The bibliographic citations are derived from Medline databases through the National Library of Medicine.
| Activity against head lice |
Hammer KA, Carson
CF, Riley TV (1998). In-vitro activity of essential oils, in particular
Melaleuca alternifolia (tea tree) oil and tea
tree oil products, against Candida spp. J Antimicrob Chemother, 42(5):591-5.
Summary: Tea
tree oil was investigated for its anti-microbial effects against 81 isolates
of Candida albicans and 33 non-albicans isolates.
The minimum concentration of oil inhibiting 90% of all isolates was 0.25% in
broth. Tests on three tea tree oil products for
intra-vaginal (topical) use showed that the products had anti-candidal activity.
The researchers conclude that tea tree may be
useful for the topical treatment of candida infections.
Williams LR (1998).
Clonal production of tea tree oil high in terpinen-4-ol for use in formulations
for the treatment of thrush.
Complement Ther Nurs Midwifery,4(5):133-6.
Summary: Tea tree
oil that is high in the chemical constituent terpinen-4-ol is desirable for
use in therapeutic formulations, particularly
those for vaginal thrush. Selective growing has led to the production of clones
which produce tea tree oil high in terpinin-4-ol.
Nenoff P, Haustein
UF, Brandt W (1996). Antifungal activity of the essential oil of Melaleuca
alternifolia (tea tree oil) against
pathogenic fungi in vitro. Skin Pharmacol, 9(6):388-94.
Summary: Tea
tree oil was evaluted against over 100 different strains of fungi, including
32 strains of Candida albicans. Tea tree inhibited
the growth of all of the isolates at concentrations of 0.5% - 0.44 %. Tea tree
is often used in commercial products at concentrations
of 5% - 10 %. The authors conclude that effect of tea tree in the treatment
of fungal infections of the skin and mucus membranes,
as well as dandruff, may be partly due to the its antifungal activity.
Carson CF, Riley
TV (1995). Antimicrobial activity of the major components of the essential oil
of Melaleuca alternifolia. J Appl
Bacteriol, 78(3):264-9.
Summary: Eight
components of tea tree oil were tested against a range of microrganisms.
Terpinin-4-ol was active against all the test organisms,
while other components were active against most of the organisms. The authors
concluded that tea tree oil may play a role in the
future as an antimicrobial agent.
Tong MM, Altman PM, Barnetson RS (1992). Tea tree oil in the treatment of tinea pedis. Australas J Dermatol, 33(3):145-9.
Summary: This study
used 104 patients with tinea pedis (athlete's foot) in a randomized, double-blind
trial to test the efficacy of tea tree oil
cream (10%) against a standard pharmaceutical cream (tolnaftate 1%) and a placebo
cream. The results showed that the tea tree
cream and the tolnaftate cream showed similar improvement in scaling, inflammation,
itching, and burning. Unlike the tolnaftate,
the tea tree was no better than the placebo at getting rid of the microbes that
caused the disease.
Buck DS, Nidorf
DM, Addino JG (1994). Comparison of two topical preparations for the treatment
of onychomycosis: Melaleuca
alternifolia (tea tree) oil and clotrimazole. J Fam Pract, 38(6):601-5.
Summary: This study
used 117 patients with toenail onychomycosis (a fungal infection) in a double-blind,
multicenter, randomized controlled
trial. The participants received either 1% clotrimazole solution or 100% tea
tree oil applied twice daily to the infection for six months.
The two treatment groups were comparable after six months of therapy, approximately
60% reporting full or partial resolution of the
condition. The researchers concluded that topical therapy showed improvement
in nail appearance and symptoms, and recommended
debridement and topical therapy as appropriate initial treatment.
Raman A, Weir U,
Bloomfield SF (1995). Antimicrobial effects of tea-tree oil and its major components
on Staphylococcus aureus,
Staph. epidermidis and Propionibacterium acnes. Lett Appl Microbiol, 21(4):242-5.
Summary: Four
major components of two tea tree oil samples were tested against bacteria common
to skin problems, including acne. Terpinen-4-ol,
alpha-terpineol and alpha-pinene were active against all three bacterial strains.
Cineole showed no activity. The authors concluded that
tea tree oil has several active constituents, and that their study supports
the use of tea tree oil for acne.
Bassett IB, Pannowitz
DL, Barnetson RS (1990). A comparative study of tea-tree oil versus benzoylperoxide
in the treatment of acne.
Med J Aust, 153(8):455-8.
Summary: 124 patients
with mild to moderate acne were used in this single-blind, randomised clinical
trial. 5% tea tree oil gel was compared with
5% benzoyl peroxide lotion. Both significantly reduced the number of lesions.
The tea tree showed fewer side effects that the benzoyl
peroxide, but the onset of action of the benzoyl peroxide was faster.
Activity against oral bacteria
Shapiro S, Meier
A, Guggenheim (1994). The antimicrobial activity of essential oils and
essential oil components towards oral bacteria.
Oral Microbiol Immunol, 9(4):202-8.
Summary: Minimal
inhibitory concentrations and minimal bactericidal concentrations of essential
oils were tested against anaerobic oral bacteria.
The most potent essential oils were Australian tea tree oil, peppermint oil,
and sage oil. The most potent essential oils components were
thymol and eugenol.
Harkenthal M, Reichling
J, Geiss HK, Saller R (1999). Comparative study on the in vitro antibacterial
activity of Australian tea tree oil,
cajuput oil, niaouli oil, manuka oil, kanuka oil, and eucalyptus oil. Pharmazie,
54(6):460-3.
Summary: The antibacterial
activity of the Australian tea tree oil and other oils from the family Myrtaceae
were tested against twelve common strains
of bacteria, including Escherichia coli, Staphylococcus aureas, and Salmonella
choleraesuis. Tea tree had the highest anti-bacterial activity,
and was effective against all bacteria except Pseudomonas aeruginosa.
Both tea tree and manuka oil had significant antibacterial effects on
various strains of antibiotic-resistant Staphylococcus species.
Carson CF, Cookson
BD, Farrelly HD, Riley T (1995). Susceptibility of methicillin-resistant Staphylococcus
aureus to the essential oil of
Melaleuca alternifolia. J Antimicrob Chemother, 35(3):421-4.
Summary: 66 isolates
of Staphylococcus aureus were tested and found susceptible to tea tree oil (Melaleuca
alternifolia). 64 of the isolates were
methicillin-resistant S. aureus (MRSA) and 33 were mupirocin-resistant.
The mean inhibitory concentrations were between 0.25 % and
0.50%. Coworkers in Britain obtained comparable results. The authors concluded
that tea tree oil may be of use in the treatment of MRSA.
Moghimi HR, Williams
AC, Barry BW (1998). Enhancement by terpenes of 5-fluorouracil permeation
through the stratum corneum:
model solvent approach. J Pharm Pharmacol, 50(9):955-64.
Summary: Using
human epidermis, 26 different terpenes were tested to enhance the permeability
of 5-flourouracil, a chemotherapy agent, through
skin. Data obtained showed that cineole enhances the effect of 5-fourouracil
much more than limonene. Cineole is a primary compound in
essential oils from the Myrtaceae and Lauraceae families, such as myrtle, eucalyptus,
tea tree, and cinnamon.
Hausen BM, Reichling
J, Harkenthal M (1999). Degradation products of monoterpenes are the sensitizing
agents in tea tree oil. Am J
Contact Dermat, 10(2):68-77.
Summary: Over 30
cases of allergic sensitivity to tea tree essential oil have been documented.
This study found that fresh tea tree oil was actually a
very weak allergen. When the oil was exposed to light for four days on a window
sill, it deteriorated, or photo-oxidized, changing the chemistry
of the oil and tripling the allergens. The occurrence of peroxides in the deteriorated
oil increased by more than ten times the amount in the
fresh oil. The researchers concluded that the degradation products from tea
tree oil caused by photo-oxidation must be considered responsible
for the development of allergic contact dermatitis.
Veal
L (1996). The potential effectiveness of essential oils as a treatment
for headlice, Pediculus humanus capitis. Complement
Ther
Nurs Midwifery 2(4):97-101.
Summary:
Essential oils of aniseed, cinnamon leaf, red thyme, tea tree, peppermint, nutmeg,
rosemary, and pine were tested in the lab against lice,
Pediculus humanus. All the oils except for rosemary and pine were found
to be effective in the laboratory. Phenols, phenolic ethers,
ketones, and oxides (1,8-cineole) appear to be the major toxic components of
these essential oils when used on lice.
Last updated 04.14.05
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