Lamiaceae Peppermint Oil with Surfactant Showing Equal Antifungal Activity against <i>Candida albicans</i> to Rosemary Chemotype CINEOL

Abstract

Oral candidiasis causes pain in oral cavity or tongue. Antifungal drugs are commonly used for the treatment of candidiasis, however, there could be several problems such as side effects, drug resistance, or contraindication to concomitant use with drugs already taken. The development of substituting antimicrobial agents, which could be used internally or as gargling agents, is expected. Some essential oils have been known for the activities against microbes. We focused on the three chemotype essential oils from rosemary and five essential oils from Lamiaceae plants including rosemary, and examined their antifungal activity against Candida albicans by broth microdilution method. The activity with or without addition of Tween 80 or Tween 20 was statistically analyzed. Minimal inhibitory concentration (MIC) values of the essential oils were significantly decreased when either of the two surfactants was added. Among the tested oils, only CAMPHOR, a rosemary chemotype, showed a significantly lower MIC with addition of Tween 20 than Tween 80. It is inferred that the antifungal activity of essential oils is influenced by the type of surfactants. Some of the essential oils showed the same values of MIC and the minimal fungicidal concentration (MFC) when surfactant was added. Peppermint showed the same MICs and MFCs in most cases, and its low MFC indicated potent fungicidal activity against C. albicans, as observed in CINEOL. We will * Corresponding author. Y. Matsuzaki et al. 59discuss peppermint oil as one of the potential candidates for antifungal agents against C. albicans.