RIRDC Completed Projects in 2000-2001 & Research in Progress as at June 2001

BACK TO INDEX

To Tea Tree Oil Completed Projects

TEA TREE OIL   RESEARCH IN PROGRESS
Project No.	Project Title	Researcher	Phone	Organisation
UF-6A	The anti-inflammatory activity and anti-itch properties of tea tree oil	Prof J. Finlay-Jones, Dr P. Hart Dr C. Carson, A/Prof. T Riley	08 8201 3909	Flinders University of South Australia
UWA-55A	Antimicrobial activity of tea tree oil against oral microorganisms	Dr C. Carson & A/Prof T. Riley	08 9346 3288	University of Western Australia
UWA-56A	Clinical efficacy of tea tree oil for treating coldsores	A/Prof T. Riley	08 9346 3690	University of Western Australia
UWA-57A	Multi-centre randomised clinical trials for tea tree oil products for vaginal infections	A/Prof T. Riley	08 9346 3690	University of Western Australia
UWA-58A	The antifungal activity of tea tree oil in vitro	A/Prof T. Riley	08 9346 3690	University of Western Australia


 

Project Title	The anti-inflammatory activity and anti-itch properties of tea tree oil
RIRDC Project No.:	UF-6A
Start Date:	1/08/2000
Finish Date:	31/07/2001
Researcher:	Prof. John Finlay-Jones, Dr Prue Hart, Dr C. Carson, Assoc. Prof. T. Riley
Organisation:	Flinders University of South Australia GPO Box 2100 ADELAIDE SA 5001
Phone:	08 8201 3909
Fax:	08 8201 3905
Email:	John.Finlay-Jones@flinders.edu.au
Objectives	To help define the potential for use of tea tree oil as a safe, topical anti-inflammatory and anti-itch therapeutic agent, as well as to confirm the relevance in vivo of studies with tea tree oil on inflammatory cells in vitro. More specifically, · to investigate the effect of tea tree oil applied prior to or post an inflammatory stimulus, on skin pathology in vivo, and · to investigate the effect of tea tree oil on mast cell activity, the cells central to immediate hypersensitivities and itch
Current Progress	For an examination of the anti-inflammatory activities of TTO in vivo, mice were sensitized to a chemical hapten on their ventral skin and 7 days later challenged (or re-exposed) on their dorsal skin with the same hapten. TTO applied 30 min before or up to 7 h after to the same dorsal site as hapten challenge caused a significant reduction in swelling of back skin after 24 h. An ointment containing 5% TTO also reduced hapten-induced swelling. Histological analysis showed that TTO suppressed the oedema associated with an influx of inflammatory cells but did not prevent the influx of inflammatory cells per se. An inability of TTO to suppress TNF?-induced E-selectin expression by human umbilical vein endothelial cells further suggested that TTO did not suppress extravasation of inflammatory cells to the site of hapten challenge. TTO could not suppress a contact hypersensitivity response to hapten in neuropeptide-depleted mice suggesting that TTO control of hapten-induced, inflammation-associated oedema was by control of activity of peripheral sensory neurons. In contrast to controlling the oedema associated with immunological processes, TTO was unable to suppress the oedema induced by UVB irradiation. The reasons for the different anti-oedema effects of TTO are not clear.

Project Title	Antimicrobial activity of tea tree oil against oral microorganisms
RIRDC Project No.:	UWA-55A
Start Date:	01/01/2001
Finish Date:	30/10/2002
Researcher:	Dr Christine F Carson A/Prof. Thomas V Riley
Organisation:	University of Western Australia Dept of Microbiology Queen Elizabeth II Medical Centre NEDLANDS WA 6009
Phone:	08 9346 3288 08 9346 3690
Fax:	08 9346 2912 08 9346 2912
Email:	ccarson@cyllene.uwa.edu.au triley@cyllene.uwa.edu.au
Objective	To determine the susceptibility of oral microorganisms to tea tree oil and to evaluate its potential as a topical antimicrobial agent for oral infections.
Current Progress	The initial work on this project largely involved extensive literature searches of medical and dental databases in order to survey work undertaken in this and related fields. There are a large number of bacterial species found in the oral cavity, although not all of them are implicated in dental disease. Therefore, a target list of these potential oral pathogens has been compiled. This includes several species from the following genera: Streptococcus, Actinomyces, Fusobacterium, Prevotella, Peptostreptococcus, Haemophilus, Porphyromonas and Treponema. The next stage in this project was to establish a collection of the required bacteria. Wherever possible, at least ten isolates of each species are required in susceptibility testing, in order to obtain sufficient data to establish the minimum inhibitory concentration of 90% of the isolates (MIC90). Work on this culture collection has begun, with about 50 isolates at present stored for future testing. A variety of methods to ascertain the antimicrobial activity of compounds against oral bacteria have been employed in a range of studies. In order to determine basic susceptibility data, it has been decided to use the broth microdilution method in this study. The testing of these isolates to establish the minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of tea tree oil and its major components has commenced. To date a number of Streptococcus and Actinomyces species have been tested for susceptibility to the whole oil. Preliminary results suggest that these oral bacteria are susceptible to tea tree oil at concentrations similar to those reported previously for other bacteria. The staff involved in the study are Ms Linda Dry (Research Assistant, UWA), Dr Christine Carson (Senior Research Fellow, UWA), Ms Kate Hammer (Graduate Research Assistant, UWA) and Assoc/Prof Thomas Riley (Principal Research Scientist, PathCentre/UWA).

Project Title	Clinical efficacy of tea tree oil for treating coldsores
RIRDC Project No.:	UWA-56A
Start Date:	01/09/2000
Finish Date:	01/07/2001
Researcher:	A/Prof. Thomas V Riley
Organisation:	University of Western Australia Dept of Microbiology Queen Elizabeth II Medical Centre NEDLANDS WA 6009
Phone:	08 9346 3690
Fax:	08 9346 2912
Email:	triley@cyllene.uwa.edu.au
Objective	To increase the national and international acceptability of tea tree oil as an anti-viral therapy in the treatment of coldsores.
Current Progress	This project looking at the effects of tea tree oil treatment on coldsores was commenced in September, 2000 and followed the completion of a pilot study earlier that year. The pilot study results were very promising and suggested that a larger study was warranted. Following several protocol modifications based on our experience in the pilot study, approvals to conduct the study were obtained obtained from The University of Western Australia Human Research Ethics Committee and the Sir Charles Gairdner Hospital Clinical Drug Trials Committee.  Recruitment for the trial commenced in October, 2000 with many volunteers coming from the Sir Charles Gairdner Hospital site and The University of Western Australia campus. Volunteers were recruited by several methods including posters, pamphlets, talks to staff, global e-mails, a television story, displays in the main hospital corridor and articles in the hospital and university magazine. Volunteers were randomised on the basis of their self-reported history of coldsores and were given a tube of either 6% tea tree oil ointment or placebo (no treatment) ointment to apply during their next coldsore episode. By providing ointment to the volunteers ahead of time they are able to apply it to their coldsores very soon after noticing the first symptoms. Recruitment has been progressing very well and 122 volunteers have been randomised and received ointment. Of these, 55 volunteers (45% of the randomised volunteers) have subsequently presented with a coldsore. Additional strategies are planned to enhance recruitment over the next few months to enable us to reach our target of treating 80-100 coldsore patients.  The staff involved in the study are Dr Christine Carson (Senior Research Fellow, UWA), Ms Gail Lampacher (Research Nurse, PathCentre), Ms Linda Dry (Research Assistant, UWA), Dr David Smith (Clinical Virologist, PathCentre) and Assoc/Prof Thomas Riley (Principal Research Scientist, PathCentre/UWA).

Project Title	Multi-centre randomised clinical trials for tea tree oil products for vaginal infections
RIRDC Project No.:	UWA-57A
Start Date:	01/09/2000
Finish Date:	05/07/2001
Researcher:	A/Prof. Thomas V Riley
Organisation:	University of Western Australia Dept of Microbiology Queen Elizabeth II Medical Centre NEDLANDS WA 6009
Phone:	08 9346 3690
Fax:	08 9346 2912
Email:	triley@cyllene.uwa.edu.au
Objective	To demonstrate that tea tree oil is safe and efficacious for the treatment of two vaginal infections (candida vaginitis and bacterial vaginosis) using randomised clinical trials, following a pilot study, to show efficacy.
Current Progress	Collaborators in Australia, the United Kingdom and Denmark have been engaged. The study will be conducted in Perth (Australia), Leeds (UK) and Aalborg (Denmark) and each site has been visited by the trial co-ordinator, Dr Christine Carson. Extensive protocol development has been carried out in concert with the local, national and international collaborators and other advisers. Although time-consuming, the protocol development is considered critical to ensure that data from the studies are acceptable to national regulatory authorities such as the Therapeutic Goods Administration in Australia, the Medicines Control Agency in the UK and the Danish Medicines Agency. Approval to conduct the bacterial vaginosis study has been obtained from the relevant institutional review boards at Royal Perth Hospital, in Perth, Western Australia. Similar approvals are now being sought in Denmark and the United Kingdom. Final product development is nearing completion and the study will commence at the Perth site in June.


 

Project Title	The antifungal activity of tea tree oil in vitro
RIRDC Project No.:	UWA-58A
Start Date:	01/07/2000
Finish Date:	01/07/2002
Researcher:	A/Prof. Thomas V Riley
Organisation:	University of Western Australia Dept of Microbiology Queen Elizabeth II Medical Centre NEDLANDS WA 6009
Phone:	08 9346 3690
Fax:	08 9346 2912
Email:	triley@cyllene.uwa.edu.au
Objective	To expand the range of clinically relevant fungi tested against tea tree oil in vitro and to develop and assess methods for investigating the mechanism of action of tea tree oil against yeasts and filamenteous fungi.
Current Progress	The testing of filamentous fungi against tea tree oil has been completed. A total of 78 isolates of Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Alternaria spp., Cladosporium spp., Fusarium spp., and Penicillium spp. was tested against the oil. The activity of the tea tree oil components terpinen-4-ol, 1,8 cineole, a -terpineol, a -terpinene, g -terpinene, terpinolene and r -cymene are being investigated for activity against representatives of these fungal species.  Studies have been performed to investigate the rate of killing of fungi when exposed to tea tree oil, so-called 'time-kill studies'. These studies were performed against one isolate each of Aspergillus niger and Aspergillus fumigatus.  Two isolates of Aspergillus niger were investigated using an assay which compared the activity of tea tree oil against non-germinated and germinated conidia. These assays showed that newly germinated conidia were significantly more susceptible to tea tree oil than non-germinated conidia. Studies investigating the mechanism of action of tea tree oil against Candida albicans have commenced. Initial studies have focussed on whether tea tree oil, and/or components, cause the leakage of intracellular constituents, which possibly indicates cell membrane damage. So far, tea tree oil, terpinen-4-ol, a -terpineol, 1,8-cineole and terpinolene have been shown to cause some leakage of intracellular constituents.