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BMC Proceedings

Open Access

Antifungal activity of essential oil of Amyrisbalsamifera against Cryptococcusneoformans

  • Fernando Abrão1,
  • Lorena Peixoto2,
  • Marcelo Ramada3,
  • Mariana Oliveira1,
  • Ana Flávia Mendonça1,
  • Carolina Treméa1,
  • Lucia Souza1 and
  • Maria Silva1
BMC Proceedings20148(Suppl 4):P32

https://doi.org/10.1186/1753-6561-8-S4-P32

Published: 1 October 2014

Background

Cryptococcus neoformans can cause infection in immunocompromissed individuals, especially in patients with acquired immunodeficiency syndrome, in which meningoencephalitis is the main clinical manifestation [1]. There are few available antifungals for cryptococcosis treatment and all of them present high toxicity, besides the reports of resistance. In this context, the natural products from plants are an important source in the search for new antifungal compounds. In this study, it was evaluated the antifungal activity of the Amyrisbalsamifera essential oil (EO) against C. neoformans. The determination was made by minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) using the microdilution broth method.

Methods

Broth microdilution protocols based on the CLSI reference document M27-A3 [2], were used to determine MIC values for 15 isolates of C. neoformans. Briefly, twofold serial dilutions, in Roswell Park Memorial Institute (RPMI 1640) broth, with final test concentrations ranging from 2 to 1024 µg/mL for A. balsamifera was tested, and the inocula was prepared in the same broth with 103 yeasts/mL. Results were read after 72 h, and MICs were defined as the lowest test concentrations causing complete growth inhibition. Quality control determinations of the MIC values of fluconazole were performed by testing Candida parapsilosis ATCC 22019 and the results obtained were within the recommended limits. To determine minimum fungicidal concentration (MFC) [3] values, after reading the corresponding MIC values, 10 µl samples from all optically clear tubes (complete growth inhibition) plus the last tube showing growth were subcultured on Sabouraud Dextrose Aagar Petri dishes. The dishes were incubated at 35°C for for 3 days, until growth was clearly visible in the control samples, and MFC values were determined as the lowest concentration EO which there was no visible growth.

Results and conclusions

A. balsamifera EO exhibited wide-spectrum antifungal activity. Evaluation of MIC and MFC values showed that the EO was active against all the tested strains. MIC values ranged from 128 to 256 µg/mL against Cryptococcus, and MFC values were between 128 to 512 µg/mL. Acording to Scorzoni [4] compounds with MICs ≤ 256 µg/mL are considered relevant in the investigation of substances for therapeutic purposes, so in our study we can conclude that the EO showed antifungal activity against yeasts of the complex C. neoformans.

Declarations

Acknowledgements

UFG, Embrapa Arroz e Feijão e Embrapa Cenargen

Authors’ Affiliations

(1)
Instituto de Patologia Tropical e Saúde Pública (IPTSP), Universidade Federal de Goiás
(2)
EMBRAPA Arroz e Feijão
(3)
EMBRAPA Recursos Genéticos e Biotecnologia - Parque Estação Biológica

References

  1. Li SS, Mody CH: Cryptococcus. Ann Am Thorac Soc. 2010, 7: 186-196. 10.1513/pats.200907-063AL.View ArticleGoogle Scholar
  2. CLSI: Reference Method for Broth Dilution Antifungal Susceptibility Testing of Yeasts. 2008, Approved Standard M27- A3. Wayne, PA: Clinical and Laboratory Standards Institute, 3Google Scholar
  3. De Logu A, Saddi M, Cardia MC, Borgna R, Sanna C, Saddi B, Maccioni E: In vitro activity of 2-cycohexylidenhydrazo-4-phenyl-thiazole compared with those of amphotericin B and fluconazole against clinical isolates of Candida spp. and fluconazole resistant Candida albicans. J Antimicrob Chemother. 2005, 55: 692-698. 10.1093/jac/dki084.View ArticlePubMedGoogle Scholar
  4. Scorzoni L, Benaducci T, Almeida AMF, Silva DHS, Bolzani VS, Mendes-Giannini MJS: Comparative study of disk diffusion and microdilution methods for evaluation of antifungal activity of natural compounds against medical yeasts Candida spp and Cryptococcus sp. Rev Ciênc Farm Básica Apl. 2007, 18: 25-34.Google Scholar

Copyright

© Abrão et al.; licensee BioMed Central Ltd. 2014

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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