Abstract
Paracoccidioidomycosis is a prevalent systemic mycosis in Latin America which requires prolonged treatment with highly toxic antifungals. Baccharis dracunculifolia is a medicinal plant in Brazil that is a candidate in the search for new drugs. Fractions of the hexanic extracts were obtained using chromatographic procedures and assessed using an antifungal assay with Paracoccidioides brasiliensis (Pb18), tumor cell lines and amastigote forms of Leishmania, L. amazonensis. Four compounds were isolated, i.e., ursolic acid (1), methyl linolenate (2), caryophyllene oxide (3), and trans-nerolidol (4). Compounds 2, 3 and 4 displayed antifungal activity against four isolates of Paracocci dioides with MIC values ranging from 3.9–250 μg/ml. Only caryophyllene oxide showed differences in the MIC values against Pb18 when the medium was supplemented with ergosterol, which suggested that the compound interacts with ergosterol. Ursolic acid was active in the cytotoxic assays and showed leishmanicidal activity. Scanning electron microscopy demonstrated that compounds 2, 3 and 4 decreased the cell size and produced an irregular cell wall surface on P. brasiliensis cells. The present results showed the biological activities of the isolated compounds and revealed that these compounds may affect the cell surface and growth of P. brasiliensis isolates.
Acknowledgements
We are grateful for the financial support of Fundação Oswaldo Cruz (FIOCRUZ), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Fundação de Amparo Pesquisa Estado de Minas Gerais (FAPEMIG) and the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES). We are also grateful to Daniela Nabak Bueno Maia and Luciana Alves Rodrigues dos Santos Lima for technical assistance.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and the writing of the paper.
This paper was first published online on Early Online on 30 April 2012.