Eucalyptol

Uses

Because of its pleasant, spicy aroma and taste, eucalyptol is used in flavorings, fragrances, and cosmetics. 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 cough suppressants.

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

Eucalyptol has a toxicity (LD50) of 2.48 grams per kg (rat). Ingestion in significant quantities is likely to cause headache and gastric distress, such as nausea and vomiting. 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.

Consequently, eucalyptol should never be ingested unless in highly diluted formulations. Toxicity is significantly reduced when administered topically. However it should not be used topically during pregnancy, breastfeeding, or on children under two.

Biosynthesis

Eucalyptol is generated from geranyl pyrophosphate (GPP) which isomerizes to (S)-linalyl diphosphate (LPP). Ionization of the pyrophosphate, catalyzed by cineole synthase, produces eucalyptol. The process involves the intermediacy of alpha-terpinyl cation.

Plants containing eucalyptol

• Aframomum corrorima
• Artemisia tridentata
• Cannabis
• Cinnamomum camphora, camphor laurel (50%)
• Eucalyptus globulus
• Eucalyptus largiflorens
• Eucalyptus salmonophloia
• Eucalyptus staigeriana
• Eucalyptus wandoo
• Hedychium coronarium, butterfly lily
• Helichrysum gymnocephalum
• Kaempferia galanga, galangal, (5.7%)
• S. officinalis subsp. lavandulifolia (syn. S. lavandulifolia), Spanish sage (13%)
• Salvia rosmarinus, rosemary
• Turnera diffusa, damiana
• Umbellularia californica, pepperwood (22.0%)
• Zingiber officinale, ginger

References

References

1. (22 April 2023). "Eucalyptol". PubChem, US National Library of Medicine.
2. "GCMS – Gas Chromatography Mass Spectrometry Analysis".
3. (2000). "Terpenes".
4. (1991). "Eucalyptus Leaf Oils: Use, Chemistry, Distillation and Marketing". Inkata Press.
5. "Cigarette Ingredients – Chemicals in Cigarettes". New York State Department of Health.
6. (December 1987). "8-Cineole (Eucalyptol), a Mosquito Feeding and Ovipositional Repellent from Volatile Oil of ''Hemizonia fitchii'' (Asteraceae)". Journal of Chemical Ecology.
7. (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 Entomology]].
8. (2004). "Odor Compound Detection in Male Euglossine Bees". Journal of Chemical Ecology.
9. (1984). "Fragrance collection and territorial display by male orchid bees". Animal Behaviour.
10. "Eucalyptus Oil: Is it Safe?".
11. (2016-11-04). "A Detailed View on 1,8-Cineol Biosynthesis by ''Streptomyces clavuligerus''". Beilstein Journal of Organic Chemistry.
12. (1998-06-12). "Monoterpene Synthases From Common Sage (''Salvia Officinalis''): cDNA Isolation, Characterization, and Functional Expression of (+)-Aabinene Synthase, 1,8-Cineole Synthase, and (+)-Bo...". Journal of Biological Chemistry.
13. (1994-02-01). "Biosynthesis of Monoterpenes: Partial Purification, Characterization, and Mechanism of Action of 1,8-Cineole Synthase". Archives of Biochemistry and Biophysics.
14. Sebsebe Demissew. (1993). "A description of some essential oil bearing plants in Ethiopia and their indigenous uses". [[Taylor & Francis]].
15. Crowell, M.M.. (2018). "Dietary partitioning of toxic leaves and fibrous stems differs between sympatric specialist and generalist mammalian herbivores". Journal of Mammalogy.
16. (2001). "Cannabis and cannabis extracts: greater than the sum of their parts?". Journal of Cannabis Therapeutics.
17. (2001). "Leaf oil of ''Cinnamomum camphora'' (L.) Nees and Eberm. From Eastern Australia". Journal of Essential Oil Research.
18. (2010). "Chemical composition of ''Eucalyptus'' spp. essential oils and their insecticidal effects on ''Lutzomyia longipalpis''". Veterinary Parasitology.
19. (2010). "Chemistry and bioactivity of Eucalyptus essential oils". Allelopathy Journal.
20. [[Charles Austin Gardner]]. (1 August 1952). "Trees of Western Australia - salmon gum and scarlet pear gum". Department of Primary Industries and Regional Development.
21. (2010). "Chemical Composition and Antimicrobial Properties of Essential Oils of three Australian ''Eucalyptus'' Species". Food Chemistry.
22. (2021). "Chemical composition of essential oils of eight Tunisian Eucalyptus species and their antibacterial activity against strains responsible for otitis". BMC Complement Med Ther.
23. (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 Research.
24. (2007). "Antimicrobial Activity and Chemical Composition of Essential Oil from ''Hedychium coronarium''". Phytotherapy Research.
25. (1997). "Chemical Composition and Analyses of Enantiomers of Essential Oils from Madagascar". Flavour and Fragrance Journal.
26. (2006). "Composition of the Essential Oil of Rhizomes of ''Kaempferia galanga'' L.". Flavour and Fragrance Journal.
27. (2000). "In-vitro inhibition of human erythrocyte acetylcholinesterase by ''Salvia lavandulaefolia'' essential oil and constituent terpenes". J Pharm Pharmacol.
28. Jiang, Yang. (2011-07-01). "Chemical composition and antimicrobial activity of the essential oil of Rosemary". Environmental Toxicology and Pharmacology.
29. Balch, P. A.. (2002). "Prescription for Nutritional Healing: the A to Z Guide to Supplements". Penguin.
30. (2007). "Bark and Leaf Essential Oil of ''Umbellularia californica'', California Bay Laurel, from Oregon". Natural Product Communications.
31. (January 2011). "Composition of a monoterpenoid-rich essential oil from the rhizome of Zingiber officinale from north western Himalayas". Natural Product Communications.