Preventive Effects of Hinokitiol Against C.albicans Adherence to Epithelial Cells

Objectives: Candida is an opportunistic pathogen that can cause serious local as well as systemic infections, especially in immunocompromised hosts such as elderly patients. Hinokitiol is a component of essential oils isolated from Cupressaceae, shows antibacterial and antifungal activities. However, preventive effects of hinokitiol on Candida adherence to epithelial cells have not been clarified. The aim of this study was to evaluate the preventive effect of hinokitiol on adherence of 7 species Candida to oral epithelial cells. Methods: 7 species Candida (C. albicans SC5314, C. tropicalis IFO0618, C. dubliniensis CD36, C. dubliniensis CD57, C. parapsilosis ATCC22019, C. parapsilosis FRCP-0201, C. glabrara 850821) were incubated by 24 h, 37°C in YPD broth. After each Candida was adjusted OD=0.5 at 660 nm absorbance, harvested by centrifugation and washed in PBS two times. Candida were treated by various concentrations of hinokitiol, range from 62.5 µM- 500 µM, added on the monolayer Ca-922 epithelium cells in 24-well polystyrene plate and incubated for 30 min at 37°C. The cells with Candida were washed in PBS three times and detached by 0.5% trypsin-EDTA. The detached cell suspensions were poured on the YPD agar plate. After incubation for 24 h at 37°C under aerobic condition, the colony of Candida were counted. The growth of Candida treated with hinokitiol was also observed.Results: Hinokitiol prevented remarkably adherence of Candida sp. to oral epithelial cells in dose dependent manner, but presented a little effect on growth of Candida. From these result, it is possible that hinokitiol is useful to control adhesion of Candida sp. to the oral epithelium cells.Conclusions: Hinokitiol showed a preventive effect on Candida adherence to oral epithelial cells rather than an antifungal effect in the optimized concentration. There may be possibility that hinokitol is an effective agent to reduce opportunistic pathogens on the oral mucosa.