Tea tree oil explained

Tea tree oil, also known as melaleuca oil, is an essential oil with a fresh, camphoraceous odor and a colour that ranges from pale yellow to nearly colourless and clear.[1] [2] It is derived from the leaves of the tea tree, Melaleuca alternifolia, native to southeast Queensland and the northeast coast of New South Wales, Australia. The oil comprises many constituent chemicals, and its composition changes if it is exposed to air and oxidizes. Commercial use of tea tree oil began in the 1920s, pioneered by the entrepreneur Arthur Penfold.

There is little evidence for the effectiveness of tea tree oil in treating mite-infected crusting of eyelids,[3] although some claims of efficacy exist.[4] [5] In traditional medicine, it may be applied topically in low concentrations for skin diseases, although there is little evidence for efficacy.[2] [6] [7] [8]

Tea tree oil is neither a patented product nor an approved drug in the United States,[2] [8] although it is approved as a complementary medicine for aromatherapy in Australia.[9] It is poisonous if consumed by mouth and is unsafe for children.

Uses

Although tea tree oil is claimed to be useful for treating dandruff, acne, lice, herpes, insect bites, scabies, and skin fungal or bacterial infections,[8] [10] insufficient evidence exists to support any of these claims due to the limited quality of research.[2] [7] A 2015 Cochrane review of acne complementary therapies found a single low-quality trial showing benefit on skin lesions compared to placebo.[11]

According to the Committee on Herbal Medicinal Products (CHMP) of the European Medicines Agency, traditional usage suggests that tea tree oil is a possible treatment for "small, superficial wounds, insect bites, and small boils" and that it may reduce itching in minor cases of athlete's foot. The CHMP states that tea tree oil products should not be used on people under 12 years of age.[12]

Tea tree oil is not recommended for treating nail fungus because it is yet to be proven effective,[13] It is not recommended for treating head lice in children because its effectiveness and safety have not been established and it could cause skin irritation or allergic reactions.[14] [15], there is uncertainty regarding the effectiveness of 5-50% tea tree oil as an effective treatment for demodex mite infestations, although products claiming efficacy exist.[16]

Toxicity

Tea tree oil is highly toxic when ingested orally.[2] [7] [17] [18] It may cause drowsiness, confusion, hallucinations, coma, unsteadiness, weakness, vomiting, diarrhea, nausea, blood-cell abnormalities, and severe rashes. It should be kept away from pets and children.[18] It should not be used in or around the mouth.[2] [7] [19]

Application of tea tree oil to the skin can cause an allergic reaction,[2] the potential for which increases as the oil ages and its chemical composition changes.[20] Adverse effects include skin irritation, allergic contact dermatitis, systemic contact dermatitis, linear immunoglobulin A disease, erythema multiforme-like reactions, and systemic hypersensitivity reactions.[10] [21] Allergic reactions may be due to the various oxidation products that are formed by exposure of the oil to light and air.[21] [22] Consequently, oxidized tea tree oil should not be used.[23]

In Australia, tea tree oil is one of the many essential oils causing poisoning, mostly of children. From 2014 to 2018, 749 cases were reported in New South Wales, accounting for 17% of essential oil poisoning incidents.[24]

Hormonal effects

Tea tree oil potentially poses a risk for causing abnormal breast enlargement in men[25] [26] and prepubertal children.[27] [28] A 2018 study by the National Institute of Environmental Health Sciences found four of the constituent chemicals (eucalyptol, 4-terpineol, dipentene, and alpha-terpineol) are endocrine disruptors, raising concerns of potential environmental health impact from the oil.[29]

In animals

In dogs and cats, death[30] [31] or transient signs of toxicity (lasting two to three days), such as lethargy, weakness, incoordination, and muscle tremors, have been reported after external application at high doses.[32]

As a test of toxicity by oral intake, the median lethal dose (LD50) in rats is 1.9–2.4 ml/kg.

Composition and characteristics

Tea tree oil composition,
as per ISO 4730 (2017)
ComponentConcentration
terpinen-4-ol35.0–48.0%
γ-terpinene14–28%
α-terpinene6.0–12.0%
1,8-cineoletraces–10.0%
terpinolene1.5–5.0%
α-terpineol2.0–5.0%
α-pinene1.0–4.0%
p-cymene0.5–8.0%
sabinenetraces–3.5%
limonene0.5–1.5%
aromadendrene0.2–3.0%
ledene0.1–3.0%
globuloltraces–1.0%
viridifloroltraces–1.0%
Tea tree oil is defined by the International Standard ISO 4730 ("Oil of Melaleuca, terpinen-4-ol type"), containing terpinen-4-ol, γ-terpinene, and α-terpinene as about 70% to 90% of whole oil, while p-cymene, terpinolene, α-terpineol, and α-pinene collectively account for some 15% of the oil (table).[1] [6] [8] The oil has been described as colorless to pale yellow[1] [2] having a fresh, camphor-like smell.[33]

Tea tree oil products contain various phytochemicals, among which terpinen-4-ol is the major component.[1] [2] [6] Adverse reactions diminish with lower eucalyptol content.[10]

History and extraction

The name "tea tree" is used for several plants, mostly from Australia and New Zealand, from the family Myrtaceae related to the myrtle. The use of the name probably originated from Captain James Cook's description of one of these shrubs that he used to make an infusion to drink in place of tea.[34]

The commercial tea tree oil industry originated in the 1920s when Australian chemist Arthur Penfold investigated the business potential of a number of native extracted oils; he reported that tea tree oil had promise, as it exhibited antiseptic properties.[35]

Tea tree oil was first extracted from Melaleuca alternifolia in Australia, and this species remains the most important commercially. In the 1970s and 1980s, commercial plantations began to produce large quantities of tea tree oil from M. alternifolia. Many of these plantations are located in New South Wales.[35] Since the 1970s and 80s, the industry has expanded to include several other species for their extracted oil: Melaleuca armillaris and Melaleuca styphelioides in Tunisia and Egypt; Melaleuca leucadendra in Egypt, Malaysia, and Vietnam; Melaleuca acuminata in Tunisia; Melaleuca ericifolia in Egypt; and Melaleuca quinquenervia in the United States (considered an invasive species in Florida[36]).

Similar oils can also be produced by water distillation from Melaleuca linariifolia and Melaleuca dissitiflora.[37] Whereas the availability and nonproprietary nature of tea tree oil would make it – if proved effective – particularly well-suited to a disease such as scabies that affects poor people disproportionately, those same characteristics diminish corporate interest in its development and validation.

See also

Notes and References

  1. Web site: Essential oil of Melaleuca, terpene-4-ol (tea tree oil): ISO 4730: 2017 (E) . International Organization for Standardization (ISO), Geneva, Switzerland . 2 February 2019 . 2017.
  2. Web site: Tea tree oil . Drugs.com . 4 May 2023 . 13 February 2023.
  3. Savla K, Le JT, Pucker AD . Tea tree oil for demodex blepharitis . Cochrane Database of Systematic Reviews . 6 . 6. CD013333 . June 2020 . 32589270 . 7388771 . 10.1002/14651858.CD013333.pub2 . Systematic review.
  4. 3 . Navel . Valentin . Mulliez . Aurélien . Benoist d’Azy . Cédric . Baker . Julien S. . Malecaze . Jean . Chiambaretta . Frédéric . Dutheil . Frédéric . 2019-10-01 . Efficacy of treatments for demodex blepharitis: A systematic review and meta-analysis . The Ocular Surface . 17 . 4 . 655–669 . 10.1016/j.jtos.2019.06.004 . 1542-0124.
  5. Koo . Hyun . Kim . Tae Hyung . Kim . Kyoung Woo . Wee . Sung Wook . Chun . Yeoun Sook . Kim . Jae Chan . 2012-12-01. Ocular Surface Discomfort and Demodex: Effect of Tea Tree Oil Eyelid Scrub in Demodex Blepharitis . Journal of Korean Medical Science . 27 . 12 . 1574–1579 . 10.3346/jkms.2012.27.12.1574 . 1011-8934 . 3524441 . 23255861.
  6. Web site: Opinion on Tea tree oil. SCCP/1155/08 Scientific Committee on Consumer Products. 16 December 2008.
  7. Web site: Tea tree oil. National Center for Complementary and Integrative Health, US National Institutes of Health. 3 May 2023. 1 October 2020.
  8. 4751955. 2016. 3. Thomas. J. Therapeutic Potential of Tea Tree Oil for Scabies. The American Journal of Tropical Medicine and Hygiene. 94. 2. 258–266. Carson. C. F. Peterson. G. M. Walton. S. F. Hammer. K. A. Naunton. M. Davey. R. C. Spelman. T. Dettwiller. P. Kyle. G. Cooper. G. M. Baby. K. E. 10.4269/ajtmh.14-0515. Review. 26787146.
  9. Web site: Summary for ARTG Entry: 79370 Tea Tree Oil, Pure Essential Oil . . 2020. 3 July 2020 .
  10. Pazyar, N . Yaghoobi, R . Bagherani, N . Kazerouni, A . A review of applications of tea tree oil in dermatology . International Journal of Dermatology . July 2013 . 52 . 7 . 784–90 . 22998411 . 10.1111/j.1365-4632.2012.05654.x. 2270233 .
  11. Cao H, Yang G, Wang Y, Liu JP, Smith CA, Luo H, Liu Y . Complementary therapies for acne vulgaris . Cochrane Database Syst Rev . 1 . CD009436 . January 2015 . 1 . 25597924 . 4486007 . 10.1002/14651858.CD009436.pub2 . Systematic Review.
  12. Web site: Committee on Herbal Medicinal Products . 24 November 2014 . Melaleucae aetheroleum .
  13. Halteh P, Scher RK, Lipner SR. Over-the-counter and natural remedies for onychomycosis: do they really work? . Cutis . 2016 . 98 . 5 . E16–E25 . 28040821 .
  14. Web site: National Health Service . Head lice and nits . 10 January 2018 .
  15. 10.1016/j.pedhc.2012.05.004. Advancements in the Treatment of Head Lice in Pediatrics. 2012. Eisenhower. Christine. Farrington. Elizabeth Anne. Journal of Pediatric Health Care. 26. 6. 451–61; quiz 462–4. 23099312.
  16. Savla K, Le JT, Pucker AD . Tea tree oil for Demodex blepharitis . Cochrane Database Syst Rev . 6 . 6. CD013333 . June 2020 . 32589270 . 7388771 . 10.1002/14651858.CD013333.pub2 . Systematic review.
  17. Web site: Tea tree oil . PubChem, US National Library of Medicine . 31 October 2021 . 30 October 2021.
  18. Book: . American Cancer Society Complete Guide to Complementary and Alternative Cancer Therapies . https://archive.org/details/americancancerso0000unse . registration . 2nd . 2009 . 9780944235713 . Russell J, Rovere A . Tea Tree Oil . registration .
  19. Web site: Tea Tree Oil. National Capital Poison Center. 4 December 2013.
  20. de Groot AC, Schmidt E. Tea tree oil: contact allergy and chemical composition. . Contact Dermatitis . 2016 . 75 . 3 . 129–43 . 27173437 . 10.1111/cod.12591 . Review . free .
  21. 616–25 . 10.1016/j.fct.2005.09.001 . A review of the toxicity of Melaleuca alternifolia (tea tree) oil . 2006 . Hammer . K . Carson . C . Riley . T . Nielsen . J . . 44 . 5 . 16243420.
  22. Aberer. W. Contact allergy and medicinal herbs. Journal der Deutschen Dermatologischen Gesellschaft. January 2008. 6. 1. 15–24. 17919303. 10.1111/j.1610-0387.2007.06425.x. 10292505.
  23. Web site: The Effectiveness and Safety of Australian Tea Tree Oil. Australian Government - Rural Industries and Development Corporation. https://web.archive.org/web/20180927165036/https://agrifutures.infoservices.com.au/downloads/07-143. September 27, 2018. 26 February 2014.
  24. Lee KA, Harnett JE, Cairns R. Essential oil exposures in Australia: analysis of cases reported to the NSW Poisons Information Centre . Medical Journal of Australia . 2019 . 212 . 3 . 132–133 . 0025-729X . 10.5694/mja2.50403 . 31709543 . free .
  25. Web site: Breast enlargement in males . Medline Plus . US National Library of Medicine . 15 November 2015 .
  26. Web site: Endocrine Society . Gynecomastia . May 2018 .
  27. Poon SW, Siu KK, Tsang AM . Isoniazid-induced gynaecomastia: report of a paediatric case and review of literature . BMC Endocr Disord . 20 . 1 . 160 . October 2020 . 33109161 . 7590456 . 10.1186/s12902-020-00639-9 . Review . free .
  28. Restrepo R, Cervantes LF, Swirsky AM, Diaz A . Breast development in pediatric patients from birth to puberty: physiology, pathology and imaging correlation . Pediatr Radiol . 51 . 11 . 1959–1969 . October 2021 . 34236480 . 10.1007/s00247-021-05099-4 . 235767694 . Review.
  29. Web site: Endocrine Society . Chemicals in lavender and tea tree oil appear to be hormone disruptors . 19 March 2018 .
  30. Web site: Tea Tree Oil and Dogs, Tea Tree Oil and Cats . Petpoisonhelpline.com . December 13, 2012.
  31. Web site: Tea Tree Oil Toxicity . Veterinarywatch . December 13, 2012 . dead . https://web.archive.org/web/20130111031504/http://www.veterinarywatch.com/Abstract-tea-tree-oil.htm . January 11, 2013 .
  32. Villar. D. Knight, MJ . Hansen, SR . Buck, WB . Toxicity of melaleuca oil and related essential oils applied topically on dogs and cats. Veterinary and Human Toxicology. April 1994. 36. 2. 139–42. 8197716.
  33. Book: Billee Sharp. Lemons and Lavender: The Eco Guide to Better Homekeeping. 18 September 2013. Cleis Press. 978-1-936740-11-6. 43–.
  34. Web site: Melaleuca alternifolia . June 23, 2023 . The University of Arizona.
  35. 10.1128/CMR.19.1.50-62.2006. Melaleuca alternifolia (Tea Tree) Oil: A Review of Antimicrobial and Other Medicinal Properties. 2006. Carson. C. F.. Hammer. K. A.. Riley. T. V.. Clinical Microbiology Reviews. 19. 50–62. 16418522. 1. 1360273.
  36. Web site: Melaleuca quinquenervia . June 23, 2023 . University of Florida.
  37. Antimicrobial activity of Melaleuca sp. oil against clinical isolates of antibiotics resistant Staphylococcus aureus. Sávia Perina Portilho Falci. Acta Cirurgica Brasileira. 30. 7. July 2015. 10.1590/S0102-865020150060000005. 26108028. 401–6. free.

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