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Previous issue date: 2012-02-29 / CAPES / Doenças infecciosas causadas por micro-organismos resistentes são alvo de estudo de cientistas, pois afetam milhares de pessoas, sendo prevalente em ambiente hospitalar. A infecção hospitalar vem sendo tratada com bastante atenção, pois se alastra pelos principais centros hospitalares no mundo, atingindo principalmente indivíduos imunocomprometidos e pacientes com câncer e AIDS. Outro tema bastante preocupante, a resistência das células neoplásicas a diversos fármacos vem dificultando o processo da quimioterapia, pois já existem relatos na literatura mostrando que esse fato prejudica o tratamento de diversos casos de câncer metastático. Diante desse quadro, existe a necessidade de buscar novos fármacos mais eficazes e seguros. As 4-tiazolidinonas vêm ganhando destaque, por estar presente em diversos compostos que apresentam amplo espectro de propriedades biológicas comprovado. Na busca de novas substâncias ativas contra micro-organismos resistentes, bem como apresentando boa atividade citotóxica, desenvolvemos a síntese de uma série de 2-[(2-piridinil-metileno)hidrazono]-4-tiazolidinona (3a-d) e seus derivados 5-benzilideno-2-[(2-piridinil-metileno)hidrazono]-4-tiazolidinona (4a-p), com a intenção de sintetizar novos compostos ativos frente à bactérias e fungos, e com atividade antineoplásica. As 5-benzilideno-4-Tiazolidinonas (4a-p) foram sintetizadas em três etapas. A primeira constituiu da obtenção das tiossemicarbazonas (2a-d), que foram sintetizadas a partir de tiossemicarbazidas (1a-d) e 2-formilpiridina e meio hidroetanólico e presença de ácido acético em quantidades catalíticas. As 4-tiazolidinonas (3a-d) foram obtidas através da condensação entre tiossemicarbazonas e ácido cloroacético, em presença de acetato de sódio anidro em meio etanólico. Já as 5-benzilideno-4-tiazolidinonas foram sintetizadas através da reação de condensação do tipo Knoevenagel, através dos intermediários (3a-d) com benzaldeídos. Após purificação, os compostos finais apresentaram rendimentos entre 44-87%. Todos foram caracterizados por métodos espectrométricos convencionais (RMN ¹H, RMN ¹³C e IV), apresentando-se consistentes com as respectivas estruturas. Todos os compostos da série (4a-p) e seus percussores (3a-d) foram testados in vitro contra bactérias e fungos e para o teste citotóxico em células tumorais. A maioria dos compostos não apresentou boas atividades diante de diversos micro-organismos, no entanto o composto 3a apresentou excelente atividade diante da Candida albicans e Fusarium moniliforme, apresentando resultados comparáveis a nistatina. No teste citotóxico os compostos 2-[(2-piridinil-metileno)hidrazono]-4-tiazolidinona (IC₅₀= 1,6 μg/mL), 2-[(4-piridinil-metileno)-hidrazono]-5-p-dimetilamino-benzilideno-4-tiazolidinona (CI50 = 0,7 μg/mL) e 2-[(4-piridinil-metileno)-hidrazono]-5-p-nitro-benzilideno-4-tiazolidinona IC₅₀ (= 0,5 μg/mL) apresentaram excelentes resultados, reduzindo significantente o crescimento de linhagens tumorais, sendo este efeito mais pronunciado nas linhagens HEp-2. Esses compostos apresentaram concentração inibitória superior ao etoposídeo (IC₅₀= 6,63 μg/mL), indicando a presença do radical benzilideno produzindo um efeito positivo na atividade citotóxica para esta série. / Infectious diseases caused by resistant microorganisms are studied by scientists, as they affect thousands of people and are prevalent in a hospital environment. The hospital infection has been treated with great attention, as it is spread through the main hospitals throughout the world, reaching mainly immunocompromised individuals and patients with cancer and AIDS. Another very worrying theme, the resistance of neoplastic cells to several drugs, has been making the chemotherapy process difficult, since there are already reports in the literature showing that this fact harms the treatment of several cases of metastatic cancer. Before this situation, there is a need to seek new, more effective and safe drugs. The 4-thiazolidinones have been gaining prominence, being present in several compounds that have a comprehensive spectrum of biological properties proven. In the search for new active substances against resistant microorganisms as well as good cytotoxic activity, we have developed the synthesis of a series of 2 - [(2-pyridinyl-methylene) hydrazono] -4-thiazolidinone (3a-d) and its derivatives 5-benzylidene-2 - [(2-pyridinyl-methylene) hydrazono] -4-thiazolidinone (4a-p), with the intention of synthesizing new active compounds against bacteria and fungi, and with antineoplastic activity. The 5-benzylidene-4-thiazolidinones (4a-p) were synthesized in three steps. The first one consisted of obtaining the thiosemicarbazones (2a-d), which were synthesized from thiosemicarbazides (1a-d) and 2-formylpyridine and hydroethanolic medium and from the presence of acetic acid in catalytic amounts. The 4-thiazolidinones (3a-d) were obtained by condensation between thiosemicarbazones and chloroacetic acid in the presence of anhydrous sodium acetate in medium ethanolic. The 5-benzylidene-4-thiazolidinones were synthesized through the Knoevenagel type condensation reaction through the intermediates (3a-d) with benzaldehydes. After purification, the final compounds showed yields of 44-87%. All were characterized by conventional spectrometric methods (RMN 1H, RMN 13C e IV), and were consistent with the respective structures. All compounds of the series (4a-p) and their percussors (3a-d) were tested in vitro against bacteria and fungi and for cytotoxic testing on tumor cells. Most of the compounds did not present good activity in the presence of several microorganisms, however, the 3a compound presented excellent activity against Candida albicans and Fusarium moniliforme, presenting results comparable to nystatin. In the cytotoxic test the 2 - [(2-pyridinyl-methylene) hydrazono]-4-thiazolidinone compounds (IC₅₀ = 1.6 μg / mL), 2 - [(4-pyridinylmethylene) hydrazono]-5-benzilidene (IC₅₀= 0.7 μg / ml) and 2-[(4-pyridinyl-methylene)-hydrazono]-5-p-nitro-benzylidene-4-thiazolidinone (IC₅₀= 0.5 μg / mL) presented excellent outcomes, reducing significantly the growth of tumoral lineages, being this effect more pronounced in the HEp-2 lineages. These compounds had a higher inhibitory concentration to the etoposide (IC₅₀= 6.63 μg / mL), indicating the presence of the benzylidene radical producing a positive effect on cytotoxic activity for this series.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufpe.br:123456789/27638 |
| Date | 29 February 2012 |
| Creators | GUIMARÃES NETO, Eraldo Antunes |
| Contributors | http://lattes.cnpq.br/8168171801247181, LIMA, José Gildo de, GÓES, Alexandre José da Silva |
| Publisher | Universidade Federal de Pernambuco, Programa de Pos Graduacao em Ciencias Farmaceuticas, UFPE, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFPE, instname:Universidade Federal de Pernambuco, instacron:UFPE |
| Rights | Attribution-NonCommercial-NoDerivs 3.0 Brazil, http://creativecommons.org/licenses/by-nc-nd/3.0/br/, info:eu-repo/semantics/openAccess |
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