In vivo antifungal activity of terpinen-4-ol, the main component of tea tree oil, against drug-susceptible or -resistant isolates of Candida albicans

Mondello1, F., De Bernardis1, F., Girolamo2, A., Cassone2, A.

Author address: 

1 Istituto Superiore di Sanití , ROME, Italy 2ISS-Infectious Diseases, ROME, Italy

Abstract: 

Recent investigations have shown the efficacy of essential oil of Melaleuca alternifolia (Tea Tree) oil (TTO) in the treatment of vaginal candidiasis. Despite some initial data (Mondello et al., J. Antimicrob. Chemother. 2003, 51:1223-9), there continues to be, however, a lack of in vivo data supporting in vitro results, especially regarding the antifungal properties of individual TTO constituents. We have started to investigate the in vitro and the in vivo anti-Candida activity of two critical bioactive constituents of TTO, terpinen-4-ol and 1,8-cineole, and compared the in vivo activity of these two constituents to that previously established for TTO mother mixture. Namely, we tested TTO and terpinen-4-ol on oophorectomized female rats treated with estrogens and challenged in experimental vaginal infections by fluconazole, itraconazole and caspofungin, susceptible or resistant strains of C. albicans . All these strains were preliminarily tested in vitro with TTO, terpinen-4-ol and 1,8-cineole for their antifungal properties using a modification of the CLSI reference M27-A2 broth microdilution method. MIC90 v/v values were 0.06% for terpinen-4-ol and 4% for 1,8-cineole, regardless of susceptibility or resistance of the strains to azoles or caspofungin. Fungicidal concentrations of terpinen-4-ol were equivalent to the candidastatic activity. In a rat vaginal infection model, terpinen-4-ol was as active as TTO in accelerating Candida clearance from rat vagina, and the compound was equally active against susceptible and -resistant C. albicans strains. Our data suggest that terpinen-4-ol is a likely mediator of the in vitro and in vivo activity of TTO. They also suggest that this compound has a therapeutic potential for acute/chronic vaginal infection by Candida irrespective of the susceptibility of the isolate to major classes of antifungal drugs such as the azoles and the echinocandins. This further in vivo demonstrates that terpinen- 4-ol could control a C. albicans vaginal infections.
2007

abstract No: 

P033

Full conference title: 

3rd Trends in Medical Mycology
    • TIMM 3rd (2011)