Interactions between carbon nanotubes and external structures of SARS-CoV-2 using molecular docking and molecular dynamics.

Molecular modeling techniques are used to describe the process of interaction between nanotubes and the main structures of the Covid-19 virus: the envelope protein, the main protease, and the Spike glycoprotein. Molecular docking studies show that the ligands have interaction characteristics capable of adsorbing the structures. Molecular dynamics simulations provide information on the mean squared deviation of atomic positions ​​between 0.5 and 3.0 Å. The Gibbs free energy model and solvent accessible surface area approaches are used. Through the results obtained through molecular dynamics simulations, it is noted that the zig-zag nanotube prefers to interact with E-pro, M-pro, and S-gly, respectively. Molecular couplings and free energy showed that the S-gly active site residues strongly interact with zigzag, chiral, and armchair nanotubes, in this order. The interactions demonstrated in this manuscript may predict some promising candidates for virus antagonists, which may be confirmed through experimental approaches.

New insights into the antiviral activity of nordihydroguaiaretic acid: Inhibition of dengue virus serotype 1 replication.

BACKGROUND: Dengue virus (DENV) is considered one of the most important pathogens in the world causing 390 million infections each year. Currently, the development of vaccines against DENV presents some shortcomings and there is no antiviral therapy available for its infection. An important challenge is that both treatments and vaccines must be effective against all four DENV serotypes. Nordihydroguaiaretic acid (NDGA), isolated from Larrea divaricata Cav. (Zygophyllaceae) has shown a significant inhibitory effect on a broad spectrum of viruses, including DENV serotypes 2 and 4. PURPOSE: We evaluated the in vitro virucidal and antiviral activity of NDGA on DENV serotype 1 (DENV1), including the study of its mechanism of action, to provide more evidence on its antiviral activity. METHODS: The viability of viral particles was quantified by the plaque-forming unit reduction method. NDGA effects on DENV1 genome and viral proteins were evaluated by qPCR and immunofluorescence, respectively. Lysosomotropic activity was assayed using acridine orange and neutral red dyes. RESULTS: NDGA showed in vitro virucidal and antiviral activity against DENV1. The antiviral effect would be effective within the first 2 h after viral internalization, when the uncoating process takes place. In addition, we determined by qPCR that NDGA decreases the amount of intracellular RNA of DENV1 and, by immunofluorescence, the number of cells infected. These results indicate that the antiviral effect of NDGA would have an intracellular mechanism of action, which is consistent with its ability to be incorporated into host cells. Considering the inhibitory activity of NDGA on the cellular lipid metabolism, we compared the antiviral effect of two inhibitors acting on two different pathways of this type of metabolism: 1) resveratrol that inhibits the sterol regulatory element of binding proteins, and 2) caffeic acid that inhibits the 5-lipoxygenase (5-LOX) enzyme. Only caffeic acid produced an inhibitory effect on DENV1 infection. We studied the lysosomotropic activity of NDGA on host cells and found, for the first time, that this compound inhibited the acidification of cell vesicles which would prevent DENV1 uncoating process. CONCLUSION: The present work contributes to the knowledge of NDGA activity on DENV. We describe its activity on DENV1, a serotype different to those that have been already reported. Moreover, we provide evidence on which stage/s of the viral replication cycle NDGA exerts its effects. We suggest that the mechanism of action of NDGA on DENV1 is related to its lysosomotropic effect, which inhibits the viral uncoating process.

Targeting Host PIM Protein Kinases Reduces Mayaro Virus Replication.

Mayaro virus (MAYV) manipulates cell machinery to successfully replicate. Thus, identifying host proteins implicated in MAYV replication represents an opportunity to discover potential antiviral targets. PIM kinases are enzymes that regulate essential cell functions and also appear to be critical factors in the replication of certain viruses. In this study we explored the consequences of PIM kinase inhibition in the replication of MAYV and other arboviruses. Cytopathic effects or viral titers in samples from MAYV-, Chikungunya-, Una- or Zika-infected cells treated with PIM kinase inhibitors were evaluated using an inverted microscope or plaque-forming assays. The expression of viral proteins E1 and nsP1 in MAYV-infected cells was assessed using an immunofluorescence confocal microscope or Western blot. Our results revealed that PIM kinase inhibition partially prevented MAYV-induced cell damage and also promoted a decrease in viral titers for MAYV, UNAV and ZIKV. The inhibitory effect of PIM kinase blocking was observed for each of the MAYV strains tested and also occurred as late as 8 h post infection (hpi). Finally, PIM kinase inhibition suppressed the expression of MAYV E1 and nsP1 proteins. Taken together, these findings suggest that PIM kinases could represent an antiviral target for MAYV and other arboviruses.

Implications of SARS-Cov-2 infection on eNOS and iNOS activity: Consequences for the respiratory and vascular systems.

Symptoms of COVID-19 range from asymptomatic/mild symptoms to severe illness and death, consequence of an excessive inflammatory process triggered by SARS-CoV-2 infection. The diffuse inflammation leads to endothelium dysfunction in pulmonary blood vessels, uncoupling eNOS activity, lowering NO production, causing pulmonary physiological alterations and coagulopathy. On the other hand, iNOS activity is increased, which may be advantageous for host defense, once NO plays antiviral effects. However, overproduction of NO may be deleterious, generating a pro-inflammatory effect. In this review, we discussed the role of endogenous NO as a protective or deleterious agent of the respiratory and vascular systems, the most affected in COVID-19 patients, focusing on eNOS and iNOS roles. We also reviewed the currently available NO therapies and pointed out possible alternative treatments targeting NO metabolism, which could help mitigate health crises in the present and future CoV's spillovers.

Inhibition of Brazilian ZIKV strain replication in primary human placental chorionic cells and cervical cells treated with nitazoxanide

ABSTRACT Zika virus (ZIKV) infection during pregnancy is associated with a congenital syndrome. Although the virus can be detected in human placental tissue and sexual transmission has been verified, it is not clear how the virus reaches the fetus. Despite the emerging severity caused by ZIKV infection, no specific prophylactic and/or therapeutic treatment is available. The aim of the present study was to evaluate the effectiveness antiviral of nitazoxanide (NTZ) in two important congenital transmission targets: (i) a primary culture of human placental chorionic cells, and (ii) human cervical epithelial cells (C33-A) infected with Brazilian ZIKV strain. Initially, NTZ activity was screened in ZIKV infected Vero cells under different treatment regimens with non-toxic drug concentrations for 48 h. Antiviral effect was found only when the treatment was carried out after the viral inoculum. A strong effect against the dengue virus serotype 2 (DENV-2) was also observed suggesting the possibility of treating other Flaviviruses. Additionally, it was shown that the treatment did not reduce the production of infectious viruses in insect cells (C6/36) infected with ZIKV, indicating that the activity of this drug is also related to host factors. Importantly, we demonstrated that NTZ treatment in chorionic and cervical cells caused a reduction of infected cells in a dose-dependent manner and decreased viral loads in up to 2 logs. Pre-clinical in vitro testing evidenced excellent therapeutic response of infected chorionic and cervical cells and point to future NTZ activity investigation in ZIKV congenital transmission models with the perspective of possible repurposing of NTZ to treat Zika fever, especially in pregnant women.

Inhibition of Brazilian ZIKV strain replication in primary human placental chorionic cells and cervical cells treated with nitazoxanide.

Zika virus (ZIKV) infection during pregnancy is associated with a congenital syndrome. Although the virus can be detected in human placental tissue and sexual transmission has been verified, it is not clear how the virus reaches the fetus. Despite the emerging severity caused by ZIKV infection, no specific prophylactic and/or therapeutic treatment is available. The aim of the present study was to evaluate the effectiveness antiviral of nitazoxanide (NTZ) in two important congenital transmission targets: (i) a primary culture of human placental chorionic cells, and (ii) human cervical epithelial cells (C33-A) infected with Brazilian ZIKV strain. Initially, NTZ activity was screened in ZIKV infected Vero cells under different treatment regimens with non-toxic drug concentrations for 48 h. Antiviral effect was found only when the treatment was carried out after the viral inoculum. A strong effect against the dengue virus serotype 2 (DENV-2) was also observed suggesting the possibility of treating other Flaviviruses. Additionally, it was shown that the treatment did not reduce the production of infectious viruses in insect cells (C6/36) infected with ZIKV, indicating that the activity of this drug is also related to host factors. Importantly, we demonstrated that NTZ treatment in chorionic and cervical cells caused a reduction of infected cells in a dose-dependent manner and decreased viral loads in up to 2 logs. Pre-clinical in vitro testing evidenced excellent therapeutic response of infected chorionic and cervical cells and point to future NTZ activity investigation in ZIKV congenital transmission models with the perspective of possible repurposing of NTZ to treat Zika fever, especially in pregnant women.

Chloroquine and Sulfadoxine Derivatives Inhibit ZIKV Replication in Cervical Cells.

Despite the severe morbidity caused by Zika fever, its specific treatment is still a challenge for public health. Several research groups have investigated the drug repurposing of chloroquine. However, the highly toxic side effect induced by chloroquine paves the way for the improvement of this drug for use in Zika fever clinics. Our aim is to evaluate the anti-Zika virus (ZIKV) effect of hybrid compounds derived from chloroquine and sulfadoxine antimalarial drugs. The antiviral activity of hybrid compounds (C-Sd1 to C-Sd7) was assessed in an in-vitro model of human cervical and Vero cell lines infected with a Brazilian (BR) ZIKV strain. First, we evaluated the cytotoxic effect on cultures treated with up to 200 µM of C-Sds and observed CC50 values that ranged from 112.0 ± 1.8 to >200 µM in cervical cells and 43.2 ± 0.4 to 143.0 ± 1.3 µM in Vero cells. Then, the cultures were ZIKV-infected and treated with up to 25 µM of C-Sds for 48 h. The treatment of cervical cells with C-Sds at 12 µM induced a reduction of 79.8% ± 4.2% to 90.7% ± 1.5% of ZIKV-envelope glycoprotein expression in infected cells as compared to 36.8% ± 2.9% of infection in vehicle control. The viral load was also investigated and revealed a reduction of 2- to 3-logs of ZIKV genome copies/mL in culture supernatants compared to 6.7 ± 0.7 × 108 copies/mL in vehicle control. The dose-response curve by plaque-forming reduction (PFR) in cervical cells revealed a potent dose-dependent activity of C-Sds in inhibiting ZIKV replication, with PFR above 50% and 90% at 6 and 12 µM, respectively, while 25 µM inhibited 100% of viral progeny. The treatment of Vero cells at 12 µM led to 100% PFR, confirming the C-Sds activity in another cell type. Regarding effective concentration in cervical cells, the EC50 values ranged from 3.2 ± 0.1 to 5.0 ± 0.2 µM, and the EC90 values ranged from 7.2 ± 0.1 to 11.6 ± 0.1 µM, with selectivity index above 40 for most C-Sds, showing a good therapeutic window. Here, our aim is to investigate the anti-ZIKV activity of new hybrid compounds that show highly potent efficacy as inhibitors of ZIKV in-vitro infection. However, further studies will be needed to investigate whether these new chemical structures can lead to the improvement of chloroquine antiviral activity.

Virucidal activity of proanthocyanidin against Mayaro virus.

Mayaro virus (MAYV) is a sublethal arbovirus transmitted by mosquitoes with possible installation of an urban cycle in the Americas. Its infection causes disabling arthralgia, and still, there is no vaccine or treatment to it. We recently investigated nearly 600 compounds by molecular docking and identified epicatechin as a potent antiviral against MAYV. The root extract of Maytenus imbricata showed anti-MAYV activity and two isolated compounds from this plant were also evaluated in vitro. Proanthocyanidin (PAC), a dimer containing epicatechin, showed an effective concentration for 50% of the cells infected by MAYV (EC50) of 37.9 ±â€¯2.4 µM and a selectivity index (SI) above 40. PAC showed significant virucidal activity, inhibiting 100% of the virus proliferation (7 log units), and caused moderate effect during adsorption and virus internalization stage. However, PAC was unable to block the infection when only the cells were pretreated. It was observed a reduction in virus yields when adding PAC at different moments after infection. The set of results indicates that PAC binds to viral and non-cellular elements and may inactivate the MAYV. The inactivation occurs before infection or when the virus reaches the extracellular environment from the 2nd cycle of infection that could block its progression cell-to-cell or to tissues not yet infected.

Decreased rotavirus infection of MA104 cells via probiotic extract binding to Hsc70 and ß3 integrin receptors / Disminución de la infección por rotavirus en células MA104 por la unión de proteínas de extractos probióticos a receptores celulares integrina ß3 y Hsc70 / Diminuição da infecção por rotavírus em células MA104 pela união de proteínas de extratos probióticos a receptores integrina ß3 e Hsc70

Abstract Probiotic bacteria are microorganisms beneficial to human health, useful to improving biological conditions. Thanks to probiotic bacteria the symptoms of viral infections can be alleviated. Different mechanisms whereby probiotic bacteria exert they antiviral effect have been proposed. The aim of this study was to determine whether probiotic bacteria extracts bind to receptors of host cells susceptible of rotavirus (RV) infection. To accomplish this objective, four probiotic bacterial strains of Lactobacillus spp. and Bifidobacterium spp. were tested. Probiotic extracts were obtained after bacterial growth, cell lysis and centrifugation. Obtained probiotic extracts were used in assays to interfere with adhesion and penetration of a RV strain in the mammal cell line MA104. Furthermore, the interaction between probiotic extracts and MA104 cell receptors was evaluated by co-immunoprecipitation assays using anti-β3-integrins and anti-Hsc70 antibodies. All four probiotic, protein-rich, extracts reduced RV infections in MA104 cells, suggesting a successful antiviral activity mediated by these probiotic extracts. All probiotic extracts significantly exerted their antiviral activity by interfering with RV adhesion on MA104 cell receptors, with proteins in probiotic extracts competitively interacting with cell surface receptors necessary to RV infection. Co-immunoprecipitation assay results showed that proteins in probiotic extracts were able to bind to β3-integrinsand Hsc70, which are two cellular receptors required to viral infection. The most significant contribution of this study is an insight into the mechanisms of probiotic antiviral activity, thus expanding current probiotics fundamental knowledge.

Resumen Las bacterias probióticas son microorganismos con efectos positivos en la salud humana, gracias a las bacterias probióticas los síntomas de infecciones virales pueden mitigarse. Al respecto, varios mecanismos antivirales de las bacterias probióticas han sido propuestos. El propósito de este estudio fue determinar, de manera experimental, si extractos de bacterias probióticas reducen la infección rotavírica al interferir con la unión entre el rotavirus y sus receptores celulares blanco. Extractos de cuatro cepas probióticas de Lactobacillus spp. y Bifidobacterium spp. fueron obtenidos a partir de cultivos bacterianos lisados y centrifugados. Cada uno de los extractos fue usado en experimentos para determinar si estos interfieren con la adhesión y penetración del rotavirus en células de mamífero MA104. Además, la interacción entre extractos probióticos y receptores de las células MA104 fue evaluada con ensayos de co-inmunoprecipitación, usando anticuerpos anti-integrina β3 y anti-Hsc70. Se observó que los cuatro extractos probióticos, ricos en proteínas, redujeron significativamente la infección de rotavirus en las células MA104. También se estableció que la que la actividad antiviral de los extractos probióticos es mediada por la interacción competitiva de sus proteínas con los receptores integrina β3 y Hsc70 de las células MA104, necesarios para iniciar la infección por rotavirus. Estos hallazgos constituyen un aporte al conocimiento de los mecanismos básicos de acción antiviral de las bacterias probióticas.

Resumo Bactérias probióticas são microrganismos com efeitos positivos na saúde humana, úteis na melhora de certas condições biológicas. Gracas a bactérias probióticas os sintomas de uma infecção viral podem ser aliviados. Diferentes mecanismos pelos quais as bactérias probióticas exercem seus efeitos antivirales têm sido propostos. O objetivo de este estudo foi determinar se extratos de bactérias probióticas reduzem a infecção de rotavírus (RV) ao interferir com a união entre o RV e seus receptores celulares alvo. Quatro cepas probióticas de Lactobacillus spp. e Bifidobacterium spp. foram testadas. Os extratos probióticos foram obtidos após o crescimento bacteriano, lise celular e centrifugação. Os extratos probióticos obtidos foram utilizados em ensaios para determinar se interferem com a adesão e penetração de uma cepa de RV em células de mamífero MA104. Adicionalmente, a interação entre os extratos probióticos e os receptores das células MA104 foi avaliada por ensaios de co-imunoprecipitação usando anticorpos anti-integrina β3 e anti- Hsc70. Os quatro extratos probióticos, ricos em proteínas, reduziram as infecções por RV em células MA104, sugerindo uma atividade antiviral mediada por estes extratos. Todos os extratos interferiram na adesão do RV aos receptores de células MA104, sendo que as proteínas presentes nos extratos mostraram uma interação competitiva com os receptores integrina β3 e Hsc70 das células MA104, necessários para iniciar a infecção por RV. Estes resultados contribuem para o conhecimento dos mecanismos básicos de ação antiviral de bactérias probióticas.

Bifidobacterium adolescentis (DSM 20083) and Lactobacillus casei (Lafti L26-DSL): Probiotics Able to Block the In Vitro Adherence of Rotavirus in MA104 Cells.

Rotavirus is the leading worldwide cause of gastroenteritis in children under five years of age. Even though there are some available vaccines to prevent the disease, there are limited strategies for challenging diarrhea induced by rotavirus infection. For this reason, researchers are constantly searching for other approaches to control diarrhea by means of probiotics. In order to demonstrate the ability of some probiotic bacteria to interfere with the in vitro rotavirus infection in MA104 cells, strains of Lactobacillus sp. and Bifidobacterium sp. were tested in MA104 cells before the viral infection. As a preliminary assay, a blocking effect treatment was performed with viable bacteria. In this screening assay, four of initial ten bacteria showed a slight reduction of the viral infection (measured by percentage of infection). L. casei (Lafti L26-DSL), L. fermentum(ATCC 9338), B. adolescentis (DSM 20083), and B. bifidum (ATCC 11863) were used in further experiments. Three different treatments were tested in order to evaluate protein-based metabolites obtained from mentioned bacteria: (i) cell exposure to the protein-based metabolites before viral infection, (ii) exposure to protein-based metabolites after viral infection, and (iii) co-incubation of the virus and protein-based metabolites before viral infection to the cell culture. The best effect performed by protein-based metabolites was observed during the co-incubation assay of the virus and protein-based metabolites before adding them into the cell culture. The results showed 25 and 37% of infection in the presence of L. casei and B. adolescentis respectively. These results suggest that the antiviral effect may be occurring directly with the viral particle instead of making a blocking effect of the cellular receptors that are needed for the viral entrance.

Clinical Analysis of Polyethylene Glycol Interferon-α Treatment in 155 Hepatitis B e Antigen (HBeAg)-Positive Chronic Hepatitis B (CHB) Patients.

PURPOSE: This study aims to investigate the antiviral effect of polyethylene glycol (PEG)-interferon α-2a and PEG-interferon α-2b treatment on hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) at the 48th week of treatment and the 24th and 48th week after withdrawal, in order to provide guidance on the antiviral treatment of HBeAg-positive CHB patients. MATERIAL AND METHODS: Antiviral treatment was performed on 155 HBeAg-positive CHB patients. Among these patients, 66 patients received PEG-interferon α-2a treatment and 89 patients received PEG-interferon α-2b treatment; and these treatments were administered by subcutaneous injection, once per week, which lasted for 48 weeks. Other antiviral and hepatoprotective drugs were not used during the treatment. RESULTS: At the 48th week of treatment, ALT recovery rate, HBsAg seroconversion rate, HBeAg seroconversion rate and HBV DNA titers dropped below 200 IU/mL rate were 69.7%, 6.1%, 27.3% and 50.0%, respectively, in the PEG-interferon α-2a group; and were 70.8%, 6.7%, 33.7% and 62.9%, respectively, in the PEG-interferon α-2b group. At the 24th and 48th week of follow-up after withdrawal, HBsAg seroconversion rate in these two groups did not change; and HBeAg seroconversion rate further increased. Furthermore, HBV DNA revealed a low recurrence rate. The difference between these two groups was not significantly significant. CONCLUSIONS: PEG-interferon α-2a and PEG-interferon α-2b are effective antiviral drugs for the treatment of HbeAgpositive CHB, which has a HBsAg seroconversion rate of more than 5%. Furthermore, this sustained response effect was maintained at the 24th and 48th week of follow-up after withdrawal.

In vitro antiviral activity of Lactobacillus casei and Bifidobacterium adolescentis against rotavirus infection monitored by NSP4 protein production.

AIMS: The aim of this study was to determine the antiviral activity of four probiotic metabolites (Lactobacillus and Bifidobacetrium species) against rotavirus in vitro infection monitored by the NSP4 protein production and Ca(2+) release. METHODS AND RESULTS: The antiviral effect of the metabolites was performed due a comparison between a blocking model and an intracelullar model on MA104 cells, with the response of NSP4 production and Ca(2+) liberation measured by flow cytometry. Significant results were obtained with the metabolites of Lactobacillus casei, and Bifidobacterium adolescentis in the reduction of the protein production (P = 0·04 and P = 0·014) and Ca(2+) liberation (P = 0·094 and P = 0·020) in the intracellular model, which suggests a successful antiviral activity against RV infection. CONCLUSIONS: This study demonstrates that probiotic metabolites were able to interfere with the final amount of intracellular NSP4 protein and a successful Ca(2+) regulation, which suggests a new approach to the mechanism exerted by probiotics against the rotavirus infection. SIGNIFICANCE AND IMPACT OF THE STUDY: A novel anti-rotaviral effect exerted by probiotic metabolites monitored by the NSP4 protein during the RV in vitro infection and the effect on the Ca(2+) release is reported; suggesting a reduction on the impact of the infection by decreasing the damage of the cells preventing the electrolyte loss.

The coelomic fluid of the sea urchin Tripneustes depressus shows antiviral activity against Suid herpesvirus type 1 (SHV-1) and rabies virus (RV).

Several studies have reported that molecules extracted from invertebrates have activity against different viruses, even against those that do not infect these organisms in their environment. One of the main mechanisms against pathogens in these organisms is the production of antimicrobial peptides. The objective of this study was to determine whether the coelomic fluid (CF) of the sea urchin Tripneustes depressus has activity against Suid herpesvirus type 1 (SHV-1) and/or rabies virus (RV). We tested the antiviral activity of CF in neutralizing assays and observed 50% inhibition against SHV-1 lytic plaque formation using 33 µg of CF, whereas 21 µg CF was sufficient to obtain more than 90% inhibition for RV. Cytotoxicity to MDBK and BHK-21 cells was found with whole CF yet was eliminated by heating at 56 or 72 °C (even when using 50 µg of heat-inactivated CF supernatant [SN or thermostable fraction]), and SN retained the antiviral effect. In both cases, the antiviral effect was direct and thermostable (SN 56 and 72 °C), and the best inhibition was observed when CF + virus was incubated prior to the addition of the cells. Therefore, the coelomic fluid of T. depressus has antiviral activity against SHV-1 and RV that is direct and stable at 72 °C. We suggest that further assays should be performed using more accurate methods to characterize new molecules with antiviral activity that may result in new drugs.

In vitro evaluation of antiviral effect of bauer-7-en-3b-yl acetate, the major constituent of a sample of Brazilian propolis, against Alphaherpesviruses / Avaliação in vitro do efeito antiviral do acetato de bauer-7-en-3b -ILA, o principal constituinte de uma amostra de própolis brasileira, contra o alphaherpesvirus

There is an increasing need for substances with antiviral activity since the treatment of viral infections with most antivirals is often unsatisfactory due to the problem of, amongst other things, viral latency and the likelihood of new viral agents arising. Previously we isolated bauer-7-en-3b-yl acetate (BA), a pentacyclic triterpenoid obtained from the chloroform extract of an sample of propolis from southeast Brazil (TEIXEIRA, et al., 2006). Here we investigated the antiviral activity of BA against the alphaherpesviruses bovine herpesvirus 1 (BoHV-1) and pseudorabiesvirus (SuHV-1, suid herpesvirus) during infection of Madin-Darby bovine kidney (MDBK) and African green monkey kidney (VERO) cells cultures, respectively. In short, BA was tested for its cytotoxic properties and antiviral effect through virus yield reduction and virucidal activity in both cells. Results showed that BA 20µg mL-1 and 15µg mL-1 were the maximal non-cytotoxic concentration (MNCC) to VERO and MDBK cells, respectively. BA reduced significantly SuHV-1 titrers in both antiviral tests (p 0.05) while inhibition was not observed against BoHV-1. However, how BA interferes on the virus multiplication still need to be elucidated.

O crescente interesse na busca por substâncias que apresentem atividade antiviral se deve, entre outros fatores, à dificuldade de tratamento de infecções virais, tanto em virtude da característica de latência viral quanto pelo surgimento de novos vírus. O triterpenóide acetato de bauer-7-en-3b-ila (BA) foi previamente isolado do extrato clorofórmico de uma amostra de própolis coletada em Minas Gerais, região sudeste do Brasil (TEIXEIRA et al., 2006). A atividade antiviral desta substância contra o herpesvírus bovino tipo 1 (BoHV-1) e o herpesvírus suíno tipo 1 (SuHV-1) foi investigada através da infecção de culturas de células de rim bovino (MDBK) e de células de rim de macaco verde africano (VERO). O efeito citotóxico do triterpenóide foi previamente avaliado e as concentrações máximas não tóxicas foram 20µg mL-1 e 15µg mL-1 para células VERO e MDBK, respectivamente. Os resultados mostraram atividade antiviral contra SuHV-1 (p 0,05), porém não contra BoHV-1. Todavia, a forma como o BA interfere na multiplicação do SuHV-1 ainda precisa ser elucidada.

In vitro evaluation of antiviral effect of bauer-7-en-3b-yl acetate, the major constituent of a sample of Brazilian propolis, against Alphaherpesviruses / Avaliação in vitro do efeito antiviral do acetato de bauer-7-en-3b -ILA, o principal constituinte de uma amostra de própolis brasileira, contra o alphaherpesvirus

There is an increasing need for substances with antiviral activity since the treatment of viral infections with most antivirals is often unsatisfactory due to the problem of, amongst other things, viral latency and the likelihood of new viral agents arising. Previously we isolated bauer-7-en-3b-yl acetate (BA), a pentacyclic triterpenoid obtained from the chloroform extract of an sample of propolis from southeast Brazil (TEIXEIRA, et al., 2006). Here we investigated the antiviral activity of BA against the alphaherpesviruses bovine herpesvirus 1 (BoHV-1) and pseudorabiesvirus (SuHV-1, suid herpesvirus) during infection of Madin-Darby bovine kidney (MDBK) and African green monkey kidney (VERO) cells cultures, respectively. In short, BA was tested for its cytotoxic properties and antiviral effect through virus yield reduction and virucidal activity in both cells. Results showed that BA 20µg mL-1 and 15µg mL-1 were the maximal non-cytotoxic concentration (MNCC) to VERO and MDBK cells, respectively. BA reduced significantly SuHV-1 titrers in both antiviral tests (p 0.05) while inhibition was not observed against BoHV-1. However, how BA interferes on the virus multiplication still need to be elucidated.

O crescente interesse na busca por substâncias que apresentem atividade antiviral se deve, entre outros fatores, à dificuldade de tratamento de infecções virais, tanto em virtude da característica de latência viral quanto pelo surgimento de novos vírus. O triterpenóide acetato de bauer-7-en-3b-ila (BA) foi previamente isolado do extrato clorofórmico de uma amostra de própolis coletada em Minas Gerais, região sudeste do Brasil (TEIXEIRA et al., 2006). A atividade antiviral desta substância contra o herpesvírus bovino tipo 1 (BoHV-1) e o herpesvírus suíno tipo 1 (SuHV-1) foi investigada através da infecção de culturas de células de rim bovino (MDBK) e de células de rim de macaco verde africano (VERO). O efeito citotóxico do triterpenóide foi previamente avaliado e as concentrações máximas não tóxicas foram 20µg mL-1 e 15µg mL-1 para células VERO e MDBK, respectivamente. Os resultados mostraram atividade antiviral contra SuHV-1 (p 0,05), porém não contra BoHV-1. Todavia, a forma como o BA interfere na multiplicação do SuHV-1 ainda precisa ser elucidada.