Eucalyptol
Eucalyptol is a monoterpenoid. A colorless liquid, it is a bicyclic ether. Eucalyptol has a fresh mint-like smell and a spicy, cooling taste. It is insoluble in water, but miscible with organic solvents. Eucalyptol makes up 90% of eucalyptus oil. Eucalyptol forms crystalline adducts with hydrohalic acids, "o"-cresol, resorcinol, and phosphoric acid. Formation of these adducts is useful for purification. In 1870, F. S. Cloez identified and ascribed the name "eucalyptol" to the dominant portion of "Eucalyptus globulus" oil. Uses. 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 to be added to improve the flavor. Eucalyptol is an ingredient in commercial mouthwashes, and has been used in traditional medicine as a cough suppressant. Other. Eucalyptol exhibits insecticidal and insect repellent properties. 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. One such study with "Euglossa imperialis", a nonsocial orchid bee species, has shown that the presence of cineole (also eucalyptol) elevates territorial behavior and specifically attracts the male bees. It was even observed that these males would periodically leave their territories to forage for chemicals such as cineole, thought to be important for attracting and mating with females, to synthesize pheromones. Toxicology. It has low toxicity (hence its use in foods), with an LD50 of 2.48g/kg (rabbits). Compendial status. N.B.  Listed as "cineole" in some pharmacopoeias.