-cells. The mechanisms specifying the contrasting fates of HSV-1 in neurons and epithelial cells may include differential genome silencing and chromatinization, dictated by variation in access of immune modulating viral tegument proteins to the cell body, and protection of neurons by autophagy. Innate responses have the capacity of recruiting additional immune cells and paracrine activity on parenchymal cells, for example via chemokines and type I interferons. In both mice and humans, HSV-1-specific CD8 and CD4 T-cells are recruited to ganglia, with mechanistic studies suggesting active roles in immune surveillance and control of reactivation. In this review we focus mainly on HSV-1 and the TG, comparing and contrasting where possible observational, interventional, and in vitro studies between humans and animal hosts.

Donkey Milk Fermentation by Lactococcus lactis subsp. cremoris and Lactobacillus rhamnosus Affects the Antiviral and Antibacterial Milk Properties

BACKGROUND

Milk is considered an important source of bioactive peptides, which can be produced by endogenous or starter bacteria, such as lactic acid bacteria, that are considered effective and safe producers of food-grade bioactive peptides. Among the various types of milk, donkey milk has been gaining more and more attention for its nutraceutical properties.

METHODS

Lactobacillus rhamnosus 17D10 and Lactococcus lactis subsp. cremoris 40FEL3 were selected for their ability to produce peptides from donkey milk. The endogenous peptides and those obtained after bacterial fermentation were assayed for their antioxidant, antibacterial, and antiviral activities. The peptide mixtures were characterized by means of LC-MS/MS and then analyzed in silico using the Milk Bioactive Peptide DataBase.

RESULTS

The peptides produced by the two selected bacteria enhanced the antioxidant activity and reduced E. coli growth. Only the peptides produced by L. rhamnosus 17D10 were able to reduce S. aureus growth. All the peptide mixtures were able to inhibit the replication of HSV-1 by more than 50%. Seventeen peptides were found to have 60% sequence similarity with already known bioactive peptides.

CONCLUSIONS

A lactic acid bacterium fermentation process is able to enhance the value of donkey milk through bioactivities that are important for human health.

Safety, tolerability of ES16001, a novel varicella zoster virus reactivation inhibitor, in healthy adults

Purpose

Herpes zoster (HZ), or shingles, is a clinical syndrome resulting from the reactivation of latent varicella zoster virus (VZV) within the sensory ganglia. We evaluated the safety and tolerability of ES16001 (ethanol extract of Elaeocarpus sylvestris var. ellipticus), a novel inhibitor of varicella zoster virus reactivation in healthy adults.

Method

Single-center, randomized, double-blind, placebo-controlled, single and multiple ascending dose (SAD and MAD, respectively) studies were conducted in 20- to 45-year-old healthy adults without chronic disease. In the SAD study (n = 32), subjects randomly received a single oral dose of 240, 480, 960, or 1440 mg ES16001 or a placebo. In the MAD study (n = 16), subjects randomly received once daily doses of 480 or 960 mg ES16001 or a placebo for 5 days. The safety and tolerability of the drug were evaluated by monitoring participants’ treatment emergent adverse events (TEAEs) and vital signs, electrocardiograms (ECGs), physical examinations, and clinical laboratory tests.

Results

In the SAD study, 11 adverse reactions were seen in 5 subjects, and in the MAD study, 8 adverse reactions were seen in 6 subjects. All adverse reactions were mild, and no serious adverse reactions occurred. The most common adverse reaction was an increase in alanine aminotransferase (ALT), but all test values were in the clinically non-significant range, and their clinical significance was judged to be small considering the fact that most of the test values returned to normal immediately after the end of drug administration.

Conclusion

ES16001 has good safety and tolerability when administered both once and repeatedly to healthy subjects. Further research is needed to identify any possible drug-induced hepatotoxicity, which appears infrequently. Our findings provide a rationale for further clinical investigations of ES16001 for the prevention of HZ.

Trial registration: CRIS, KCT0006066. Registered 7 April 2021—Retrospectively registered, https://cris.nih.go.kr/cris/search/detailSearch.do/19071).

Supplementary Information

The online version contains supplementary material available at 10.1186/s40001-021-00565-z.

Inactivation of Herpes Simplex Virus by Photosensitizing Anthraquinones Isolated from Heterophyllaea pustulata

Heterophyllaea pustulata is a phototoxic plant from Argentina. Aerial parts extracts, high in photosensitizing anthraquinones, have shown in vitro antiviral activity. The purpose of this study was to study the antiherpetic activity of the main purified anthraquinones, even evaluating their competence as photodynamic sensitizers to photo-stimulate the antiviral effect. In vitro antiviral activity against Herpes Simplex virus type I and the photo-inactivation of viral particle were studied by the Neutral Red uptake test and observation of the cytopathic effect. Rubiadin 1-methyl ether and 5,5'-bisoranjidiol produced a significant effect (≥ 80% inhibition) with minimal damage to host cells (subtoxic concentration). Anthraquinones with poor antiherpetic activity at its maximum noncytotoxic concentration showed an important photo-stimulated effect, such is the case of soranjidiol and 5,5'-bisoranjidiol (28.0 ± 6.3 vs. 81.8 ± 2.1% and 15.5 ± 0.3 vs. 89.8 ± 1.7%, respectively). The study also proved the decrease of viral particles, necessary to reduce infection. Therefore, photosensitizing anthraquinones from natural resources could be proposed to develop new treatments for localized viral lesions with antimicrobial photodynamic therapy.

Metal Nanoparticles: a Promising Treatment for Viral and Arboviral Infections

Globally, viral diseases continue to pose a significant threat to public health. Recent outbreaks, such as influenza, coronavirus, Ebola, and dengue, have emphasized the urgent need for new antiviral therapeutics. Considerable efforts have focused on developing metal nanoparticles for the treatment of several pathogenic viruses. As a result of these efforts, metal nanoparticles are demonstrating promising antiviral activity against pathogenic surrogates and clinical isolates. This review summarizes the application of metal nanoparticles for the treatment of viral infections. It provides information on synthesis methods, size-related properties, nano-bio-interaction, and immunological effects of metal nanoparticles. This article also addresses critical criteria and considerations for developing clinically translatable nanosized metal particles to treat viral diseases.

Phytochemical screening of Cordia glabrata (MART.) A.DC. extracts and its potential antioxidant, photoprotective, antimicrobial and antiviral activities

Species of the genus Cordia have shown biological activities, such as anti-inflammatory, analgesic, antioxidant, antiviral, and antifungal activities. The species Cordia glabrata (MART) A.DC. Has no information concerning its phytochemical profile and possible biological activities. Thus, this study aimed to evaluate this profile in ethanolic extracts of young, adult and senescent leaves, as well as their antioxidant, photoprotective, antimicrobial, and virucidal potentials. Phytochemical analysis was performed by TLC (thin-layer chromatography) and showed the presence of flavonoids, tannins, and terpenes. The evaluation by UPLC-MS/MS (Ultra performance liquid chromatography - tandem mass spectrometer) evidenced the presence of caffeic (3.89 mgL-1), p-cumaric (6.13 mgL-1), and ferulic (0.58 mgL-1) acids, whilst, in GC/MS (Gas chromatography-mass spectrometry) analysis there was a greater amount of palmitic (51.17%), stearic (20.34%), linoleic (9.62%), and miristic (8.16%) fatty acids. The DPPH (2,2-Diphenyl-1-picrylhydrazyl) and ABTS+ (2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) radicals were used to verify the potential antioxidant activity, observing a better activity for the leaf extract in the adult phenological stage: 54.63 ± 1.06 µgmL-1 (DPPH) and 44.21 ± 1.69 mM (ABTS). The potential photoprotective activity of the extracts was determined by spectrophotometry and the in vitro values of SPF (Sun Protection Factor) in young and adult leaves (5.47 and 5.41, respectively) showed values close to the minimum SPF of 6.0 required by ANVISA (Brazilian Health Regulatory Agency). It was not observed an antimicrobial activity for Staphylococcus aureus with a minimum inhibitory concentration of 2000 μgmL-1, however the anti-herpetic assay against the Herpes simplex virus type 2 (HSV-2) showed a potent virucidal activity at the tested concentrations with CV50 value <0.195 μgmL-1 and a Selectivity Index (SI = CC50 / CV50) greater than 448. The results obtained in this study suggest that extracts of leaves of C. glabrata in their adult phenological stage have potential antioxidant, photoprotective and virucidal activity, considering in vitro test results.

Pyrimido[1,2-a]benzimidazoles: synthesis and perspective of their pharmacological use

The review presents data on the synthesis as well as studies of biological activity of new derivatives of pyrimido[1,2-a]benzimidazoles published over the last decade. The bibliography of the review includes 136 sources.

Advancement on Sustained Antiviral Ocular Drug Delivery for Herpes Simplex Virus Keratitis: Recent Update on Potential Investigation

The eyes are the window to the world and the key to communication, but they are vulnerable to multitudes of ailments. More serious than is thought, corneal infection by herpes simplex viruses (HSVs) is a prevalent yet silent cause of blindness in both the paediatric and adult population, especially if immunodeficient. Globally, there are 1.5 million new cases and forty thousand visual impairment cases reported yearly. The Herpetic Eye Disease Study recommends topical antiviral as the front-line therapy for HSV keratitis. Ironically, topical eye solutions undergo rapid nasolacrimal clearance, which necessitates oral drugs but there is a catch of systemic toxicity. The hurdle of antiviral penetration to reach an effective concentration is further complicated by drugs’ poor permeability and complex layers of ocular barriers. In this current review, novel delivery approaches for ocular herpetic infection, including nanocarriers, prodrugs, and peptides are widely investigated, with special focus on advantages, challenges, and recent updates on in situ gelling systems of ocular HSV infections. In general congruence, the novel drug delivery systems play a vital role in prolonging the ocular drug residence time to achieve controlled release of therapeutic agents at the application site, thus allowing superior ocular bioavailability yet fewer systemic side effects. Moreover, in situ gel functions synergistically with nanocarriers, prodrugs, and peptides. The findings support that novel drug delivery systems have potential in ophthalmic drug delivery of antiviral agents, and improve patient convenience when prolonged and chronic topical ocular deliveries are intended.

Anti-herpetic Activity of Macrocystis pyrifera and Durvillaea antarctica Algae Extracts Against HSV-1 and HSV-2

Herpes simplex viruses (HSVs) type 1 (HSV-1) and type 2 (HSV-2) are highly prevalent in the human population, and the infections they produce are lifelong with frequent reactivations throughout life. Both viruses produce uncomfortable and sometimes painful lesions in the orofacial and genital areas, as well as herpetic gingivostomatitis, among other clinical manifestations. At present, the most common treatments against HSVs consist of nucleoside analogs that target the viral polymerases. However, such drugs are poorly effective for treating skin lesions, as they only reduce in 1-2 days the duration of the herpetic lesions. Additionally, viral isolates resistant to these drugs can emerge in immunosuppressed individuals, and second-line drugs for such variants are frequently accompanied by adverse effects requiring medical supervision. Thus, novel or improved therapeutic drugs for treating HSV lesions are needed. Here, we assessed the potential antiviral activity of aqueous extracts obtained from two brown macroalgae, namely Macrocystis pyrifera and Durvillaea antarctica against HSVs. Both extracts showed antiviral activity against acyclovir-sensitive and acyclovir-resistant HSV-1 and HSV-2. Our analyses show that there is a significant antiviral activity associated with proteins in the extract, although other compounds also seem to contribute to inhibiting the replication cycle of these viruses. Evaluation of the algae extracts as topical formulations in an animal model of HSV-1 skin infection significantly reduced the severity of the disease more than acyclovir, as well as the duration of the herpetic lesions, when compared to mock-treated animals, with the D. antarctica extract performing best. Taken together, these findings suggest that these algae extracts may be potential phytotherapeutics against HSVs and may be useful for the treatment and reduction of common herpetic manifestations in humans.

Acyclovir-Loaded Solid Lipid Nanoparticles: Optimization, Characterization and Evaluation of Its Pharmacokinetic Profile

Acyclovir is an antiviral drug used for the treatment of herpes simplex virus infection. Its oral bioavailability is low; therefore, frequent and high doses are prescribed for optimum therapeutic efficacy. Moreover, the current therapeutic regimen of acyclovir is associated with unwarranted adverse effects, hence prompting the need for a suitable drug carrier to overcome these limitations. This study aimed to develop solid lipid nanoparticles (SLNs) as acyclovir carriers and evaluate their in vivo pharmacokinetic parameters to prove the study hypothesis. During the SLN development process, response surface methodology was exploited to optimize the composition of solid lipid and surfactant. Optimum combination of Biogapress Vegetal 297 ATO and Tween 80 was found essential to produce SLNs of 134 nm. The oral bioavailability study showed that acyclovir-loaded SLNs possessed superior oral bioavailability when compared with the commercial acyclovir suspension. The plasma concentration of acyclovir-loaded SLNs was four-fold higher than the commercial suspension. Thus, this investigation presented promising results that the method developed for encapsulation of acyclovir offers potential as an alternative pathway to enhance the drug’s bioavailability. In conclusion, this study exhibited the feasibility of SLNs as an oral delivery vehicle for acyclovir and therefore represents a new promising therapeutic concept of acyclovir treatment via a nanoparticulate drug delivery system.

Imprinted Contact Lenses for Ocular Administration of Antiviral Drugs

A variety of ocular diseases are caused by viruses, and most treatments rely on the use of systemic formulations and eye drops. The efficient ocular barriers that oppose antiviral drug penetration have prompted the development of improved topical delivery platforms. The aim was to design hydrogel contact lenses endowed with an affinity for acyclovir (ACV) and its prodrug valacyclovir (VACV), first-choice drugs against herpes simplex virus (HSV) ocular keratitis, and that can sustain the release of therapeutic doses during daily wearing. Functional monomers suitable for interaction with these drugs were screened using computational modeling. Imprinted and non-imprinted hydrogels were prepared with various contents in the functional monomer methacrylic acid (MAA) and characterized in terms of swelling, transmittance, mechanical properties, and ocular compatibility (hen’s egg test on chorioallantoic membrane (HET-CAM) assay). The values were in the range typical of soft contact lenses. Compared to ACV, the capability to load VACV was remarkably higher due to stronger electrostatic interactions with MAA. The advantages of the imprinting technology were evidenced for VACV. Stability of VACV loading solution/hydrogels under steam heat sterilization and subsequent drug release was investigated. Permeability studies through bovine and porcine cornea and sclera of the drug released from the hydrogels revealed that VACV accumulates in the cornea and can easily cross the sclera, which may facilitate the treatment of both anterior and posterior eye segments diseases.

Plants Metabolites: Possibility of Natural Therapeutics Against the COVID-19 Pandemic

COVID-19, a disease induced by SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus-2), has been the cause of a worldwide pandemic. Though extensive research works have been reported in recent days on the development of effective therapeutics against this global health crisis, there is still no approved therapy against SARS-CoV-2. In the present study, plant-synthesized secondary metabolites (PSMs) have been prioritized to make a review focusing on the efficacy of plant-originated therapeutics for the treatment of COVID-19. Plant metabolites are a source of countless medicinal compounds, while the diversity of multidimensional chemical structures has made them superior to treat serious diseases. Some have already been reported as promising alternative medicines and lead compounds for drug repurposing and discovery. The versatility of secondary metabolites may provide novel antibiotics to tackle MDR (Multi-Drug Resistant) microbes too. This review attempted to find out plant metabolites that have the therapeutic potential to treat a wide range of viral pathogens. The study includes the search of remedies belonging to plant families, susceptible viral candidates, antiviral assays, and the mode of therapeutic action; this attempt resulted in the collection of an enormous number of natural therapeutics that might be suggested for the treatment of COVID-19. About 219 plants from 83 families were found to have antiviral activity. Among them, 149 plants from 71 families were screened for the identification of the major plant secondary metabolites (PSMs) that might be effective for this pandemic. Our investigation revealed that the proposed plant metabolites can serve as potential anti- SARS-CoV-2 lead molecules for further optimization and drug development processes to combat COVID-19 and future pandemics caused by viruses. This review will stimulate further analysis by the scientific community and boost antiviral plant-based research followed by novel drug designing.