Síntese e avaliação da atividade biológica de derivados quinolínicos

O desenvolvimento de novos fármacos tem sido uma busca constante e progressiva ao longo do tempo. Doenças com alta incidência e deficiências no tratamento como o câncer e infecções causadas por fungos tem alcançado significativa relevância e carecem de pesquisas constantes a fim de desenvolver novos medicamentos para trata-las. Desta maneira, este trabalho buscou desenvolver novas metodologias sintéticas para obtenção de moléculas bioativas baseadas no núcleo quinolínico, assim como avaliar a atividade biológica das mesmas frente a linhagens tumorais e cepas de fungos leveduriformes e dermatófilos. A partir dos resultados é possível concluir que as metodologias desenvolvidas possibilitaram a síntese 9 quinolinas cujas estruturas foram identificadas através de RMN e espectroscopia de massas. As quinolinas estudadas apresentaram atividade antitumoral, levando-se em consideração a potência e eficácia das moléculas testadas. Além disso nos estudos de mecanismo de morte, a maioria das moléculas induziu a morte celular através de apoptose. É possível destacar as quinolinas Q11 e Q12 quanto a atividade citotóxica frente as linhagens tumorais e ótimos índices de seletividade (SI) superiores a 10 para Q11 e entre 1,5-3 para a Q12. Quanto aos valores ADMET, as simulações in silico demonstraram que a maioria das quinolinas em estudo tem grande probabilidade de biodisponibilidade oral, permeação da barreira hemato-encefálica sem ser substrato para glicoproteina-P, o que representa carcterísticas muito desejáveis. Por fim, a partir da avaliação da atividade antifúngica foi possível observar que as quinolinas apresentam atividade antifúngica frente a leveduras e dermatófilos. A quinolina Q11 foi ativa frente a praticamente todas as cepas de cândica testadas com CIM de 50 μg/mL e com SI de 2. Já frente a dermatófilos as quinolinas mais ativas foram a Q13 e Q14 que obtiveram CIM de 12,5 a 25 μg/mL e 50 μg/mL respectivamente. Quanto ao SI as quinolinas Q13 e Q14 também alcançaram resultados excelentes com valores de SI de 12 e 6 respectivamente.The development of new drugs has been a constant and progressive search over time. Diseases with high incidence and deficiencies in treatment such as cancer and fungal infections have reached significant relevance and require constant research in order to develop new drugs to treat them. In this way, this work sought to develop new synthetic methodologies to obtain bioactive molecules based on the quinolinic nucleus, as well as to evaluate the biological activity of the same against tumoral strains and yeast and dermatophile fungi strains. From the results it is possible to conclude that the methodologies developed allowed the synthesis of 9 quinolines whose structures were identified through NMR and mass spectroscopy. The quinolines studied showed antitumor activity. Furthermore, in the death mechanism studies, most molecules induced cell death through apoptosis. It is possible to highlight the Q11 and Q12 quinolines in relation to cytotoxic activity against tumor lines and excellent selectivity indexes (SI) higher than 10 for Q11 and between 1.5-3 for Q12. As for the ADMET values, the in silico simulations demonstrated that most of the quinolines under study have a high probability of oral bioavailability, permeation of the blood-brain barrier without being substrate for P-glycoprotein, which represents very desirable characteristics. Finally, from the evaluation of the antifungal activity it was possible to observe that the quinolines present antifungal activity against yeasts and dermatophiles. Quinoline Q11 was active against virtually all strains tested with MIC of 50 μg / mL and SI of 2. Already to dermatophiles the most active quinolines were Q13 and Q14, which obtained MICs of 12.5 to 25 μg / ml and 50 μg / ml respectively. As for SI, quinolines Q13 and Q14 also achieved excellent results with SI values of 12 and 6, respectively.Le développement de nouveaux médicaments a été une recherche constante et progressive au fil du temps. Les maladies à incidence élevée et les carences de traitement, telles que le cancer et les infections fongiques, ont désormais une pertinence significative et nécessitent des recherches constantes afin de développer de nouveaux médicaments pour les traiter. De cette manière, ces travaux visaient à développer de nouvelles méthodologies de synthèse pour obtenir des molécules bioactives basées sur le noyau quinolinique, ainsi qu’à évaluer l’activité biologique de celles-ci contre les souches tumorales et les souches de champignons de levure et de dermatophiles. A partir des résultats, il est possible de conclure que les méthodologies développées ont permis la synthèse de 9 quinoléines dont les structures ont été identifiées par RMN et spectroscopie de masse. Les quinoléines étudiées ont montré une activité antitumorale. De plus, dans les études sur le mécanisme de la mort, la plupart des molécules ont induit la mort cellulaire par apoptose. Il est possible de mettre en évidence les quinolines Q11 et Q12 en relation avec l'activité cytotoxique contre les lignées tumorales et avec d'excellents indices de sélectivité (IS) supérieurs à 10 pour Q11 et compris entre 1,5 et 3 pour Q12. En ce qui concerne les valeurs ADMET, les simulations in silico ont montré que la plupart des quinoléines étudiées présentaient une probabilité élevée de biodisponibilité orale, de pénétration de la barrière hémato-encéphalique sans constituer de substrat pour la glycoprotéine P, ce qui représente des caractéristiques très souhaitables. Enfin, l'évaluation de l'activité antifongique a permis de constater que les quinoléines présentaient une activité antifongique contre les levures et les dermatophiles. La quinoléine Q11 était active contre pratiquement toutes les souches testées avec une CMI de 50 μg / mL et une IS de 2. Déjà pour les dermatophiles, les quinoléines les plus actives étaient les Q13 et Q14, qui obtenaient des CMI de 12,5 à 25 μg / ml et de 50 μg / ml respectivement. En ce qui concerne l'IS, les quinolines Q13 et Q14 ont également obtenu d'excellents résultats avec des valeurs d'IS de 12 et 6, respectivement

Avaliação da atividade antimalárica de compostos semissintéticos

A malária é uma doença tropical antiga que continua sendo um dos principais problemas de saúde pública do mundo. Faz-se necessário, assim, desenvolver novas classes de antimaláricos que sejam eficazes e seguros contra a malária. Neste contexto, nosso grupo de pesquisa tem trabalhado, com dois triterpenos semissintéticos derivados dos ácidos ursólico (1) e betulínico (2), os compostos 1c e 2c respectivamente. Estes derivados (1c e 2c) apresentaram elevada potência in vitro frente a cepas de Plasmodium falciparum, alcançaram índices de seletividade em relação à linhagem celular humana satisfatórios e uma rota semissintética convergente foi estabelecida facilitando sua obtenção. Com base nestes resultados e visando dar continuidade a pesquisa, estudos de avaliação da toxicidade in vitro e aguda e da atividade antimalárica in vivo foram propostos como objetivos deste trabalho. Na avaliação da toxicidade in vitro foram realizados ensaios de cito e genotoxicidade frente a linfócitos, ensaios de hemólise e coagulação. Já na análise da toxicidade in vivo, foi realizada a avaliação da toxicidade aguda por meio do protocolo 423 em camundongos BALB/c. A atividade antimalárica in vivo foi avaliada, utilizando o ensaio supressivo de 4 dias em camundongos BALB/c, usando a linhagem de Plasmodium berghei ANKA. Os resultados demonstraram que o derivado 1c apresentou baixa genotoxicidade e efeitos citotóxicos frente a linfócitos. Porém este derivado demonstrou atividade pro-coagulante e hemolítica, com a DL50 aferida entre 300 e 125 mg/kg. Já o derivado 2c demonstrou relativa genotoxicidade e efeitos citotóxicos frente a linfócitos, apresentando também atividade pro-coagulante e hemolítica. A DL50 deste derivado foi aferida entre 300 e 50 mg/kg, sendo classificado como tóxico. A ED50 e o Emax foram calculados a partir dos resultados de parasitemia nos animais tratados apenas para o derivado 1c. A ED50 do derivado 1c foi de 19,68 mg/kg, enquanto que o Emax ficou em 52,18%. A partir destes resultados podemos sugerir que embora apresente sinais de toxicidade em concentrações e doses superiores às efetivas, o derivado 1c possui efetividade e segurança suficiente para que se de seguimento na investigação pré-clínica.Malaria is an ancient tropical disease that remains a major public health problem in the world. It is necessary, therefore, to develop new classes of antimalarial drugs that are safe and effective against malaria. In this context, our research group has been working with two semisynthetic triterpene derivatives of ursolic (1) and betulinic (2) acids, compounds 1c and 2c respectively. Both derivatives showed high in vitro potency against strains of Plasmodium falciparum, with satisfactory index of selectivity regarding to a human cell line. A convergent semisynthetic route has been established, which facilitates its obtaining. Based on these results and in order to continue the research, this work proposed as objectives to carry evaluation studies on acute toxicity and in vitro and in vivo antimalarial activity. In the assessment of in vitro toxicity, assays against cyto-and genotoxicity lymphocytes were performed, as well as hemolysis and coagulation tests. In the analysis of in vivo toxicity, it was performed the acute toxicity evaluation by means of the protocol 423 in BALB /c mice. The in vivo antimalarial activity was evaluated by using the 4 days suppressive test in BALB / c mice, using a strain of Plasmodium berghei ANKA. The results showed that 1c derivative had low genotoxicity and cytotoxic effects against lymphocytes. However this derivative showed pro-coagulant and hemolytic activities, with LD50 between 300 and 125 mg / kg, at toxic levels. Derivative 2c demonstrated genotoxicity and cytotoxic effects against lymphocytes, also showing pro-coagulant and hemolytic activities. Its LD50 was measured between 300 and 50 mg / kg, being classified as toxic. ED50 and Emax were calculated only from the results of parasitaemia of the animals treated with 1c, being 19,68 mg/kg and 52,18%, respectively. From these results, we suggest that although showing signs of toxicity at concentrations and doses higher than the effective ones, derivative 1c owns enough effectiveness and safety to follow to the pre-clinical investigation

Toxicological and pharmacological evaluation of Discaria americana Gillies & Hook (Rhamnaceae) in mice

As plantas medicinais (i. e. Discaria americana) têm sido utilizadas pela população por séculos, entretanto, o conhecimento popular não é suficiente para validá-las como medicamentos seguros e/ou efetivos. Assim, o presente estudo teve por objetivo avaliar a toxicidade aguda e subaguda, bem como o efeito ansiolítico e antinociceptivo dos extratos da casca da raiz e das partes aéreas da D. americana em camundongos. A toxicidade aguda foi avaliada pela administração dos extratos, via intraperitoneal. Para o estudo da toxicidade subaguda os animais foram tratados oralmente com os extratos por 14 dias. O efeito ansiolítico dos extratos foi determinado através do modelo do labirinto em cruz elevado e o efeito antinociceptivo, mediante o teste da placa quente. O valor da DL50 para o extrato das partes aéreas da D. americana foi definido como >; 500 mg/kg, enquanto que para o extrato da casca da raiz foi estabelecido em 400 mg/kg. O extrato das partes aéreas da D. americana apresentou atividade ansiolítica (250 mg/kg) e antinociceptiva (125, 200 e 250 mg/kg). O extrato da casca da raiz da D. americana não apresentou efeito ansiolítico nem antinociceptivo.Medicinal plants (e.g. Discaria americana) have been used by populations for centuries. However, popular use is not enough to validate these plants as safe and effective medicinal products. The present study sought to evaluate the acute and subacute toxicity as well as the anxiolytic and antinociceptive effects of D. americana root bark and aerial parts extracts in mice. In acute toxicity studies, mice were treated with single intraperitoneal doses of the aforementioned extracts. Subacute toxicity studies were performed by oral administration of the extracts over 14 days. Anxiolytic studies consisted of the elevated plus maze method, and antinociceptive studies were based on the hot plate test. The LD50 value for D. americana aerial parts extract was established at >;500 mg/kg, and for the root bark extract, 400 mg/kg. D. americana aerial parts extract produced anxiolytic (250 mg/kg) and antinociceptive effects (125, 200 and 250 mg/kg). Conversely, D. americana root bark extract showed neither anxiolytic nor antinociceptive effects in mice

Ex vivo potential of a quinoline-derivative nail lacquer as a new alternative for dermatophytic onychomycosis treatment

International audienceIntroduction. Onychomycosis infections currently show a significant increase, affecting about 10 % of the world population. Trichophyton rubrum is the main agent responsible for about 80 % of the reported infections. The clinical cure for onychomycosis is extremely difficult and effective new antifungal therapy is needed.Hypothesis/Gap Statement. Ex vivo onychomycosis models using porcine hooves can be an excellent alternative for evaluating the efficacy of new anti-dermatophytic agents in a nail lacquer.Aim. Evaluation of the effectiveness of a nail lacquer containing a quinoline derivative on an ex vivo onychomycosis model using porcine hooves, as well as the proposal of a plausible antifungal mechanism of this derivative against dermatophytic strains.Methodology. The action mechanism of a quinoline derivative was evaluated through the sorbitol protection assay, exogenous ergosterol binding, and the determination of the dose-response curves by time-kill assay. Scanning electron microscopy evaluated the effect of the derivative in the fungal cells. The efficacy of a quinoline-derivative nail lacquer on an ex vivo onychomycosis model using porcine hooves was evaluated as well.Results. The quinoline derivative showed a time-dependent fungicidal effect, demonstrating reduction and damage in the morphology of dermatophytic hyphae. In addition, the ex vivo onychomycosis model was effective in the establishment of infection by T. rubrum.Conclusion. Treatment with the quinoline-derivative lacquer showed a significant inhibitory effect on T. rubrum strain in this infection model. Finally, the compound presents high potential for application in a formulation such as nail lacquer as a possible treatment for dermatophytic onychomycosis

Revista de Microbiologia

Fungal infections have emerged as a current serious global public health problem. Themain probleminvolving these infections is the expansion of multidrug resistance. Therefore, the prospection of new compounds with efficacy antifungal becomes necessary. Thus, this study evaluated the antifungal profile and toxicological parameters of quinolines derivatives against Candida spp. and dermatophyte strains. As a result, a selective anti-dermatophytic action was demonstrated by compound 5 (geometric means (GM= 19.14 μg ml−1)). However, compounds 2 (GM= 50 μg ml−1) and 3 (GM=47.19 μg ml−1) have presented only anti- Candida action. Compounds 3 and 5 did not present cytotoxic action. Compound 5 did not produce dermal and mucosal toxicity. In addition, this compound showed the absence of genotoxic potential, suggesting safety for topical and systemic use. Quinolines demonstrated a potent anti-dermatophytic and anti-yeast action. Moreover, compound 5 presented an excellent toxicological profile, acting as a strong candidate for the development of a new effective and safe compound against dermatophytosis of difficult treatment

Comparação da temperatura do ar obtida por estação meteorológica convencional e automática Comparison of the air temperature obtained by conventional and automatic meteorological stations

Este trabalho teve como objetivos comparar os dados da temperatura do ar (temperatura média e extrema), obtidos em uma Estação Meteorológica Convencional com os de uma Estação Meteorológica Automática, e avaliar as estimativas da temperatura média diária do ar por diferentes métodos. As estações meteorológicas estavam localizadas na Estação Agroclimatológica de Pelotas, Capão do Leão (31º52' S, 52º21' W e 13,2 m), Rio Grande do Sul, Brasil. A série de cada elemento foi obtida simultaneamente na Estação Automática e na Estação Convencional durante o período de 22/12/2005 a 21/12/2006. Existe alta equivalência para as medidas das temperaturas extremas e das estimativas das temperaturas médias entre as Estações Meteorológicas Convencional e Automática, independente do método utilizado para o cálculo da temperatura média do ar. O termohigrógrafo mede, com alta precisão, as temperaturas extremas do ar. Verificam-se pequenas diferenças nos horários de ocorrência das temperaturas mínimas e máximas entre as Estações Meteorológicas Convencional e Automática. A análise dos dados indica que a substituição da Estação Meteorológica Convencional pela Estação Meteorológicas Automática, na região Sul do Rio Grande do Sul, não acarreta mudanças significativas na série de dados de temperatura do ar.<br>The objective of this work was to compare the air temperature data (average and extreme) obtained by a Conventional Meteorological Station and an Automatic Meteorological Station and evaluate different methods of estimating the average air temperature. The Meteorological Stations were located at the Agroclimatological Station of Pelotas, Capão do Leão (31º52' S, 52º21' W and 13,2 m), Rio Grande do Sul, Brazil. The data series were collected simultaneously in Conventional Meteorological Station and Automatic Meteorological Station during the period from 12/22/2005 to 12/21/2006. There is high equivalence in the measures of extreme temperature and average air temperature obtained from the Conventional and Automatic Meteorological Station, independently of the methods used for the calculation of average air temperature. The termo-hygrograph measures with high precision the extreme air temperature. There are small differences in the times of occurrence of the minimum and maximum temperatures between Conventional and Automatic Meteorological Stations. The data analysis indicated that the substitution of the Conventional Meteorological Station by Automatic Meteorological Station in Southern of Rio Grande do Sul does not changes significantly the air temperature data series