Characterization and Promising in vitro Antiherpetic Effect of Galactomannan from Delonix regia Seeds.

Herpes simplex virus (HSV) infections can occur throughout life, thereby allowing transmission to new hosts, with an impact on public health. Acyclovir remains the treatment of choice for these infections; however, an increase in resistant strains in recent years has been observed. In this study, the activity of a native Delonix regia galactomannan (NDr) against HSV-1 was investigated in vitro. NDr was characterized using infrared spectroscopy and NMR. Evaluation of cytotoxicity and the antiviral effect was determined, respectively, by MTT and plaque reduction assays. The NDr concentrations that inhibited cell viability (CC50) and viral infection (IC50) by 50% were above 2000 and 64 µg/mL, respectively. Thus, the polysaccharide showed a high selectivity index (> 31.25). When NDr was added at different stages of HSV-1 replication, a strong inhibitory effect was found by direct interaction with the virus (71-67%, virucidal effect) or previously with the cell, 6 h before infection (99.8-68.4%, prophylactic effect) at concentrations from 200 to 50 µg/mL. NDr showed similar effects in prophylactic 1 h (52%) and adsorption inhibition (55%) assays at 200 µg/mL. A reduction in the antiherpetic effect was observed after infection. These results suggest that NDr is effective in the early stages of HSV-1 infection and is a promising agent for controlling herpetic infections.

Proteus mirabilis from community-acquired urinary tract infections (UTI-CA) shares genetic similarity and virulence factors with isolates from chicken, beef and pork meat.

Proteus mirabilis is an opportunistic pathogen associated with a variety of infections in humans, especially those in the urinary tract. The isolation of this pathogen in foods of animal origin such as meat is poorly documented and should not be neglected, in view of the zoonotic risk that this can pose to human health. Thus, the objective of this study was to evaluate the prevalence, virulence profile, and similarity between P. mirabilis strains isolated from chicken, beef, and pork meat and those causing community-acquired urinary tract infections (UTI-CA), in order to better understand the role of this bacterium as a zoonotic pathogen. P. mirabilis was isolated from the three types of meat and was found to be more prevalent in chicken. All isolates exhibited several genotypic and phenotypic virulence characteristics, such as adhesion capacity in HEp-2 cell culture, biofilm formation, cytotoxicity in Vero cells and genes that express fimbriae (mrpA, pmfA, ucaA, atfA), hemolysin (hpmA), proteases (zapA and ptA) and siderophore receptor (ireA). UTI-CA strains showed a higher prevalence of ucaA and ireA genes, whereas those from the chicken meat had a higher prevalence of the atfA gene compared with the isolates from the beef and pork meat. It was observed that chicken meat and UTI-CA strains mainly formed very strong biofilms, whereas strains isolated from beef and pork formed more weak and moderate biofilms. Several strains from meat showed close genetic similarity to those from UTI-CA and had the same virulence profiles. Thus, meats may be an important source of the dissemination of P. mirabilis responsible for causing UTIs in the community.

Viral infections and their relationship to neurological disorders.

The chronic dysfunction of neuronal cells, both central and peripheral, a characteristic of neurological disorders, may be caused by irreversible damage and cell death. In 2016, more than 276 million cases of neurological disorders were reported worldwide. Moreover, neurological disorders are the second leading cause of death. Generally, the etiology of neurological diseases is not fully understood. Recent studies have related the onset of neurological disorders to viral infections, which may cause neurological symptoms or lead to immune responses that trigger these pathological signs. Currently, this relationship is mostly based on epidemiological data on infections and seroprevalence of patients who present with neurological disorders. The number of studies aiming to elucidate the mechanism of action by which viral infections may directly or indirectly contribute to the development of neurological disorders has been increasing over the years but these studies are still scarce. Comprehending the pathogenesis of these diseases and exploring novel theories may favor the development of new strategies for diagnosis and therapy in the future. Therefore, the objective of the present study was to review the main pieces of evidence for the relationship between viral infection and neurological disorders such as Alzheimer's disease, Parkinson's disease, Guillain-Barré syndrome, multiple sclerosis, and epilepsy. Viruses belonging to the families Herpesviridae, Orthomyxoviridae, Flaviviridae, and Retroviridae have been reported to be involved in one or more of these conditions. Also, neurological symptoms and the future impact of infection with SARS-CoV-2, a member of the family Coronaviridae that is responsible for the COVID-19 pandemic that started in late 2019, are reported and discussed.

Sulfonated and Carboxymethylated ß-Glucan Derivatives with Inhibitory Activity against Herpes and Dengue Viruses.

The infection of mammalian cells by enveloped viruses is triggered by the interaction of viral envelope glycoproteins with the glycosaminoglycan, heparan sulfate. By mimicking this carbohydrate, some anionic polysaccharides can block this interaction and inhibit viral entry and infection. As heparan sulfate carries both carboxyl and sulfate groups, this work focused on the derivatization of a (1→3)(1→6)-ß-D-glucan, botryosphaeran, with these negatively-charged groups in an attempt to improve its antiviral activity. Carboxyl and sulfonate groups were introduced by carboxymethylation and sulfonylation reactions, respectively. Three derivatives with the same degree of carboxymethylation (0.9) and different degrees of sulfonation (0.1; 0.2; 0.4) were obtained. All derivatives were chemically characterized and evaluated for their antiviral activity against herpes (HSV-1, strains KOS and AR) and dengue (DENV-2) viruses. Carboxymethylated botryosphaeran did not inhibit the viruses, while all sulfonated-carboxymethylated derivatives were able to inhibit HSV-1. DENV-2 was inhibited only by one of these derivatives with an intermediate degree of sulfonation (0.2), demonstrating that the dengue virus is more resistant to anionic ß-D-glucans than the Herpes simplex virus. By comparison with a previous study on the antiviral activity of sulfonated botryosphaerans, we conclude that the presence of carboxymethyl groups might have a detrimental effect on antiviral activity.

COVID-19: The question of genetic diversity and therapeutic intervention approaches.

Coronavirus disease 2019 (COVID-19), caused by the Severe Acute Respiratory Syndrome Coronavirus type 2 (SARS-CoV-2), is the largest pandemic in modern history with very high infection rates and considerable mortality. The disease, which emerged in China's Wuhan province, had its first reported case on December 29, 2019, and spread rapidly worldwide. On March 11, 2020, the World Health Organization (WHO) declared the COVID-19 outbreak a pandemic and global health emergency. Since the outbreak, efforts to develop COVID-19 vaccines, engineer new drugs, and evaluate existing ones for drug repurposing have been intensively undertaken to find ways to control this pandemic. COVID-19 therapeutic strategies aim to impair molecular pathways involved in the virus entrance and replication or interfere in the patients' overreaction and immunopathology. Moreover, nanotechnology could be an approach to boost the activity of new drugs. Several COVID-19 vaccine candidates have received emergency-use or full authorization in one or more countries, and others are being developed and tested. This review assesses the different strategies currently proposed to control COVID-19 and the issues or limitations imposed on some approaches by the human and viral genetic variability.

Mangiferin: A promising natural xanthone from Mangifera indica for the control of acyclovir - resistant herpes simplex virus 1 infection.

Mangiferin is found in many plant species as the mango tree (Mangifera indica) with ethnopharmacological applications and scientific evidence. The emergence of resistant herpes simplex virus (HSV) strains to Acyclovir (ACV) has encouraged the search for new drugs. We investigated the in vitro and in vivo activity of mangiferin obtained from M. indica against ACV-resistant HSV-1 (AR-29) and sensitive (KOS) strains. The in vitro activity was performed under varying treatment protocols. The substance showed a CC50 > 500 µg/mL and IC50 of 2.9 µg/mL and 3.5 µg/mL, respectively, for the AR-29 and KOS strains. The in vivo activity was performed in Balb/c mice treated with 0.7% topical mangiferin formulation. This formulation inhibited most effectively the AR-29 strain, attenuated the lesions, postponed their appearance or enhanced healing, in comparison to control group. We demonstrated the potentiality of mangiferin from M. indica to control HSV replication with emphasis to ACV-resistant infection.

Antiherpetic Effect of Topical Formulations Containing Sulfated Polysaccharide from Adenanthera pavonina.

Adenanthera pavonina is a native tree of Africa and Asia, introduced in Brazil for reforestation and wood industry. Several pharmacological activities have described scientifically, including antiviral activity. This study evaluated the antiviral effect of sulfated polysaccharide of Adenanthera pavonina (SPAp) against acyclovir (ACV)-resistant (AR-29) and sensitive (KOS) herpes simplex virus strains. The 50% cytotoxic concentration (CC50) was determined by MTT method and the 50% inhibitory concentration (IC50) was evaluated by plaque reduction assay. The in vivo SPAp antiviral activity was performed in Balb/c mice infected by skin scarification and treated with topical 0.5% (w/w) SPAp formulations. SPAp showed a CC50 of 47.81 µg/mL and the IC50 were 0.49 µg/mL (SI = 97.5) and 0.54 µg/mL (SI = 88.5) for the strains KOS and AR-29, respectively. Our results demonstrated that mice treated with SPAp presented a delay in the development and progression of skin lesions compared with the control group.

Structural relationship of regioselectively-sulfonated botryosphaeran derivatives on activity against herpes simplex virus type 1.

The bioactivities of sulfonated polysaccharides are frequently related to their substitution pattern. In this study, the regioselective sulfonation of an exocellular fungal (1→3)(1→6)-ß-D-glucan (botryosphaeran) was performed by two different methods: mild sulfonation (MS) and via pivaloyl ester (PS), in order to study the influence of the sulfonation pattern on the antiviral activity of the respective derivatives. Two sulfonated derivatives with substitution degrees of 0.82 (MS) and 0.49 (PS) were obtained, with substitution patterns at positions C-6, and C-2/C-4 of the glucose units, respectively. All derivatives were chemically characterized and evaluated for antiviral activity against Herpes simplex virus type 1 (HSV-1) KOS strain, and dengue type 2 (DENV-2). The sample sulfonated at positions C-6 (MS) showed a remarkable antiviral effect on HSV-1 (IC50 of 5.38 µg mL1), while PS remained inactive. The investigation of the mode of action of sample MS pointed to the inhibition of HSV-1 adsorption to the host cells. Both samples were inactive towards the dengue virus strain. This study demonstrated that the presence of sulfate groups at the C-6 positions of botryosphaeran is the preferred substitution pattern that enables the antiviral activity towards HSV-1.

Anti-respiratory syncytial virus and anti-herpes simplex virus activity of chemically engineered sulfated fucans from Cystoseira indica.

Seaweed polysaccharides, particularly sulfated ones, exhibited potent antiviral activity against a wide variety of enveloped viruses, such as herpes simplex virus and respiratory viruses. Different mechanisms of action were suggested, which may range from preventing infection to intracellular antiviral activity, at different stages of the viral cycle. Herein, we generated two chemically engineered sulfated fucans (C303 and C304) from Cystoseira indica by an amalgamated extraction-sulfation procedure using chlorosulfonic acid-pyridine/N,N-dimethylformamide and sulfur trioxide-pyridine/N,N-dimethylformamide reagents, respectively. These compounds exhibited activity against HSV-1 and RSV with 50 % inhibitory concentration values in the range of 0.75-2.5 µg/mL and low cytotoxicity at concentrations up to 500 µg/mL. The antiviral activities of chemically sulfated fucans (C303 and C304) were higher than the water (C301) and CaCl2 extracted (C302) polysaccharides. Compound C303 had a (1,3)-linked fucan backbone and was branched. Sulfates were present at positions C-2, C-4, and C-2,4 of Fucp, and C-6 of Galp residues of this polymer. Compound C304 had a comparable structure but with more sulfates at C-4 of Fucp residue. Both C303 and C304 were potent antiviral candidates, acting in a dose-dependent manner on the adsorption and other intracellular stages of HSV-1 and RSV replication, in vitro.

Production and characterization of rhamnolipids by Pseudomonas aeruginosa isolated in the Amazon region, and potential antiviral, antitumor, and antimicrobial activity.

Biosurfactants encompass structurally and chemically diverse molecules with surface active properties, and a broad industrial deployment, including pharmaceuticals. The interest is growing mainly for the low toxicity, biodegradability, and production from renewable sources. In this work, the optimized biosurfactant production by Pseudomonas aeruginosa BM02, isolated from the soil of a mining area in the Brazilian Amazon region was assessed, in addition to its antiviral, antitumor, and antimicrobial activities. The optimal conditions for biosurfactant production were determined using a factorial design, which showed the best yield (2.28 mg/mL) at 25 °C, pH 5, and 1% glycerol. The biosurfactant obtained was characterized as a mixture of rhamnolipids with virucidal properties against Herpes Simplex Virus, Coronavirus, and Respiratory Syncytial Virus, in addition to antimicrobial properties against Gram-positive bacteria (Staphylococcus aureus and Enterococcus faecium), at 50 µg/mL. The antitumor activity of BS (12.5 µg/mL) was also demonstrated, with potential selectivity in reducing the proliferation of breast tumor cells, after 1 min of exposure. These results demonstrate the importance of studying the interconnection between cultivation conditions and properties of industrially important compounds, such as rhamnolipid-type biosurfactant from P. aeruginosa BM02, a promising and sustainable alternative in the development of new antiviral, antitumor, and antimicrobial prototypes.

Dermatological Manifestations in COVID-19: A Case Study of SARS-CoV-2 Infection in a Genetic Thrombophilic Patient with Mthfr Mutation.

The present case study describes the dermatological manifestations of COVID-19 in a patient with genetic thrombophilia (MTHFR-C677T mutation) and the identification of a SARS-CoV-2 variant of interest (VOI). A female patient, 47 years old, unvaccinated, with thrombophilia, was diagnosed with COVID-19. She presented with urticarial and maculopapular eruptions from the seventh day of symptoms, which progressed to multiple lesions with dark centers (D-dimer value > 1450 ng/mL). The dermatological manifestations disappeared after 30 days, corroborating the reduction in D-dimer levels. Viral genome sequencing revealed infection by the VOI Zeta (P.2). Antibody testing, performed 30 days after the onset of symptoms, detected only IgG. The virus neutralization test showed the highest neutralizing titer for a P.2 strain, validating the genotypic identification. Lesions were suggested to be due to infection in skin cells causing a direct cytopathic effect or release of pro-inflammatory cytokines triggering erythematous and urticarial eruptions. In addition, vascular complications are also proposed to be due to the MTHFR mutation and increased D-dimer values. This case report is an alert about COVID-19 in patients with pre-existing vascular diseases, especially in unvaccinated patients, by VOI.

In silico approaches and in vitro assays identify a coumarin derivative as antiviral potential against SARS-CoV-2.

COVID-19, a disease caused by SARS-CoV-2, was declared a pandemic in 2020 and created a global crisis in health systems, with more than 545 million confirmed cases and 6.33 million deaths. In this sense, this work aims to identify possible inhibitors of the SARS-CoV-2 RdRp enzyme using in silico approaches. RdRp is a crucial enzyme in the replication and assembly cycle of new viral particles and a critical pharmacological target in the treatment of COVID-19. We performed a virtual screening based on molecular docking from our in-house chemical library, which contains a diversity of 313 structures from different chemical classes. Nine compounds were selected since they showed important interactions with the active site from RdRp. Next, the ADME-Tox in silico predictions served as a filter and selected the three most promising compounds: a coumarin LMed-052, a hydantoin LMed-087, and a guanidine LMed-250. Molecular dynamics simulations revealed details such as changes in the positions of ligands and catalytic residues during the simulations compared to the complex from molecular docking studies. Binding free energy analysis was performed using the MMGBSA method, demonstrating that LMed-052 and LMed-087 have better affinities for the RdRp by energetic contributions to the stability of the complexes when compared to LMed-250. Furthermore, LMed-052 showed significant in vitro inhibition against MHV-3, decreasing 99% of viral titers. Finally, these findings are useful to guide structural modifications aiming to improve the potential of these compounds to act as inhibitors of SARS-CoV-2.Communicated by Ramaswamy H. Sarma.

Development of a Melting-Curve-Based Multiplex Real-Time PCR Assay for the Simultaneous Detection of Viruses Causing Respiratory Infection.

The prompt and accurate identification of the etiological agents of viral respiratory infections is a critical measure in mitigating outbreaks. In this study, we developed and clinically evaluated a novel melting-curve-based multiplex real-time PCR (M-m-qPCR) assay targeting the RNA-dependent RNA polymerase (RdRp) and nucleocapsid phosphoprotein N of SARS-CoV-2, the Matrix protein 2 of the Influenza A virus, the RdRp domain of the L protein from the Human Respiratory Syncytial Virus, and the polyprotein from Rhinovirus B genes. The analytical performance of the M-m-qPCR underwent assessment using in silico analysis and a panel of reference and clinical strains, encompassing viral, bacterial, and fungal pathogens, exhibiting 100% specificity. Moreover, the assay showed a detection limit of 10 copies per reaction for all targeted pathogens using the positive controls. To validate its applicability, the assay was further tested in simulated nasal fluid spiked with the viruses mentioned above, followed by validation on nasopharyngeal swabs collected from 811 individuals. Among them, 13.4% (109/811) tested positive for SARS-CoV-2, and 1.1% (9/811) tested positive for Influenza A. Notably, these results showed 100% concordance with those obtained using a commercial kit. Therefore, the M-m-qPCR exhibits great potential for the routine screening of these respiratory viral pathogens.

The heparin-mimicking arabinogalactan sulfates from Anogeissus latifolia gum: Production, structures, and anti-herpes simplex virus activity.

Herpes simplex virus type 1(HSV-1) attaches to cell surface heparan sulfate aiming to enter into susceptible cells. In this work, we utilized a sulfur trioxide-pyridine in N,N-dimethylformamide (SO3·Pyr/DMF) based amalgamated extraction-sulfation procedure for producing arabinogalactan sulfates from Anogeissus latifolia gum. Chemical, chromatographic, spectroscopic and chemical data revealed that the derived polymers contained varying molecular masses (31-69 kDa) and degrees of sulfation (0.1-0.5), but similar saccharide compositions. The highly active polymer (HSV-1: IC50 and SI, respectively, of 127 µg/mL and 15.7) was a 69 kDa arabinogalactan holding sulfates at O-5 of arabinofuranosyl residues and showed no cytotoxicity as far as 2 mg/mL concentration. This chemically sulfated macromolecule acted by obstructing viral attachment and entry. Thus, SO3·Pyr/DMF is suitable for producing new molecules with varied structures and altered pharmacological activities from plant sources.

Cucumis melo pectin as potential candidate to control herpes simplex virus infection.

The herpes simplex virus, also known as HSV, is an important human pathogen. Acyclovir (ACV) is the first-line antiviral for the treatment of HSV infections; nevertheless HSV resistance to ACV has been increasingly reported and, therefore, search for alternative drugs have been encouraged. Herein, the effect of Cucumis melo sulfated pectin (SPCm) was evaluated in the HSV-1 infection. Pectin cytotoxicity and its antiherpetic action were determined by assays of MTT and plaque reduction, respectively. The SPCm concentration that reduced the cell viability by 50% (CC50) was 1440 µg/mL, while the concentration that reduced PFU in 50% (IC50) was 6 µg/mL against ACV-sensitive (KOS) strain and 12 µg/mL for ACV-resistant (AR-29) strain. The pectin showed high selectivity index (SI) for both viral strains. Therefore, we suggest that SPCm has been effective for HSV-1, strenghten by viral protein and DNA syntheses inhibition. In conclusion, we have found that SPCm is a promising alternative compound to control HSV infection.

Antiviral therapies: advances and perspectives.

Viral infections cause high morbidity and mortality, threaten public health, and impose a socioeconomic burden. We have seen the recent emergence of SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2), the causative agent of COVID-19 that has already infected more than 29 million people, with more than 900 000 deaths since its identification in December 2019. Considering the significant impact of viral infections, research and development of new antivirals and control strategies are essential. In this paper, we summarize 96 antivirals approved by the Food and Drug Administration between 1987 and 2019. Of these, 49 (51%) are used in treatments against human immunodeficiency virus (HIV), four against human papillomavirus, six against cytomegalovirus, eight against hepatitis B virus, five against influenza, six against herpes simplex virus, 17 against hepatitis C virus and one against respiratory syncytial virus. This review also describes future perspectives for new antiviral therapies such as nanotechnologies, monoclonal antibodies and the CRISPR-Cas system. These strategies are suggested as inhibitors of viral replication by various means, such as direct binding to the viral particle, blocking the infection, changes in intracellular mechanisms or viral genes, preventing replication and virion formation. We also observed that a large number of viral agents have no therapy available and the majority of those approved in the last 32 years are restricted to some groups, especially anti-HIV. Additionally, the emergence of new viruses and strains resistant to available antivirals has necessitated the formulation of new antivirals.

Assessment of antiherpetic activity of nonsulfated and sulfated polysaccharides from Azadirachta indica.

Azadirachta indica leaf is used by Indian population for the healing of various diseases including viral infection. Herein, we analyzed the antiherpetic (HSV-1) activity of two polysaccharides (P1 and P2) isolated from the leaf of A. indica and their chemically sulfated derivatives (P1S and P2S). The molecular weights of P1S and P2S are 41 and 11 kDa, respectively. Sulfate groups are located at positions C3 of the Araf and C6 of both Galp and Glcp residues of the most active polysaccharide (P1S). These compounds were not cytotoxic in HEp-2 cells, up to 1000 µg/mL. Both P1S and P2S exhibited antiviral activity when used simultaneously to HSV-1, with 50% inhibitory concentration/selectivity index, respectively, of 31.1 µg/mL/>51.4 and 80.5 µg/mL/>19.8. P1S showed better inhibitory effect (91.8%) compared to P1 (50%), P2 (71.1%) and P2S (70%) at 200 µg/mL. Synthesis of viral protein showed a dose-dependent response and the nucleic acid synthesis was inhibited up to 25 µg/mL, by P1 and P1S and up to 50 µg/mL, by P2 and P2S. The antiviral effect is probably due to the interference of polysaccharides at the early stages of HSV-1 replication, including adsorption. Further studies are under way to get insight into the mechanism of action of the substances.

Botryosphaeran and sulfonated derivatives as novel antiviral agents for herpes simplex and dengue fever.

Sulfated polysaccharides are known to display activity against enveloped viruses, such as herpes and dengue. The aim of this work was to assess the antiviral activity of botryosphaeran, a fungal exocellular (1 → 3)(1 → 6)-ß-d-glucan devoid of sulfate groups, and its chemically sulfonated derivatives, against herpes simplex virus (HSV), dengue virus (DENV) and poliovirus (PV). The natural parent polysaccharide inhibited acyclovir-sensitive HSV (HSV-KOS) infection in Vero cells (IC50 of 39.3 µg mL-1), while the IC50 against acyclovir-resistant HSV (HSV-AR) was 47.5 µg mL-1. Botryosphaeran was derivatized by sulfonylation with chlorosulfonic acid to prepare two sulfonated derivatives, S1 and S2, with degrees of substitution (DS) of 0.4 and 1.1, respectively. Antiviral evaluation of S1 and S2 gave the IC50 of 3.0 and 2.4 µg mL-1 against HSV-KOS, and 7.3 and 2.7 µg mL-1 against HSV-AR, respectively. This study demonstrated for the first time that native botryosphaeran inhibited HSV infection, albeit moderately, while its sulfonated derivatives developed high activity against viral infection. DENV inhibition was weak for botryosphaeran, but remarkably stronger for S1 and S2. All compounds were inactive against PV, as it lacked a viral envelope. The presence of sulfate groups and the DS were confirmed to be important features for antiviral activity.

Structural characterization and antiviral activity of pectin isolated from Inga spp.

Several studies have been conducted on polysaccharides derived from natural sources, and their different biological properties have been reported. Their low toxicity and antiviral effects i.e., their action on several steps of viral replication, have been extensively examined. In this work, pectin isolated from Inga spp. fruit pulp was first characterized and evaluated using HEp-2 cells against the herpes simplex virus type 1 (HSV-1) and the poliovirus (PV). The isolated pectin (denoted as PDTS) was characterized by infrared spectroscopy, NMR and Gel permeation chromatography. The cytotoxicity was analyzed by the MTT method and antiviral activity by plaque reduction assay, immunofluorescence assay (IF) and polymerase chain reaction (PCR). The cytotoxic concentration (CC50) of PDTS was 870 µg.mL-1 and the inhibitory concentrations (IC50) were 179 µg.mL-1 and 58 µg.mL-1 for HSV-1 and PV, respectively. Greater inhibitory effect was observed when the cells were simultaneously treated with PDTS and infected, suggesting that PDTS inhibited the initial viral replication stages, revealing its antiviral potential.