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Antifungal effects of Ellagitannin isolated from leaves of Ocotea odorifera (Lauraceae)
Brazilian plants with ethnomedical uses have been widely studied in recent years. Plants of the genus Ocotea have been reported to have antimicrobial properties [1,2]. Candida species are the major cause of healthcare-related bloodstream and invasive infections. The frequency of nosocomial bloodstream infections by Candida non-albicans species such as C. parapsilosis has risen dramatically in the past decade [3,4]. This increase in fungal infections is accompanied by significant excess mortality and length of hospital stays. In the present study, the antifungal property of the methanol extract (F5) of dried leaves from Ocotea odorifera was investigated. The antifungal activity was attributed to an Ellagitannin, obtained by F5 fractionation on a Sephadex LH-20 column, and identified by spectral analyses of 1H, 13C-NMR, H-H COSY, DEPT, HMQC, HMBC and LC MS/MS. The minimum inhibitory concentration (MIC) was determined on a C. parapsilosis strain through the broth microdilution technique. The F5 extract and Ellagitannin compound exhibited the same value of MIC=12.5µg/ml. Cytotoxicity was determined in vitro using the sulforhodamine B assay on Vero cells, showing 50% cytotoxicity concentration (CC50)=51µg/ml. Morphological alterations in hyphae of C. parapsilosis treated with Ellagitannin at MIC and sub-MIC concentrations were demonstrated by scanning electron microscopy (SEM). The inhibitory property makes Ellagitannin a promising phytotherapeutic agent for treatment of some fungal diseases.
Acknowledgements: This study was supported through grants from the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Financiadora de Estudos e Projetos (FINEP), and PRONEX/Fundação Araucária.
References: 1. Bruni, R. et al. (2004) Food Chemistry 85:415–421
2. Guerrini, A. et al. (2006)J. Agric. Food Chem. 54:7778–7788.
3. Safdara, A. et al. (2002) Diagnostic Microbiology and Infectious Disease 44:11–16
4. Caggiano, G. et al. (2004) Mycoses 51:121–128.