Laboratory study of anticandidal activity of thyme, pennyroyal and lemon essential oils by micro dilution method

Introduction and objective: Patients with candidiasis could be treated with antifungal drugs. Due to side effects and drug resistance, many studies have been conducted to investigate essential oils’ antifungal effects. The aim of the present study was to determine anticandidal activity of some essential oils.

Materials and methods: In this study, the effect of thyme, pennyroyal and lemon essential oils on Candida isolated from vulvovaginal infection were investigated experimentally by using micro dilution method. Serial dilution of thyme (0.002-4%), pennyroyal (0.004-8%) and lemon (0.15-32%) essential oils accompanying to controls and also amphotericin B (0.008-16µg/ml) and fluconazole (1-2048µg/ml) were used. 

Results: Thyme’s essential oils had the most anti-candidal activity followed by pennyroyal. Candida albicans was the most sensitive species (0.008-0.062%). Thyme and lemon essential oils had the most (0.008-0.271%) and least (1-32%) anticandidal activities, respectively. The candidal growth was inhibited by amphotericin B at 1µg/ml; whereas the anticandidal activity of fluconazole was 29.647-978.824µg/ml. the effect of thyme essential oil was similar to amphotericin B.

Conclusion: Because of the strong anti-candidal effects of thyme which was proved through in vitro tests in our study, it is proposed to do further research in the treatment of candidiasis with thyme experimentally.