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Evidence-Based Complementary and Alternative Medicine
Volume 2015 (2015), Article ID 673962, 9 pages
http://dx.doi.org/10.1155/2015/673962
Research Article

Antifungal Properties of Crude Extracts, Fractions, and Purified Compounds from Bark of Curatella americana L. (Dilleniaceae) against Candida Species

1Laboratory of Microbiology Applied to Natural and Synthetic Products, State University of Maringá, Colombo Avenue 5790, 87020-900 Maringá, PR, Brazil
2Faculty of Medicine and Pharmacy, Ingá College, Rodovia PR317, 6114, 87035-510 Maringá, PR, Brazil
3Laboratory of Pharmacognosy-Palafito, State University of Maringá, Colombo Avenue 5790, 87020-900 Maringá, PR, Brazil

Received 3 May 2015; Revised 2 July 2015; Accepted 21 July 2015

Academic Editor: Sandy van Vuuren

Copyright © 2015 Cleyton Eduardo Mendes de Toledo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The ethnomedicinal plant Curatella americana L. (Dilleniaceae) is a common shrub in the Brazilian cerrado, in which crude extract showed antifungal activity in a preliminary study. In this work, the antifungal and cytotoxic properties of the crude extract, fractions, and isolated compounds from C. americana were evaluated against the standard yeast strains Candida albicans, C. tropicalis, and C. parapsilosis, clinical isolates, and fluconazole-resistant strains. The combinatory effects between subfractions and isolated compounds and effects on cell morphology, virulence factors, and exogenous ergosterol were also evaluated. The MIC obtained against the Candida species including fluconazole-resistant strain ranged from 15.3 to 31.3 µg/mL for crude extract, 3.9 to 15.6 µg/mL for ethyl acetate fraction, and 7.8 to 31.3 µg/mL for subfractions. The isolated compounds identified as 4′-O-methyl-catechin, epicatechin-3-O-gallate, and 4′-O-methyl-catechin-3-O-gallate showed lower antifungal activity than the crude extract and fractions (MIC ranging from 31.3 to 125.0 µg/mL). The addition of exogenous ergosterol to yeast culture did not interfere in the antifungal activity of the extract and its fractions. Synergistic antifungal activity was observed between subfractions and isolated compounds. The effects on virulence factors and the different mechanisms of action compared to fluconazole and nystatin suggest that this ethnomedicinal plant may be an effective alternative treatment for candidiasis.