China produces about 70% of the world trade, but most of this is derived from camphor oil fractions rather than being true eucalyptus oil. 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. 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.
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.
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.
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. For this reason, household eucalyptus oil needs to be kept out of reach from children, and is best stored in child resistant containers.
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. 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. 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. 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.
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.
Non-cineole oil producing species:
Formulation development of eucalyptus oil microemulsion for intranasal delivery.(Proceedings of the Symposium on Advances in Pulmonary and Nasal Drug Delivery, October 2007, Mumbai)(Clinical report)
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