In Vitro, In Vivo and In Silico Effectiveness of LASSBio-1386, an N-Acyl Hydrazone Derivative Phosphodiesterase-4 Inhibitor, Against Leishmania amazonensis.

Leishmaniasis are group of neglected diseases with worldwide distribution that affect about 12 million people. The current treatment is limited and may cause severe adverse effects, and thus, the search for new drugs more effective and less toxic is relevant. We have previously investigated the immunomodulatory effects of LASSBio-1386, an N-acylhydrazone derivative. Here we investigated the in vitro and in vivo activity of LASSBio-1386 against L. amazonensis. LASSBio-1386 inhibited the proliferation of promastigotes of L. amazonensis (EC50 = 2.4 ± 0.48 µM), while presenting low cytotoxicity to macrophages (CC50 = 74.1 ± 2.9 µM). In vitro incubation with LASSBio-1386 reduced the percentage of Leishmania-infected macrophages and the number of intracellular parasites (EC50 = 9.42 ± 0.64 µM). Also, in vivo treatment of BALB/c mice infected with L. amazonensis resulted in a decrease of lesion size, parasitic load and caused histopathological alterations, when compared to vehicle-treated control. Moreover, LASSBio-1386 caused ultrastructural changes, arrested cell cycle in G0/G1 phase and did not alter the membrane mitochondrial potential of L. amazonensis. Aiming to its possible molecular interactions, we performed docking and molecular dynamics studies on Leishmania phosphodiesterase B1 (PDB code: 2R8Q) and LASSBio-1386. The computational analyses suggest that LASSBio-1386 acts against Leishmania through the modulation of leishmanial PDE activity. In conclusion, our results indicate that LASSBio-1386 is a promising candidate for the development of new leishmaniasis treatment.

Dual and selective inhibitors of pteridine reductase 1 (PTR1) and dihydrofolate reductase-thymidylate synthase (DHFR-TS) from Leishmania chagasi.

Leishmaniasis is a tropical disease found in more than 90 countries. The drugs available to treat this disease have nonspecific action and high toxicity. In order to develop novel therapeutic alternatives to fight this ailment, pteridine reductase 1 (PTR1) and dihydrofolate reductase-thymidylate synthase (DHF-TS) have been targeted, once Leishmania is auxotrophic for folates. Although PTR1 and DHFR-TS from other protozoan parasites have been studied, their homologs in Leishmania chagasi have been poorly characterized. Hence, this work describes the optimal conditions to express the recombinant LcPTR1 and LcDHFR-TS enzymes, as well as balanced assay conditions for screening. Last but not the least, we show that 2,4 diaminopyrimidine derivatives are low-micromolar competitive inhibitors of both enzymes (LcPTR1 Ki = 1.50-2.30 µM and LcDHFR Ki = 0.28-3.00 µM) with poor selectivity index. On the other hand, compound 5 (2,4-diaminoquinazoline derivative) is a selective LcPTR1 inhibitor (Ki = 0.47 µM, selectivity index = 20).

Identification, Characterization and Molecular Modelling Studies of Schistosoma mansoni Dihydrofolate Reductase Inhibitors: From Assay Development to Hit Identification.

INTRODUCTION: Schistosoma mansoni is responsible for virtually all reported cases of schistosomiasis in Latin America and the emergence of praziquantel- and oxaminiquine-resistant strains makes it urgent to develop new schistosomicide agents. Dihydrofolate reductases (DHFR) from bacteria and protozoan parasites are considered validated macromolecular targets for this goal, but S. mansoni DHFR (SmDHFR) has been largely overlooked. To fill this gap in knowledge, the present work describes optimized conditions to carry out thermal shift assays with SmDHFR, as well as a balanced kinetic assay that supports 2,4-diaminopyrimidine derivatives as SmDHFR inhibitors. The most potent inhibitor (2a) shows a large shift of the melting temperature (ΔTm = + 8 ± 0,21 ºC) and a low micromolar IC50 value (12 ± 2,3 µM). Both thermal shift and classical kinectic assay suggest that 2a binds to the substrate binding site (competitive inhibition mechanism). This information guided docking and molecular dynamics studies that probed 2a interaction profile towards SmDHFR. CONCLUSION: In conclusion, this work not only provides standardized assay conditions to identify SmDHFR inhibitors, but also describes the binding profile of the first low micromolar inhibitor of this macromolecular target.

Tobacco cultivation in the Reconcavo Baiano:sociodemographic profile and workers’ health conditions / Cultivo do tabaco no Recôncavo Baiano: perfil sociodemográfico e condições de saúde dos trabalhadores

Despite the economic importance of tobacco farming in Brazil, pesticides and wet tobacco leaf handling affect workers´health. Thus, the aim of this study was to assess the socio-demographic profile, health and behavioral aspects of tobaccogrowers in a Reconcavo da Bahia county. It was a descriptive and experimental research within a quantitative approach. Itstarget population were members of the Quixabeiras´ Tobacco Growers Association located in the county of Cabaceirasdo Paraguaçú, Bahia. Data were collected by means of questionnaires from April to September of 2014. Most tobaccogrowers were women, 46 years old in average, with incomplete basic education, who had been working as tobaccogrowers for over 20 years. With regard to pesticides, 54.54% used pyrethroids (Decis 25) in combination with herbicides(Sempra). Of the interviewed workers, 18.18% reported absence of health symptoms, while 57.57% complained ofbody aches, 33.36% suffered from headaches and 27.27% from tiredness. Personal protection equipment (PPE) was notused by 60.60% of the farmers due to its high cost, and correct pesticide packaging disposal was performed by 12.12%of them. The results of this study indicate that tobacco farmers are exposed to health risks and that the use of PPE andthe correct packaging disposal is of the utmost importance to prevent nicotine and pesticide intoxication.(AU)

Embora a fumicultura desempenhe grande relevância na economia do país, a qualidade da saúde dos trabalhadoresvem sendo questionada frente à utilização de agrotóxicos e a manipulação da folha úmida do tabaco. Dessa maneira,o presente estudo teve como objetivo conhecer o perfil sócio-demográfico de saúde e aspectos comportamentaisno ambiente laboral dos fumicultores no município do Recôncavo Baiano. O estudo teve um enfoque exploratório,descritivo do tipo experimental com abordagem de cunho quantitativo, tendo como população alvo os produtoresrurais afiliados na Associação de Fumicultores de Quixabeira, localizada no Município de Cabaceiras do Paraguaçu,Bahia. A aplicação do formulário para a coleta de dados da população foi realizada no período de abril a setembrode 2014. No estudo verificou-se a predominância do sexo feminino, média de idade de 46 anos, ensino fundamentalincompleto e que trabalham na cultura há mais de 20 anos. Com relação à utilização de agrotóxicos 54,54% utilizampiretróide (Decis25) associado a herbicida (Sempra). Apenas 18,18% dos entrevistados afirmaram não sentir sintomas, eos demais fumicultores relataram sentir dores no corpo (57,57%), dor de cabeça (33,36%) e cansaço (27,27%). Quantoà utilização de equipamentos de proteção individual 60,60% não faz uso em função do seu alto custo; e a destinaçãocorreta das embalagens de agrotóxicos é realizada por apenas 12,12% dos fumicultores. Constata-se no presente estudoque as condições de trabalho e as práticas realizadas diariamente pelos fumicultores os expõem a riscos ocupacionais.Portanto, é imprescindível que esses agricultores compreendam que a adesão aos equipamentos de proteção individuale destinação correta das embalagens podem prevenir problemas de saúde decorrentes da intoxicação ocupacionalproveniente da nicotina e dos agrotóxicos.(AU)

Tobacco cultivation in the Reconcavo Baiano:sociodemographic profile and workers’ healthconditions / Cultivo do tabaco no Recôncavo Baiano: perfil sociodemográfico econdições de saúde dos trabalhadores

Despite the economic importance of tobacco farming in Brazil, pesticides and wet tobacco leaf handling affect workers´health. Thus, the aim of this study was to assess the socio-demographic profile, health and behavioral aspects of tobaccogrowers in a Reconcavo da Bahia county. It was a descriptive and experimental research within a quantitative approach. Itstarget population were members of the Quixabeiras´ Tobacco Growers Association located in the county of Cabaceirasdo Paraguaçú, Bahia. Data were collected by means of questionnaires from April to September of 2014. Most tobaccogrowers were women, 46 years old in average, with incomplete basic education, who had been working as tobaccogrowers for over 20 years. With regard to pesticides, 54.54% used pyrethroids (Decis 25) in combination with herbicides(Sempra). Of the interviewed workers, 18.18% reported absence of health symptoms, while 57.57% complained ofbody aches, 33.36% suffered from headaches and 27.27% from tiredness. Personal protection equipment (PPE) was notused by 60.60% of the farmers due to its high cost, and correct pesticide packaging disposal was performed by 12.12%of them. The results of this study indicate that tobacco farmers are exposed to health risks and that the use of PPE andthe correct packaging disposal is of the utmost importance to prevent nicotine and pesticide intoxication.

Embora a fumicultura desempenhe grande relevância na economia do país, a qualidade da saúde dos trabalhadoresvem sendo questionada frente à utilização de agrotóxicos e a manipulação da folha úmida do tabaco. Dessa maneira,o presente estudo teve como objetivo conhecer o perfil sócio-demográfico de saúde e aspectos comportamentaisno ambiente laboral dos fumicultores no município do Recôncavo Baiano. O estudo teve um enfoque exploratório,descritivo do tipo experimental com abordagem de cunho quantitativo, tendo como população alvo os produtoresrurais afiliados na Associação de Fumicultores de Quixabeira, localizada no Município de Cabaceiras do Paraguaçu,Bahia. A aplicação do formulário para a coleta de dados da população foi realizada no período de abril a setembrode 2014. No estudo verificou-se a predominância do sexo feminino, média de idade de 46 anos, ensino fundamentalincompleto e que trabalham na cultura há mais de 20 anos. Com relação à utilização de agrotóxicos 54,54% utilizampiretróide (Decis25) associado a herbicida (Sempra). Apenas 18,18% dos entrevistados afirmaram não sentir sintomas, eos demais fumicultores relataram sentir dores no corpo (57,57%), dor de cabeça (33,36%) e cansaço (27,27%). Quantoà utilização de equipamentos de proteção individual 60,60% não faz uso em função do seu alto custo; e a destinaçãocorreta das embalagens de agrotóxicos é realizada por apenas 12,12% dos fumicultores. Constata-se no presente estudoque as condições de trabalho e as práticas realizadas diariamente pelos fumicultores os expõem a riscos ocupacionais.Portanto, é imprescindível que esses agricultores compreendam que a adesão aos equipamentos de proteção individuale destinação correta das embalagens podem prevenir problemas de saúde decorrentes da intoxicação ocupacionalproveniente da nicotina e dos agrotóxicos.

8-Methoxypsoralen is a competitive inhibitor of glutathione S-transferase P1-1.

The blood-brain barrier (BBB) is known to protect healthy brain cells from potentially dangerous chemical agents, but there are many evidences supporting the idea that this protective action is extended to tumor cells. Since the process of angiogenesis in brain tumors leads to BBB breakdown, biochemical characteristics of the BBB seem to be more relevant than physical barriers to protect tumor cells from chemotherapy. In fact, a number of resistance related factors were already demonstrated to be component of both BBB and tumor cells. The enzyme glutathione S-transferases (GST) detoxify electrophilic xenobiotics and endogenous secondary metabolites formed during oxidative stress. A role has been attributed to GST in the resistance of cancer cells to chemotherapeutic agents. This study characterized 8-methoxypsoralen (8-MOP) as a human GST P1-1 (hGST P1-1) inhibitor. To identify and characterize the potential inhibitory activity of 8-MOP, we studied the enzyme kinetics of the conjugation of 1-chloro-2,4-dinitrobenzene (CDNB) with GSH catalyzed by hGST P1-1. We report here that 8-MOP competitively inhibited hGST P1-1 relative to CDNB, but there was an uncompetitive inhibition relative to GSH. Chromatographic analyses suggest that 8-MOP is not a substrate. Molecular docking simulations suggest that 8-MOP binds to the active site, but its position prevents the GSH conjugation. Thus, we conclude that 8-MOP is a promising prototype for new GST inhibitors pharmacologically useful in the treatment of neurodegenerative disorders and the resistance of cancer to chemotherapy.

Estudos QSAR e Ancoragem Molecular de Inibidores da Atividade Biológica do Fator de Inibição da Migração dos Macrófagos (MIF) / QSAR Modeling and Molecular Docking Study of Inhibitors of Macrophage Migration Inhibitory Factor (MIF)

Cumarina e 4-Cromonas são promissores inibidores de fator inibição da migração de macrófagos (MIF), uma proteína envolvida em doenças inflamatórias, como artrite reumatóide e outras patologias. Estudos teóricos de QSAR e ancoragem molecular de um conjunto de compostos mostraram correlação com estudos experimentais. Os descritores doadores de ligação hidrogênio e momento dipolo total foram capazes de prever atividade inibitória de compostos contra o MIF (MIFi). Paralelamente, estudos de ancoragem molecular também foram capazes de identificar ligações hidrogênio e hidrofóbicas entre os ligantes e o MIF. Como resultado, ambas as metodologias mostraram as contribuições de ligação de hidrogênio e interações hidrofóbicas para explicar a atividade de compostos inibidores de MIF, descrevendo os grupos farmacofóricos destes compostos. Adicionalmente, um conjunto de cumarinas naturais e sintéticas foi submetido aos modelos QSAR e de ancoragem molecular a fim de que as suas atividades contra MIF fossem preditas. Ambas as metodologias de modelagem molecular puderam estimar as interações intermoleculares entre inibidores e a enzima, os quais foram muito similares a compostos descritos previamente. Estes resultados podem ser úteis para o desenho de novos compostos contra doenças inflamatórias como artrite reumatóide.

Coumarin and Chromen-4-one are promising inhibitors of Macrophage Migration Inhibitory Factor (MIF), a protein involved in rheumatoid arthritis and other inflammatory diseases. Quantum structure-activity relationship (QSAR) and docking theoretical studies were undertaken on a set of compounds of known activity and showed agreement with previous experimental studies. Two descriptors, hydrogen donor sites and the total dipole, were able to predict MIF inhibitory activity (MIFi). The docking studies corroborated the QSAR studies. As a result, both methods indicated contributions of hydrogen bonds and hydrophobic interactions that explain the activity of the MIF inhibitors, describing the pharmacophore groups these molecules. Additionally, a set of natural and synthetic coumarins was subjected to the QSAR and docking models in order to predict their possible MIF inhibitory activity. Both molecular modeling methods were able to estimate the intermolecular interactions between inhibitors and enzyme, which were very similar to those of previously described compounds. These results could be useful to design new compounds against inflammatory diseases such as rheumatoid arthritis.