eucalyptol

Eucalyptol
IUPAC name	1,3,3-trimethyl- 2-oxabicyclo[2,2,2]octane
Other names	1,3,3-Trimethyl-2-oxabicyclo[2.2.2]octane 1,8-Cineole 1,8-Epoxy-p-menthane
Identifiers
CAS number	470-82-6 Y
SMILES	CC1(C2CCC(O1)(CC2)C)C
ChemSpider ID	2656
Properties
Molecular formula	C10H18O
Molar mass	154.249 g/mol
Density	0.9225 g/cm³
Melting point	1.5 °C (274.6 K)
Boiling point	176 - 177 °C (449 - 450 K)
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Eucalyptol is a natural organic compound which is a colorless liquid. It is a cyclic ether and a monoterpenoid.

Eucalyptol is also known by a variety of synonyms: 1,8-cineol, 1,8-cineole, limonene oxide, cajeputol, 1,8-epoxy-p-menthane, 1,8-oxido-p-menthane, eucalyptol, eucalyptole, 1,3,3-trimethyl-2-oxabicyclo[2,2,2]octane, cineol, cineole.

In 1870, Cloez, identified and ascribed the name eucalyptol to the dominant portion of Eucalyptus globulus oil.^[1] "Eucalyptus oil", a generic collective name for oils from the eucalyptus genus, should not be confused with the chemical compound, eucalyptol.

Composition

Eucalyptol comprises up to 90 percent of the essential oil of some species of the generic product Eucalyptus oil,^[1] hence the common name of the compound. It is also found in camphor laurel, bay leaves, tea tree, mugwort, sweet basil, wormwood, rosemary, sage and other aromatic plant foliage. Eucalyptol with a purity from 99.6 to 99.8 percent can be obtained in large quantities by fractional distillation of eucalyptus oil.

Although it can be used internally as a flavoring and medicine ingredient at very low doses, typical of many essential oils (volatile oils), eucalyptol is toxic if ingested at higher than normal doses.^[2]

Properties

Eucalyptol has a fresh camphor-like smell and a spicy, cooling taste. It is insoluble in water, but miscible with ether, ethanol and chloroform. The boiling point is 176 °C and the flash point is 49 °C.

Uses

Flavoring and fragrance

Because of its pleasant spicy aroma and taste, eucalyptol is used in flavorings, fragrances, and cosmetics. 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.^[3] In a 1994 report released by five top cigarette companies, eucalyptol was listed as one of the 599 additives to cigarettes. It is claimed that it is added to improve the flavor.

Medicinal

Eucalyptol suppository, for the treatment of some respiratory ailments

Eucalyptol is an ingredient in many brands of mouthwash and cough suppressant. It controls airway mucus hypersecretion and asthma via anti-inflammatory cytokine inhibition.^[4][5] Eucalyptol is an effective treatment for nonpurulent rhinosinusitis.^[6] Research showed that treated subjects experienced less headache on bending, frontal headache, sensitivity of pressure points of trigeminal nerve, impairment of general condition, nasal obstruction, and rhinological secretion. Side effects from treatment were minimal.

Eucalyptol reduces inflammation and pain when applied topically.^[7] It kills leukaemia cells in vitro.^[8]

Insecticide and repellent

Eucalyptol is used as an insecticide and insect repellent.^{[9] [10]}

Conversely, eucalyptol is one of many compounds that is attractive to males of various species of orchid bees, who apparently gather the chemical to synthesize pheromones; it is commonly used as bait to attract and collect these bees for study.^[11]

List of plants that contain the chemical

• Cinnamomum camphora, Camphor laurel (50%)^[12]
• 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
• Kaempferia galanga, Galangal, (5.7%)^[13]
• Laurus nobilis, Bay Laurel, (45%)
• Melaleuca alternifolia, Tea-tree, (0-15%)

Toxicology

In higher than normal doses eucalyptol is hazardous via ingestion, skin contact or inhalation. It can have acute health effects on behaviour, respiratory tract and nervous system. The acute oral toxicity (LD50) is 2480 mg/kg(rat). It is classified as a reproductive toxin for males and females.^[2]

Compendial status

• British Pharmacopoeia ^[14]
• Martindale: The Extra Pharmacopoeia 31 ^[15]

N.B. Listed as "cineole" in some pharmacopoeia.

Notes & References

Further reading

• Boland, D.J., Brophy, J.J., and A.P.N. House, Eucalyptus Leaf Oils, 1991, ISBN 0-909605-69-6.

See also

• Camphor
• Citral
• Eucalyptus oil
• Lavender
• Menthol
• Mouthwash
• Vaporizer

External links

• Eucalyptus at Botanical.com
• Oleum Eucalypti, B.P. Oil of Eucalyptus at Henriette's Herbal
• Safety data for eucalyptol from Oxford University Chemistry Department