Tea Tree Oil

(Melaleuca altemifolia)

Michael Wiggins and Chris Sugg

GENERAL DESCRIPTION

• tea tree is native to only northeast coastal region of New South Wales, Australia
• small tree, leaves are used medicinally
• more than fifty members of Melaleuca genus, Melaleuca altemifolia most researched

CHEMICAL COMPOSITION

• leaves contain 1.8 % oil (obtained by steam distillation)
• oil, contains more than 48 compounds
  • main constituents:
    • 1-terpinen-4-oi
    • 1,8-cineol
    • gamma-terpinene
    • p-cymene
    • other terpenes

• Australian Standard for "Oil of Melaleuca"
  • minimum terpinen-4-ol content of 30%
  • maximum 1,8-cineol content of 15%

HISTORY AND FOLK USE

• Bundjalung aborigines of northern new South Wales
  • viewed lagoon where tea tree leaves fell and decayed for hundreds of years as having tremendous healing properties
• first report of medicinal use: Medical Journal of Australia (1930)
  • Sydney surgeon used: solution of tea tree oil to clean wound
  • ". . . it dissolved pus and left the surface of infected wounds clean so that its germicidal action became more effective without any apparent damage to the tissues ... most efficient germicides destroy tissues as well as bacteria...."
• World War II - tea tree oil issued to soldiers to use as a disinfectant

PHARMACOLOGY

• antiseptic - considered by many to be the ideal skin disinfectant
• antifungal
• good penetration, lack of irritation
• Effective against:
  • Candida albicans
  • Propionibactenum acnes
  • Pseudomonas aeruginosa
  • Staphylococcus aureus
  • Streptococcus pyrogenes
  • Trichomonas vaginalis
  • Trichophyton mentagrophytes

CLINICAL APPLICATIONS AND DOSAGE

• Skin infections:
  • broad-spectrum antiseptic
  • mixes with sebaceous secretions and penetrates epidermis
  • apply oil two to three times per day
• Acne:
  • alliterative to benzoyl peroxide
  • less side effects (dryness, redness, pruritus, stinging, burning)
  • 5% tea tree oil gel applied daily

• Common Foot Problems:
  • tinea pedis (athlete's foot) foot irritation
  • bromhidrosis (severely foul-smelling feet)
  • 8% tea tree oil emollient massaged into feet daily
• Fungal Nail Infection
  • 100% tea tree oil twice daily
  • improvement in nail appearance and symptoms (with long-term use)
• Vaginal Infections:
  • germicidal activity versus Candida albicans and Trichomonas vaginalis
  • 40% tea tree oil solution emulsified with isopropyl alcohol and water
  • used tampon saturated with this tea tree oil solution (once wkly for 4 to 6 wks)
  • for treatment of cervicitis and chronic endocervicitis
  • daily vaginal douches (1 quart water with 0.4% tea tree oil) prescribed
  • for treatment of trichomonas and candidiasis
  • no irritation, burning, or other side effects noted

• Cold Sores:
  • mix essential oil with 10 times its volume of carrier oil
  • dab on affected area as soon as developing cold sore starts to tingle
• Nits:
  • eggs of head lice on the hair
  • put a few drops of oil on a fine comb and comb hair well
  • OR...add 5-10 drops of oil to shampoo or hair rinse and repeat daily

TOXICITY

• extremely safe for topical use
• oral ingestion not recommended

• limited evidence that oral ingestion causes CNS depression
  • 23-month old boy
    • confused
    • unable to walk
    • ingested less than 10mL of 100% tea tree oil
    • 5 hours following ingestion - patient was fine
  • patient ingested a half tea cup of neat tea tree oil
    • comatose for 12 hours
    • semi-conscious for a further 36 hours

DRUG AND DISEASE INTERACTIONS

• none reported

EVALUATION OF CLINICAL TRIALS

Onychomycosis Study

This was a double-blind, multi-center, randomized controlled trial. The trial included 117 patients with distal subungual onychomycosis proven by culture. Subjects received BID treatments of either 1% clotrimazole solution or 100% tea tree oil for 6 months. The nails were debrided and clinically assessed at 0, 1, 3, and 6 months, with cultures being taken at 0 and 6 months. The subjects also provided their own subjective assessment 3 months after the conclusion of therapy. The pre-treatment characteristics of the group were not significantly different. Following 6 months, the groups had comparable results with similar culture cure rates (CL = 11%, -TT = 18%), as well as similar clinical assessment documenting partial or full n solution of infection (CL = 61%, TT = 60%). Three months later, with the subjective evaluations provided by the patients, about half of each group repor1ed continued improvement (CL = 55%, TT = 564/o). it was determined that while all therapies have high recurrence rates (and this study did not follow-up to determine how many patients had recurrence), these products used topically provide improvement of symptoms and nail appearance.

Acne Study

This study involved 124 patients (60 female, 64 male; age(l 12 to 35 years - median age = 19.7 years) in a single-blind, randomized clinical trial. Patients were initially evaluated for baseline assessments and all met study criteria (e.g., no smoking, no facial hair, no oral contraceptive use, no oral acne therapy or drugs that may cause acne, etc.). Patients received either 5% tea tree oil gel or 5% benzoyl peroxide lotion to be used once daily. Patients were evaluated at the end of 1, 2 and 3 months of therapy by using the counting technique and an assessment of skin tolerance (oiliness, erythema, scaling, pruritis, and dryness). Both treatments were effective in reducing the total number of inflamed and non-inflamed lesions throughout the length of the trial. However, the benzoyl peroxide was significantly better at reducing the number of inflamed lesions throughout the study. Alternatively, tea tree oil had less complaints of unwanted side effects from subjects (79% vs. 44%). The results of this study prove that 5°/O tea tree oil gel is effective in the treatment of acne, but less effective than 5% benzoyl peroxide lotion because of TTO s slower onset of action. It must be kept in mind, however, that 5% TTO gel may be a sub-therapeutic dosage, since most TTO products contain a 100% concentration of TTO

Tea Tree Oil in Treatment of Methicillin-resistant Staph. Aureus

This sought to find an alternative to mupirocin to be used in the prevention of carriage of methicillin-resistant Staphylococcus aureus (MRSA) by hospital staff and patients because of its highly-recognized risk for nosocomial infection. Mupirocin has been very effective in this capacity, but recently mupirocin-resistant MRSA has emerged and this represents a major threat to the ability to control MRSA carriage. All 66 of the isolates of Staphylococcus aureus were tested by disc diffusion and modified broth microdilution methods. All of these isolates were found to be susceptible to tea tree oil (1,8-cineol content = 3.1% and terpirlen-4-ol level = 35.7°MO), 64 of these being MRSA and 33 being mupirocin-resistant MRSA. The minimum inhibitory concentration (MIC) for the 60 Australian isolates was 0.25% and the minimum bactericidal concentration (MBC) was 0.50%. These results, while performed in-vitro, suggest that tea tree oil may be a viable alternative to mupirocin in the prevention of mechanical MRSA spread.

REFERENCES

Bassett IB, et al.: "A comparative study of tea-tree oil versus benzoyl peroxide in the treatment of acne." Med J Aust 153, 455-458, 1990.

Buck DS, Nidorf DM, and Addino JG: "Comparison of two topical preparations for the treatment of onychomycosis: Melaleuca alternifolia (tea tree) oil and clotrimazole." J Fam Pract 38, 601 405, 1994.

Carson CF, Cookson BD, Farrelly HD, Riley 1V. "Susceptibility of methicillin-resistant Staphylococcus aureus to the essential oil of Melaleuca altemifolia." Antimicrobial Chemotherapy 35(3):421 424, 1995 March.

Carson CF, Riley TV. Toxicity of the essential oil of Melaleuca altemifolia or tea tree oil." Journal of Toxicology - Clinical Toxicology. 33(2): 193-194, 1995.

Jacobs MR, Hornfeldt CS. "Melaleuca oil poisoning." Journal of Toxicology Clinical Toxicology. 32(4): 461 464,1994.

Murray MT. The Healing Power of Herbs. Rocklin, CA: Prima Publishing, 1996, pp. 321-326.

Murray MT and Pizorno JE. Encyclopedia of Natural Medicine. Rocklin, CA: Prima Publishing,1991, pp. 532.

Ody, P. The Complete Medicinal Herbal. New York, NY: DK Publishing, Inc.,1993, pp.142-143,144-145, 176-177.