AROMATHERAPY

Eucalyptus oil is the generic name of distilled oil from the leaf of 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.

The leaves of selected Eucalyptus species are steam distilled to extract eucalyptus oil.

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.

China produces about 75% of the world trade, but most of this is derived from the cineole fractions of camphor laurelrather than being true eucalyptus oil. Significant producers of true eucalyptus oil include South Africa, Portugal,Spain, Brazil, Australia, Chile and Swaziland.

Eucalyptus polybractea or Blue-leaf Mallee, a species yielding high quality eucalyptus oil
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 is 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.The eucalyptus genus also produces non-cineole oils, including piperitone,phellandrene, citral, methyl cinnamate and geranyl acetate.

Uses
Medicinal and antiseptic
The cineole-based oil is used as component in pharmaceutical preparations to relieve the symptoms of influenza and colds, in products like cough sweets, lozenges, ointments and inhalants. Eucalyptus oil has antibacterial effects on pathogenic bacteria in the respiratory tract. Inhaled eucalyptus oil vapor is a decongestant and treatment for bronchitis. Cineole controls airway mucus hyper-secretion and asthma via anti-inflammatory cytokine inhibition. Pre-clinical results also show that eucalyptus oil stimulates innate cell-mediated immune response by effects on the phagocytic ability of human monocyte derived macrophages.

Eucalyptus oil also has anti-inflammatory and analgesic qualities as a topically applied liniment ingredient

Eucalyptus oil is also used in personal hygiene products for antimicrobial properties in dental care and soaps. It can also be applied to wounds to prevent infection.

Repellent and biopesticide
Cineole-based eucalyptus oil is used as an insect repellent and biopesticide. In the U.S., eucalyptus oil was first registered in 1948 as an insecticide and miticide.

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. Eucalyptus oil has antimicrobial activity against a broad range of foodborne human pathogens and food spoilage microorganisms.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. It is known for its pungent, intoxicating scent.

Industrial
Research shows that cineole-based eucalyptus oil (5% of mixture) prevents the separation problem with ethanol andpetrol 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 for the oil to be economically viable as a fuel.

Phellandrene- and piperitone-based eucalyptus oils have been used in mining to separate sulfide minerals viaflotation.

Safety and toxicity
If consumed internally at low dosage as a flavouring component or in pharmaceutical products at the recommended rate, cineole-based 'oil of eucalyptus' is safe for adults. However, systemic toxicity can result from ingestion or topical application at higher than recommended doses.

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 high body surface area to mass ratio, children are more vulnerable to poisons absorbed transdermally. Severe poisoning has occurred in children after ingestion of 4 mL to 5 mL of eucalyptus oil.

Reference Source:Wikipedia