Preparação e determinação da atividade toxicológica do pró-fármaco hidroximetilnitrofural, potencialmente antichagásico
Carregando...
Arquivos
Data
2006-06-05
Autores
Melo, Mara Filomena Ferreira [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
A doença de Chagas representa um dos mais sérios problemas médico-sanitários da América Latina. Nos 21 países endêmicos, estima-se que 18 a 20 milhões de pessoas estejam infectadas e cem milhões estão sob risco. No Brasil apenas o benznidazol está disponível para o tratamento apresentando alta incidência de efeitos adversos e ineficácia na fase crônica da doença. O desenvolvimento de fármacos mais eficazes e com menor toxicidade contra a doença de Chagas é necessário, e para tal é importante o conhecimento dos alvos terapêuticos para o planejamento racional por novos compostos. Estudos demostraram que a tripanotiona redutase (TR) é a enzima chave do metabolismo anti-oxidativo do T. cruzi. Os nitrofuranos atuam como substratos da TR e são também efetivos inibidores enzimáticos da redução do tripanotiona dissulfeto. Entre os compostos nitrofurânicos, o nitrofural apresentou atividade contra T. cruzi, mas alta toxicidade por via oral e severos efeitos adversos. A latenciação de fármacos é um dos métodos de modificação molecular que tem como objetivo melhorar as características de fármacos protótipos. Sabendo disto, Chung (1996) sintetizou uma série de pró-fármacos recíprocos seletivos de nitrofural e primaquina, culminando na obtenção do derivado hidroximetilnitrofural (NFOH). Este se mostrou mais ativo de todos os derivados sintetizados, tanto em formas amastigotas quanto em tripomastigotas nos ensaios in vitro contra T. cruzi. Os compostos que possuem grupos nitro na sua molécula geralmente apresentam atividade mutagênica, estudos indicaram que a latenciação do nitrofural em NFOH foi capaz de diminuir a atividade mutagênica em aproximadamente 4 vezes. Diante do exposto, o objetivo deste trabalho foi iniciar os estudos de toxicidade do derivado... .
The Chagas' disease represents one of the most serious sanitary medical problems of Latin America. In the 21 endemic countries, it is estimated that 18 to 20 million people are infected and 100 million are under risk. Only one drug is available in Brazilian market: benznidazole, which shows high side effects and is ineffective in the chronic phase of the disease. The development of more efficient drugs with lower toxicity against the Chagas disease is necessary and for it, it is important the knowledge of therapeutic targets for the design of new compounds. Studies showed that trypanothione reductase (TR) is a key enzyme of the antioxidant metabolism of T. cruzi. Nitrofurans act as substrates of TR and are also effective enzymatic inhibitors of the reduction of trypanothione disulfide. Among the nitrofurans conpounds, nitrofurazone presented activity against T cruzi, but showed high toxicity by oral route and severe side effects. Latentiation is one process of molecular modification, which has the purpose to improve pharmaceutical and physical-chemical properties and decrease drug toxicity. In this way, Chung (1996) has synthesized the prodrug hydroxymethylnitrofurazone (NFOH), showing high activity in amastigotes forms in vitro assay against T. cruzi. Nitrocompounds generally presents mutagenic activitys. Studies suggested that the latentiantion of nitrofurazone giving NFOH was able to reduce toxicity activity in four times. According to this, the purpose of this work was to accomplish toxicity studies of the derivative compound. The results obtained in the tests acute toxicity in mice and rate suggested a lower toxicity of NFOH, obtaining a median lethal dose in relation to NF...(Complete abstract, click electronic address below).
The Chagas' disease represents one of the most serious sanitary medical problems of Latin America. In the 21 endemic countries, it is estimated that 18 to 20 million people are infected and 100 million are under risk. Only one drug is available in Brazilian market: benznidazole, which shows high side effects and is ineffective in the chronic phase of the disease. The development of more efficient drugs with lower toxicity against the Chagas disease is necessary and for it, it is important the knowledge of therapeutic targets for the design of new compounds. Studies showed that trypanothione reductase (TR) is a key enzyme of the antioxidant metabolism of T. cruzi. Nitrofurans act as substrates of TR and are also effective enzymatic inhibitors of the reduction of trypanothione disulfide. Among the nitrofurans conpounds, nitrofurazone presented activity against T cruzi, but showed high toxicity by oral route and severe side effects. Latentiation is one process of molecular modification, which has the purpose to improve pharmaceutical and physical-chemical properties and decrease drug toxicity. In this way, Chung (1996) has synthesized the prodrug hydroxymethylnitrofurazone (NFOH), showing high activity in amastigotes forms in vitro assay against T. cruzi. Nitrocompounds generally presents mutagenic activitys. Studies suggested that the latentiantion of nitrofurazone giving NFOH was able to reduce toxicity activity in four times. According to this, the purpose of this work was to accomplish toxicity studies of the derivative compound. The results obtained in the tests acute toxicity in mice and rate suggested a lower toxicity of NFOH, obtaining a median lethal dose in relation to NF...(Complete abstract, click electronic address below).
Descrição
Palavras-chave
Chagas, Doença de - Tese, Nitrofuranos, Pró-fármaco - Tese, Testes toxicológicos, Hidroximetilnitrofural, Chagas disease
Como citar
MELO, Mara Filomena Ferreira. Preparação e determinação da atividade toxicológica do pró-fármaco hidroximetilnitrofural, potencialmente antichagásico. 2006. 91 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Farmacêuticas, 2006.