Made available in DSpace on 2015-02-24T17:42:50Z (GMT). No. of bitstreams: 1 MagdaRAF_DISSERT.pdf: 2639129 bytes, checksum: 3c6efd5066d343bdfde86e4cf41e1a70 (MD5) Previous issue date: 2012-02-28 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The increase in the incidence of fungal infections due to the drug-resistance or to the number of patients with immune alterations such as AIDS, chemotherapy or organ transplantation, has done the research necesseray for new antifungal drugs. The species from Northeastern Brazil may become an important source of innovative natural molecules. To evaluate the antifungal activity of 10 medicinal plants from Northeastern Brazil, traditionally used as antimicrobial agents, 30 crude extracts (CE) were tested in vitro against four standard species of Candida spp. The CE most promising of these plants were evaluated against yeasts of the oral cavity of kidney transplant patients and through a bioassay-guided fractionation. The extracts form leaves of E. uniflora, the stem bark of L. ferrea and leaves of P. guajava showed significant activity against all yeasts evaluated, with MIC values between 15.62 and 62.5 μg/mL. E. uniflora also showed fungicidal properties against all yeasts, especially against Candida dubliniensis. In patients with immune systems compromised, such as transplanted, oral candidiasis manifests mainly due to immunosuppressive therapy, and resistance to conventional antifungals. The CE of E. uniflora presented range of MIC values between 1.95 to 1000 μg/mL, and lower MIC50 and MIC90 values were observed against C. non-albicans. Due the better results, the CE of E. uniflora was elected to performe the bioassay-guided fractionation. Thus it was possible to obtain enriched fractions, which showed good inhibitory ability against ATCC strains of Candida spp. It was also possible to perform experiments to verify the production of biofilm in two strains of C. dubliniensis and action of extracts and fractions on the same. With this, we observed a behavior between the yeast ATCC and clinical isolate. In addition, CE, fractions and subfractions of E. uniflora inhibit planktonic cells to preventing the growth of biofilm. The preliminary chemical characterization of the fractions obtained revealed the presence of polyphenols (especially flavonoids and tannins). Finally, the results suggests that among the plant species studied, E. uniflora showed a pattern very promising as regards the antifungal, requiring further study of purification and structural elucidation of compounds in order to verify that the antifungal effect found can be attributed to a specific compound or some mechanism depends on synergistic the mixture of polyphenols / O aumento na incid?ncia de infec??es por fungos, devido ? resist?ncia ?s drogas ou ao n?mero de pacientes com altera??es imunol?gicas, tais como SIDA, quimioterapia ou transplante de ?rg?os; tem feito a investiga??o de novas drogas antif?ngicas necess?ria. As esp?cies vegetais da regi?o Nordeste do Brasil podem se tornar uma importante fonte de mol?culas naturais inovadoras. Para avaliar a atividade antif?ngica de 10 plantas medicinais da regi?o Nordeste do Brasil, tradicionalmente usadas como antimicrobianas, 30 extratos brutos (EB) foram submetidos ? teste in vitro contra quatro cepas padr?o ATCC de Candida spp. Extratos das folhas de E. uniflora, cascas do caule de L. ferrea, e folhas de P. guajava mostraram atividade significativa contra as leveduras avaliadas, com valores MIC entre 15,62 e 62,5 μg/mL. E. uniflora tamb?m mostrou propriedade fungicida contra todas as leveduras, principalmente contra C. dubliniensis. O EB de E. uniflora apresentou intervalo de valores CIM entre 1,95-1000 μg/mL, e menores valores de MIC50 e MIC90 foram observados contra C. n?o albicans. Devido ao melhor desempenho, o EB de E. uniflora foi eleito para realiza??o do fracionamento biomonitorado. Assim, foi poss?vel obter fra??es enriquecidas, as quais apresentaram boa capacidade inibit?ria, na faixa entre 0,48 a 500 μg/mL, frente ?s cepas ATCC de Candida spp. Tamb?m foi poss?vel realizar experimentos para verificar a produ??o de biofilme de duas cepas de C. dubliniensis e a??o dos extratos e fra??es sobre o mesmo. Com isso, observou-se um comportamento diferente entre a levedura ATCC e o isolado cl?nico. Al?m disso, extrato bruto, fra??es e subfra??es de E. uniflora inibiram as c?lulas planct?nicas impedindo de se agragarem ao biofilme. A caracteriza??o qu?mica preliminar das fra??es obtidas revelou a presen?a de polifen?is (principalmente, flavon?ides e taninos). Por fim, os resultados permitiram afirmar que entre as esp?cies vegetais estudadas, E. uniflora apresentou comportamento bastante promissor no que diz respeito a a??o antif?ngica, sendo necess?rio a continua??o do estudo de purifica??o e elucida??o estrutural dos compostos presentes, a fim de verificar se a a??o antif?ngica encontrada poder? ser atribu?da a um composto espec?fico ou depende de algum mecanismo sin?rgico da mistura de polifen?is