Ashley Dowell – Essential Oil Producers Association of Australia & Southern Cross University

23rd October 2019

Introduction

Australia has a unique flora largely of Gondwanan origin with later influence from the Indian

subcontinent and South East Asia. Gondwana land was a pre-historic super continent including Australia, New Zealand, South America, Antarctica, Africa and the Indian sub-continent. Although

separating early, it is proposed that Australia and India re-connected for a period of time before

separating again. In more recent history Australia was connected to South-east Asia by land bridges

which arose due to falling sea levels resulting from ice age glaciation

Dominant plant families present in Australia include the essential oil bearing genus:

Myrtaceae – Eucalyptus, Melaleuca, Leptospermum

Rutaceae – Boronia, Citrus

Other significant essential oil bearing plant families found in Australia are the Santalaceae,

Myoporaceae, and Cupressaceae.

Australia is often perceived as a land of deserts but is in fact a diverse collection of fire and drought

adapted environments.

Eucalypt woodlands make up to 39% of Australian vegetative cover, predominantly in New South

Wales and Queensland followed by Hummock grasslands at 23% found mostly in Western Australia,

Queensland and New SouthWales and Acacia woodlands occupying 10-20%, mostly in Western

Australia, Queensland and New South Wales. There are significant areas of Acacia shrublands,

Tussock grasslands and Chenopod shrubs and forblands, particularly in South Australia.

There are relatively small (less than 70,000 Km2) but biologically significant areas of tropical and

temperate rainforest in eastern coastal areas from Queensland to Tasmania, as well as Tall

eucalypts forests and Callitris and Casuarina forests further inland and in sub-alpine areas.

Figure 1. illustrates the current distribution of Australian vegetative cover with areas displayed in

orange being highly modified pastures and annual crops; dark green, native forests and woodlands;

light green, native grasslands and minimally modified pastures and pink being native shrub and

heathlands.

Australian Essential Oils –

History and Emerging Trends

Figure 1. Contemporary satellite image of Australian vegetative cover.

Figure 2. is a historical map of Australian vegetative cover prepared in the early 20th century which

more clearly illustrates the distribution of Australian vegetative cover prior to significant

agricultural manipulation of the landscape This maps highlights the limited areas of tropical

rainforest which existed in Australia, of which very little lowland rainforest exists today due to

intensive agriculture. Essential oil bearing plant families are distributed across the majority of

Australia’s diverse environments.

Figure 2. Historical map of Australian vegetative cover.

EssentEssentEssentEssential Oil Production in Australiaial Oil Production in Australiaial Oil Production in Australiaial Oil Production in Australia

Australia was first settled by the British in 1788 and in that same year Surgeon General White

distilled the essential oil of Eucalyptus piperita found naturally at Sydney cove, the location of their

first colony. The product was exported to Britain and purported to be more efficacious than oil of

peppermint in alleviating pulmonary disorders.

Although indigenous Australians are not known to have distilled essential oils they were commonly

used in therapeutic inhalations made by “smoking” leaves on campfires, the sick person lain

downwind of the therapeutic smoke. There are also reports of Cypress bark being used as a

therapeutic blanket as an anti-febrile treatment.

Significant commercial distillation of Eucalyptus radiata (var. Autraliana) was undertaken by Joseph

Bosisto at Dandenong Creek (just outside of Melbourne) by the 1880’s. Eucalyptus oil production

continued as a significant export industry until the 1950’s, when the post war for synthetic

pharmaceuticals replaced “phyto-pharmaceuticals”.

Australian SandalwoodAustralian SandalwoodAustralian SandalwoodAustralian Sandalwood

From the 1820’s Pacific sandalwood (S. Yasi, S. austrocaledonicum and S. insulare) were initially exploited by Australian traders. By the 1840’s Western Australian Sandalwood extraction commenced with large export market in China. This trade was exclusively in timber and not distilled essential oil.

Attempts by government regulatory bodies to regulate the harvest quotas began in the 1800’s and continue today. Until recently all Australian Sandalwood extraction has been from wild harvest.

Distillation of Australian Sandalwood oil began with Braddock in Perth by 1913. By the 1920-30’s the industry grew to produce significant exports of both wood and oil derived from S. spicatum in Western Australia and Santalum lanceolatum in Queensland.

Australia’s involvement on two fronts during the Second World War resulted in substantial human casualties from a relatively small population. This resulted in a significant post war labour shortage which contributed to a decline in Sandalwood production.

By the 1950-60’s the price for wood increasingly exceeded value of oil to the extent that commercial production of distilled Australian Sandalwood oil ceased by the 1970’s.

Early Researchers

Early researchers into the identification, classification and chemical analysis of Australian Native oils include most notably, R.T. Baker, H.G. Smith, AR Penfold and J. Morrison

Henry George Smith (1852 –1924) was a chemist who produced pioneering work on the chemistry

of the essential oils of the Australian flora. He began working with the Sydney Technological

Museum in 1884 and by 1895 was working in collaboration with famous Australian botanist Joseph

Maiden. He began work with botanist R.T Baker in 1896 looking at essential oils of Eucalyptus

piperita. Their work resulted in publication of “A Research on the Eucalyptus especially in Regard to

their Essential Oils” in 1902. This collaboration also resulted in the important publication “ A

research on the Australian Pines” in 1910.

Smith had been appointed assistant curator and economic chemist at the Sydney technological

museum in 1899 and held this position until his retirement in 1921.

Smith was the author of more than 100 papers with his work on the essential oils of the Australian

flora achieving worldwide recognition. He is honoured in the name Eucalyptus smithii R. T. Bak.

(1899)

Figure 3. H.G. Smith

Richard Thomas Baker (1854 -1941) was an Economic Botanist with the Sydney Technological

museum, working initially as assistant curator to Joseph Maiden and later succeeding Maiden in this

role. He worked closely with H.G. smith producing most significantly “A Research on the Eucalyptus

especially in Regard to their Essential Oils” and “ A Research on the Australian Pines” mentioned

previously.

Figure 4. R.T. Baker

Arthur de Ramon Penfold (1890 – 1980) was an Australian chemist and museum director. He

worked initially with H. G. Smith and achieved world recognition largely in the field of the essential

oils of the Australian flora. He published some hundred original research papers, many in

collaboration with F. R. Morrison, in Journal and Proceedings of the Royal Society of New South

Wales.

Figure 5. A.R. Penfold

Frank Richard Morrison (1895 – 1967) was an Australian chemist and Museum director who

worked initially as an assistant to Smith and Penfold and later collaborated with Penfold extensively

on the research programme investigated in the diversity of essential oils produced by Australian

plants. He succeeded Penfold as Director of the Australian Museum.

The work of Penfold and Morrison demonstrated that chemotypic diversity in Australian native

plant species is the norm rather than the exception in contrast to the thesis of their predecessors

Baker and Smith who proposed that chemical consistency prevailed throughout a species to the

extent that it could be used for taxonomic classification.

This chemotypic diversity supports the adaptive nature of Australian plant species required to

survive in a relatively harsh and unpredictable environments.

Recent researchers

In the latter half of the 20th century there are numerous significant researchers in the field of

Australian Native oils but most notably: Erick Lassak, Joseph Brophy, Emilio Ghisalberti and Ian

Southwell.

Erich V. Lassak (1934 - 2015) began work with the Sydney Museum in 1964 gaining his

Ph.D in chemistry from the University of NSW in 1972. He worked as the Senior Research Scientist

with the NSW Department of Agriculture from 1979 and published approximately 50 papers on

Australian Native Oils. He most famously co-authoured with T. McCarthy, the classic book

“Australian Medicinal Plants “published in 1983.

He was President of the Australian Society of Perfumers and Flavourists, Chairman of Standards

Australia Committee CH-021 Essential oils and founding Secretary of EOPAA (Essential Oil Producers

Association of Australia)

Figure 6. Erich Lassak

Associate Professor Emilio Ghisalberti (1943 – 2015) was a Natural Products

Chemist who worked on the isolation and structural elucidation of natural products from Western Australian plants. Amongst a wide range of work he produced comprehensive reviews of genus Eremophila and Boronia, looking in particular at their respective aromatic components. He worked as a lecturer at University of Western Australia from 1970 – 2012 producing more than 100 scientific publications.

Figure 7. E. L. Ghisaberti

Joseph John (JJ) Brophy is the most prolific author of the chemistry of Australian essential

oils having published over 100 papers from 1969 to the present day. He has worked primarily at the

University of NSW where he currently holds the post of Research Fellow.

Brophy produced an extensive collection of Australian Native oils with ~ 5000 specimens currently

held by Southern Cross University and is author of important compendia of essential oil

compositions of the Genus Melaleuca, Leptospermum and Eucalyptus.

Figure 8. J.J. Brophy

Professor Ian Southwell

Known to many in the global essential oil industry, Ian Southwell worked as the Principal Research

Scientist at NSW Department of Agriculture from 1983 – 2005. His comprehensive research

includes most notably seminal studies on the chemistry of Backhousia citriodora (Lemon Myrtle),

Melaleuca alternifolia (Tea Tree Oil).

He was Secretary of EOPAA from 2005 – 2015 and is the current chairman of the Standards Australia

Committee CH-021 for Essential Oils.

To date he has published over 50 papers on Australian Native oils and continues to do so in his role

as Adjunct Professor with Southern Cross University.

Figure 9. I. A. Southwell

Australian Native Oils - Emerging Trends

A number of Australian native oils which were commercialised in the early 20th century later waned

in popularity and thus production, including Tea Tree Oil and Lemon Myrtle. Interest in these oils

and others gathered momentum in the 1970-1980’s with an increase in consumer demand for

natural alternatives for antiseptic, insect repellence and fragrance and flavours.

Since the 1980’s production of Tea Tree has moved from traditional wild harvested “bush cut”

production to mechanised broad acre production. The growth in global popularity of Tea Tree Oil

has seen an increase in annual production of ~ 50 tonne pa in the late 1990’s to record production

of ~1000 tonne in recent years.

Lemon myrtle gained a huge resurgence in interest in the mid 1990’s with cultivators actively

seeking and selecting optimal varieties for essential oil production and the creation of the

Australian Standard for Essential Oil of Backhousia citriodora in 2000. Interest waned through the

2000’s with a resurgence in popularity in recent years resulting in a shortage of supply.

Despite waning in the 1970’s, production of WA Sandalwood (Santalum spicatum) has grown

significantly since the 1990’s led largely by a shortage in supply of Santalum album. Significant

plantations of S. spicatum and S. album have been produced since the late 1990’s and are now

starting to produce significant oil yields.

Although the genus Eucalyptus is amongst Australia’s most renowned plants and the cineole type

oils being the principal product of the early Australian essential oils industry, current production is

relatively low on a global scale with production as low as 100 tonne pa. This is largely due to high

labour costs of production in Australia as compared with other nations producing the bulk of

Eucalyptus oil. Apart from essential oils Eucalyptus produce high quality hardwoods for use in

construction and paper production and are readily adaptable to a range of environments. In an

attempt to cost effectively produce Eucalyptus oil in Australia there is a move to develop “Mallee”

Eucalyptus species such as E. polybractea and E. kochii which have good coppicing attributes,

produce high grade cineole oils and grow in relatively arid environments as compared to well

known forest species such as E. globulus, E. radiata and E. dives.

There are numerous other Australian native oils which are relatively under-developed and have

significant potential for growth including: Boronia megastigma (Boronia absolute), Leptospermum

petersonnii (Lemon Scented Tea Tree Oil), Melaleuca quinquenervia (Nerolina), Melaleuca ericifolia

(Rosalina), Callitris intratropica (Blue Cypress) and Eremophila mitchellii (False Sandalwood) and

Kunzea ambigua (Tick-bush oil).

MelaleMelaleMelaleMelaleuca ericifoliauca ericifoliauca ericifoliauca ericifolia (Rosalina)(Swamp paperbark)(Rosalina)(Swamp paperbark)(Rosalina)(Swamp paperbark)(Rosalina)(Swamp paperbark)

Melaleuca ericifolia commonly known as Swamp paperbark is distributed along the south-eastern

coast of mainland Australia and also occurs in southern islands including Tasmania.

The essential oil (coined as “Rosalina”) can vary in relative abundance of common constituents

dependent upon geographical source is and is reported to occur in two different chemotypes. One

high in cineole (up to 44%)the other high in linalool (up to 44%). Limonene content can also vary

significantly (3-15%). Variation in these components can influence the aroma profile substantially.

Figure Figure Figure Figure 11110000. . . . M. ericifoliaM. ericifoliaM. ericifoliaM. ericifolia distributiondistributiondistributiondistribution Figure Figure Figure Figure 11111111. . . . M. ericoliaM. ericoliaM. ericoliaM. ericolia flowersflowersflowersflowers Figure 1Figure 1Figure 1Figure 12222. . . . M. ericifolia M. ericifolia M. ericifolia M. ericifolia standstandstandstand

Melaleuca quinquenervia (Broad Leaved Paperbark)

Melaleuca quinquenervia is widely distributed along the east coast of mainland Australia north of

Sydney and grows predominantly in low lying coastal areas.

It occurs in two distinct major chemotypes one high in cineole and viridiflorol (Niaouli) and the

other high in linalool and nerolidol (coined as Nerolina). The species is also found in New Caledonia

where it occurs as an upland trees species as well as parts of Papua New Guinea and Indonesia.

Historically high yielding Niaouli varieties have been exported to Madagascar, Sri Lanka and some

African nations where it has been exploited for commercial production of Niaouli oil for the last

century. The species is also well known as an invasive weed in North America where it was

introduced through the nursery trade in the early 1900’s and is now a significant environmental

problem in the Florida everglades.

In Australia the naturally occurring Niaouli varieties are low yielding so have not been used for oil

production. South of the Queensland border the Nerolina chemotype is predominant and can be

high yielding. Production is currently limited due in part to longer distillation times required for oil

production but there is significant scope for targeted selection and varietal development.

Figure 1Figure 1Figure 1Figure 13333. . . . M. quinquenerviaM. quinquenerviaM. quinquenerviaM. quinquenervia leafleafleafleaf Figure 1Figure 1Figure 1Figure 14444. . . . M. quinquenervia M. quinquenervia M. quinquenervia M. quinquenervia distributiondistributiondistributiondistribution

Figure 1Figure 1Figure 1Figure 15555. . . . M. quinquenervia M. quinquenervia M. quinquenervia M. quinquenervia forestforestforestforest

Figure 16. Nerolidol Figure 17. Linalool

Boronia megastigma (Boronia absolute)

Native to the winter swamps of the southern Western Australian highlands Boronia megastigma is a

herbaceosu shrub which produces a highly fragrant floral essential oil traditionally extracted by

enfleurage. The principle fragrant components are β-ionone and heptadec-8-ene. These components are

degradation products of the carotenoids which provide the rich pigments of Boronia flowers in the same way

that damascenones in Rose oil are derived from the carotenoid pigments of Rose flowers.

Although native to Southern Western Australia, Boronia megastigma can be grown successfully in similar

microclimates found in Tasmania and other southern regions of Australia.

Figure 18. B. megastigma flowers Figure 19. β-ionone Figure 20. B. megastigma distribution

Leptospermum petersonii (Lemon Scented Tea Tree Oil)

Leptposperum personnii grows naturally on the Mid-east coast of mainland Australia on sandy or

rocky escarpments in rainforest or sclerophyll forest. It occurs in range of chemotypes with varying

amounts of neral, geranial and citronellal. It has a pleasant lemon scented aroma and is

used as a topical insect repellent.

Figure 21. L. petersonnii leaf and flowers Figure 22. L. petersonnii leaf distribution

Figure 20. Citronellal Figure 21. Neral

Eremophila mitchellii (False Sandalwood)(Desert Rosewood)(Buddha

wood)

Widespread in semi-arid regions of NSW and QLD, Eremophila mitchelli is a tree species of the

genus Eremophila, most species of which are herbaceous shrubs and feature in material medica of

indigenous Australians.

It goes by a range of common names including False Sandalwood, Buddha wood and Desert

Rosewood. It produces a heartwood essential oil rich in fragrant sesquiterpene ketones known as

Eremophilones. The aroma is rich and balsamic and reminiscent of Sandalwood and Agar oil. The

distribution and availability of Eremophila mitchelli is vast and in many areas it is cleared felled to

create /maintain semi-arid pasture. While current production is relatively small there is significant

scope for increased production from sustainable wild harvest subject to demand.

Figure 2Figure 2Figure 2Figure 23333. . . . EremophiloneEremophiloneEremophiloneEremophilone Figure 2Figure 2Figure 2Figure 24444. . . . E. mitchelliiE. mitchelliiE. mitchelliiE. mitchellii distributiondistributiondistributiondistribution

Figure 2Figure 2Figure 2Figure 25555. E. mitcehelli flowers. E. mitcehelli flowers. E. mitcehelli flowers. E. mitcehelli flowers Figure 2Figure 2Figure 2Figure 26666. . . . E. mitchelliiE. mitchelliiE. mitchelliiE. mitchellii harvested timberharvested timberharvested timberharvested timber

Figure 2Figure 2Figure 2Figure 27777. . . . E. mitchelliiE. mitchelliiE. mitchelliiE. mitchellii forest standforest standforest standforest stand

Callitris intratropicaCallitris intratropicaCallitris intratropicaCallitris intratropica (Blue Cypress)(Blue Cypress)(Blue Cypress)(Blue Cypress)

Found naturally in far northern Australia (Arnhem land and Cape York), Callitris intratropica

Produces heartwood oil rich in guiaol which can produce guaiazulene upon distillation making the

oil blue. The oil has a distinctive and pleasant aroma and is reported to have anti-inflammatory and

anti-fungal properties.

Figure 2Figure 2Figure 2Figure 28888. . . . E. E. E. E. mitchelliimitchelliimitchelliimitchellii distributiondistributiondistributiondistribution

Figure 2Figure 2Figure 2Figure 29999. . . . GuaiaolGuaiaolGuaiaolGuaiaol FFFFigure igure igure igure 30303030. Guaiazulene. Guaiazulene. Guaiazulene. Guaiazulene

Figure 31. C. intratropica leaf and seed Figure 32. C. intratropica “blue” oil

Taxandria (syn. Agonis) fragrans (Fragonia)

Taxandria fragrans, formerly identified as Agonis fragrans is a shrub species that is found in

swamps, rivers and valleys in coastal areas south-west region of Western Australia.

The essential oil occurs in a range of chemotypes with one being trademarked as Fragonia®. It contains 4 significant components occurring in the following ranges: cineole 22 – 33%;

a-pinene 22 – 31%; linalool 6 – 13%; a-terpineol 5 – 8%.

Figure 33. T. fragrans distribution Figure 34. T. fragrans stand

Figure 33. T. fragrans flowers

Kunzea ambigua – Tick Bush

Kunzea ambigua is found from north eastern New South Wales through Victoria to Tasmania in

coastal and near coastal regions of sandstone soils. Other occurrences are reported in southern

Western Australia and parts of New Zealand. However, as its name suggests taxonomy of this species

is somewhat confounded by hybridisation. The species produces a range of chemotypes but those of

particular interest are high in viridiflorol and globulol. Some chemotypes also produce β-triketones

which are phloroglucinol derivatives found in myrtaceous plant species.

Figure 35. K. ambigua flowers Figure 36. K. ambigua leaf and flowers

Figure 38. Viridflorol

Figure 37. K. ambigua distribution

Unique and Rare Australian Native Oils

There are also a range of unique oils produced by Australian plants which are either limited in finite

production such as Australian Rosewood oil, or are relatively under explored such as beta (β)

triketone chemotypes of Eucalyptus (E. cloeziana), Backhousia (B. angustifolia) and Leptospermum

(Leptospermum scoparium – Manuka, Jellybush).

Australian Native Oils Australian Native Oils Australian Native Oils Australian Native Oils ---- Beta TriBeta TriBeta TriBeta Tri----ketonesketonesketonesketones

β-triketones (BTK) are a class of acylphloroglucinols found in Myrtaceous species in Australia and New Zealand. BTK chemotypes are commonly found amongst more common terpene chemotypes and their occurrence seems to be environmentally guided and may be an adaptive feature.

BTK’s are typically highly insecticidal/repellent and patents exist which encompass all BTK analogues for insecticidal activity.

The occurrence of BTK’s was comprehensively reported by JJ Brophy . They are found in various species including:

Eucalyptus cloeziana (Tasmanone, Conglomerone, Agglomerone)

Eucalyptus grandis (Grandflorone)

Eucalyptus jensennii(Jensenone)

Melaleuca platyphylla (Platyphyllol)

Leptospermum scoparium (Manuka, Jellybush)

Backhousia angustifolia (Angustiones)

Kunzea sp. (Kunzeanones)

Figure 39. Leptospermone Figure 40. Tasmanone

Dysoxylum fraserianum (Australian Rosewood)

Dysoxylum fraserianum is a large tree growing in sub-tropical rainforest in New South Wales and

Southern QLD. It produces a valuable and fragrant cabinet timber highly sought after for

manufacture of furniture.. The essential oil is produced by distillation of the heartwood and waste

form the production of cabinet timber production is used for this purpose. The oil is comprised

predominantly of a-cadinol but also produces guaiazulene with a rich sapphire blue colour. It has a

pleasant earthy aroma reminiscent of the Australian rainforest.

Figure 41. D. fraserianum tree Figure 42. D. fraserianum distribution Figure 43. D. fraserianum oil

Figure 44. α-cadinol Figure 45. guaiazulene

Standardisation of Australian Native Oils

A significant factor limiting development of emerging Australian native oils is a lack of

standardisation. Due to the adaptive nature of Australian plants there are typically a range of

existing chemotypes across the natural botanical provenance of a given species For example

Melaleuca alternifolia (Tea Tree oil) exists in three distinct chemotypes (cineole, terpinen-4-ol and

a-terpinolene) across a geographical distribution of ~ 500 kms. Similarly, Melaleuca quinquenervia

exists in two predominant types (viridiflorol/ cineole and linalool/nerolidol) but with this there are

up to six definable sub-chemotypes.

Without significant production, officiating bodies such as Standards Australia and ISO won’t

generate quality control standards for Australian native oils, but without standardisation it is

difficult for the products to be traded. In recent years review of the EOPAA (Essential Oil Producers

Association of Australia) membership has identified the development of industry standards for

Australian Native oils to be of the highest research priority. As such EOPAA has applied for and

been recently awarded substantial grant funding from Agrifutures Australia for the development of

industry standards for up to 10 emerging Australian Native oils. The aim of this project is to

develop the Australian Native Oil industry to generate in excess of AU$10 million per annum. This

project began in earnest in August 2019 and will run over the next four years.

The project objectives include:

- Development of Industry standards for emerging Australian Native Oils

- Establishment of Primary botanical reference collections which help to characterise the

natural variation

- Establishment of an R&D database to facilitate trade of Australian Native oils.

Acknowledgments

The Essential Oil Producers Association of Australia (EOPAA)

Southern Cross Plant Science – Southern Cross University

The Atlas of Living Australia

The rich and diverse Flora of Australia