A research update on
the tea tree industry from RIRDC distributed to researchers, industry,
government, farmers, libraries and consultants. Contributions are welcome.
Contact Roslyn Prinsley, RIRDC General Manager Research on Phone 026272
4033, Email:
roslynp@rirdc.gov.au
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In this issue:
Soothing effects of tea tree oil shown
The ability of tea tree oil to reduce swelling has been shown in trials on mice by a team of South Australian researchers.
Team leader Professor John Finlay-Jones of Flinders University says the effect of tea tree oil on inflammation resulting from exposure to a chemical that induces a skin reaction was tested as part of the research.
"The trial induced a chemical sensitivity in mice to mimic a condition that is experienced by up to 1 in 10 people. This type of reaction was chosen to test the effectiveness of tea tree to sooth this type of delayed inflammatory reaction.
"We showed that tea tree oil applied 30 minutes before or up to 7 hours after exposure to the chemical signifi- cantly reduced skin swelling. This reduction of oedema was achieved with neat tea tree oil or ointment containing 5% of the oil," he said.
The effectiveness of tea tree oil in reducing a mild sunburn induced swelling in mice was also tested, but it was found to be ineffective.
In further trials the ability of tea tree oil to reduce the inflammation resulting from skin allergies is now being tested.
In this research a tiny amount of histamine will be injected into the mice to induce a localised immediate hypersensitive skin reaction, a bit like hives.
Human trials follow up promising pilot study
Further research on the use of tea tree oil to treat cold sores is underway, with nearly 150 cold sore sufferers recruited and more than 60 treated for a project running in Western Australia.
This trial follows an earlier pilot study that showed that people who treated their cold sores using a gel containing 6% tea tree oil up to 5 times a day had faster times to healing (9 versus 12.5 days).
Researcher Dr Christine Carson says these very promising results suggested this larger study was warranted.
"We are recruiting volunteers from the Sir Charles Gairdner Hospital, The University of Western Australia campus and the Perth metropolitan area for the trial.
"There is strong interest in treatments for cold sores because 20% - 40% of people are prone to developing cold sores because they carry the herpes simplex virus 1, which at this stage has no cure," she said.
The trial will be completed late this year with results available in 2002. The project is co-funded by RIRDC and Australian Bodycare Pty Ltd.
Contact: A/Professor Tom Riley ph: (08) 9346 3690, email: triley@cyllene.uwa.edu.au This current research is being co-funded by RIRDC and Thursday Plantation.
The team has also applied for funds to run further trials to test these findings in humans.
"Once underway we will be looking for volunteers who are either sensitive to nickel or have other skin allergies who wish to be test the effectiveness of tea tree oil to reduce swelling and itching.
This research proposal has received support from RIRDC, pending the signing of an agreement with a joint funding partner," added Dr Finlay-Jones.
Contact: Dr Prue Hart Ph: (08) 8204 5414, Email: Prue.Hart@flinders.edu.au
Tests on tea tree oil show it works
Tea tree oil has been proven to be effective in inhibiting a wide range of fungi found in our environment. Laboratory trials at The University of Western Australia’s Department of Microbiology show that tea tree oil kills yeasts, like candida, and dermatophytes, that cause diseases such as tinea and ringworm.
Research leader Associate Professor Tom Riley says the effect of different concentrations of tea tree oil on the fungi has been laboratory tested and the way in which tea tree oil inhibits growth of these organisms investigated.
"Results of test tube trials show that yeasts (including members of the genera Candida, Cryptococcus, Rhodotorula, Saccharomyces and Trichosporon) are inhibited by tea tree oil in the range of 0.03% to 0.5%, and are killed by tea tree oil in the range 0.06% to 1.0%.
Similarly, filamentous fungi, some of which are also known as dermatophytes, are inhibited in the range of 0.04% to 0.03% and killed in the range of 0.06% to 1.0%.
"These results provide the basic information needed to develop and finally evaluate tea tree oil products for the treatment of fungal infections." "There are a limited number of topical antifungal treatments on the market and there is growing resistance to these products, so finding alternative treatments would be very useful for people who suffer as a result of infections with these types of fungi." said Associate Professor Riley.
Fungi that lurk in air conditioning
In the latest research into the antifungal activity of tea tree oil, an additional group of fungi have been tested. They include a total of 78 isolates of Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Alternaria spp., Cladosporium spp., Fusarium spp.
and Penicillium spp.
Researcher Kate Hammer says that some of the aspergillus species can cause a disease called aspergillus or ‘farmers lung’.
"Many of the organisms tested are also found in air conditioning ducts and cause problems such as sick building syndrome.
"Some companies are already using tea tree products to reduce the bacterial and fungal load in air conditioning systems, but to date there has been no hard data showing the effectiveness of tea tree oil for this process," she said. "The good news is we are well on the way to providing that evidence." This recent research into the fungicidal effects of tea tree oil is cofunded by RIRDC and Australian Bodycare Pty Ltd.
Contact: Kate Hammer ph: (08) 9346 1986, email: khammer@cyllene.uwa.edu.au
High hopes for vaginal infection trials
An important clinical trial has just commenced to test the effectiveness of tea tree oil products in treating two common vaginal infections (candida vaginitis and bacterial vaginosis).
This international trial will take place at three sites - in Perth, Western Australia, Leeds in the UK and Aalborg in Denmark.
Research Leader Associate Professor Tom Riley says that bacterial vaginosis is the most common complaint that women present to GP’s.
"In the US for example this problem is responsible for something like 10 million GP visits by women each year. Treatments for this condition are currently limited and there is a high relapse rate after their use.
"If tea tree oil products are demonstrated to be an effective cure then a large new market will be opened to the industry," he said.
Extensive protocol development has been carried out with local, national and international collaborators in the trial. Although timeconsuming, this will be critical to ensure that the data from the studies are acceptable to national regulatory authorities in Australia, the UK and Denmark.
The project is co-funded by RIRDC and Australian Bodycare Pty Ltd.
Fighting oral microorganisms can improve wellbeing
There are a large number of bacterial species found in the mouth, with some of them causing a with some of them causing a number of systemic problems including dental disease, and even extending to diseases like bacterial endocarditis, a cause of heart disease.
A project is underway at The University of Western Australia’s Department of Microbiology to determine the susceptibility of oral microorganisms to tea tree oil and to evaluate its potential as a topical antimicrobial agent for oral infections.
Project Leader Dr Christine Carson says to date their research shows that a number of Streptococcus and Actinomyces species are susceptible to tea tree oil at concentrations similar to those reported previously for other bacteria.
Other oral pathogens to be laboratory tested include the following genera: Fusobacterium, Prevotella, Peptostreptococcus, Haemophilus, Porphyromonas and Treponema.
This Project is co-funded by RIRDC and Australian Bodycare Pty Ltd.
Contact: Dr Christine Carson, Ph: (08) 9346 3288, email: ccarson@cyllene.uwa.edu.au
Skin Sensitivity to Tea Tree Oil
Packaging important in avoiding reactions
Research into skin sensitivity to tea tree oil has come up with good evidence that storage conditions of tea tree oil have a strong influence on oxidation of the oil, which is linked to skin sensitivity.
Associate Professor Tom Riley of The University of Western Australia’s Microbiology Department says that while they know that the products of oil oxidation cause skin sensitivity they are not yet sure which oxidation product is the main cause.
"The industry should look at how it packages its oil. Clear packaging is not great, instead storage and sale of pure oil in dark bottles is recommended to prevent oxidation. It is also preferable to store the oil in small containers as the oil in large bottles is exposed to air regularly over a longer period of time," he said.
Associate Professor Riley also recommends that the pure tea tree oil be packaged with childproof caps to prevent poisoning of young children.
Previous studies have shown that only about 2% of people are sensitive to tea tree oil, but there have been a few cases of severe reactions.
Associate Professor Riley says that irritancy to tea tree oil is definitely concentration dependant and the industry should get away from selling 100% oil and sell products with around 5% tea tree oil.
Contact: A/Professor Tom Riley ph: (08) 9346 3690, email: triley@cyllene.uwa.edu.au
Improved seed the only way to go
In 1992 the average plantation production of tea tree oil was 148kg/ha. This was considered well below potential and unviable during periods of low prices. Today the average yield of improved stands of tea tree is more like 192kg/ha due to the establishment of the Tea Tree Breeding Project.
The Rural Industries Research and Development Corporation (RIRDC) and the Australia Tea Tree Industry Association (ATTIA) recognised the potential to provide progressive, economically significant gains in oil yield and quality of Melaleuca alternifolia when they supported the first phase of breeding in May 1993.
Eight years down the track the Tea Tree Breeding Project based at Wollongbar Agricultural Institute recently had its second positive review.
The Tea Tree Breeding Project has successfully released seed to the industry for the fourth consecutive year. This brings a total of 7 kg of seed distributed, enough to plant over 1000 ha of tea tree plantation. Improvements in yields of around 30% have already been achieved and by 2003 the yield of oil is expected to be 60% over 1992 levels.
Chairman of the Breeding Committee and tea tree grower Richard Davis of G.R. Davis says the program has both met and exceeded expectations.
"There is now industry-wide recognition of the success of this breeding program. Everyone you talk to at industry meetings, whether they be large corporate operators or smaller operators, all say you would be mad to plant anything other than the seed produced from the program." "The improvements are very obvious. Some people are seeing a 40% to 60% improvement in yield from the seed that is only supposed to be 17% to 20% improved. This shows it is almost certain the program will result in the 60% yield improvement it aimed for.
"Up to the price crash all the seed from the program was over-subscribed. Now there is a small amount of seed still available because the demand for new plantations has slowed.
However, there will be continued demand from existing growers looking to replant around 450 hectares each year, and from all reports they will only be looking for the seed from the breeding program.
"The project has brought in around $270,000 in income so far and this shows that it will be feasible in due course for the breeding program to be self-funding, which is very unusual for a research project!" he said.
Where to from here?
The conclusions of a recent economic analyses of the tea tree breeding program concluded that a third phase (2001-2006) would be likely to yield significant benefits, with uptake of new seed still likely to occur at oil prices ranging from $22/kg to $16/kg. This compares with the uptake of current seed requiring a price of $27/kg to be attractive to growers. In addition high-yielding materials will be needed to keep producers in business, or attract new investors.
The proposed third phase of the breeding program concentrates on work needed in developing orchards and exploring cloning to deliver the highly improved germplasm that may be essential to the future economic viability of the industry in Australia.
Contact: Dr Gary Baker,
Wollongbar Agricultural Institute, Ph (02) 6626 1224, email: gary.baker@agric.nsw.gov.au.
| INDUSTRY
SNAPSHOT
The Australian tea tree industry has become an important regional industry in Australia with a farm-gate value in excess of $20 million. Approximately 90% of tea tree oil is exported. There are presently some 300 producers in the industry with a total plantation of an estimated 6000 ha. |
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Last updated: 10 August 2001
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