Abstracts of studies on Tea Tree Oil
(Acknowledgements is
given to researchers of all these Abstracts)
Citation
<1>
Unique Identifier: 12121393
Medline Identifier: 22116986
Authors Satchell AC. Saurajen A. Bell C. Barnetson RS.
Institution: Department of Dermatology, Royal Prince Alfred Hospital,
Camperdown, New South Wales, Australia.
Title: Treatment of interdigital tinea pedis with 25% and 50% tea tree oil
solution: a randomized, placebo-controlled, blinded study.
Source: Australasian Journal of Dermatology. 43(3):175-8, 2002 Aug.
Abstract:
Tea
tree oil has been shown to have activity against dermatophytes in vitro. We have
conducted a randomized, controlled, double-blinded study to determine the
efficacy and safety of 25% and 50% tea tree oil in the treatment of interdigital
tinea pedis. One hundred and fifty-eight patients with tinea pedis clinically
and microscopy suggestive of a dermatophyte infection were randomized to receive
either placebo, 25% or 50% tea tree oil solution. Patients applied the solution
twice daily to affected areas for 4 weeks and were reviewed after 2 and 4 weeks
of treatment. There was a marked clinical response
seen in 68% of the 50% tea tree oil group and 72% of the 25% tea tree oil group,
compared to 39% in the placebo group. Mycological cure was assessed
by culture of skin scrapings taken at baseline and after 4 weeks of treatment.
The mycological cure rate was 64% in the 50% tea tree oil group, compared to 31%
in the placebo group. Four (3.8%) patients applying tea tree oil devel!
oped moderate to severe dermatitis that improved quickly on stopping the study
medication.
Citation <2>
Unique
Identifier: 11548201
Medline Identifier: 21430202
Authors:HadaT.FuruseS. MatsumotoY.HamashimaH.MasudaK.ShiojimaK.AraiT. Sasatsu
M.
Institution: Department of Microbiology, Showa Pharmaceutical University,
Machida, Tokyo, Japan.
Title: Comparison of the effects in vitro of tea tree oil and plaunotol on
methicillin-susceptible and methicillin-resistant strains of Staphylococcus
aureus.
Source: Microbios. 106 Suppl 2:133-41, 2001.
Abstract
The
effects in vitro of tea tree oil (TTO) and plaunotol were examined by monitoring
the growth of a standard strain of Staphylococcus aureus FDA 209P and of
fourteen methicillin-susceptible strains of S. aureus (MSSA), together with
twenty methicillin-resistant strains (MRSA). The minimum inhibitory
concentrations (MIC) and the doses for 50% inhibition of growth (ID50) were
determined by the micro-broth dilution (MD) method, and the broth dilution with
shaking (BDS) method, respectively. The MIC of plaunotol for 50 and 90% of the
MSSA and MRSA were assessed by the MD method, as 16 microg/ml and > or =
1,024 microg/ml, respectively. No antibacterial effects of TTO on MSSA and MRSA
were detected by the MD method. The growth-inhibitory effects of TTO on S.
aureus by the BDS method were examined, and it appeared that TTO was effective
over a lower range of concentrations than previously reported. It seems that TTO
is very effective in vitro against MSSA and MRSA at high concent!
rations but less effective below 40 microg/ml of TTO.
Citation <5>
Unique Identifier: 11575735
Medline Identifier: 21459556
Authors: Banes-Marshall L. Cawley P. Phillips CA.
Institution: Department of Microbiology, Kettering General Hospital NHS
Trust, Northamptonshire, UK.
Title: In vitro activity of Melaleuca alternifolia (tea tree) oil against
bacterial and Candida spp. isolates from clinical specimens.
Source: British Journal of Biomedical Science. 58(3):139-45, 2001.
Local Messages: Some years online fulltext - link from library journal
list
Abstract
This study investigates the in vitro activity of tea tree oil (TTO)
against a range of wild strains of microorganisms isolated from clinical
specimens of leg ulcers and pressure sores. The antimicrobial effectiveness of
TTO is determined in terms of minimum inhibitory concentration (MIC) and minimum
bactericidal concentration (MBC) or minimum fungicidal concentration (MFC). The
isolates include methicillin-resistant Staphylococcus aureus (MRSA), S. aureus,
faecal streptococci, beta-haemolytic streptococci, coagulase-negative
staphylococci, Pseudomonas spp. and coliform bacilli. Eleven Candida spp.
isolates from skin and vaginal swabs also are tested. Using an agar dilution
assay, the MICs of TTO in 88 out of 90 isolates was 0.5-1.0% (v/v), whilst with
P. aeruginosa it was >2% (v/v). A broth microdilution method was used to
determine MIC and minimum cidal concentration (MCC) of 80 isolates. In
64 isolates, TTO produced an inhibitory and cidal effect at 3% and 4% (v/v),
respectively. S. aureus and Candida spp. were the most susceptible to TTO, with
MICs and MBCs of 0.5% and 1%, respectively. P. aeruginosa and the
faecal streptococci isolates, with MICs and MBCs of >8%, were resistant to
TTO.
Citation <6>
Unique Identifier: 11446601
Medline Identifier: 21339437
Authors: Petry JJ. Hadley SK.
Institution: Vermont Healing Tools Project, Brattleboro Middlesex
Hospital, Middletown, Conn, USA.
Title: Medicinal herbs: answers and advice, part 1. [Review] [9 refs]
Source:
Hospital Practice (Office Edition). 36(7):57-60, 2001 Jul 15.
Local Messages: Some years online fulltext - link from library journal
list
Abstract
Many
herbal medicines have been used for centuries but have only recently been
subjected to rigorous scientific scrutiny. Fever-few, milk thistle, tea tree
oil, and valerian are considered safe for use by most patients. All
four appear to provide some benefits in treating or preventing illness,
but the supporting evidence is inconclusive in some cases. [References: 9]
Citation <7>
Unique Identifier: 11392609
Medline Identifier: 21283763
Authors: Brand C. Ferrante A. Prager RH. Riley TV.
Carson CF. Finlay-Jones JJ. Hart PH.
Institution: Department of Microbiology and Infectious Diseases, School of
Medicine, Flinders University, Adelaide, Australia.
Title: The water-soluble components of the essential oil of Melaleuca
alternifolia (tea tree oil) suppress the production of superoxide by human
monocytes, but not neutrophils, activated in vitro.
Source: Inflammation Research. 50(4):213-9, 2001 Apr.
Abstract:
OBJECTIVE: To evaluate the regulatory properties of the essential oil
of Melaleuca alternifolia (tea tree oil) on the production of oxygen derived
reactive species by human peripheral blood leukocytes activated in vitro.
MATERIALS AND METHODS: The ability of tea tree oil to reduce superoxide
production by neutrophils and monocytes stimulated with N-formyl-methionyl-leucyl-phenylalanine
(fMLP), lipopolysaccharide (LPS) or phorbol 12-myristate 13-acetate (PMA) was
examined. RESULTS: The water-soluble fraction of tea tree oil had no significant
effect on agonist-stimulated superoxide production by neutrophils, but
significantly and dose-dependently suppressed agonist-stimulated superoxide
production by monocytes. This suppression was not due to cell death. Chemical
analysis identified the water-soluble components to be terpinen-4-ol, alpha-terpineol
and 1,8-cineole. When examined individually, terpinen-4-ol significantly
suppressed fMLP- and LPS- but not PMA-stimulated superoxide production; alpha-terpineol
significantly suppressed fMLP-, LPS- and PMA-stimulated superoxide production;
1,8-cineole was without effect. CONCLUSION: Tea tree
oil components suppress the production of superoxide by monocytes,
but not neutrophils, suggesting the potential for selective regulation of cell
types by these components during inflammation.
Citation <8>
Unique Identifier: 11338678
Medline Identifier: 21237351
Authors: Schnitzler P. Schon K. Reichling J.
Institution: Dept of Virology, Hygiene Institute, University of Heidelberg,
Germany.
Title: Antiviral activity of Australian tea tree oil and eucalyptus oil
against herpes simplex virus in cell culture.
Source: Pharmazie. 56(4):343-7, 2001 Apr.
Abstract
The antiviral effect of Australian tea tree oil (TTO) and eucalyptus
oil (EUO) against herpes simplex virus was examined. Cytotoxicity of TTO and EUO
was evaluated in a standard neutral red dye uptake assay. Toxicity of TTO and
EUO was moderate for RC-37 cells and approached 50% (TC50) at concentrations of
0.006% and 0.03%, respectively. Antiviral activity of TTO and EUO against herpes
simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2) was tested
in vitro on RC-37 cells using a plaque reduction assay. The 50% inhibitory
concentration (IC50) of TTO for herpes simplex virus plaque formation was
0.0009% and 0.0008% and the IC50 of EUO was determined at 0.009% and 0.008% for
HSV-1 and HSV-2, respectively. Australian tea tree
oil exhibited high levels of virucidal activity against HSV-1 and HSV-2 in viral
suspension tests. At noncytotoxic concentrations of TTO plaque formation was
reduced by 98.2% and 93.0% for HSV-1 and HSV-2, respectively.
Noncytotoxic concentrations of EUO reduced virus titers by 57.9% for HSV-1 and
75.4% for HSV-2. Virus titers were reduced significantly with TTO, whereas EUO
exhibited distinct but less antiviral activity. In order to determine the mode
of antiviral action of both essential oils, either cells were pretreated before
viral infection or viruses were incubated with TTO or EUO before infection,
during adsorption or after penetration into the host cells. Plaque formation was
clearly reduced, when herpes simplex virus was pretreated with the essential
oils prior to adsorption. These results indicate that TTO and EUO affect the
virus before or during adsorption, but not after penetration into the host cell.
Thus TTO and EUO are capable to exert a direct antiviral effect on HSV. Although
the active antiherpes components of Australian tea tree and eucalyptus oil are
not yet known, their possible application as antiviral agents in recurrent
herpes infection is promising.
Citation <9>
Unique Identifier: 11218503
Medline Identifier: 21087058
Authors:ArweilerNB.Donos N.Netuschil L.Reich E.Sculean A.
Institution:
University of the Saarland, Dept of Periodontology & Conservative Dentistry,
D-66421 Homburg/Saar, Germany.
Title: Clinical and antibacterial effect of tea tree oil--a pilot study.
Source: Clinical Oral Investigations. 4(2):70-3, 2000 Jun.
Abstract
The
aim of this clinical pilot study was to compare the effect of tea tree oil with
the effect of water and chlorhexidine on supragingival plaque formation and
vitality. Eight subjects were asked to refrain from any kind of mechanical oral
hygiene for 4 days after professional tooth cleaning (day 0), and to rinse with
water instead for 1 week, with chlorhexidine in a second and tea tree oil in a
third test week. The plaque index (PI), which was evaluated daily (days 1-4),
served as a clinical control parameter. On the last day of the study (day 4),
the plaque covering the front teeth was stained, photographed, and therefrom the
plaque area (PA; %) was estimated using a digital measuring system. Each day of
the study (days 1-4), the sampled plaque was examined using a vital fluorescence
technique. Tea tree oil reduced neither the clinical parameters (PI and PA) nor
the vitality of the plaque flora significantly. Within the limitations of the
study design, it was determined that a solution with tea tree oil--utilized as
ordinary mouthwash--has no positive effect on the quantity or quality of
supragingival plaque.
Citation <10>
Unique Identifier: 11131302
Medline Identifier: 21015258
Authors: Hart PH. Brand C. Carson CF. Riley TV.
Prager RH. Finlay-Jones JJ.
Institution: Department of Microbiology and Infectious Diseases, School of
Medicine, Flinders University, Adelaide, Australia.
Title: Terpinen-4-ol, the main component of the essential oil of Melaleuca
alternifolia (tea tree oil), suppresses inflammatory mediator production by
activated human monocytes.
Source: Inflammation Research. 49(11):619-26, 2000 Nov.
Abstract
OBJECTIVE AND DESIGN: To evaluate potential antiinflammatory
properties of tea tree oil, the essential oil steam distilled from the
Australian native plant, Melaleuca alternifolia. MATERIAL AND METHODS: 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 examined. RESULTS: Tea tree oil emulsified by sonication in a glass tube
into culture medium containing 10% fetal calf serum (FCS) was toxic for
monocytes at a concentration of 0.016% v/v. However, 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 h. 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. CONCLUSION:
The water-soluble components of tea tree oil can
suppress pro-inflammatory mediator production by activated human monocytes.
Citation <12>
Unique Identifier: 11123417
Medline Identifier: 20573379
Authors: Khanna M. Qasem K. Sasseville D.
Institution: Division of Dermatology, McGill University Health Center,
Royal Victoria Hospital, Montreal, Quebec, Canada.
Title: Allergic contact dermatitis to tea tree oil with erythema
multiforme-like id reaction.
Source: American Journal of Contact Dermatitis. 11(4):238-42, 2000
Dec.
Abstract
The commercial production of tea tree oil, extracted from Melaleuca
alternifolia Cheel, has considerably increased over the past 15 years in
response to a strong demand for natural remedies and aromatic substances. The
number of case reports that describe allergic contact dermatitis (ACD) to this
essential oil is also on the rise. We report an additional case of ACD to tea
tree oil that presented with an extensive erythema multiforme-like reaction. A
skin biopsy was performed from a targetlike lesion distant from the site of the
initial dermatitis. The patient was treated with systemic and topical
corticosteroids. Five months later, he was patch tested to the North American
standard series, to his own tea tree oil, to a fresh batch of tea tree oil, and
to some related allergens. The skin biopsy showed a spongiotic dermatitis
without histological features of erythema multiforme. Patch testing elicited a
3+ reaction to old, oxidized tea tree oil, a 2+ reaction to fresh tea tree oil,
a 2+ reaction to colophony, a 1+ reaction to abitol, and a 1+ reaction to balsam
of Peru. We believe this is the first report of erythema multiforme-like
reaction secondary to ACD from tea tree oil. Other interesting features are the
stronger reaction to oxidized than to fresh tea tree oil, and concomitant
reactivity to colophony, abitol, and balsam of Peru. Copyright 2000 by W.B.
Saunders Company
Citation <13>
Unique Identifier: 11092382
Medline Identifier: 20540929
Authors: Hammer KA. Carson CF. Riley TV.
Institution: Department of Microbiology, The University of Western
Australia, Queen Elizabeth II Medical Centre, Nedlands.
Title: Melaleuca alternifolia (tea tree) oil inhibits germ tube formation
by Candida albicans.
Source: Medical Mycology. 38(5):355-62, 2000 Oct.
Abstract
The effect of tea tree oil (TTO) on the formation of germ tubes by
Candida albicans was examined. Two isolates were tested for germ tube formation
(GTF) in the presence of TTO concentrations (% v/v) ranging from 0.25% (1/2
minimum inhibitory concentration [MIC]) to 0.004% (1/128 MIC). GTF at 4 h in the
presence of 0.004 and 0.008% (both isolates) and 0.016% (one isolate) TTO did
not differ significantly (P > 0.05) from controls. At all other
concentrations at 4 h, GTF differed significantly from controls (P < 0.01). A
further eight isolates were tested for GTF in the presence of 0.031% TTO, and at
4h the mean GTF for all 10 isolates ranged 10.0-68.5%. Two isolates were
examined for their ability to form germ tubes after 1 h of pre-exposure to
several concentrations of TTO, prior to induction of germ tubes in horse serum. Cells
pre-exposed to 0.125 and 0.25% TTO formed significantly fewer germ tubes than
control cells at 1 h (P < 0.05), but only those cells pre-exposed to 0.25%
differed significantly from control cells at later time points (P < 0.01).
GTF by C. albicans is affected by the presence of, or pre-exposure to,
sub-inhibitory concentrations of TTO. This may have therapeutic implications.
Citation <14>
Unique Identifier: 11073734
Medline Identifier: 20528462
Authors: Caelli M. Porteous J. Carson CF. Heller R.
Riley TV.
Institution: Department of Clinical Epidemiology, University of Newcastle,
Callaghan, NSW, Australia.
Title: Tea tree oil as an alternative topical decolonization agent for
methicillin-resistant Staphylococcus aureus.
Source: Journal of Hospital Infection. 46(3):236-7, 2000 Nov.
Local Messages: Held at RCH and RWH: 1980 onwards
Abstract
The combination of a 4% tea tree oil nasal ointment and 5% tea tree
oil body wash was compared with a standard 2% mupirocin nasal ointment and
triclosan body wash for the eradication of methicillin-resistant Staphylococcus
aureus carriage. 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. Copyright 2000 The Hospital Infection Society.
Citation <15>
Unique Identifier: 10865458
Medline Identifier: 20323779
Authors: Mikus J. Harkenthal M. Steverding D. Reichling
J.
Title: Invitro effect of essential oils & isolated mono-&
sesquiterpenes on Leishmania major and Trypanosoma brucei.
Source: Planta Medica. 66(4):366-8, 2000 May.
Abstract
The effect of different essential oils as well as of isolated mono-
and sesquiterpenes on the viability of bloodstream forms of Trypanosoma brucei,
promastigotes of Leishmania major and human HL-60 cells was evaluated using the
Almar Blue assay. Of the 12 essential oils and 8 terpenes investigated, only
three essential oils, Melissa officinalis (balmmint) oil, Thymus vulgaris
(thyme) oil, and Melaleuca alternifolia (tea tree) oil were about 50-fold and
80-fold more toxic to bloodstream forms of T. brucei than to HL-60 cells,
respectively. Terpinen-4-ol, the main compound of the Australian tea tree oil,
was even 1000-fold more toxic to trypanosomes than to the human cells. On the
other hand, none of the essential oils and terpenes tested were more toxic to
promastigotes of L. major than to HL-60 cells.
Citation <16>
Unique Identifier: 10797086
Medline Identifier: 20259465
Authors: May J. Chan CH. King A. Williams L.
French GL.
Institution: Microbiology Department, St Thomas' Hospital, London SE1 7EH,
UK.
Title: Time-kill studies of tea tree oils on clinical isolates.
Source: Journal of Antimicrobial Chemotherapy. 45(5):639-43, 2000
May.
Local Messages: Held at RCH: 1980 onwards, also available online
Abstract
Tea tree oil has recently emerged as an effective topical
antimicrobial agent active against a wide range of organisms. Tea tree oil may
have a clinical application in both the hospital and community, especially for
clearance of methicillin-resistant Staphylococcus aureus (MRSA) carriage or as a
hand disinfectant to prevent cross-infection with Gram-positive and Gramnegative
epidemic organisms. Our study, based on the time-kill approach, determined the
kill rate of tea tree oil against several multidrug-resistant organisms,
including MRSA, glycopeptide-resistant enterococci, aminoglycoside-resistant
klebsiellae, Pseudomonas aeruginosa and Stenotrophomonas maltophilia, and also
against sensitive microorganisms. The study was performed with two chemically
different tea tree oils. One was a standard oil and the other was Clone 88
extracted from a specially bred tree, which has been selected and bred for
increased activity and decreased skin irritation. Our results confirm that the
cloned oil had increased antimicrobial activity when compared with the standard
oil. Most results indicated that the susceptibility pattern and Gram reaction of
the organism did not influence the kill rate. A rapid
killing time (less than 60 min) was achieved with both tea tree oils with most
isolates, but MRSA was killed more slowly than other organisms.
Citation <17>
Unique Identifier: 10800248
Medline Identifier: 20260042
Authors: Ernst E. Huntley A.
Institution: Department of Complementary Medicine, School of Postgraduate
Medicine and Health Sciences, University of Exeter, UK.
Title: Tea tree oil: a systematic review of randomized clinical trials.
[Review] [23 refs]
Source: Forschende Komplementarmedizin und Klassische Naturheilkunde.
7(1):17-20, 2000 Feb.
Abstract
AIM: Tea tree oil (TTO) is immensely popular for various topical
applications. In vitro studies have repeatedly demonstrated that it has
antibiotic activity. This article is an attempt to systematically review the
evidence from randomised clinical trials for or against effectiveness of
external TTO in dermatological conditions. METHODS: Six electronic databases
were searched. Methodological quality was assessed by Jadad score. Data were
extracted and validated in a standardised fashion by two independent reviewers.
RESULTS: Only 4 trials were located. They suggest
that TTO may be effective as a treatment of acne and fungal infections.
The evidence is promising but by no means compelling. The adverse effects of TTO
are usually mild and transient. They mainly consist of allergic reactions.
CONCLUSIONS: It is concluded that, so far, there is no compelling evidence to
show that TTO is efficacious in any dermatological condition. However, in view
of promising findings, TTO deserves to be investigated more closely.
[References: 23]
Citation <20>
Unique Identifier: 10639388
Medline Identifier: 20107007
Authors: Hammer KA. Carson CF. Riley TV.
Institution: Department of Microbiology, The University of Western
Australia, Nedlands, Australia.
Title: In vitro activities of ketoconazole, econazole, miconazole, and
Melaleuca alternifolia (tea tree) oil against Malassezia species.
Source: Antimicrobial Agents & Chemotherapy. 44(2):467-9, 2000
Feb.
Local Messages: Some years online fulltext - link from library journal
list
Abstract
The in vitro activities of ketoconazole, econazole, miconazole, and
tea tree oil against 54 Malassezia isolates were determined by agar and broth
dilution methods. Ketoconazole was more active than both econazole and
miconazole, which showed very similar activities. M. furfur was the least
susceptible species. M. sympodialis, M. slooffiae, M. globosa, and M. obtusa
showed similar susceptibilities to the four agents.
Citation <23>
Unique Identifier: 10519561
Medline Identifier: 99447050
Authors: Budhiraja SS. Cullum ME. Sioutis SS.
Evangelista L. Habanova ST.
Institution:Dept of Research, National College of Chiropractic, Lombard, Ill,
USA.
Title: Biological activity of Melaleuca alternifola (Tea Tree) oil
component, terpinen-4-ol, in human myelocytic cell line HL-60.
Source: Journal of Manipulative & Physiological Therapeutics.
22(7):447-53, 1999 Sep.
Abstract
BACKGROUND: Tea tree oil is an aboriginal Australian traditional
medicine for bruises, insect bites, and skin infections. It was rediscovered in
the 1920s as a topical antiseptic that is more effective than Phenol. Previous
studies have demonstrated its antiseptic qualities, but its effects on human
white blood cells have never been investigated. OBJECTIVE: To test the
hypothesis that tea tree oil exerts its antiseptic action through white blood
cell activation. METHODS: Crude oil and the purified "active"
component were studied by using a model system that responds to bioactive
components by induction of differentiation in white blood cells. Methods used
included white blood cell oxidative burst assay (nitroblue tetrazolium [NBT] dye
reduction); cell proliferation assay (tritiated thymidine incorporation); cell
surface differentiation marker assay (flow cytometric quantitation of
phycoerythrin-anti-CD 11b binding); cell viability assay (trypan blue
exclusion); and cellular differentiation enzyme assay (white cell esterase
staining). RESULTS: Collectively, five assays that measure differentiation in
white blood cells indicated monocytic differentiation after treatment with
either crude oil or the purified active component. Both the crude oil and the
purified active component, (+:-) terpinene-4-ol, caused a similar type and
amount of differentiation. The culture of cells in medium containing serum
caused more activation than in medium containing no serum. CONCLUSION: The
antiseptic activity of tea tree oil appears to be due, in part, to white blood
cell activation.
Citation <24>
Unique Identifier: 10357864
Medline Identifier: 99301164
Authors: Syed TA. Qureshi ZA. Ali SM. Ahmad S.
Ahmad SA.
Institution: Department of Dermatology, University of California, San
Francisco, USA.
Title: Treatment of toenail onychomycosis with 2% butenafine and 5%
Melaleuca alternifolia (tea tree) oil in cream. [see comments.].
Comment in: Trop Med Int Health. 1999 Sep;4(9):630 ; 10540304
Source: Tropical Medicine & International Health. 4(4):284-7,
1999 Apr.
Local Messages: Some years online fulltext - link from library journal list
Abstract
The prevalence of onychomycosis, a superficial fungal infection that
destroys the entire nail unit, is rising, with no satisfactory cure. The
objective of this randomized, double-blind, placebo-controlled study was to
examine the clinical efficacy and tolerability of 2% butenafine hydrochloride
and 5% Melaleuca alternifolia oil incorporated in a cream to manage toenail
onychomycosis in a cohort. Sixty outpatients (39 M, 21 F) aged 18-80 years (mean
29.6) with 6-36 months duration of disease were randomized to two groups (40 and
20), active and placebo. After 16 weeks, 80% of
patients using medicated cream were cured, as opposed to none in the
placebo group. Four patients in the active treatment group experienced
subjective mild inflammation without discontinuing treatment. During follow-up,
no relapse occurred in cured patients and no improvement was seen in
medication-resistant and placebo participants.
Citation <25>
Unique Identifier: 10357714
Medline Identifier: 99286336
Authors: Hausen BM. Reichling J. Harkenthal M.
Institution: Dermatologisches Zentrum Buxtehude and the Institut fur
Pharmazeutische Biologie, Heidelberg, Germany.
Title: Degradation products of monoterpenes are the sensitizing agents in
tea tree oil.
Source: American Journal of Contact Dermatitis. 10(2):68-77, 1999
Jun.
Abstract
BACKGROUND: Patients using tea tree oil (TTO) topically may become
sensitized to this natural remedy. More than 30 cases have been documented in
the literature since 1991. OBJECTIVE: Freshly distilled, as well as oxidized TTO,
some fractions, and single constituents were used for experimental sensitization
in guinea pigs. TTO was stored on a window sill to study the influence of light,
oxygen, and warmth. The oxidized oil and different fractions were devoted to
experimental sensitization in guinea pigs to determine their sensitizing
potency. Fifteen constituents were patch tested in TTO-sensitive patients to
find how many may play a role as contact allergens. METHODS: Guinea pigs were
sensitized by a modified FCA-method (Freund's complete adjuvant) with freshly
distilled TTO, oxidized TTO, the monoterpene and sesquiterpene fraction, and 1,
8-cineole. TTO-sensitive patients were tested with 15 typical constituents and
degradation products. Gas chromatographic analysis was used to detect
degradation products of the deteriorated TTO. RESULTS: Fresh TTO was revealed
to be a very weak sensitizing material whereas oxidized TTO was 3 times stronger.
The monoterpene fraction showed to be a stronger sensitizer than the
sesquiterpene fraction. All 11 patients reacted mostly with a ++-plus or even a
-plus reaction to alpha-terpinene, terpinolene and ascaridol. alpha-Phellandrene
became positive in four patients, myrcene in only two. Gas chromatographic
analyses showed that the formation of peroxides increased within 4 days from
less than 50 to more than 500 ppm. Peroxides, epoxides and endoperoxides were
formed. Deterioration products of alpha-terpinene were found to be mainly
p-cymene, ascaridol, isoascaridol, a ketoperoxide, and colorless crystals that
likely were 1,2,4-trihydroxy menthane. The p-cymene content increased
dramatically from 2% to 11.5%. alpha- and gamma-terpinene, as well as
terpinolene, were reduced to one half of their former concentration. Ascaridol
and isoascaridol have never before been found in TTO. CONCLUSION: Tea tree oil
kept in open and closed bottles or other containers undergoes photooxidation
within a few days to several months, leading to the creation of degradation
products that are moderate to strong sensitizers. Peroxides, epoxides and
endoperoxides, like ascaridol and 1,2,4-trihydroxy menthane, are formed. These
must be considered responsible for the development of allergic contact
dermatitis seen in individuals treating themselves with the oil. A test series
with 15 characteristic constituents is recommended for patch testing.
Citation <27>
Unique Identifier: 9830943
Medline Identifier: 99048635
Authors: Williams LR.
Institution: School of Chemistry, Macquarie University, Sydney, NSW,
Australia.
Title: Clonal production of tea tree oil high in terpinen-4-ol for use in
formulations for the treatment of thrush. [Review] [16 refs]
Source: Complementary Therapies in Nursing & Midwifery.
4(5):133-6, 1998 Oct.
Abstract
A programme of evaluation and selection of superior trees has led to
the vegetative propagation of highly productive clones which produce tea tree
oil high in terpinen-4-ol. These will soon provide commercial quantities of a
particularly active oil of consistent quality for use
in formulations for therapeutic use and in particular for vaginal thrush.
[References: 16]
Citation <28>
Unique Identifier 9848442
Medline Identifier: 99063188
Authors: Hammer KA. Carson CF. Riley TV.
Institution: Department of Microbiology, The University of Western
Australia, The Queen Elizabeth II Medical Centre, Nedlands.
Title: In-vitro activity of essential oils, in particular Melaleuca
alternifolia (tea tree) oil and tea tree oil products, against Candida spp.
Source: Journal of Antimicrobial Chemotherapy. 42(5):591-5, 1998
Nov.
Local Messages: Held at RCH: 1980 onwards, also available online
Abstract
The in-vitro activity of a range of essential oils, including tea
tree oil, against the yeast candida was examined. Of the 24 essential oils
tested by the agar dilution method against Candida albicans ATCC 10231, three
did not inhibit C. albicans at the highest concentration tested, which was 2.0%
(v/v) oil. Sandalwood oil had the lowest MIC, inhibiting C. albicans at 0.06%.
Melaleuca alternifolia (tea tree) oil was investigated for activity against 81
C. albicans isolates and 33 non-albicans Candida isolates. By the broth
microdilution method, the minimum concentration of oil inhibiting 90% of
isolates for both C. albicans and non-albicans Candida species was 0.25% (v/v). The
minimum concentration of oil killing 90% of isolates was 0.25% for C. albicans
and 0.5% for non-albicans Candida species. Fifty-seven Candida
isolates were tested for sensitivity to tea tree oil by the agar dilution
method; the minimum concentration of oil inhibiting 90% of isolates was 0.5%.
Tests on three intra-vaginal tea tree oil products showed 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 has
retained its anticandidal activity. These data indicate that some essential oils
are active against Candida spp., suggesting that they may be useful in the
topical treatment of superficial candida infections.
Citation <30>
Unique Identifier: 9838722
Medline Identifier: 99056101
Authors: Rubel DM. Freeman S. Southwell IA.
Institution: Skin and Cancer Foundation, Darlinghurst, New South Wales,
Australia.
Title: Tea tree oil allergy: what is the offending agent? Report of three
cases of tea tree oil allergy and review of the literature. [Review] [9 refs]
Source: Australasian Journal of Dermatology. 39(4):244-7, 1998 Nov.
Abstract
Tea tree oil is currently enjoying popularity as a 'cure-all' for a
variety of skin conditions, from infections to psoriasis, and many household and
personal products containing Melaleuca oil are available. However, despite its
chemical complexities and enthusiastic use, there have been only a few reports
of allergic reactions to tea tree oil. At the Skin and Cancer Foundation
(Sydney, NSW, Australia), three of 28 normal volunteers tested strongly positive
to patch testing with tea tree oil. Following further patch testing with tea
tree oil constituents, all three patients reacted strongly to two preparations
containing sesquiterpenoid fractions of the oil. Because patients often neglect
to mention that they have used 'natural' remedies, it is important that
physicians are aware of the potential adverse effects of these products.
Furthermore, identification of the allergenic ingredients in tea tree oil may
assist the growing industry to produce safer products. [References:9]
Citation <31>
Unique Identifier: 9791953
Medline Identifier: 99008165
Authors: Concha JM. Moore LS. Holloway WJ.
Institution: Department of Podiatric Medicine and Surgery, Christiana Care
Health System, Wilmington Hospital, DE, USA.
Title: 1998 William J. Stickel Bronze Award. Antifungal activity of
Melaleuca alternifolia (tea-tree) oil against various pathogenic organisms.
Source:Journal of the American Podiatric Medical Association. 88(10):489-92,
1998 Oct.
Abstract
Tea-tree oil (oil of Melaleuca alternifolia) has recently received
much attention as a natural remedy for bacterial and fungal infections of the
skin and mucosa. As with most naturally occurring agents, claims of
effectiveness have been only anecdotal; however, several published studies have
recently demonstrated tea-tree oil's antibacterial activity. This study was
conducted to determine the activity of tea-tree oil against 58 clinical
isolates: Candida albicans (n = 10), Trichophyton rubrum (n = 8), Trichophyton
mentagrophytes (n = 9), Trichophyton tonsurans (n = 10), Aspergillus niger (n =
9), Penicillium species (n = 9), Epidermophyton floccosum (n = 2), and
Microsporum gypsum (n = 1). Tea-tree oil showed
inhibitory activity against all isolates tested except one strain of E floccosum.
These in vitro results suggest that tea-tree oil may be useful in the treatment
of yeast and fungal mucosal and skin infections.
Citation <34>
Unique Identifier: 9402533
Medline Identifier: 98066153
Authors: Hammer KA. Carson CF. Riley TV.
Institution: Department of Microbiology, University of Western Australia,
Nedlands. Title:In vitro susceptibility of Malassezia furfur to the essential
oil of Melaleuca alternifolia.
Source: Journal of Medical & Veterinary Mycology. 35(5):375-7,
1997 Sep-Oct.
Abstract
The susceptibility of 64 Malassezia furfur isolates to Melaleuca
alternifolia oil was determined. The minimum inhibitory concentration for 90% of
isolates was 0.25% by agar dilution and 0.12% by broth dilution. These
data indicate that tea tree oil may be useful in the treatment of skin
conditions involving M. furfur.
Citation <36>
Unique Identifier: 9248647
Medline Identifier: 97391904
Authors: Faoagali J. George N. Leditschke JF.
Institution: Royal Brisbane Hospital, Herston, Queensland, Australia.
Title: Does tea tree oil have a place in the topical treatment of burns?
[see comments.].
Comment in: Burns. 1998 Feb;24(1):80-2 ; 9601599
Source: Burns. 23(4):349-51, 1997 Jun.
Local Messages Held at RCH: 1980 onwards
Abstract
Burnaid is a sorbalene-based cream containing 40 mg/g of tea tree oil
and 1 mg/g of triclosan. This investigation was carried out to determine the
effect of Burnaid, a commercial tea tree oil preparation, against Enterococcus
faecalis (ATCC29212), Staphylococcus aureus (ATCC29213), Escherichia coli
(ATCC25922), and Pseudomonas aeruginosa (ATCC27853), with the activity of the
base product in the commercial preparation. The organisms were suspended in
sterile saline (0.5 McFarland Standard) and inoculated onto horse blood agar (E.
faecalis and S. aureus) or Mueller-Hinton agar (E. coli and P. aeruginosa). One
hundred microliters of Burnaid unsterilized, Burnaid sterilized and the base
product (Tinasolve) were placed in duplicate in wells cut into the agar plates.
Sterility and inactivation cultures were also performed on the samples. None of
the samples were found to be contaminated with bacteria prior to testing. Only
S. aureus and E. coli showed zones of growth inhibition around the Burnaid and
Tinasolve. Zones of growth inhibition (22 mm) were similar for the active
product (Burnaid) and the base (Tinasolve). There was no activity against E.
faecalis or P. aeruginosa. In view of our 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.
Citation <38>
Unique Identifier: 9055360
Medline Identifier: 97208133
Authors: Nenoff P. Haustein UF. Brandt W.
Institution: Department of Dermatology, University of Leipzig, Germany.
Title: Antifungal activity of the essential oil of Melaleuca alternifolia
(tea tree oil) against pathogenic fungi in vitro.
Source: Skin Pharmacology. 9(6):388-94, 1996.
Abstract
The in vitro antifungal activity of tea oil, the essential oil of
Melaleuca alternifolia, has been evaluated against 26 strains of various
dermatophyte species, 54 yeasts, among them 32 strains of Candida albicans and
other Candida sp. as well as 22 different Malassezia furfur strains. Minimum
inhibitory concentrations (MIC) of tea tree oil were measured by agar dilution
technique. Tea tree oil was found to be able to inhibit growth of all clinical
fungal isolates. For the investigated dermatophytes MIC values from 1,112.5 to
4,450.0 micrograms/ml with a geometric mean of 1,431.5 micrograms/ml were
demonstrated. Both C. albicans strains and the other strains belonging to the
genus Candida and Trichosporon appeared to be slightly less susceptible to tea
tree oil in vitro. However, their MIC values, which varied from 2,225.0 to
4,450.0 micrograms/ml (geometric mean 4,080 micrograms/ml), indicated moderate
susceptibility to the essential oil of M. alternifolia. The lipophilic yeast M.
furfur seemed to be most susceptible to tea tree oil. MIC values between 556.2
and 4,450.0 micrograms/ml (geometric mean 1,261.5 micrograms/ml) were found
against the tested M. furfur strains. However, when calculated as percentage tea
tree oil of the agar, the above-mentioned concentrations correspond to 0.5-0.44%
tea tree oil content. These values are far below the usual relatively high
therapeutic concentrations of the agent; approximately 5-10% solution or even
the concentrated essential oil are used for external treatment. In comparison
with tea tree oil, in vitro susceptibility against miconazole, an established
topical antifungal, was tested. As expected, very low MIC values for miconazole
were found for dermatophytes (geometric mean 0.2 microgram/ml), yeasts
(geometric mean 1.0 microgram/ml), and M. furfur (geometric mean 2.34
micrograms/ml). It is suggested that the in vivo
effect of tea tree oil ointment in the therapy of fungal infections of the skin
and mucous membranes as well as in the treatment of dandruff, a mild form of
seborrheic dermatitis, may be at least partly due to an antifungal activity of
tea tree oil.
Citation <40>
Unique Identifier: 8806995
Medline Identifier: 96400619
Authors: Hammer KA. Carson CF. Riley TV.
Institution: Department of Microbiology, University of Western Australia.
Title: Susceptibility of transient and commensal skin flora to the
essential oil of Melaleuca alternifolia (tea tree oil).
Source: AJIC: American Journal of Infection Control. 24(3):186-9,
1996 Jun.
Local Messages: Held at RCH: 1981 onwards, also available online
Abstract
OBJECTIVES: The purpose of this study was to determine the
susceptibility of a range of transient and commensal skin flora to the essential
oil of Melaleuca alternifolia, or tea tree. METHODS: A modified broth
microdilution method was used. Polyoxyethylene sorbitan mono-oleate detergent
was added to the test medium to enhance solubility of the tea tree oil. RESULTS:
Serratia marcescens had the lowest minimum inhibitory concentration (MIC90) of
0.25%. The highest MIC90 was 3% for Pseudomonas aeruginosa. The lowest minimum
bactericidal concentration (MBC90) was 0.25% for S. marcescens and Klebsiella
pneumoniae, whereas the highest was 8% for Staphylococcus capitis. CONCLUSIONS:
S. aureus and most of the gram-negative bacteria tested were more susceptible to
tea tree oil than the coagulase-negative staphylococci and micrococci. These
results suggest that tea tree oil may be useful in removing transient skin flora
while suppressing but maintaining resident flora.
Citation <41>
Unique Identifier: 8599176
Medline Identifier: 96176681
Authors: Soderberg TA. Johansson A. Gref R.
Institution: Department of Clinical Bacteriology, Pathology and
Nutritional Research, University of Umea, Sweden.
Title: Toxic effects of some conifer resin acids and tea tree oil on human
epithelial and fibroblast cells.
Source: Toxicology. 107(2):99-109, 1996 Feb 22.
Abstract
The present study was undertaken to assess and compare the in vitro
cytotoxic effects of three resin acid analogues: dehydrobietic acid, podocarpic
acid, O-methylpodocarpic acid; an essential oil from Australia (tea tree oil);
and tapped oleoresin from Thailand, on human epithelial and fibroblast cells,
using a quantitative neutral red spectrophotometric assay. All
of the investigated compounds except for tea tree oil exhibited a cytotoxic
activity which was proportional to their concentrations and time of
exposure up to 24 h, i.e. higher concentrations and longer time of exposure
caused increased cell death. Dehydroabietic acid and the oleoresin were the most
toxic compounds followed by O-methylpodocarpic acid, whereas podocarpic acid and
tea tree oil showed a lower level of toxicity.
On the basis on these findings it is concluded that an isopropyl group on the
aromatic C-ring is of great importance for the cytotoxicity of the tested
abietane resin acids, thus indicating that the cytotoxic activity of oleoresins
most probably is caused by synergistic or additive effects of resin acids. The
results from this work support the view that antibacterial activity parallels
cytotoxic activity which suggests a similar mode of action, most probably
exerted by membrane-associated reactions.