Cineole

# Overview
Eucalyptol is a natural organic compound that 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, cajeputol, 1,8-epoxy-p-menthane, 1,8-oxido-p-menthane, eucalyptol, eucalyptole, 1,3,3-trimethyl-2-oxabicyclooctane, cineol, cineole.
In 1870, F.S. Cloez identified and ascribed the name eucalyptol to the dominant portion of Eucalyptus globulus oil. Eucalyptus oil, the 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, hence the common name of the compound. It is also found in camphor laurel, bay leaves, tea tree, mugwort, sweet basil, wormwood, rosemary, common sage, cannabis sativa, 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.

# 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. Eucalyptol forms crystalline adducts with halogen acids, o-cresol, resorcinol, and phosphoric acid. Formation of these adducts are useful for purification.

# 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. 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 is an ingredient in many brands of mouthwash and cough suppressant, as well as an inactive ingredient in body powder.

## Insecticide and repellent
Eucalyptol is used as an insecticide and insect repellent.
In contrast, eucalyptol is one of many compounds that are attractive to males of various species of orchid bees, which gather the chemical to synthesize pheromones; it is commonly used as bait to attract and collect these bees for study.

# Toxicology
In higher-than-normal doses, eucalyptol is hazardous via ingestion, skin contact, or inhalation. It can have acute health effects on behavior, respiratory tract, and nervous system. The acute oral Template:LD50 is 2480 mg/kg (rat). It is classified as a reproductive toxin for females and a suspect reproductive toxin for males.

# Scientific study
- In a 2003 study, eucalyptol was found to control airway mucus hypersecretion and asthma; after, in a previous study, the authors found eucalyptol to suppress arachidonic acid metabolism and cytokine production in human monocytes.
- In a 2004 study, it was found to inhibit cytokine production in cultured human lymphocytes and monocytes.
- In a 2004 study, eucalyptol was found to be an effective treatment for nonpurulent rhinosinusitis. 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.
- A 2000 study found eucalyptol to reduce inflammation and pain when applied topically.
- In a 2002 study, it was found to kill leukaemia cells of two cultured human leukemia cell lines, but not cells of a human stomach cancer cell line in vitro.

# List of plants that contain the chemical
- Cannabis
- Cinnamomum camphora, Camphor laurel (50%)
- 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 staigeriana
- Eucalyptus tereticornis
- Eucalyptus viridis
- Helichrysum gymnocephalum 
- Kaempferia galanga, Galangal, (5.7%)
- Laurus nobilis, Bay Laurel, (45%)
- Melaleuca alternifolia, Tea-tree, (015%)
- Salvia lavandulifolia, Spanish sage (13%)
- Turnera diffusa, Damiana
- Umbellularia californica, Pepperwood (22.0%)
- Zingiber officinale, Ginger

# Compendial status
- British Pharmacopoeia 
- Martindale: The Extra Pharmacopoeia 31 
N.B. Listed as "cineole" in some pharmacopoeia.