Comparison of the cidal activity of tea tree oil and terpinen-4-ol against clinical bacterial skin isolates and human fibroblast cells.
OBJECTIVE
The aim of this study was to compare both the antimicrobial activity of terpinen-4-ol and tea tree oil (TTO) against clinical skin isolates of meticillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococci (CoNS) and their toxicity against human fibroblast cells.


RESULTS
Antimicrobial activity was compared by using broth microdilution and quantitative in vitro time-kill test methods. Terpinen-4-ol exhibited significantly greater bacteriostatic and bactericidal activity, as measured by minimum inhibitory and bactericidal concentrations, respectively, than TTO against both MRSA and CoNS isolates. Although not statistically significant, time-kill studies also clearly showed that terpinen-4-ol exhibited greater antimicrobial activity than TTO. Comparison of the toxicity of terpinen-4-ol and TTO against human fibroblasts revealed that neither agent, at the concentrations tested, were toxic over the 24-h test period.


CONCLUSIONS
Terpinen-4-ol is a more potent antibacterial agent against MRSA and CoNS isolates than TTO with neither agent exhibiting toxicity to fibroblast cells at the concentrations tested.


CONCLUSIONS
Terpinen-4-ol should be considered for inclusion as a single agent in products formulated for topical treatment of MRSA infection. However, further work would initially be required to ensure that resistance would not develop with the use of terpinen-4-ol as a single agent.
Loughlin
R
R
School of Pharmacy, Medical Biology Centre, Queen's University Belfast, Belfast, UK.
Gilmore
B F
BF
McCarron
P A
PA
Tunney
M M
MM
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000633:toxicity; D002460:Cell Line; D005347:Fibroblasts / Q000187:drug effects*; D006801:Humans; D016106:Methicillin Resistance; D051379:Mice; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects*; D012867:Skin / Q000382:microbiology; D013210:Staphylococcus / Q000187:drug effects* / Q000302:isolation & purification; D020947:Tea Tree Oil / Q000494:pharmacology* / Q000633:toxicity; D013729:Terpenes / Q000494:pharmacology* / Q000633:toxicity
D000900:Anti-Bacterial Agents; D013729:Terpenes; C034019:terpinenol-4; D020947:Tea Tree Oil