Eucalyptus oil

Eucalyptus oil is the generic name for distilled oil from "Eucalyptus", a genus of the plant family Myrtaceae native to Australia and cultivated worldwide. Eucalyptus oil has a history of wide application, as a pharmaceutical, antiseptic, repellent, flavouring, fragrance and industrial uses.

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. [ Lawless, J., "The Illustrated Encyclopedia of Essential Oils", Element Books 1995 ISBN 1-85230-661-0 ]

China produces about 70% of the world trade, but most of this is derived from camphor oil fractions rather than being true eucalyptus oil. [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] ] 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" 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. [Eucalyptus history [http://www.fgb.com.au/AdditionalInfo/EucHistory.html] ] Rectification is used to bring lower grade oils up to the high cineole standard required. Global annual production of eucalyptus oil is estimated at 3,000 tonnes. [FOA [http://www.fao.org/docrep/v5350e/v5350e07.htm] ]

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 antiseptic

The cineole based oil is used as component in pharmaceutical preperations to relieve the symptoms of influenza and colds, in products like cough sweets, lozenges, and inhalants. Eucalyptus oil has antibacterial effects on pathogenic bacteria in the respiratory tract. [Salari, M. H., Amine, G., Shirazi, M. H., Hafezi, R., and Mohammadypour, M. “Antibacterial effects of Eucalyptus globulus leaf extract on pathogenic bacteria isolated from specimens of patients with respiratory tract disorders.” "Clin Microbiol.Infect." 2006;12(2):194-196. [http://www3.interscience.wiley.com/journal/118633029/abstract] ] Inhaled eucalyptus oil vapor is a decongestant and treatment for bronchitis. [Lu XQ, Tang FD, Wang Y, Zhao T, Bian RL, Effect of Eucalyptus globulus oil on lipopolysaccharide-induced chronic bronchitis and mucin hypersecretion in rats, "Zhongguo Zhong Yao Za Zhi", 2004 Feb;29(2):168-71. [http://www.ncbi.nlm.nih.gov/pubmed/15719688] ] Cineole controls airway mucus hypersecretion and asthma via anti-inflammatory cytokine inhibition. [Juergens, U. "et al", Anti-inflammatory activity of 1.8-cineol (eucalyptol) in bronchial asthma: a double-blind placebo-controlled trial, "Respiratory Medicine", 2003, Vol. 97, Iss. 3, pp250 - 256. [http://linkinghub.elsevier.com/retrieve/pii/S0954611103914326] ] [Juergens, U., Engelen, T., Racké, K., Stöber, M., Gillissen, A., Vetter, H., Inhibitory activity of 1,8-cineol (eucalyptol) on cytokine production in cultured human lymphocytes and monocytes, "Pulmonary Pharmacology & Therapeutics", 2004, Vol. 17 , Iss. 5, pp281 - 287 [http://linkinghub.elsevier.com/retrieve/pii/S1094553904000562] ] Eucalyptus oil also stimulates immune system response by affects on the phagocytic ability of human monocyte derived macrophages. [Serafino, A., Vallebona, P.S., Andreola, F., Zonfrillo, M., Mercuri, L., Federici, M., Rasi, G., Garaci, E., and Pierimarchi, P., Stimulatory effect of Eucalyptus essential oil on innate cell-mediated immune response, "BMC Immunol." 2008; 9: 17. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2374764] ]

Eucalyptus oil also has anti-inflammatory and analgesic qualities as a topically applied liniment ingredient. [Göbel, H., Schmidt, G., Soyka, D., Effect of peppermint and eucalyptus oil preparations on neurophysiological and experimental algesimetric headache parameters, "Cephalalgia", Vol. 14, Iss. 3, pp228 - 234, 19 Jan 2002. ] [Hong, C-Z., Shellock, F.G., Effects of a topically applied counterirritant (Eucalyptmint) on cutaneous blood flow and on skin and muscle temperatures: a placebo-controlled study, "American Journal of Physical Medicine & Rehabilitation" 70(1):29-33, February 1991. [http://www.amjphysmedrehab.com/pt/re/ajpmr/abstract.00002060-199102000-00006.htm;jsessionid=LptcHMpK0vLyfpybLwJZtLtTFC9nmWD0vhv6QhkNNtPvGyC321py!1902130097!181195629!8091!-1] ]

Eucalyptus oil is also used in personal hygiene products for antimicrobial properties in dental care [Nagata, H., Inagaki, Y., Tanaka, M., Ojima, M., Kataoka, K., ­Kuboniwa, M., Nishida, N., Shimizu, K., Osawa, K., and Shizukuishi, S., "Effect of Eucalyptus Extract Chewing Gum on Periodontal Health: A Double-Masked, Randomized Trial", "Journal of Periodontology",2008, Vol. 79, No. 8, pp1378-1385. [http://www.joponline.org/doi/abs/10.1902/jop.2008.070622] ] and soaps. It 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. [ [http://www.asthma.org.au/Portals/0/AsthmaAndAllergy_DoHA_0505.pdf Asthma Foundation of Victoria] ]

Flavouring

Eucalyptus oil is used in flavouring. Cineole based eucalyptus oil is used as a flavouring at low levels (0.002%) in various products, including baked goods, confectionery, meat products and beverages. [Harborne, J.B., Baxter, H., "Chemical Dictionary of Economic Plants", ISBN 0-471-49226-4] Non-cineole peppermint gum, strawberry gum and lemon ironbark are also used as flavouring.

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 separate metallic sulphides via flotation.

Research shows that cineole based eucalyptus oil (5% of mixture) prevents the separation 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. [ Boland, D.J., Brophy, J.J., and A.P.N. House, "Eucalyptus Leaf Oils", 1991, p8 ISBN 0-909605-69-6]

afety and toxicity

If consumed internally at low dosage as a flavouring component or in pharmaceutical products at the recommended rate, eucalyptus oil is safe for adults. However, eucalyptus oil in its pure form is poisonous according to dosage.

The probable lethal dose of pure eucalyptus oil for an adult is in the range of 0.05 mL to 0.5 mL/per kg of body weight. [ Hindle, R.C., Eucalyptus oil ingestion, "New Zealand Medical Journal", 1994, pp185-186]

Because of their low body weight, children are more vulnerable to poisons. Severe poisoning has occurred in children after ingestion of 4 mL to 5 mL of eucalyptus oil. [Allan, J., Poisoning by oil of eucalyptus, "British Medical Journal", 1910 Vol.1, p569.] [Foggie, W.E., Eucalyptus oil poisoning, "British Medical Journal", Vol. 1, pp359-360, 1911.] For this reason, household eucalyptus oil needs to be kept out of reach from children, and is best stored in child resistant containers.

History

Australian Aboriginals use eucalyptus leaf infusions - whereby eucalyptus oil is a fraction - as a traditional medicine for treating body pains, sinus congestion, fever, and colds. [Low, T., "Bush Medicine, A Parmacopeia of Natural Remedies", Angus & Robertson, p85, 1990.] [ Barr, A., Chapman, J., Smith, N., Beveridge, M., "Traditional Bush Medicines, An Aboriginal Pharmacopoeia", Greenhouse Publications, pp116-117, 1988, ISBN 0 86436 167.]

Dennis Considen and John White, surgeons on the First Fleet, distilled eucalyptus oil from "Eucalyptus piperita" found growing on the shores of Port Jackson in 1788 to treat convicts and marines. [ Maiden, J.H., "The Forest Flora of New South Wales", vol. 4, Government Printer, Sydney, 1922.] [Copy of letter received by Dr Anthony Hamiltion, from Dennis Considen, 18 November, 1788, and sent onto Joseph Banks. [http://www2.sl.nsw.gov.au/banks/series_23/23_26.cfm] ] [ Lassak, E.V., & McCarthy, T., "Australian Medinal Plants", Methuen Australia, 1983, p15, ISBN 0 454 00438 9.] [ White, J., "Journal of a Voyage to New South Wales", 1790. [http://gutenberg.net.au/ebooks03/0301531h.html] ] Eucalyptus oil was subsequently extracted by early colonialists, but was not commercially exploited for some time.

Baron Ferdinand von Mueller, Victorian botanist, promoted the qualities of Eucalyptus as a disinfectant in 'fever districts', and also encouraged Joseph Bosisto, a Melbourne pharmacist, to investigate the commercial potential of the oil. [Grieve, M.,(author) & Leyel, C.F., (ed), "A Modern Herbal", Jonathon Cape, 1931 p287.] Bosisto started the commercial eucalyptus oil industry in 1852 when he built a distillation plant near Dandenong, Victoria, Australia.

French chemist, F.S. Cloez, identified and ascribed the name "eucalyptol" - now more often called cineole - to the dominant portion of "E. globulus" oil. [ Boland, D.J., Brophy, J.J., and A.P.N. House, "Eucalyptus Leaf Oils", 1991, p6 ISBN 0-909605-69-6] By the 1870s oil from "Eucalyptus globulus", Tasmanian blue gum, was being exported worldwide and eventually dominated world trade, while other higher quality species were also being distilled to a lesser extent. Surgeons were using eucalyptus oil as an antiseptic during surgery by the 1880s. [Maiden, J.H., "The Useful Native Plants of Australia", p255, 1889 ]

The Australian eucalyptus oil industry peaked in the 1940s, but 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".

pecies 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.

ee also

* Eucalypts

References

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

External links

* [http://www.inchem.org/documents/pims/pharm/pim031.htm#SectionTitle:7.2 Toxicity] Eucalyptus oil profile, Chemical Safety Information from Intergovernmental Organizations