Tea tree oil
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226013695
2008-07-16T13:11:57Z
John Moss
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[[Image:Teatreeoil.jpg|thumb|Tea Tree Oil (Melaleuca Oil)]]
Tea tree oil is an extraction from the ''[[Melaleuca]]'' tree. Tea tree oil should not be confused with [[tea oil]], the sweet seasoning and cooking oil from pressed seeds of the tea plant (drinking tea) ''[[Camellia sinensis]]'' or the tea oil plant ''[[Camellia oleifera]]''.
'''Tea tree oil''' or '''melaleuca oil''' is a clear to very pale golden color [[essential oil]] with a fresh [[camphor]]aceous [[odour]]. It is taken from the [[leaf|leaves]] of the ''[[Melaleuca alternifolia]]'' which is native to the northeast coast of [[New South Wales]], [[Australia]]. The oil has beneficial [[medicine|medical]] properties (including [[antiseptic]] and [[antifungal]] action), and is also believed to have beneficial [[cosmetics|cosmetic]] properties.
== History and extraction ==
[[Image:Terpinen-4-ol.svg|thumb|[[Terpinen-4-ol]]]]
The [[Indigenous Australians|indigenous]] Bundjalung people of eastern Australia use “tea trees” as a [[traditional]] [[medicine]] by inhaling the oils from the crushed leaves to treat coughs and [[colds]]. They also sprinkle leaves on wounds, after which a [[poultice]] is applied. In addition, tea tree leaves are soaked to make an [[infusion]] to treat sore throats or [[skin]] ailments.<ref>Shemesh, A., and W. L. Mayo. 1991. "Australian tea tree oil: a natural antiseptic and fungicidal agent." ''Aust. J. Pharm.'' 72:802-803</ref><ref>Low, T. 1990. ''Bush medicine.'' Harper Collins Publishers, North Ryde, NSW, Australia</ref>
Use of the oil itself, as opposed to the unextracted plant material, did not become common practice until researcher Arthur Penfold published the first reports of its [[antimicrobial]] activity in a series of papers in the 1920s and 1930s. In evaluating the antimicrobial activity of ''M. alternifolia'', tea tree oil was rated as 11 times more active than [[phenol]].<ref>Penfold, A. R., and R. Grant. 1925. "The germicidal values of some Australian essential oils and their pure constituents, together with those for some essential oil isolates, and synthetics. Part III." ''J. R. Soc. New South Wales'' 59:346-349.
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The commercial tea tree oil [[industry]] was born after the medicinal properties of the oil were first reported by Penfold in the 1920s. It was produced from natural bush stands of ''M. alternifolia'' that produced oil with the appropriate [[chemotype]]. The plant material was hand cut and often [[distilled]] on the spot in makeshift, mobile, wood-fired bush [[stills]].
Production ebbed after [[World War II]] as demand for the oil declined, presumably due to the development of effective [[antibiotics]] and the waning image of [[natural products]]. Interest in the oil was rekindled in the 1970s as part of the general renaissance of interest in natural products. Commercial [[plantations]] were established in the 1970s and 1980s, which lead to [[mechanization]] and large-scale production of a consistent essential oil product.<ref>Johns, M. R., J. E. Johns, and V. Rudolph. 1992. "Steam distillation of tea tree (Melaleuca alternifolia) oil." ''J. Sci. Food Agric.'' 58:49-53</ref>
Among over 98 [[chemical compound|compounds]] contained in the oil, [[terpinen-4-ol]] is responsible for most of the antimicrobial actions.
Although tea tree oil is normally extracted from ''[[Melaleuca alternifolia]]'' commercially, it can also be extracted from ''[[Melaleuca dissitiflora]]'' and ''[[Melaleuca linariifolia]].'' Tea tree oil is defined by international standard [[International Organization for Standardization|ISO]] 4730 (2004) ("Oil of ''Melaleuca'', Terpinen-4-ol type"), which specifies levels of 15 components which are needed to define the oil as "tea tree oil."
==Composition==
{| class="wikitable"
! Compound
! Tea tree oil ISO 4730 (2004) Concentration [%]
|-
|[[terpinen-4-ol]] || align="center" | 30-48
|-
|[[terpinene|γ-terpinene]] || align="center" | 10–28
|-
|[[α-terpinene]] || align="center" | 5–13
|-
|[[1,8-Cineole]] || align="center" | 0–15
|-
|[[α-terpinolene]] || align="center" | 1.5–5
|-
|[[α-terpineol]] || align="center" | 1.5–8
|-
|[[α-pinene]] || align="center" | 1–6
|-
|[[p-cymene]] || align="center" | 0.5–8
|}
== Medicinal use ==
Tea tree oil has been recognized as a potent [[antiseptic]] in [[Australia]] anecdotally for much longer than there has been scientific evidence. However, recent studies support a role for tea tree oil in skin care and treatment of various ailments.
Tea tree oil is a known [[Antifungal medication|antifungal]] agent, effective ''[[in vitro]]'' against multiple [[dermatophyte]]s found on the skin.<ref>{{cite journal | author=Nenoff P, Haustein UF, Brandt W | title=Antifungal activity of the essential oil of Melaleuca alternifolia (tea tree oil) against pathogenic fungi in vitro | journal=Skin Pharmacol. | year=1996 | pages=388–94 | volume=9 | issue=6 | pmid=9055360}}</ref> ''[[In vivo]]'', shampoo with 5% tea tree oil has been shown to be an effective treatment for [[dandruff]] due to its ability to treat [[Malassezia furfur]], the most common cause of the condition.<ref>{{cite journal | author=Satchell AC, Saurajen A, Bell C, Barnetson RS | title=Treatment of dandruff with 5% tea tree oil shampoo | journal=J Am Acad Dermatol. | year=2002 | pages=852–5 | volume=47 | issue=6 | pmid=12451368 | doi=10.1067/mjd.2002.122734}}</ref>
It is also effective in treating the eye ailment, blepharitis.{{Fact|date=July 2008}}
Tea Tree Oil is used medically as well as in cosmetic products.
Effectiveness of topical tea tree oil preparations for [[Candidiasis]] is supported by their ability to kill [[Candida (genus)|Candida]] ''in vitro.''<ref>{{cite journal | author=Hammer K, Carson C, Riley T | title=In-vitro activity of essential oils, in particular Melaleuca alternifolia (tea tree) oil and tea tree oil products, against Candida spp | journal=J Antimicrob Chemother | volume=42 | issue=5 | pages=591–5 | year=1998 | pmid=9848442 | doi=10.1093/jac/42.5.591}}</ref>
In the treatment of moderate [[Acne vulgaris|acne]], topical application of 5% tea tree oil has shown an effect comparable to 5% [[benzoyl peroxide]], albeit with slower onset of action.<ref>{{cite journal | author=Bassett I, Pannowitz D, Barnetson R | title=A comparative study of tea-tree oil versus benzoylperoxide in the treatment of acne | journal=Med J Aust | volume=153 | issue=8 | pages=455–8 | year=1990 | pmid=2145499}}</ref> Another study in 2007 5% strength gel was compared against a placebo, with statistically significant results.<ref>[http://www.level1diet.com/research/id/852871 The efficacy of 5% topical tea tree oil gel in mild to moderate acne vulgaris: a randomized, double-blind placebo-controlled study<!-- Bot generated title -->]</ref>
Tea tree oil is also effective for treating insect bites,<ref>[http://www.teatreeoiluses.com/ TeaTreeOilUses.com]</ref> boils and minor wounds.<ref>{{cite book | author=Clark, S. T.| title=The Great Melaleuca Fact Book | pages=54 | year=1994 }}</ref> It has also been known to help soothe sunburn,<ref>[http://www.webmd.com/skin-problems-and-treatments/acne/features/tea-tree-oil-treats-skin-problems WebMD.com]</ref><ref>[http://www.auracacia.com/auracacia/aclearn/eo_teatree.html AuraCacia.com]</ref> poison ivy,<ref>[http://www.health911.com/remedies/rem_pois.htm Health911.com]</ref><ref>[http://www.healthychild.com/first-aid-summer.htm HealthyChild.com]</ref> ear infections,<ref>[http://www.innvista.com/health/herbs/teatree.htm InnVista.com]</ref> and bee stings.<ref>[http://www.rd.com/1563/article.html RD.com]</ref><ref>{{cite book | author=Clark, S. T.| title=The Great Melaleuca Fact Book | year=1994 }}</ref>
Diluted solutions of tea tree oil are sold as remedies which claim to treat bacterial and fungal infection in pet fish.
Toothpastes and mouthwashes containing tea tree oil are shown to be effective for a number of oral problems. Some of these include [[halitosis]] (bad breath), gum disease, and [[canker]] sores.<ref>{{cite journal | author=Shemesh, A. and Mayo, W.L.| title=A Natural Antiseptic and Fungicide | journal=International Journal of Alternative and Complementary Medicine | year=1991 }}</ref><ref>{{cite journal | author=Walsh, L.J. and Longstaff, J. | title=The Antimicrobial Effects of an Essential Oil on Selected Oral Pathogens | journal=Periodontology | volume=8 | pages=11–15 | year=1987 | doi=10.1111/j.1600-0757.1995.tb00041.x }}</ref><ref>{{cite journal | author=Shapiro, S., Meier, A. and Guggenheim, B.| title=The Anti-microbial Activity of Essential Oils and Essential Oil Components Towards Oral Bacteria," | journal=Oral Microbiology Immunology | place=Denmark |volume=9:4 | pages=202–208| year=1994| doi=10.1111/j.1399-302X.1994.tb00059.x }}</ref>
There is some limited research that has shown that tea tree oil may have topical anti-viral activity, especially with the [[Herpes]] virus (cold sores, [[chicken pox]] and [[shingles]] blisters, warts, etc.)<ref>{{cite journal | author=Bishop, C.D. | title=Anti-viral Activity of the Essential Oil of Melaleuca alternifolia | journal=Journal of Essential Oil Research | pages=641–644| year=1995 }}</ref>
== Safety ==
Melaleuca oil is used almost exclusively externally.
Data on oral use of tea tree oil in humans in large quantities is sparse aside from several anecdotal reports of side effects following oral ingestion.<ref>{{cite journal | author=Morris M, Donoghue A, Markowitz J, Osterhoudt K | title=Ingestion of tea tree oil (Melaleuca oil) by a 4-year-old boy | journal=Pediatr Emerg Care | volume=19 | issue=3 | pages=169–71 | year=2003 | pmid=12813303 | doi=10.1097/01.pec.0000081241.98249.7b}}</ref> Symptoms may include [[ataxia]] and [[drowsiness]].
A small number of people experience allergic contact dermatitis as a reaction to dermal contact with tea tree oil. In an Italian study of 725 consecutive patients, patients were patch tested with undiluted, 1% and 0.1% Tea Tree Oil. For undiluted tea tree oil, nearly 6% of the patients observed positive reactions of skin irritation. Only 1 of 725 patients observed a positive reaction of skin irritation with the 1% dilution. None of the 725 patients observed adverse reactions with the 0.1% dilution.<ref>{{cite journal | author=Lisi P, Melingi L, Pigatto P, Ayala F, Suppa F, Foti C, Angelini G| title=Prevalenza della sensibilizzazione all´olio essenziale di Melaleuca | journal=Ann Ital Dermatol Allergol 54 | pages=141–144 | year=2000 }}</ref> Allergic reactions may be due to the various oxidation products that are formed by exposure of the oil to light and/or air.<ref>{{cite journal | author=Hammer KA, Carson CF, Riley TV, Nielsen JB| title=A review of the toxicity of Melaleuca alternifolia (tea tree) oil | journal=Food Chemistry Toxicology | pages=616–625 | month=May |year=2006 | volume=44 | doi=10.1016/j.fct.2005.09.001}}</ref><ref>{{cite journal | author=Rutherford T, Nixon R, Tam M, Tate B| title=Allergy to tea tree oil: retrospective review of 41 cases with positive patch tests over 4.5 years | journal=Australasian Journal of Dermatology | pages=83–87 | month=May |year=2007 | volume=48 | doi=10.1111/j.1440-0960.2007.00341.x}}</ref>
External application of undiluted tea tree oil and/or at inappropriate high doses has been associated with toxicity, including death, in cats and other animals.<ref>{{cite journal | author=Bischoff, K. and Guale, F.| title=Australian Tea Tree (Melaleuca alternifolia) Oil Poisoning in Three Purebred Cats | journal=Journal of Veterinary Diagnostic Investigation | volume=10 | year=1998 | pages=208 }}</ref><ref>{{cite journal | author=Villar D, Knight MJ, Hansen SR, Buck WB | title=Toxicity of melaleuca oil and related essential oils applied topically on dogs and cats | journal=Veterinary Human Toxicology | month=April | year=1998 | pps=139-142}}</ref><ref>{{cite journal | author=Small, B.E.J. | title=Tea Tree Oil | journal=Australian Journal of Experimental Agriculture and Animal Husbandry | year=1981 | doi=10.1071/EA9810439 | volume=21 | pages=439 }}</ref>
A disputed case study reported in The New England Journal of Medicine concluded that "repeated topical exposure to lavender and tea tree oils probably caused prepubertal [[gynecomastia]]" (abnormal breast development) in three young boys.<ref>{{cite journal |author=Henley D, Lipson N, Korach K, Bloch C |title=Prepubertal gynecomastia linked to lavender and tea tree oils |journal=N Engl J Med |volume=356 |issue=5 |pages=479–85 |year=2007 |pmid=17267908 |doi=10.1056/NEJMoa064725}}</ref> The study involved just three individuals and found lavender to be the only common ingredient used by the boys in the study. While all three cases involved the use of products containing [[lavender oil]] as an ingredient, only one boy also used products containing tea tree oil. In all cases, the prepubertal gynecomastia reversed after several months. Use of the products containing lavender and tea tree oils were also discontinued during this time. In the same paper, results from cell culture assays indicated that both essential oils exhibit weak estrogenic and antiandrogenic properties ''in vitro'', (i.e. in a test tube, an artificial environment outside the living human organism) but no tests were conducted in vivo. Researchers also indicated that other components in these products may also have contributed to the gynecomastia, or that genetics might play a role. Researchers also noted that estrogenic or antiandrogenic activities have also been reported for some other commonly used essential oils as well as some foods such as almonds and peanuts, but cited no associated cases of prepubertal gynecomastia.<ref>{{cite journal |author=Henley D, Lipson N, Korach K, Bloch C |title=Prepubertal gynecomastia linked to lavender and tea tree oils |journal=N Engl J Med |volume=356 |issue=5 |pages=479–85 |year=2007 |pmid=17267908 |doi=10.1056/NEJMoa064725}}</ref> Others have cast doubt on the conclusions of the article and dismissed the study as having used "poor methodology".<ref>[http://www.cosmeticsandtoiletries.com/newsletter/6114476.html Cosmetics and Toiletries Magazine]</ref><ref>[http://www.soap-wire.com/2007/02/essential_oils_.html Essential Oils Not Linked to Breast Growth in Young Boys]</ref><ref>[http://www.personalcarecouncil.org/Template.cfm?Section=CTFA_News&template=/ContentManagement/ContentDisplay.cfm&ContentID=4843 Personal Care Products Council | CTFA Statement on Essential Oils<!-- Bot generated title -->]</ref><ref>http://www.fmafragrance.org/sub_pages/020107henleyresponse.pdf</ref><ref>http://www.naha.org/articles/Tisserand,%20R.%20Gynecomastia2_2007.pdf</ref>
If used in concentrations below 4% or particularly below 1%, tea tree oil may fail to kill bacteria and create an evolutionary pressure which may result in them becoming less sensitive to tea tree oil and even some antibiotics ''in vitro''.<ref>[http://jac.oxfordjournals.org/cgi/content/full/59/1/125 Habituation to sub-lethal concentrations of tea tree oil (Melaleuca alternifolia) is associated with reduced susceptibility to antibiotics in human pathogens]</ref>
Tea tree oil is not recommended for use in the ears.<ref>[http://www.drugdigest.org/DD/PrintablePages/herbMonograph/0,11475,551982,00.html eDrugDigest]</ref>
== References ==
{{reflist|2}}
== External links ==
* [http://www.herbmed.org/Herbs/Herb105.htm HerbMed]
* [http://www.acnecuresecrets.com/Tea_tree_oil_acne_treatment.html Tea Tree Oil as Acne Treatment]
* [http://www.meddent.uwa.edu.au/teatree/ Tea Tree Oil Research Group, University of Western Australia.]
{{Acne Agents}}
{{Antifungals}}
[[Category:Essential oils]]
[[Category:Antiseptics]]
[[Category:Antifungals]]
[[Category:Skin care]]
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