Eucalyptol (also called cineole) is a monoterpenoid colorless liquid, and a bicyclic ether.[1] It has a fresh camphor-like odor and a spicy, cooling taste.[1] It is insoluble in water, but miscible with organic solvents. Eucalyptol makes up about 70–90% of eucalyptus oil.[2][3] Eucalyptol forms crystalline adducts with hydrohalic acids, o-cresol, resorcinol, and phosphoric acid. Formation of these adducts is useful for purification.[4]
Because of its pleasant, spicy aroma and taste, eucalyptol is used in flavorings, fragrances, and cosmetics.[1] Cineole-based eucalyptus oil is used as a flavoring at low levels (0.002%) in various products, including baked goods, confectionery, meat products, and beverages.[1][5] In a 1994 report released by five top cigarette companies, eucalyptol was listed as one of the 599 additives to cigarettes.[6] It is claimed to be added to improve the flavor.[1]
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.[10] 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.[11]
Toxicology
Eucalyptol has a toxicity (LD50) of 2.48 grams per kg (rat).[1] Ingestion in significant quantities is likely to cause headache and gastric distress, such as nausea and vomiting.[1] Because of its low viscosity, it may directly enter the lungs if swallowed, or if subsequently vomited. Once in the lungs, it is difficult to remove and can cause delirium, convulsions, severe injury or death.[1]
↑Klocke, J. A.; Darlington, M. V.; Balandrin, M. F. (December 1987). "8-Cineole (Eucalyptol), a Mosquito Feeding and Ovipositional Repellent from Volatile Oil of Hemizonia fitchii (Asteraceae)". Journal of Chemical Ecology13 (12): 2131–41. doi:10.1007/BF01012562. PMID24301652.
↑Sfara, V.; Zerba, E. N.; Alzogaray, R. A. (May 2009). "Fumigant Insecticidal Activity and Repellent Effect of Five Essential Oils and Seven Monoterpenes on First-Instar Nymphs of Rhodnius prolixus". Journal of Medical Entomology46 (3): 511–515. doi:10.1603/033.046.0315. PMID19496421.
↑Schiestl, F. P.; Roubik, D. W. (2004). "Odor Compound Detection in Male Euglossine Bees". Journal of Chemical Ecology29 (1): 253–257. doi:10.1023/A:1021932131526. PMID12647866.
↑Schemske, Douglas W.; Lande, Russell (1984). "Fragrance collection and territorial display by male orchid bees". Animal Behaviour32 (3): 935–937. doi:10.1016/s0003-3472(84)80184-0.
↑Sebsebe Demissew (1993). "A description of some essential oil bearing plants in Ethiopia and their indigenous uses". Journal of Essential Oil Research (Taylor & Francis) 5 (5): 465–479. doi:10.1080/10412905.1993.9698266. "The chemical composition of … Aframomum corrorima (l, 8-cineole 41.9%) … is also presented.".
↑Crowell, M.M. (2018). "Dietary partitioning of toxic leaves and fibrous stems differs between sympatric specialist and generalist mammalian herbivores". Journal of Mammalogy99 (3): 565–577. doi:10.1093/jmammal/gyy018.
↑Stubbs, B. J.; Brushett, D. (2001). "Leaf oil of Cinnamomum camphora (L.) Nees and Eberm. From Eastern Australia". Journal of Essential Oil Research13 (1): 51–54. doi:10.1080/10412905.2001.9699604.
↑Gilles, M.; Zhao, J.; An, M.; Agboola, S. (2010). "Chemical Composition and Antimicrobial Properties of Essential Oils of three Australian Eucalyptus Species". Food Chemistry119 (2): 731–737. doi:10.1016/j.foodchem.2009.07.021.
↑Ali, S.; Sotheeswaran, S.; Tuiwawa, M.; Smith, R. (2002). "Comparison of the Composition of the Essential Oils of Alpinia and Hedychium Species—Essential Oils of Fijian Plants, Part 1". Journal of Essential Oil Research14 (6): 409–411. doi:10.1080/10412905.2002.9699904.
↑Joy, B.; Rajan, A.; Abraham, E. (2007). "Antimicrobial Activity and Chemical Composition of Essential Oil from Hedychium coronarium". Phytotherapy Research21 (5): 439–443. doi:10.1002/ptr.2091. PMID17245683.
↑Möllenbeck, S.; König, T.; Schreier, P.; Schwab, W.; Rajaonarivony, J.; Ranarivelo, L. (1997). "Chemical Composition and Analyses of Enantiomers of Essential Oils from Madagascar". Flavour and Fragrance Journal12 (2): 63. doi:10.1002/(SICI)1099-1026(199703)12:2<63::AID-FFJ614>3.0.CO;2-Z.
↑Wong, K. C.; Ong, K. S.; Lim, C. L. (2006). "Composition of the Essential Oil of Rhizomes of Kaempferia galanga L.". Flavour and Fragrance Journal7 (5): 263–266. doi:10.1002/ffj.2730070506.
↑Perry, N. S.; Houghton, P. J.; Theobald, A.; Jenner, P.; Perry, E. K. (2000). "In-vitro inhibition of human erythrocyte acetylcholinesterase by Salvia lavandulaefolia essential oil and constituent terpenes". J Pharm Pharmacol52 (7): 895–902. doi:10.1211/0022357001774598. PMID10933142.
↑Kelsey, R. G.; McCuistion, O.; Karchesy, J. (2007). "Bark and Leaf Essential Oil of Umbellularia californica, California Bay Laurel, from Oregon". Natural Product Communications2 (7): 779–780. doi:10.1177/1934578X0700200715.
↑"Composition of a monoterpenoid-rich essential oil from the rhizome of Zingiber officinale from north western Himalayas". Natural Product Communications6 (1): 93–6. January 2011. doi:10.1177/1934578X1100600122. PMID21366054.