Plant Part Used
Volatile oil
Active Constituents
Volatile oils. (1)
[span class=alert]This section is a list of chemical entities identified in this dietary supplement to possess pharmacological activity. This list does not imply that other, yet unidentified, constituents do not influence the pharmacological activity of this dietary supplement nor does it imply that any one constituent possesses greater influence on the overall pharmacological effect of this dietary supplement.[/span]
Introduction
Melaleuca alternifolia, or tea tree, is a small tree native to only one area of the world, the northeast coastal region of New South Wales, Australia. The leaves of tea tree were used by the early settlers of Australia to make tea, hence the name “tea tree.” Oil from the leaves has been used medicinally for centuries and was first reported to the western world by the crew of Captain James Cook’s expeditions in the 1700s. The plant gained widespread notoriety because of claims of its ability to treat various problems including skin ailments, cuts, and burns. As early as 1930, the antiseptic properties of the plant were recognized by the Australian dental profession.(2)
During World War II, tea tree oil was issued worldwide to soldiers for use as a disinfectant. The Australian Army exempted leaf cutters from military service in order to maintain production of tea tree oil.(3) Also, during World War II, tea tree oil was routinely incorporated into machine “cutting” oils in Australian ammunition factories, where it was said to have reduced the number of infections resulting from abrasions on the hands of workers caused by metal filings. The production of tea tree oil in Australia was deemed an “essential” industry during WW II.
Tea tree oil has historically been used in many conditions including the treatment of acne, aphthous stomatitis, tinea pedis, boils, burns, carbuncles, corns, gingivitis, herpes, empyema, impetigo, infections of the nail bed, insect bites, lice, mouth ulcers, pharyngitis, psoriasis, root canal treatment, ringworm, sinus infections, skin and vaginal infections, thrush, and tonsillitis – a literal panacea for topical infectious conditions.(32)
Dosage Info
Dosage Range
Topically: Apply diluted tea tree oil to affected area 3-4 times daily. Topical oil products to infected areas as needed. Tea tree oil may be incorporated into ointments, creams, gels and shampoos. Vaginal use may require a suppository product.
Oral: Dilute 5-10 drops of undiluted oil in cup of water, gargle, and expectorate.
Most Common Dosage
Topically: Apply diluted tea tree oil to affected areas 3-4 times daily. Tea tree oil may be incorporated into ointments, creams, gels and shampoos. Vaginal use may require a suppository product.
Oral: Dilute 5-10 drops of undiluted oil in cup of water, gargle, and expectorate.
Standardization
[span class=doc]Standardization represents the complete body of information and controls that serve to enhance the batch to batch consistency of a botanical product, including but not limited to the presence of a marker compound at a defined level or within a defined range.[/span]
The Australian standard (AS 2782-1985) for “Oil of Melaleuca (Terpinen-4-ol type)” sets a minimum content of terpinen-4-ol between 30-48% and a maximum 1,8-cineol content of 15%.(3)
Uses
Frequently Reported Uses
- Antibacterial
- Antifungal
- Antiviral
- Acne
- Tinea pedis (Athlete’s foot)
- Cuts
- Skin Conditions
- Wound Healing Agent
- Gingivitis
- Periodontal Disease
Other Reported Uses
- Vaginal Candidiasis
- Warts (HPV)
Toxicities & Precautions
General
For External Use Only.(33) The human skin penetration of tea tree oil is limited; however internal use may cause toxicity.(34) Toxicity has developed with internal use of tea tree oil. One report describes a 17 month old male who ingested less than 10ml of the oil and developed ataxia and drowsiness.(4) Another report describes a 23 month old boy who also ingested approximately 10ml of tea tree oil and experienced difficulty walking and confusion.(5) Supportive care for volatile oil poisoning is necessary – do NOT induce vomiting.
Allergy
Contact dermatitis may develop in sensitive individuals.(6),(7) A recent case report describes extensive erythema multiforme-like reaction due to tea tree oil application.(8) An Australian retrospective review found allergy to tea tree oil in 2320 individuals was 1.8% when using patch-test.(35) Discontinue use if rash or skin sensitivity develops.
Side Effects
Although tea tree oil shows promise as an effective treatment against a number of micro-organisms commonly associated with otitis externa and otitis media, high concentrations of tea tree oil have demonstrated some ototoxicity to the high-frequency region of the cochlea.(9)
There has been a case report of tea tree oil mixed with lavender oil and applied topically as a shampoo leading to gynecomastia in a 10 year old boy. An in vitro study confirmed that tea tree oil has weak estrogenic and antiandrogenic activity which man contribute to imbalances in hormones in sensitive individuals.(36)
Pharmacology
General Skin Infections: The therapeutic use of tea tree oil is largely based on its antiseptic and antifungal properties. This claim is supported by its efficacy against a wide range of organisms in laboratory studies including Candida albicans, Propionibacterium acnes, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermis, Streptococcus pyogenes, Trichomonas vaginalis, and Trichomonas mentagrophytes, influenza A/PR/8 virus subtype H1N1.(10),(11),(12),(37) The ability of tea tree oil to disrupt the permeability barrier of cell membrane structures and the accompanying loss of chemosmotic control is the most likely source of its lethal action at minimum inhibitory levels.(13) Reports suggest that P. aeruginosa is less sensitive than other bacteria listed due to its outer membrane, and tolerance may develop to the oil in these cases.(10)
In vitro studies have determined that methicillin-resistant Staphylococcus aureus (MRSA) is susceptible to tea tree oil.(14),(38) MRSA is a common pathogen recognized in hard to treat nosocomial (hospital acquired) infections. In the human study, all 60 MRSA subjects tested against tea tree oil by the disc diffusion method and modified broth microdilution were susceptible, with MICs and MBCs of 0.25% and 0.5%, respectively. Also tested were mupirocin-susceptible and mupirocin-resistant MRSA, and there was no difference in tea tree oil susceptibility between the two. The universal susceptibility to tea tree oil of all MRSA isolated tested, including those who were mupirocin-resistant, represents a significant result which may find application in the control of MRSA. Another human study tested a combination of a 4% tea tree oil nasal ointment and 5% tea tree oil body wash compared with a standard 2% mupirocin nasal ointment and triclosan body wash for the eradication of methicillin-resistant Staphylococcus aureus carriage.(15) The tea tree oil combination appeared to perform better than the standard combination, although the difference was not statistically significant due to the small number of patients. Researchers found that treatment with tree tea oil was effective, safe and well tolerated in patients with MRSA.(16) Another report also describes the use of tea tree oil in the hospital and community setting to help prevent the spread of multi-resistant bacteria such as MRSA, glycopeptide-resistant enterococci, aminoglycoside-resistant Klebsiella, Pseudomonas aeruginosa and Stenotrophomonas maltophilia.(17)
An in vitro study found synergism between tea tree oil plus the aminoglycoside tobramycin as agents against Staph. aureus and E. coli.(39) Other studies also report synergism when using tea tree oil in combination with antibiotics.(40),(41)
Data indicates that some essential oils are active against Candida spp., suggesting that they may be useful in the topical treatment of superficial candida infections.(18),(42) Laboratory tests on three intravaginal tea tree oil products reported these products to have MICs and minimum fungicidal concentrations comparable to those of non-formulated tea tree oil, indicating that the tea tree oil contained in these products had retained its anti-candidal activity.(19)
Tinea Pedis
Tea tree oil was reported effective in tinea pedis.(20) One hundred and four patients completed a randomized, double-blind trial to evaluate the efficacy of 10% w/w tea tree oil cream compared with 1% tolnaftate and placebo creams in the treatment of this infection. Results of this study reported that tea tree oil cream (10% w/w) appeared to reduce the symptomatology of tinea pedis as effectively as tolnaftate 1%, but are no more effective than placebo in achieving a mycological cure.
Onychomycosis: A tea tree oil preparation was used in a double-blind study in the treatment of onychomycosis.(21) Onychomycosis is the most frequent cause of nail disease, ranging from 2-13% of the population.(22) This study compared the use of either a 1% clotrimazole or 100% tea tree oil applied topically twice daily to 117 patients over a six month period. The two treatment groups were comparable based on culture cure (clotrimazole = 11%; tea tree = 18%) and clinical assessment documenting partial or full resolution (clotrimazole = 61%; tea tree = 60%). Three months later, about one-half of each group reported continued improvement or resolution (clotrimazole = 55%; tea tree = 56%). This study reports that topical tea tree oil may be effective in treating onychomycosis with effectiveness comparable to systemic therapies such as itraconazole. Another more recent study reported that a mixture of 2% butenafine and 5% tea tree oil in a cream base was effective in managing onychomycosis.(23)
Acne: Human studies have reported that tea tree oil application topically (5% solution) is effective for mild to moderate acne vulgaris.(43) A study compared the use of topical tea tree oil (5% gel) with benzoyl peroxide (5% gel) in the treatment of mild to moderate acne.(24) The results of this study reported that both 5% tea-tree oil and 5% benzoyl peroxide had a significant effect in ameliorating the patients’ acne by reducing the number of inflamed and non-inflamed lesions (open and closed comedones), although the onset of action in the case of tea-tree oil was slower. Encouragingly, patients treated with tea-tree oil experienced fewer side effects.
Vaginal Infections: As stated above, tea tree oil has demonstrated germicidal activity against a number of common vaginal pathogens and opportunistic organisms including Trichomonas vaginalis and Candida albicans.(25),(26) A 40% solution of tea tree oil emulsified with isopropyl alcohol was used in the study and applied to a tampon that was inserted into the vagina where it remained for 24 hours. This study reported the preparation to be effective in the treatment of cervicitis, chronic endocervicitis, trichomonal vaginitis, and vaginal candidiasis. Another study has reported the use of tea tree vaginal suppositories effective in the treatment of vaginal candidiasis.(27) Tea tree oil can be compounded in a suppository base such as cocoa butter (at a percentage of 2%) for vaginal use. However, due to the potential problem of topical irritation using tea tree oil in some individuals, testing of sensitivity to the oil should be performed prior to initiating vaginal therapy.(28)
Burns: A recent study was undertaken to investigate the cooling and healing effect of a proprietary tea tree oil product (Melaleuca alternifolia Hydrogel) as a coolant following application onto a fresh deep partial thickness hot water burn in a porcine model.(29) Clinical and histological assessment at 21 days indicated more rapid healing in both the tea tree oil hydrogel product and also water-cooled burns compared with the untreated controls. Effective cooling of the burn wound and an increased rate of wound healing was achieved by both repeated tap water compresses and by immediate or delayed application of the tea tree oil hydrogel product. The authors concluded that cooling is an effective means to reduce tissue damage and increase wound healing.
An in vitro study of a proprietary product (Burnaid, a sorbalene-based cream containing 40 mg/g of tea tree oil and 1 mg/g of triclosan) was conducted to determine its effectiveness against Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, commonly seen pathogens in burn victims.(30) There was no activity against E. faecalis or P. aeruginosa, and the authors suggested that in view of the findings and literature indicating the cytotoxicity of tea tree oil against human fibroblasts and epithelial cells, it is recommended that this product should not be used on burn wounds.
Other Uses: The ability of tea tree oil to reduce the production in vitro of tumour necrosis factor-alpha (TNFalpha), interleukin (IL)-1beta, IL-8, IL-10 and prostaglandin E2 (PGE2) by lipopolysaccharide (LPS)-activated human peripheral blood monocytes was recently studied.(31) The water soluble components of tea tree oil at concentrations equivalent to 0.125% significantly suppressed LPS-induced production of TNFalpha, IL-1beta and IL-10 (by approximately 50%) and PGE2 (by approximately 30%) after 40 hours. Gas chromatography /mass spectrometry identified terpinen-4-ol (42 %), a-terpineol (3 %) and 1,8-cineole (2%, respectively, of tea tree oil) as the water soluble components of tea tree oil. When these components were examined individually, only terpinen-4-ol suppressed the production after 40 h of TNFalpha, IL-1beta, IL-8, IL-10 and PGE2 by LPS-activated monocytes. The authors concluded that the water-soluble components of tea tree oil may suppress pro-inflammatory mediator production by activated human monocytes. Induction of necrosis and cell cycle arrest in various cancer cell lines by tea tree oil has also been reported in in vitro studies.(44) Tea tree oil’s antifungal activity may be useful in oral candidiasis in immunocompromised patients including cancer and HIV/AIDs.(45) Tea tree oil has also been reported in an In vitro study to have anti-inflammatory effects mediated through antioxidant activity and the ability to decrease inflammatory cytokines.(46)
Tea tree oil application was also reported to be effective in treating hand warts (HPV) in a patient after 12 days of therapy.(47)
References
- Mennie A. An essential and ancient oil. Nurs Times. Nov1997;93(47):31-2.
- Penfold AR, et al. Some notes on the Essential oil of M. alternifolia. Aust J Dent. 1930;417-418.
- Altman PM. Australian tea tree oil. Australian J Pharmacy. 1988;69:276-78.
- View Abstract: Del Beccaro MA. Melaleuca oil poisoning in a 17-month-old. Vet Hum Toxicol. Dec1995;37(6):557-8.
- View Abstract: Jacobs MR, et al. Melaleuca oil poisoning. J Toxicol Clin Toxicol. 1994;32(4):461-4.
- View Abstract: Knight TE, et al. Melaleuca oil (tea tree oil) dermatitis. J Am Acad Dermatol. Mar1994;30(3):423-7.
- Greig JE, et al. Allergic contact dermatitis following use of a tea tree oil hand-wash not due to tea tree oil. Contact Dermatitis. Dec1999;41(6):354-5.
- View Abstract: Khanna M, Qasem K, Sasseville D. Allergic Contact Dermatitis to Tea Tree Oil with Erythema Multiforme-like ID Reaction. Am J Contact Dermat. Dec2000;11(4):238-42.
- View Abstract: Zhang SY, Robertson D. A Study of Tea Tree Oil Ototoxicity. Audiol Neurootol. Mar2000;5(2):64-8.
- View Abstract: Mann CM, et al. The outer membrane of pseudomonas aeruginosa NCTC 6749 contributes to its tolerance to the essential oil of melaleuca alternifolia. Lett Appl Microbiol. Apr2000;30(4):294-7.
- Carson CF, et al. Efficacy and safety of tea tree oil as a topical antimicrobial agent. J Hosp Infect. Nov1998;40(3):175-8.
- View Abstract: Concha JM, Moore LS, Holloway WJ. 1998 William J. Stickel Bronze Award. Antifungal Activity of Melaleuca alternifolia (Tea-tree) Oil Against Various Pathogenic Organisms. J Am Podiatr Med Assoc. Oct1998;88(10):489-92.
- View Abstract: Cox SD, et al. The mode of antimicrobial action of the essential oil of Melaleuca alternifolia (tea tree oil). J Appl Microbiol. Jan2000;88(1):170-5.
- View Abstract: Carson CF, et al. Susceptibility of methicillin-resistant Staphylococcus aureus to the essential oil of Melaleuca alternifolia. J Antimicrob Chemother. Mar1995;35(3):421-4.
- View Abstract: Caelli M, Porteous J, Carson CF, et al. Tea Tree Oil as an Alternative Topical Decolonization Agent for Methicillin-resistant Staphylococcus aureus. J Hosp Infect. Nov2000;46(3):236-7.
- View Abstract: Dryden MS, Dailly S, Crouch M. A randomized, controlled trial of tea tree topical preparations versus a standard topical regimen for the clearance of MRSA colonization. J Hosp Infect. Apr2004;56(4):283-6.
- View Abstract: May J, et al. Time-kill studies of tea tree oils on clinical isolates. J Antimicrob Chemother. May2000;45(5):639-643.
- View Abstract: Nenoff P, et al. Antifungal activity of the essential oil of Melaleuca alternifolia (tea tree oil) against pathogenic fungi in vitro. Skin Pharmacol. 1996;9(6):388-94.
- View Abstract: Hammer KA, et al. In-vitro activity of essential oils, in particular Melaleuca alternifolia (tea tree) oil and tea tree oil products, against Candida spp. J Antimicrob Chemother. Nov1998;42(5):591-5.
- View Abstract: Tong MM, et al. Tea tree oil in the treatment of tinea pedis. Australas J Dermatol. 1992;33(3):145-9.
- View Abstract: Buck DS, et al. Comparison of two topical preparations for the treatment of onychomycosis: Melaleuca alternifolia (tea tree) oil and clotrimazole. J Fam Pract. Jun1994;38(6):601-5.
- Andre J, et al. Onychomycosis. Int J Dermatol. 1987;26:481-90.
- View Abstract: Syed TA, et al. Treatment of toenail onychomycosis with 2% butenafine and 5% Melaleuca alternifolia (tea tree) oil in cream. Trop Med Int Health. Apr1999;4(4):284-87.
- View Abstract: Bassett IB, et al. A comparative study of tea-tree oil versus benzoylperoxide in the treatment of acne. Med J Aust. Oct1990;153(8):455-8.
- Pena EF. M. alternifolia oil, uses for trichomonal vaginitis and other vaginal infections. Ob Gynecol. 1962;19:793-95.
- Hammer KA, Carson CF, Riley TV. In Vitro Susceptibilities of Lactobacilli and Organisms Associated with Bacterial Vaginosis to Melaleuca alternifolia (Tea Tree) Oil. Antimicrob Agents Chemother. Jan1999;43(1):196.
- Belaiche P. Treatment of vaginal infections of Candida albicans with the esential oil of Melaleuca alternifolia. Phytotherapie. 1985:15.
- Wolner-Hanssen P, Sjoberg I. Warning Against a Fashionable Cure for Vulvovaginitis. Tea Tree Oil May Substitute Candida Itching with Allergy Itching. Lakartidningen. Jul1998;95(30-31):3309-10.
- View Abstract: Jandera V, Hudson DA, de Wet PM, et al. Cooling the Burn Wound: Evaluation of Different Modalites. Burns. May2000;26(3):265-70.
- View Abstract: Faoagali J, George N, Leditschke JF. Does Tea Tree Oil Have a Place in the Topical Treatment of Burns? Burns. Jun1997;23(4):349-51.
- View Abstract: Hart PH, Brand C, Carson CF, et al. Terpinen-4-ol, the Main Component of the Essential Oil of Melaleuca alternifolia (Tea Tree Oil), Suppresses Inflammatory Mediator Production by Activated Human Monocytes. Inflamm Res. Nov2000;49(11):619-26.
- Carson CF, Hammer KA, Riley TV. Melaleuca alternifolia (Tea Tree) oil: a review of antimicrobial and other medicinal properties. Clin Microbiol Rev. Jan 2006;19(1):50-62. Review.
- Hammer KA, Carson CF, Riley TV, Nielsen JB. A review of the toxicity of Melaleuca alternifolia (tea tree) oil. Food Chem Toxicol. May 2006;44(5):616-625. Epub 2005 Oct 21. Review.
- Cross SE, Russell M, Southwell I, Roberts MS. Human skin penetration of the major components of Australian tea tree oil applied in its pure form and as a 20% solution in vitro. Eur J Pharm Biopharm. May 2008;69(1):214-222. Epub 2007 Oct 5.
- Rutherford T, Nixon R, Tam M, Tate B. Allergy to tea tree oil: retrospective review of 41 cases with positive patch tests over 4.5 years. Australas J Dermatol. May 2007;48(2):83-87. Review.
- Kemper KJ, Romm AJ, Gardiner P. Prepubertal gynecomastia linked to lavender and tea tree oils. N Engl J Med. 14 Jun 2007;356(24):2541-2542; author reply 2543-2544. No abstract available.
- Garozzo A, Timpanaro R, Bisignano B, Furneri PM, Bisignano G, Castro A. In vitro antiviral activity of Melaleuca alternifolia essential oil. Lett Appl Microbiol. Dec 2009;49(6):806-808. Epub 2009 Sep 18.
- Park H, Jang CH, Cho YB, Choi CH. Antibacterial effect of tea-tree oil on methicillin-resistant Staphylococcus aureus biofilm formation of the tympanostomy tube: an in vitro study. In Vivo. Nov-Dec 2007;21(6):1027-1030.
- D’Arrigo M, Ginestra G, Mandalari G, Furneri PM, Bisignano G. Synergism and postantibiotic effect of tobramycin and Melaleuca alternifolia (tea tree) oil against Staphylococcus aureus and Escherichia coli. Phytomedicine. Apr 2010;17(5):317-322. Epub 2009 Aug 20.
- LaPlante KL. In vitro activity of lysostaphin, mupirocin, and tea tree oil against clinical methicillin-resistant Staphylococcus aureus. Diagn Microbiol Infect Dis. Apr 2007;57(4):413-418. Epub 2006 Dec 1.
- Ferrini AM, Mannoni V, Aureli P, et al. Melaleuca alternifolia essential oil possesses potent anti-staphylococcal activity extended to strains resistant to antibiotics. Int J Immunopathol Pharmacol. Jul-Sep 2006;19(3):539-544.
- Terzi V, Morcia C, Faccioli P, Valè G, Tacconi G, Malnati M. In vitro antifungal activity of the tea tree (Melaleuca alternifolia) essential oil and its major components against plant pathogens.Lett Appl Microbiol. Jun 2007;44(6):613-618.
- Enshaieh S, Jooya A, Siadat AH, Iraji F. The efficacy of 5% topical tea tree oil gel in mild to moderate acne vulgaris: a randomized, double-blind placebo-controlled study. Indian J Dermatol Venereol Leprol. Jan-Feb 2007;73(1):22-25.
- Greay SJ, Ireland DJ, Kissick HT, Levy A, Beilharz MW, Riley TV, Carson CF. Induction of necrosis and cell cycle arrest in murine cancer cell lines by Melaleuca alternifolia (tea tree) oil and terpinen-4-ol. Cancer Chemother Pharmacol. Apr 2010;65(5):877-888. Epub 2009 Aug 13.
- Bagg J, Jackson MS, Petrina Sweeney M, Ramage G, Davies AN. Susceptibility to Melaleuca alternifolia (tea tree) oil of yeasts isolated from the mouths of patients with advanced cancer. Oral Oncol. May 2006;42(5):487-492. Epub 2006 Feb 20.
- Caldefie-Chézet F, Fusillier C, Jarde T, Laroye H, Damez M, Vasson MP, Guillot J. Potential anti-inflammatory effects of Melaleuca alternifolia essential oil on human peripheral blood leukocytes. Phytother Res. May 2006;20(5):364-370.
- Millar BC, Moore JE. Successful topical treatment of hand warts in a paediatric patient with tea tree oil (Melaleuca alternifolia). Complement Ther Clin Pract. Nov 2008;14(4):225-227. Epub 2008 Jul 11.
