Detalhes bibliográficos
| Ano de defesa: |
2017 |
| Autor(a) principal: |
Silva, Thaísa Cristina
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| Orientador(a): |
Silva, Maria do Rosário Rodrigues
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| Banca de defesa: |
Silva, Maria do Rosário Rodrigues,
Oliveira, Valéria de,
Espíndola, Laila Salmen,
Costa, Carolina Rodrigues,
Bara, Maria Teresa Freitas |
| Tipo de documento: |
Tese
|
| Tipo de acesso: |
Acesso aberto |
| Idioma: |
por |
| Instituição de defesa: |
Universidade Federal de Goiás
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| Programa de Pós-Graduação: |
Programa de Pós-graduação em Medicina Tropical e Saúde Publica (IPTSP)
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| Departamento: |
Instituto de Patologia Tropical e Saúde Pública - IPTSP (RG)
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| País: |
Brasil
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| Palavras-chave em Português: |
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| Palavras-chave em Inglês: |
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| Área do conhecimento CNPq: |
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| Link de acesso: |
http://repositorio.bc.ufg.br/tede/handle/tede/8293
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Resumo: |
Introduction: the high incidence and mortality rate due to fungal infections arouse interest in the search for more effective and less toxic drugs for the treatment of these infections. Medicinal plants represent a promising source of discovery of antifungal agents. Among the medicinal plants, Lafoensia pacari A. St.-Hil (Lythraceae), plant of the cerrado, stands out for having medicinal properties popularly known in Brazil. Punicalagina, a secondary metabolite extracted from L. pacari leaf, has proven biological activities. Objective: in this work the biological activity of punicalagin on yeasts belonging to the Cryptococcus neoformans species complex and Candida species was evaluated. Methods: the in vitro susceptibility of the yeast to the compound punicalagin was verified using the broth microdilution method. The possible mechanism of action was verified by different methods such as: ergosterol assay of the fungal cell membrane, by morphological and ultrastructural analyzes of the yeasts, by flow cytometry (cell cycle, cytoplasmic membrane injury, reactive oxygen species production and loss of the mitochondrial membrane potential). The in vitro cytotoxicity of punicalagin was verified using Balb/c 3T3 cells, A549 lung carcinoma cells and sheep erythrocytes. Results: the punicalagin was able to inhibit yeast growth at concentrations ≤4 μg/mL with minimum fungicidal concentration (CFM) of >256 μg/mL. The punicalagin reduced the ergosterol synthesis of the fungal cell membrane and promoted alterations in the morphology and the cellular arrangement of the yeasts. The action mechanism analyzed by flow cytometry showed alteration of the cell cycle with increase of the G0/G1 phases and reduction of the G2/M phases, interfering in the cellular division of the DNA of the fungal cells. The compound showed low toxicity on the Balb/c cells 3T3, A549 and sheep erythrocytes. Conclusion: the results presented by punicalagin showed that this compound presents low cytotoxicity to the animal cells, with important antifungal activity against the yeasts of the Cryptococcus neoformans species complex and Candida species. |
