Avaliação da atividade antifúngica e mecanismo de ação de compostos naturais e sintéticos em leveduras do complexo Cryptococcus neoformans

• Ano de defesa: 2014
• Autor(a) principal: Silva, Kamila Pereira da
• Orientador(a): Fernandes, Orionalda Fatima Lisboa
• Banca de defesa: Silva, Maria do Rosário Rodrigues, Paula, José Realino de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Programa de Pós-graduação em Biologia das Interações PH (IPTSP)
• Departamento: Instituto de Patologia Tropical e Saúde Pública - IPTSP (RG)
• País: Brasil
• Palavras-chave em Português: Antifúngico; Cryptococcus neoformans; Suscetibilidade in vitro; Citometria de fluxo
• Palavras-chave em Inglês: Antifungal; In vitro susceptibility; Flow cytometry
• Área do conhecimento CNPq: CIENCIAS BIOLOGICAS::PARASITOLOGIA
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tede/4180

Fungal infections caused by yeasts of Cryptococcus neoformans complex have increased considerably among immunosuppressed especially in patients infected with human immunodeficiency virus (HIV). Antifungal drugs available to treat these infections have a wide spectrum of action, but the high costs, side effects, besides the acquisition of resistance of fungi make their limited effectiveness. In these circumstances, the search for new drugs is needed. In the present study, we evaluated the antifungal activity of tamoxifen, bisabolol, indinavir, didanosine, UFMG, Labiocon 241, solasodine, Labiocon 237, Clonazepam, semicarbonado Benzaldehyde, Cardanol, AB 36 and three natural extracts of Psychotria spp, Sclerolobium paniculatum, Hymenaea courbaril and cell viability and mechanism of action of the compound showed antifungal activity of 20 isolates of Cryptococcus neoformans. To evaluate the antifungal activity , we used the in vitro susceptibility to yeast broth microdilution protocol M27 - A3 ( CLSI 2008) and to verify the mechanism of action, flow cytometry was performed with the cellular marker Propidium Iodide ( PI ) and cell viability assay with MTT salt. Among the compounds analyzed, only tamoxifen and olanzapine showed inhibitory action on fungal samples at concentrations 128-256 μg/mL. Analysis by flow cytometry was performed with tamoxifen and showed that the compound did not alter the cell membrane of Cryptococcus neoformans ATCC 28957 , however, the cell viability test showed that tamoxifen was able to inhibit the metabolism of the fungus in different concentrations ranging 4-1024 μg/mL.