Thujone
From Wikipedia, the free encyclopedia
| Thujone | |
|---|---|
| |
| Systematic name | (1S-(1-,4-,5-alpha))4-methyl-1-propan-2-yl-bicyclo[3.1.0]hexan-3-one |
| Chemical formula | C10H16O |
| Molecular mass | 152.23 g/mol |
| Density | 0.92 g/cm³ |
| Solubility | insoluble (water) soluble (ethanol) |
| Melting point | xx.x °C |
| Boiling point | 201 °C |
| CAS number | [546-80-5] (α-thujone) [471-15-8] (β-thujone) |
| SMILES | C[C@@H]([C@@H](C2)[C@]2([C@@H](C)C)C1)C1=O (β) |
| Disclaimer and references | |
Thujone is a ketone and a monoterpene that exists in two stereoisomeric forms: (+)-3-thujone or α-thujone and (-)-3-thujone or β-thujone and has a menthol odor. Even though it is best known for being a chemical in absinthe, recent tests show absinthe contains only small quantities. In the early 20th century thujone was blamed for the supposed dangerous and even hallucinatory effects of absinthe, however modern studies show these concerns to be unfounded. Thujone acts on the GABA receptors in the brain and does not cause hallucinations. In many countries the amount of thujone allowed in food or drink products is regulated.
Contents |
[edit] Sources
Thujone is found in a number of plants, such as arborvitae (genus Thuja, hence the derivation of the name), Nootka Cypress, some junipers, mugwort, sage, tansy and wormwood, most notably grand wormwood (Artemisia absinthium), usually as a mix of isomers in a 1:2 ratio.
[edit] Pharmacology
For many years thujone was thought to act on the cannabinoid receptors similar to THC based on studies that only looked at the molecules shape. <ref name="thc">Conrad III, Barnaby; (1988). Absinthe History in a Bottle. Chronicle books. ISBN 0-8118-1650-8 Pg. 152</ref> This is known to be false today and studies show thujone does not bind to these receptors. Thujone is a GABA-a receptor antagonist. By inhibiting GABA receptor activation neurons may fire more easily which can cause muscle spasms and convulsions. <ref name="gaba">Thujone Gamma-Aminobutyric acid type A receptor modulation and metabolic detoxification. Hold K.,Sirisoma N., Ikeda T., Narahashi T. and Casida J. (2000). Retrieved Oct.28, 2006</ref>
A toxicology study of alpha-thujone, the more active of the two isomers, in mice found the median lethal dose, or LD50, is around 45 mg/kg, with 0% mortality rate at 30 mg/kg and 100% at 60 mg/kg. Those exposed to the higher dose had convulsions that led to death in 1 minute. From 30 to 45 mg/kg the mice would experience muscle spasms in the legs which progressed to general convulsions until death or recovery. Pretreatment of diazepam, phenobarbital or 1 g/kg of ethanol protected against a lethal 100 mg/kg dose. These findings are inline with other GABA antagonists. This study also found alpha-thujone was quickly metabolized in the mouse's liver. <ref name="gaba"/>
The LD50 dose in humans is not known however a study in the "Journal of Studies of alcohol" tested attention performance with low, and high doses of thujone in alcohol. The researchers administered 0.28 mg/kg thujone in alcohol, 0.028 mg/kg in alcohol and just alcohol to their subjects. The high dose had a short term negative effect on attention performance. The lower dose showed no noticeable effect. <ref>Absinthe: Attention Performance and Mood under the Influence of Thujone. DETTLING, A., GRASS, H., SCHUFF, A., SKOPP, G., STROHBECK-KUEHNER, P. AND HAFFNER, H.-TH. (2004) Retrieved Oct. 28, 2006.</ref>
There is no evidence any size dose will cause hallucinations.
[edit] Thujone in absinthe
Thujone is most famous for being a chemical in the drink absinthe and many modern producers list their supposed thujone levels on the bottle. At one time it was estimated absinthe contained up to 260-350 mg/l thujone.<ref>Absinthism: a fictitious 19th century syndrome with present impact, Padosch et al. Retrieved Oct. 28, 2006.</ref> However this has been shown false through testing. A 2005 study recreated three 1899 high wormwood recipes and tested them with a GC-MS, the highest contained 4.3 mg/l thujone. A 1930s Pernod Tarragona was also tested and contained 1.8 mg/l thujone. <ref>Thujone—Cause of absinthism? Lachenmeier, Emmert et al. Retrieved Oct. 28, 2006.</ref> These results match earlier findings showing a vintage 1900s bottle contained 6 mg/l.<ref>Thujone Separating Myth from Reality Ian Hutton Retrieved Oct. 28, 2006.</ref> It is important GC-MS testing is done as other chemicals may appear to be thujone in tests using only gas chromatography which causes an abnormally high reading. <ref>Determination of a-/b-Thujone and Related Terpenes in Absinthe using Solid Phase Extraction and Gas Chromatography, Emmert et al. Retrieved Oct. 28, 2006.</ref> Through these tests it has become evident absinthe contains very little thujone.
Contrary to these studies many companies still play up the myth that absinthe contains a large amount of thujone and that it will produce some sort of effect on the drinker.
[edit] History
Thujone was an unknown chemical until absinthism hit the scene in the mid 1800s. Dr. Valentin Magnan, who studied alcoholism, tested pure wormwood oil on animals and discovered it caused an epileptic reaction different from plain alcohol. Based on this it was assumed absinthe, which contains a small amount of wormwood oil, was more dangerous than ordinary alcohol. Eventually thujone was isolated as the cause of these reactions. Magnan went on to study 250 alcoholics noting that those who drank absinthe had epileptic attacks and hallucinations. In light of modern evidence these conclusions are questionable and probably based on a poor understanding of other chemicals and diseases and were clouded by Magnan's belief alcohol and absinthe was "degenerating" the French race. <ref>Conrad III, Barnaby; (1988). Absinthe History in a Bottle. Chronicle books. ISBN 0-8118-1650-8 Pg. 101-105</ref>
After absinthe was banned research dropped off until the 1970s when Nature magazine published an article comparing the molecular shape of thujone to THC, and hypothesized it would act the same way on the brain, sparking the myth that thujone is a cannabinoid. <ref name="thc"/>
[edit] Regulations
[edit] European Union
Maximum thujone levels in the EU are: <ref>Opinion of the Scientific Committee on Food on Thujone Scientific Committee on Food (2003) Retrieved Oct 28, 2006.</ref>
- 0.5 mg/kg in food not prepared with sage and non alcoholic beverages.
- 5 mg/kg in alcoholic beverages with 25% or less ABV.
- 10 mg/kg in alcoholic beverages with more than 25% ABV.
- 25 mg/kg in food prepared with sage.
- 35 mg/kg in alcohol labeled as bitters.
[edit] United States
Foods or beverages that contain Artemisia species, White Cedar, oak moss, tansy or Yarrow must be thujone free.<ref>Food Additives Permitted for Direct Addition to Food for Human Consumption. Food and Drug Administration (2003). Retrieved Oct 28, 2006.</ref> Other herbs that contain thujone have no restrictions. For example, sage and sage oil (which can be 50%+ thujone) are on the Food and Drug Administration's list of Substances generally recognized as safe. <ref>Substances generally recognized as safe. Food and Drug Administration (2003). Retrieved Oct 28, 2006.</ref>
[edit] References
<references/>
[edit] External links
- Thujone.Info — Databank of peer reviewed articles on thujone, absinthe, absinthism, and independent thujone ratings of some commercial brands.
- The Shaky History of Thujone - Wormwood Society article on thujone and its history.cs:Thujon
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