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 Registration As A Medicine Critical
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Weed Control Options Offer Huge Savings |
Registration As A Medicine Critical
Registration of tea tree oil as an over-the-counter
medicine both in Australia and overseas will be critical to the
future of the tea tree industry.
That was one of the
main findings of a review of the Tea Tree Oil Research and Development
(R&D) program in 1994. The panel concluded that the lack
of credible data on the effectiveness of tea tree oil as an antimicrobial
agent is likely to be a major constraint on increasing the demand
for the oil.
There is concern that
the anticipated increased production of tea tree oil will drive
supplies beyond demand, and thus reduce prices. Therefore ways
of building demand must be the focus of future work by the industry.
The panel concluded
that "Funding for R&D, particularly that on the antimicrobial
efficacy of tea tree oil, must be increased if current obstacles
to profitability are to be addressed promptly and effectively".
The panel assessed
that investment in R&D on the production aspect of tea tree
has been timely and effective in providing knowledge and technology
to the industry. A critical factor in this being the establishment
of close relationships between the industry, the Rural Industries
Research and Development Corporation(RIRDC) and research providers.
The 1994 program review
recommended that RIRDC should maintain its tea tree R&D program,
but seek an increased level of industry funding.
The panel recommended
that about $250,000 be spend on 'building demand' related R&D
and $125,000 for 'supply-related' R&D, thus requiring a yearly
budget of $375,000.
The Board of RIRDC
agreed to continue supporting the program but required funding
to be on a $1 for $1 basis from 1996/97 onwards. RIRDC requires
that each of its 20-odd programs has a formal 5-year plan that
is developed in consultation with the industry or stakeholders
concerned.
Some of the returns
to date on the investment made in R&D in the tea tree industry
are outlined in this newsletter.
Key R&D Objective and
Strategies
The panel that reviewed
the Tea Tree R&D program in 1994 considered the likely future
of the industry to be as outlined below:
The panel concluded
that a future tea tree oil program should have the following major
objectives:
Tea-tree - Melaleuca
alternifolia - occurs naturally in Australia only in a small
area of northern New South Wales.
It has been used medically
on a small scale ever since European settlement in Australia in
Australia more than 200 years ago. Before that Aborigines also
used it - in non-processed form - as a treatment for headaches,
other pains and colds, and as an insect repellent.
Today, a growing number
of plantations in Australia are now believed to produce between
180 and 200 tonnes of tea tree oil each year. With the average
oil price of$50/kg, this takes the farm-gate value of the industry
to around $10 million/year.
NSW is still the predominant
producer, with increasing interest in North Queensland and in
WA, and there is also small planting in the Ord River.
The oil is incorporated
into many products, ranging from shampoos and conditioners to
soap and cream. It is also used in liniments, foot balms, insect
repellent and germicides.
While Australia currently produces about 99% of the worlds tea tree oil, there are indications strong prices are enticing other countries to consider establishing tea tree oil production.
China is apparently planning to plant large areas of the crop, and there is also interest coming from other Asian countries including India, Vietnam, Malaysia and Indonesia.
Zimbabwe is reported to have recently placed tea tree oil onto the market.
The Tea Tree Oil R&D
Program was established by RIRDC's predecessor, the Australian
Special Rural Research Council, in February 1990.
At the time, the industry
was only operating in Northern NSW, and was producing some 70
tonnes of oil, worth about $4 million. The farmgate price of
tea tree oil was $55/kg.
Since 1990/91 $1.68
million has been directed into the tea tree R&D program by
RIRDC and the industry. RIRDC is funded by the Commonwealth Government.
The industry's contribution began at 13% and built up to 20%
in 1994/95.
In addition, research
organisations and the industry have contributed significantly
to the cost of the program. For example, NSW Agriculture has directed
around $2 million into the tea tree R&D program to date.
Tea Tree Research Program 1989-1996
| Production R&D | Organisation | Funding
| Completion | |
| DAN-19A | 41,100 | 1990 | |
| UMA-4A | 15,000 | 1991 | |
| CSF-43A | 1992 | ||
| ANU-11A | 20,846 | 1993 | |
| DAN-87A | 210,822 | current | |
| DAN-61A | 5,000 | 1992 | |
| DAN-74A | 71,953 | 1994 | |
| DAN-91A | 81,087 | current | |
| US-20A | 110,480 | ?? | |
| DAN-60A | 10,065 | 1992 | |
| DAN-58A | 92,124 | 1993 | |
| DAN-59A | 5,000 | 1994 | |
| HAC-5A | 5,500 | 1991 | |
| DAQ-184A | 28,620 | current | |
| Safety & Efficacy R&D | ||||
| PHA-1A | 29,350 | 1991 | |
| PHA-2A | 93,150 | 1992 | |
| PHA-3A | 20,750 | ||
| SA-1A | 7,500 | 1992 | |
| UMA-12A | 57,240 | 1994 | |
| UMA-11A | 1995 | ||
| UWA-24A | 144,492 | current | |
| DAN-104A | 99,656 | current | |
| Mitech 1 | 73,000 | ||
Genetic Improvement of Tea Tree
Expansion of the tea
tree oil industry requires the use of plantations of high genetic
quality.
In the first stage
in the development of a breeding program, researchers Drs Penny
Butcher and Mike Slee set out to establish the degree of genetic
variation within the species used for oil production (ANU-11A).
Five different oil
types were identified in Melaleuca alternifolia trees,
including the one useful 'type' variety that has cineole levels
ranging from 0.8% to 8% and terpinen 4-ol levels from 38-42%.
Differences in leaf
oil composition between natural populations provide opportunities
for selection for oil quality.
Results from progeny tests of high heritability for oil yield together with the wide range of variation in growth rate and biomass production, in oil yield and coppicing ability indicate considerable gains can be expected from selection for single traits.
Negative correlations
between oil and yield and plant biomass suggest it is not possible
to simultaneously achieve major gains in the two traits.
Maintaining biomass
production at current levels, gains of 17% in oil yield and 14%
in coppicing ability can be expected in one generation, following
selection of the best one in ten trees.
For more information contact Ms Penny Butcher at the CSIRO Division of Forestry on (06) 281 8206.
Strategy Aims for 60% Improvement
As a result of a tea
tree breeding strategy that was instigated in May 1993, the first
improved tea tree seeds should be available by the end of the
1996.
The $430,000 program,
funded by RIRDC and Australian Tea Tree Industry Association(ATTIA),
NSW Agriculture and CSIRO, is being run by Gary Baker and John
Murtagh of NSW Agriculture, and John Doran of CSIRO Division of
Forestry and Forest Products.
The aim is to provide
seed of progressively improving genetic quality up to the year
2000.
Dr John Doran says
the profitability of tea tree plantations is very sensitive to
yield and price. "At current prices and yields (120-200 kg
per ha) growers are doing well, but they would need a substantial
increase in productivity to remain ahead in the price dropped
significantly", he said.
There is big scope
to improve yield per ha and oil quality. "We hope to improve
yields by 30% in the first instance and by progressively thinning
out the poorer lines within provenances to increase yield by 60%",
he said.
The basic elements
of the breeding strategy have been established in various parts
of the NSW North Coast including:
in a natural stand
of tea tree south of Casino where 783 trees in the stand have
been analysed and ranked for oil concentration, terpinen-4-ol
and 1,8-cineole. The best 74 trees were selected. The first
improved seed from the area was available in Spring 1995.
at Warallah, south
of Lismore, and 2 coppicing trials, one adjacent to the seedling
seed orchard and one on the coast Teven near Ballina were planted
in January 1994. The orchard is being thinned down and the best
trees for growth and oil producing characteristics will be kept
and grown on to flower and to produce seed by 1996.
was established at
the Wollongbar Agricultural Institute in Spring 1995 based on
cloned cuttings from the best 50 trees in the trial.
For more information
contact Dr John Doran, CSIRO Division of Forestry, phone: (06)
281 8206.
Naturally growing tea
tree is found in swampy areas of the NSW North Coast.
This prompted scientists
to investigate the benefits of irrigating tea tree so as to reproduce
a wetter environment than exists on plantations (RIRDC Project
No. DAN-19A).
The trials at Warallah,
near Lismore, were run over three years, of which all had dry
spells. Irrigation produced a response of increased herbage and
oil production in only one of these years.
The plant appears to
be adapted to producing flush growth even under dry conditions
(mid-September to mid-November). Even though water stress will
reduce production after that, in many districts rainfall increases
during summer to acceptable levels.
Dr John Murtagh points
out that the trial was located in an area where the sub-soil was
kept moist by groundwater. He says it is important to choose
sites like this to avoid the need for irrigations.
He emphasises that
it is vital to irrigate tea tree at establishment. "That
is for the first month or two, while the seedlings are being established",
he said. Many growers in NSW set up temporary irigation systems
for this period.
For more information
contact Dr John Murtagh at Wollongbar Agricultural Institute on
(066) 261 200.
North Queensland Yields Double NSW
Tea tree oil yields
1.5-2 times higher than the average in northern NSW are being
experienced on tea tree plantations in North Queensland.
This has been reported
by James Drinnan, Horticulturalist with the Queenland DPI, in
the Mareeba-Dimbulah Irrigation area.
James is working
on a R&D project (DAQ-184A) which is facilitating the development
of the tea tree industry in this area, where many tobacco growers
are seeking alternative crops.
There are currently
40 growers with about 220 hectares of tea tree, and harvesting
has only occured for the last 2 1/2 years. The crop is being
growing under existing irrigation systems set up for the tobacco,
so the production costs are higher, although James says this is
more than made up by the increased growth rates and oil yields
of the tea tree.
"The aim is
to develop irrigation scheduling for maximum oil yield and quality
and to establish a gene pool of selected superior plants for the
area," he said. Irrigation of tea tree in this area is vital
because of the lack of sub-soil moisture, except for the wet season.
For further information
contact: James Drinnan on (070) 928 555 or fax (066) 923 593.
In early research on
management options for plantation raised tea tree (UMA-4A), Dr
Lyall Williams found that while tea tree occurs naturally in swamps
and water courses, it does not flourish in these conditions. Optimum
production of oil the trees require good soil with adequate irrigation
and drainage.
Oil content was found
to vary seasonally, with higher levels in the summer months of
November to May and gradual reduction during the winter months
to the end of October.
Weed control was found
to be desirable, either by chemicals, harrowing or grazing. The
recommended plant spacing of around 25,000/ha allows access for
weeding activities, insect control, fertilising etc.
For more information
contact Dr Lyall Williams at Macquarie University School of Chemistry
on (02) 805 8303.
Weed Control Options Offer Huge Savings
A minimum of $1,100
per hectare can be returned to tea tree growers in weedy situations
by adopting the results of a recently completed research project
on improving weed control options (DAN-74A).
Project Leader Tony
Cook of NSW Agriculture says apart from these financial gains,
new recommendations will allow for increased managerial choices,
superior weed control and less likelihood of developing herbicide
resistance.
Approximately 80% of
tea tree growers surveyed as part of the project stated that weeds
were a major limitation to production and half were dissatisfied
with their current weed control techniques.
The five most abundant
weeds were kidney weed (Dichondra repens), carpet grass
(Axonopus affinis), sedges (Cyperus spp.), fleabane
(Conyza spp) and couch grass (Cynodon dactylon). It
was shown that a 97% reduction in yield was a consequence of high
weed densities in the first few months after planting.
Sixty five herbicides
were screened for a range of tea tree growth stages, in order
to identify treatments that were safe to tea tree, provided adequate
weed control and were not too cost prohibitive.
In some cases, recommended
treatments arising from the project are 80% cheaper that previously
recommended treatments and exhibit little difference in weed control
and safety. There was no detectable level of herbicide residue
in oil samples from tea trees treated with some of the new recommended
treatments.
"Although considerable
cost savings were made with new treatments (blanket applied),
there are further savings and benefits if the practice of directed
spraying was properly developed," says Tony Cooke. "This
could allow the use of herbicides normally damaging to tea trees."
A weeds identification
and weed control booklet will transfer information gained from
this project to relevant people and will be published in 1996.
For more information
contact Tony Cook at the Tamworth Centre for Crop Improvement
on phone (067) 631 100 or fax (067) 631 222.
Concern over the use
of chemicals for pests in tea tree plantations, and the potential
for residual pesticide contamination of the oil, has led to a
recent study of sustainable pest management strategies for tea
tree plantations.
Defoliating insect
pests, particularly the Pyrgo beetle, sap sucking mites and psyllids,
greatly affect the oil yield of plantations. These pests cause
the loss of leat tissue and reduce plant growth. Losses of millions
of dollars to producers can occur.
Project Leader Gus
Campbell of NSW Agriculture is looking for ways of minimising
the use of synthetic pesticides in the tea tree industry. Gus
has been monitoring the effects of climatic conditions on insect
pests. He has found that the number of insects affecting tea
tree is increasing. "Damage by some of the weavils, such
as the Elephant weavil, is growing, and this pre-disposes the
tea trees to fungal infections," he said.
The industry is facing
a difficult situation. Its commitment to the policy of zero residues
in tea tree oil, means that chemical companies are unwilling to
register chemicals for use on tea tree.
"Currently methonyl
is the only chemical registered for use, and it needs to be used
at quite high rates to be effective. While some of the synthetic
pyrethroids may be effective against these insect pests, and may
not lead to residues, chemical companies are concerned about the
nil residue level and are not registering these chemicals for
use on tea tree. Although some growers are getting permits to
use them for use in special one-off situations," he
said.
Gus has been conducting
trials on a monitoring technique to detect early flight activity
by Pyrgo beetles. If successful, this could allow better control
in early spring and when combined with strategic spraying delay
the pests building up in crops in summer or early autumn.
For more information
contact Gus Campbell on (066) 28 0604 or fax (066) 285 209.
Determing the best
time to harvest tea tree and ways of increasing oil yield was
the focus of a research program based at the Wollongbar Agricultural
Institute (DAN-58A).
Researcher Dr John
Murtagh says oil concentration in tea tree varies widely. In the
same plantation it changes from month tomonth, and sometimes from
day to day. Oil concentration also varies between plantations.
"These variable
trends make it difficult to identify what controls the oil concentration
and to decide when the oil concentration is at the best level
to harvest", he said.
The average oil concentrations
were found to be highest in summer/autumn when most of the leaves
on a tree had developed during the warmer months. The tea trees
were water stressed even when they were irrigated. Irrigation
only gave a 10% increase in oil yield.
Whilst water stress
persisted throughout most of the dry season (September-December),
the oil concentration generally increased over this period and
more than doubled in one experiment. No one cultural practice
or local environment appeared to be able to reduce the water stress
which is endemic in tea trees grown in plantations.
The researchers concluded
that from a production perspective, harvesting should be delayed
until the crop canopy is fully developed.
For more information
contact Dr John Murtagh at the Wollongbar Agricultural Institute
on 066 261 200.
In 1992/93 Dr John
Murtagh of NSW Agriculture visited Washington State University
to investigate how peak periods of oil yield in tea tree can be
predicted.
He worked with the
world renowned essential-oils research groups at the University
assessing the different ways oil concentration varies, using methods
developed for peppermint.
Dr Murtagh was looking
for an explanation for what happened to tea tree oil when oil
levels dropped. He found some was lost into the air through volatisation
from the oil glands in leaves, but was unable to prove definitively
that the balance was used as plant food with current research
techniques.
For more information
contact Dr John Murtagh, Agricultural Water Management, Lismore,
on (066) 25 1510.
In early 1992,
Sue Ackroyd reviewed the paths the industry must take to achieve
clearance of its products for medicinal use was completed by Sue
Ackroyd. She described the registration system for tea tree oil
products in Australia and the American monograph systems.
She said the industry
lacked the hard data needed to easily gain entry into the monographs,
which is required to generate a solid basis for entry into the
US and other world markets.
In 1994 Thomas Riley,
of t he Department of Microbioloty at the University of Western
Australia, reviewed the current information on the efficacy and
safety of tea tree oil.
He concluded that the
work done on antimicrobial activity of the oil so far had been
done in a fragmented way. He said there lacked valid susceptibility
testing methods, and there was only one or two published clinical
trials and little susceptibility data.
Dr Riley was concerned
about the lack of tea tree oil data published in respected and
scrutinised journals.
He recommended that
susceptibility tests for bacteria, fungi, and possibly viruses,
be developed and validated; for a wide number of organisms to
be tested against tea tree; and for other tests to be carried
out relating to the action of tea tree oil, oil quality, animal
experiments and human clinical trials.
The Cineole Question
The present trend
in the tea tree oil industry is to produce and market oils that
contain as little cineole as possible.
However, researcher
Dr Ian Southwell of NSW Agriculture says there is no scientific
evidence published to justify this.
Some authors suggest
cineole is a skin irritant while others report clinical trials
that did not detect any irritation. Indeed, the results of Dr
Southwell's research shows that cineole is not harmful to the
skin and is not detrimental to the anti-bacterial action of tea
tree oil.
The industry has
set a limit on 1,8-cineole of 15% and many would like to see levels
as low as 5%. Ian Southwell says there is a perception that oils
with ultra low levels of cineole are superior to oils with higher
levels of cineole. He says cineole, in concentrations above 15%
is not detrimental to the antimicrobial activity of the oil and
does not cause skin irritation.
The trials are being
conducted in such a way that they will be recognised by the US
Food and Drug Administration. The aim is to assist the acceptance
of tea tree oil as a pharmaceutical, particularly by the US.
What do you think
about cineole? We need your advice on the relative importance
of oil concentration versus cineole concentration!
There is hope that
further markets may be developed in Europe. Prospects and attitudes
to botanical medicines such as tea tree oil in the UK and Europe
were investigated by Dr Southwell in 1995.
He identified potential
strategies for gaining entry for tea tree oil to the British and
European pharmacopoeias and hence lessening the industry's current
reliance on gaining entry to the US registration system. As a
result, the German Pharmaceutical Codex (DAC) has elaborated a
draft monograph for tea tree oil.
For more information
contact Dr Ian Southwell, Wollongbar Agricultural Institute, on
(066) 261 200.
Proving the Value of Tea Tree Oil
Tomas Riley has followed
up his recommendations, with actions, having proof of tea tree
oils antimicrobial action published in several internationally
recognised medical journals.
His preliminary research
results show that the oil kills many bacteria present in common
infections, including some staphylococci and streptococci.
The research is being
conducted by researchers at the University of Western Australia
and the new Western Australian Centre for for Pathology and Medical
Research (RIRDC Project No. UWA-24A).
In related research,
being funded by a commercial company, Associate Professor Riley
is currently testing the effectiveness of tea tree oil for treating
thrush in a trial in Perth
The aim is to provide
the necessary information to help make tea tree recognised by
the world's pharmaceutical and medical communities as a therapeutic
agent.
If the research succeeds
it will greatly benefit the Australian tea tree industry by increasing
demand for the oil, particularly from the United States market.
For more information
contact Tomas Riley, Department of Microbiology, University of
WA, on (09) 346 3690
In early research at
Macquarie University (UMA-12A) the antimicrobial activity of a
large number of commercial tea tree oils was examined.
Results demonstrated
the importance of terpinen-4-ol for activity against microbes
including those causing acne, tinea, dandruff.
The powerful antimicrobial
activity of p-cymene, a minor component of tea tree oil,
was confirmed. Some micro-organisms are highly susceptible to
a combination of terpinen-4-ol and p-cymene.
Contact Dr L Williams,
Macquarie University, (02) 850 8612).
Tests of the treatment
of tinea with tea tree oil showed that the symptoms of the problem
were much reduced when tea tree oil was applied.
In the trial, Professor
Barnetson of Sydney's Royal Prince Alfred Hospital Department
of Dermatology, treated 104 patients (PHA-2A).
The tea tree oil treatment
however, did not cure the actual fungal infection as effectively
as the commonly used manufactured product based on tolfonate.
Contact: Professor
R. StC. Barnetson on (02) 516 6862.
Although tea tree oil
has been used for more than 60 years in non-prescription pharmaceutical
products, no skin sensitivity or irritation potential tests appear
to have been published.
In a project conducted
by Pharmaco (PHA-3), creams containing a range of concentrations
of tea tree oil were formulated in a non-irritating base and stability
tested and applied daily to volunteers over a period of 28 days.
Tea tree oil was not
found to produce any significant skin sensitivity or irritation
even at the higher concentrations.
Further tests on
skin irritancy to tea tree oil is being conducted by Dr Ian Southwell
of NSW Agriculture (DAN-104A).
Contact Dr S
Freeman, Pharmarco, on (02) 413 4760.
Last updated: 30 August 1996
Copyright © RIRDC
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