Eucalyptus oil
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2008-07-16T07:29:24Z
John Moss
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'''Eucalyptus oil''' is the generic name for distilled oil from the [[Eucalyptus]] genus of the [[Myrtaceae]] plant family originating from [[Australia]], and now cultivated worldwide.
Global annual production of eucalyptus oil is estimated at 3,000 tonnes.<ref>FOA [[http://www.fao.org/docrep/v5350e/v5350e07.htm]]</ref>
==Types and production==
Eucalyptus oils in the trade are categorized into three broad types according to their composition and main end-use: [[medicinal]], [[perfumery]] and [[industrial]].The most prevalent is the standard [[cineole]] based 'oil of eucalyptus', a colourless mobile liquid (yellow with age) with a penetrating, [[camphoraceous]], [[woody]]-sweet scent.<ref> Lawless, J., ''The Illustrated Encyclopedia of Essential Oils'', Element Books 1995 ISBN 1-85230-661-0 </ref>
[[China]] produces about 70% of the world trade, but most of this is derived from [[camphor oil]] fractions rather than being true eucalyptus oil. <ref>Akehurst, P.R., ''Food Flavorings'', 1999, [[http://books.google.com.au/books?id=hrWuqmtwJiEC&pg=PA20&lpg=PA20&dq=china+eucalyptus+oil+use&source=web&ots=IsiuQiHnDX&sig=p4113dfJqln9BdWCcwQv5xKmBio&hl=en]] </ref> Significant producers of true eucalyptus oil include [[South Africa]], [[Portugal]], [[Spain]], [[Brazil]], [[Australia]], [[Chile]] and [[Swaziland]].
Global production is dominated by ''[[Eucalyptus globulus]]''. However, ''[[Eucalyptus kochii|Eucalyptus kochii]]'' and ''[[Eucalyptus polybractea]]'' have the highest cineole content - ranging from 80-95%. The [[British Pharmacopoeia]] states that the oil must have a minimum cineole content of 70% if it's [[pharmaceutical]] grade.<ref>Eucalyptus history [http://www.fgb.com.au/AdditionalInfo/EucHistory.html]</ref> [[Rectification]] is used to bring lower grade oils up to the high cineole standard required.
The eucalyptus genus also produces non-cineole oils, including [[piperitone]], [[phellandrene]], [[citral]], [[methyl cinnamate]] and [[geranyl acetate]].
Eucalyptus oil should not be confused with the term '[[eucalyptol]]' - another name for [[cineole]].
==Uses==
===Medicinal and germicidal===
The cineole based oils are used medicinally to relieve the symptoms of [[influenza]] and [[colds]], in products like [[cough]] sweets, [[lozenges]], and [[inhalants]]. They also have [[anti-inflammatory]] and [[analgesic]] qualities and are [[topically]] applied as an ingredient in [[liniments]]. Inhaled eucalyptus oil vapor is a decongestant.
They are also used in [[personal hygiene]] products for [[antimicrobial]] properties in [[dental care]] and [[soaps]]. They can also be applied to [[wounds]] to prevent [[infection]].
===Repellent and biopesticide===
The cineole based oils can also be used as an [[insect repellent]] and [[biopesticide]]. Eucalyptus oil has been used as an effective way of killing dust mites according to the Asthma Foundation of Victoria.<ref>[http://www.asthma.org.au/Portals/0/AsthmaAndAllergy_DoHA_0505.pdf Asthma Foundation of Victoria]</ref>
===Flavoring===
Eucalyptus oil is used in [[flavoring]]. Cineole based eucalyptus oil is used as a flavoring at low levels (0.002%) in various products, including [[baked goods]], [[confectionary]], [[meat]] products and [[beverages]].<ref>Harborne, J.B., Baxter, H., ''Chemical Dictionary of Economic Plants'', ISBN 0-471-49226-4</ref> Non-cineole [[Eucalyptus dives|peppermint gum]], [[Eucalyptus olida|strawberry gum]] and [[Eucalyptus staigeriana|lemon ironbark]] are also used as flavoring.
===Fragrance===
Eucalyptus oil is also used as a [[fragrance]] component to impart a fresh and clean aroma in [[soaps]], [[detergents]], lotions and [[perfumes]].
===Industrial===
Phellandrene and piperitone based eucalyptus oils have been used in [[mining]] to seperate [[metallic sulphides]] via [[flotation]].
Research shows that cineole based eucalyptus oil (5% of mixture) prevents the seperation problem with [[ethanol]] and [[petrol]] [[fuel]] blends. Eucalyptus oil also has a respectable [[octane rating]] and can be used as a fuel in its own right. However, production costs are currently too high to be economically viable as a fuel.<ref> Boland, D.J., Brophy, J.J., and A.P.N. House, ''Eucalyptus Leaf Oils'', 1991, p8 ISBN 0-909605-69-6</ref>
==History==
[[Australian]] [[Aboriginals]] used eucalyptus leaves as [[medicine]]. They steeped the leaves in water to make [[infusion]]s to treat [[bronchial]] [[ailment]]s (Barr ''et al.'' 1988).
In 1788, the first non-Aboriginal use occurred when the Surgeon-General of the [[First Fleet]], [[John White (surgeon)|John White]], recorded the presence of olfactory oil in the eucalyptus. White distilled a quart of oil from the "Sydney Peppermint", ''[[Eucalyptus piperita]]'' Sm., which was found growing on the shores of [[Port Jackson]], where [[Sydney]] now stands. White's assistant, Denis Considen, who was familiar with English peppermint, said that ''E.piperita'' was ''"...much more efficacious in removing all cholicky complaints"''. Eucalyptus oil was subsequently extracted by early colonialists, but was not commercially exploited initially.
Baron [[Ferdinand von Mueller]], the Government Botanist in Victoria, encouraged Joseph Bosisto, a [[Melbourne]] [[pharmacist]], to investigate the commercial potential of the oil. Bosisto started the commercial eucalyptus oil industry in 1852 when he built a [[distillation]] plant near [[Dandenong]], [[Victoria (Australia)|Victoria]], Australia. Bosisto originally distilled ''[[Eucalyptus radiata]]'' under the name of "''Eucalyptus amygdalina''".
The distilling of eucalyptus spread, and by the 1870s ''Eucalyptus globulus'', Tasmanian blue gum, was being exported worldwide. French chemist, [[F.S. Cloez]], identified and ascribed the name ''eucalyptol'' - now more often called [[cineole]] - to the dominant portion of ''E. globulus'' oil.<ref> Boland, D.J., Brophy, J.J., and A.P.N. House, ''Eucalyptus Leaf Oils'', 1991, p6 ISBN 0-909605-69-6</ref>. By the 1930s ''E. globulus'' dominated world trade in eucalyptus oil, while other species producing higher quality oil were also being distilled to a lesser extent.
At its' peak in the 1940s the Australian eucalyptus oil industry produced almost 1,000 tonnes per annum, exporting 70%.
The global establishment of eucalyptus plantations for [[timber]] resulted in increased volumes of eucalyptus oil as a plantation by-product. By the 1950s the cost of producing eucalyptus oil in Australia had increased so much that it could not compete against cheaper Spanish and Portuguese oils. Non-Australian sources now dominate commercial eucalyptus oil supply, although Australia continues to produce high grade oils of mainly blue mallee, ''E. polybractea''.
==Species utilised==
Commercial cineole based eucalyptus oils are produced from several species of ''Eucalyptus'':
* ''[[Eucalyptus cneorifolia]]''
* ''[[Eucalyptus dives]]''
* ''[[Eucalyptus dumosa]]''
* ''[[Eucalyptus globulus]]''
* ''[[Eucalyptus goniocalyx]]''
* ''[[Eucalyptus horistes]]
* ''[[Eucalyptus kochii]]''
* ''[[Eucalyptus leucoxylon]]''
* ''[[Eucalyptus oleosa]]''
* ''[[Eucalyptus polybractea]]''
* ''[[Eucalyptus radiata]]''
* ''[[Eucalyptus sideroxylon]]''
* ''[[Eucalyptus smithii]]''
* ''[[Eucalyptus tereticornis]]''
* ''[[Eucalyptus viridis]]''
Non-cineole oil producing species:
* ''[[Eucalyptus dives]]'' - phellandrene variant
* ''Eucalyptus dives'' - piperitone variant
* ''[[Eucalyptus elata]]'' - piperitone variant
* ''[[Eucalyptus macarthurii]]'' - geranyl acetate
* ''[[Eucalyptus olida]]'' - methyl cinnamate
* ''[[Eucalyptus radiata]]'' - phellandrene variant
* ''[[Eucalyptus staigeriana]]'' - citral, limonene
The former lemon eucalyptus species ''[[Eucalyptus citriodora]]'' is now classified as ''Corymbia citriodora'', which produces a [[citronellal]] based oil.
==References==
{{reflist}}
==Further reading==
* Boland, D.J., Brophy, J.J., and A.P.N. House, ''Eucalyptus Leaf Oils'', 1991, ISBN 0-909605-69-6
* FAO Corporate Document Repository, Flavours and fragrances of plant origin
==See also==
* [[Eucalypts]]
[[Category:Essential oils]]
[[Category:Eucalyptus]]