Resumo

The current antifungal arsenal of drugs is limited while the frequency and diversity of severe fungal infections are increasing, mainly in developing countries. Thus, new antifungal drugs more efficient and less toxic are needed. Microorganisms are source of important bioactive secondary metabolites and in this aspect Brazilian mangrove is an unexplored biome. The fungus Epicoccum sp. was isolated from the leaves of Rhizophora mangle and showed antifungal activity against pathogenic fungi through the antagonism assay. In this approach the aim of this study is to purify the crude extract obtained by the culture of Epicoccum sp. and to physical chemically characterize the antifungal isolated molecules. Epicoccum sp. was cultivated in potato dextrose broth at 28ºC, 150 rpm for 14 days. The culture supernatant was extracted with hexane (HEX) and dichloromethane (DCM). The crude extract was fractionated by High Performance Liquid Chromatography and the antifungal activity of the crude extract, fractions or subfractions were evaluated in vitro by microdilution assay (Minimal Inhibitory Concentration - MIC) at concentrations lower than 500 µg/mL against Candida albicans ATCC 36802/IOC 3704 (CA), Trichophyton rubrum IOC 4527 (TR), Criptococcus neoformans IOC 4528 (CN) and Aspergillus fumigatus IOC 4526 (AF). The MIC was defined as the lowest concentration that inhibits at least 90% of the pathogens growth. The HEX and DCM crude extract inhibited all pathogens with MIC values ranging from 31.25 to 250 µg/mL. The HEX and DCM crude extracts were both fractionated (from HEX-F1 to HEX-F9 and from DCM-F1 to DCM-F10). Among HEX fractions, only HEX-F9 showed promising antifungal activity, with MIC ranging from 31.25 to 250 µg/mL against all the pathogens, except AF. The DCM-F3, F5, F6, F9 and F10 fractions were more effective, mainly DCM-F6 with MIC values of 31.25 or 62.5 against all the pathogens, and DCM-F9 with MIC values of 62.5, 125 and 250 µg/mL against CN, TR or CA, respectively. DCM-F6 and F9 were subfractionated and the isolated active compounds are under physical chemical characterization by Nuclear Magnetic Ressonance (NMR 1H and 13C), infra red (IR) and mass spectrometry. The results are indicating promising antifungal activity of the isolated compounds.