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BEPA. Boletim Epidemiológico Paulista (Online)

versão On-line ISSN 1806-4272

BEPA, Bol. epidemiol. paul. (Online) vol.10 no.113 São Paulo maio 2013

 

RESUME

Action of essential oils against Cryptococcus neoformans

 

Avaliação in vitro da atividade antifúngica de óleos essenciais sobre Cryptococcus neoformans

 

 

Patrícia de Souza Santos, Maria de Fátima Costa Pires (Orientadora)

Programa de Pós-Graduação em Ciências da Coordenadoria de Controle de Doenças – Secretaria de Estado da Saúde de São Paulo, Brasil – 2011.

 


ABSTRACT

Cryptococcus neoformans is a yeast and the pathogenic agent of cryptococcosis, a cosmopolitan infectious disease that affects humans, domestic and wild animals. Infection occurs by inhalation of the yeast and the disease manifests itself most often in people and animals with low cellular immunity. C. neoformans has tropism for the central nervous system. Effective treatment for cryptococcosis is amphotericin B with or without 5-flucytosine despite the high toxicity and nephrotoxicity. The objective of this study was to evaluate the in vitro activity of essential oils of Eucalyptus citriodora, Eucalyptus globulus, Eugenia caryophyllus, Thymus vulgaris and Melaleuca alternifolia and a mixture of E. caryophyllus, M. alternifolia and T. vulgaris called Blend on Cryptococcus neoformans. At doses sub inhibitory assess capsule production and exoenzymes proteinase and phospholipase. We used 21 isolates of human origin, 29 environmental isolates and a standard sample of C. neoformans ICB 163 D (NIH 163D). To evaluate the antifungal activity and obtaining the minimum inhibitory concentration (MIC) used the technique of microdilution in RPMI 1640 with Tween-20 to 0.02% as an emulsifier. And the confirmation of inhibition in Sabouraud dextrose agar at 37°C for 48 hours to obtain the minimum fungicidal concentration (CFM). To evaluate the sensitivity fluconazol we used broth microdilution with RPMI 1640 and for the evaluation of sensitivity to amphotericin B was used to test commercial Etest®. For each essential oil were found the following results for CFM50 and CFM90 E. citriodora – CFM50 21.97 to 2812,5 µg/mL and CFM90 703,12 to 2812,5 µg/mL, E. globulus – CFM50 175,78 to 703,12 µg/mL and CFM90 703,12 to 2812,5 µg/mL, E. caryophyllus – CFM50 87,89 to 175,78 µg/mL and the CFM90 703,12 µg/mL; M. alternifolia – CFM50 of 11.250 – 45.000µg/mL and the CFM90 45.000µg/mL, T. vulgaris – CFM50 21,97 to 175,78 µg/mL and CFM90 351,56 to 703,12 µg/mL, Blend – CFM50 175,78 to 351,56 µg/mL and CFM90 1406,25 to 2812,5µg/mL. The CFM50 for Fluconazole was 87,89µg/mL and the CFM90 175,78 – 22.500µg/mL and amphotericin B was CFM50 0,25 to 0,125 and CFM90 0,38 to 0,5µg/mL. The production of proteinase and phospholipase all isolates were strongly positive and after exposure to all essential oils have become negative. The presence of all isolates had capsules capsule and after contact with the oil caused a reduction or lack of it, as well as yeast cells tended to cluster number 2, 4 or more cells. For these reasons and conditions of this study concluded that the essential oils of Eugenia caryophyllus, Thymus vulgaris, showed fungicidal activity with the lowest inhibitory concentrations in relation to the essential oils of Eucalyptus citriodora, Eucalyptus globules, Melaleuca alternifolia and – Blend on C. neoformans.

KEYWORDS: Cryptococcus neoformans. Essential oil. Natural antifungals. Broth microdilution. Eucalyptus citriodora. Eucalyptus globulus. Eug.