Antifungal activity of essential oils of Origanum vulgare and Rosmarinus officinalis against three Candida albicans strains

Abstract

Due to general growing resistance and side effects to common antifungal drugs nowadays, there have been many studies reported on the use of herbal essential oils as antifungal agents in recent years. In this study, essential oils of Origanum vulgare and Rosmarinus officinalis (Lamiaceae) were examined for their in vitro antifungal activity against three Candida albicans strains (laboratory - CAL, human pulmonary - CAH, and reference ATCC10231-CAR) in comparison to Nystatin (0.30 mg/ml) and Fluconazole (2 mg/ml) as standard antifungal agents. The antifungal activity was evaluated by comparing inhibition zone diameters obtained both by disc-and well-diffusion assays, as well as by comparing MIC and MBC values detected by microdilution assay. Diffusion test results revealed stronger antifungal effect of O. vulgare against all analyzed C. albicans strains identifying CAL strain as the most susceptible one. Inhibition zones ranged from 12.65 to 25.10 mm depending on the concentrations applied. The highest concentrations of Rosemary essential oil (5.00 mg/ml) demonstrated activity against two strains: CAL and CAR ATCC 10231 in both diffusion assays applied, while no antifungal activity was recorded against CAH isolate. Microdilution assay showed that both oils demonstrated the same MIC values for all tested strains (0.11 mg/ml), except MIC value against ATCC strain (0.23 mg/ml) obtained for Rosemary essential oil. The obtained results indicated that oregano and rosemary essential oils might be highly effective in the natural prevention treatment of candidiasis, although toxicity assays should be previously preformed.