The aim of this study was to evaluate the antifungal activity of essential oils from Ocimum basilicum L. (basil), Cymbopogon martinii L. (palmarosa), Thymus vulgaris L. (thyme) and Cinnamomum cassia Blume (Chinese cinnamon) against Candida albicans strains isolated from HIV-positive patients and the standard strain (ATCC 76845). Fifteen clinical samples of C. albicans (C1-C15) were subcultured in Sabouraud Dextrose agar to prepare suspensions in sterile saline solution (0.9%) containing 1.5 x 10(6) CFU mL-1. The emulsions of essential oils were prepared in sterile distilled water and Tween 80, with concentrations ranging between 1024 µg mL-1 and 4 µg mL-1. The antifungal action was determined by means of the Minimum Inhibitory Concentration (MIC), using the microdilution technique. Nystatin and miconazole (50 µg mL-1) were used as positive controls. The tests were performed in triplicate and the MIC was the lowest concentration capable of inhibiting the growth of yeasts, which was observed by the visual method, according to the turbidity of the culture medium. For C. albicans (ATCC 76845), the MIC of C. cassia essential oil was 64 µg mL-1, while the MIC for C. martini was 1024 µg mL-1. Considering the clinical strains, the MIC of C. cassia was 64 µg mL-1 for 80% of the strains, and the variation in MIC values was between 128 µg mL-1 and 64 µg mL-1. For 66.6% of the clinical samples, the MIC of C. matinii was 612 µg mL-1. Nystatin did not present activity against the clinical strains (C1-C15), while the antifungal activity of miconazole was noticed for 100% of the samples. The antimicobrial activity of essential oils from O. basilicum and T. vulgaris was not identified at the evaluated concentrations. It was concluded that the essential oils from C. cassia and C. martinii, at different concentrations, presented antifungal activity against C. albicans strains isolated from HIV-positive patients and the standard strain (ATCC 76845). However, antifungal activity was not observed for the essential oils from O. basilicum and T. vulgaris.
Candida albicans; natural products; thyme; basil; cinnamon
