Resumo

The diseases caused by opportunistic fungi gain increasing importance, particularly in the hospital setting, accounting for a significant cause of morbidity and mortality in critically ill patients. Dematiaceous or demaceous moulds are opportunistic pathogens that could get into the human or animal body by repeated traumatic inoculation. Toxic and unwanted drugs of choice for treating fungal infections effects arouse interest for research on medicinal plants with antifungal activity. Thus, the aim of this study was to evaluate the antifungal activity in vitro of essential oils obtained from plant species against dematiaceous moulds. Microbiological screening of seven essential oils (Laurus nobilis L., Mentha arvensis, Mentha piperita L., Mentha spicata, Ocimun basilicum L., Cymbopogon nardus and Origanum vulgare) was performed by fungal growth inhibition in microdilution plates. The antifungal activity of essential oils with higher percentage of inhibition in the screening was evaluated by determination of the Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC) by microdilution assay and spread on solid medium, respectively. In the screening assay of antifungal activity was observed that the essential oils of M. spicata and C. nardus showed a higher capacity to inhibit the fungal growth, with respective percentage of inhibition on the six strains tested: 100% and 83,3%. Subsequently, we evaluated the antifungal activity of these two oils by determining the Minimum Inhibitory Concentration (MIC) and it was observed that the MICs were similar in the strains tested, except for one of them, C. carrionii URM- 5109, that was more sensitive. The essential oils of M. spicata and C. nardus were active against the strains of dematiaceous moulds tested, with MICs between 32 and 128 µg/mL for M. spicata and 64 and 128 µg/mL for C. nardus. The MFCs found were equal MICs for all strains tested. Essential oils with an MIC between 50 and 500 µg/mL are considered a strong antimicrobial activity. Thus, we can consider that the essential oils of M. spicata and C. nardus have a strong antimicrobial activity, since their MIC was between 32 and 128 µg/mL. The essential oils of M. spicata and C. nardus showed high antifungal activity against strains of dematiaceous moulds tested and can be a source of drugs originated from natural products. Sponsoring agency: National Council for Scientific and Technological Development- CNPq.