It has antimicrobial & antiinflammatory activity.
Int Dent J 2002 Dec;52(6):433-7 Related Articles, Links
Antimicrobial activity of garlic, tea tree oil, and chlorhexidine against oral microorganisms.
Groppo FC, Ramacciato JC, Simoes RP, Florio FM, Sartoratto A.
Antimicrob Agents Chemother 2002 Jun;46(6):1914-20 Related Articles, Links
Mechanism of action of Melaleuca alternifolia (tea tree) oil on Staphylococcus aureus determined by time-kill, lysis, leakage, and salt tolerance assays and electron microscopy.
Carson CF, Mee BJ, Riley TV.
Department of Microbiology, The University of Western Australia, Crawley.
ccarson@cyllene.uwa.edu.au
The essential oil of Melaleuca alternifolia (tea tree) has broad-spectrum antimicrobial activity. The mechanisms of action of tea tree oil and three of its components, 1,8-cineole, terpinen-4-ol, and alpha-terpineol, against Staphylococcus aureus ATCC 9144 were investigated. Treatment with these agents at their MICs and two times their MICs, particularly treatment with terpinen-4-ol and alpha-terpineol, reduced the viability of S. aureus. None of the agents caused lysis, as determined by measurement of the optical density at 620 nm, although cells became disproportionately sensitive to subsequent autolysis. Loss of 260-nm-absorbing material occurred after treatment with concentrations equivalent to the MIC, particularly after treatment with 1,8-cineole and alpha-terpineol. S. aureus organisms treated with tea tree oil or its components at the MIC or two times the MIC showed a significant loss of tolerance to NaCl. When the agents were tested at one-half the MIC, only 1,8-cineole significantly reduced the tolerance of S. aureus to NaCl. Electron microscopy of terpinen-4-ol-treated cells showed the formation of mesosomes and the loss of cytoplasmic contents. The predisposition to lysis, the loss of 260-nm-absorbing material, the loss of tolerance to NaCl, and the altered morphology seen by electron microscopy all suggest that tea tree oil and its components compromise the cytoplasmic membrane.
Piracicaba Dental School - UNICAMP, Av. Limeira 901, Bairro Areiao, Piracicaba, Sao Paulo, Brazil CEP 13 414 - 900.
fcgroppo@fop.unicamp.br
OBJECTIVE: To compare the antimicrobial activity of tea tree oil, garlic, and chlorhexidine solutions against oral microorganisms. METHOD: The five-week study consisted of thirty subjects. The first week was considered baseline. All subjects used a control solution (second week), and were randomly divided into the three groups (third week): G1-0.12% chlorhexidine; G2 - 2.5% garlic (Allium sativum, L.); and G3 - 0.2% tea tree oil (Melaleuca alternifolia). Dishes containing blood agar and Mitis Salivarius Bacitracin agar (MSB) were inoculated with the subjects' saliva (collected twice a week). Total microorganisms and mutans streptococci were counted in blood agar and MSB, respectively. RESULTS: Chlorhexidine and garlic groups showed antimicrobial activity against mutans streptococci, but not against other oral microorganisms. The tea tree oil group showed antimicrobial activity against mutans streptococci and other oral microorganisms. Maintenance of reduced levels of microorganisms was observed only for garlic and tea tree oil during the two consecutive weeks (fourth and fifth). Unpleasant taste (chlorhexidine 40%, tea tree oil 30%, garlic 100%), burning sensation (chlorhexidine 40%, tea tree oil 60%, garlic 100%), bad breath (chlorhexidine 40%, tea tree oil 20%, garlic 90%), and nausea (chlorhexidine 0%, tea tree oil 10%, garlic 30%) were reported. CONCLUSION: Garlic and tea tree oil might be an alternative to chlorhexidine.
Inflamm Res 2002 May;51(5):236-44 Related Articles, Links
Tea tree oil reduces the swelling associated with the efferent phase of a contact hypersensitivity response.
Brand C, Grimbaldeston MA, Gamble JR, Drew J, Finlay-Jones JJ, Hart PH.
Department of Microbiology and Infectious Diseases, School of Medicine, Flinders Medical Research Institute, Flinders University, Adelaide, Australia.
OBJECTIVE: To examine the anti-inflammatory activities of tea tree oil (TTO) in vivo. METHODS: Mice were sensitized to a chemical hapten, trinitrochlorobenzene, on their ventral skin and 7 days later challenged (or re-exposed) on their dorsal skin with the same hapten. RESULTS: TTO applied 30 min before or up to 7 h after to the same dorsal site as hapten challenge caused a significant reduction in skin swelling after 24 h. TTO reduced oedema but not the influx of inflammatory cells. This finding was supported by the inability of TTO to suppress TNFalpha-induced E-selectin expression by human umbilical vein endothelial cells. TTO did not suppress irritant- or ultraviolet B-induced oedema. CONCLUSION: Topical TTO, specifically the TTO components, terpinen-4-ol and alpha-terpineol can regulate the oedema associated with the efferent phase of a contact hypersensitivity response.
Forsch Komplementarmed Klass Naturheilkd 2000 Feb;7(1):17-20 Related Articles, Links
Tea tree oil: a systematic review of randomized clinical trials.
Ernst E, Huntley A.
Department of Complementary Medicine, School of Postgraduate Medicine and Health Sciences, University of Exeter, UK.
E.Ernst@ex.ac.uk
AIM: Tea tree oil (TTO) is immensely popular for various topical applications. In vitro studies have repeatedly demonstrated that it has antibiotic activity. This article is an attempt to systematically review the evidence from randomised clinical trials for or against effectiveness of external TTO in dermatological conditions. METHODS: Six electronic databases were searched. Methodological quality was assessed by Jadad score. Data were extracted and validated in a standardised fashion by two independent reviewers. RESULTS: Only 4 trials were located. They suggest that TTO may be effective as a treatment of acne and fungal infections. The evidence is promising but by no means compelling. The adverse effects of TTO are usually mild and transient. They mainly consist of allergic reactions. CONCLUSIONS: It is concluded that, so far, there is no compelling evidence to show that TTO is efficacious in any dermatological condition. However, in view of promising findings, TTO deserves to be investigated more closely.
