Anethole is an aromatic,unsaturatedether related tolignols. It exists as bothcis–trans isomers (see alsoE–Z notation), involving the double bond outside the ring. The more abundant isomer, and the one preferred for use, is thetrans orE isomer.[3]
Like related compounds, anethole is poorly soluble in water. Historically, this property was used to detect adulteration in samples.[4]
Most anethole is obtained fromturpentine-like extracts from trees.[2][5] Of only minor commercial significance, anethole can also be isolated from essential oils.[6][7][8]
Essential oil
World production
Trans-anethole
Anise
8 tonnes (1999)
95%
Star anise
400 tonnes (1999), mostly from China
87%
Fennel
25 tonnes (1999), mostly from Spain
70%
Currently Banwari Chemicals Pvt Ltd situated in Bhiwadi, Rajasthan, India is the leading manufacturer of anethole. It is prepared commercially from 4-methoxypropiophenone,[3][9] which is prepared fromanisole.[2]
Anethole is distinctlysweet, measuring 13 times sweeter thansugar. It is perceived as being pleasant to the taste by many even at higher concentrations. It is used in alcoholic drinksouzo,rakı,anisette andabsinthe, among others. It is also used in seasoning and confectionery applications, such as GermanLebkuchen, oral hygiene products, and in small quantities in natural berryflavors.[7]
Dilutingabsinthe with water produces a spontaneous microemulsion (ouzo effect)
Anethole is responsible for the "ouzo effect" (also "louche effect"), the spontaneous formation of amicroemulsion[26][27] that gives many alcoholic beverages containing anethole and water their cloudy appearance.[28] Such a spontaneous microemulsion has many potential commercial applications in the food and pharmaceutical industries.[29]
Anethole is an inexpensive chemical precursor forparamethoxyamphetamine (PMA),[30] and is used in its clandestine manufacture.[31] Anethole is present in the essential oil fromguarana, which has psychoactive effects typically attributed to its caffeine content. The absence of PMA or any other known psychoactive derivative of anethole in human urine after ingestion of guarana leads to the conclusion that any psychoactive effect of guarana is not due to aminated anethole metabolites.[32]
Fennel, which contains anethole, has been found to have agalactagogue effect in animals. Anethole bears a structural resemblance tocatecholamines likedopamine and may displace dopamine from its receptors and thereby disinhibitprolactin secretion, which in turn may be responsible for the galactagogue effects.[38]
In the USA, anethole isgenerally recognized as safe (GRAS). After a hiatus due to safety concerns, anethole was reaffirmed byFlavor and Extract Manufacturers Association (FEMA) as GRAS.[39] The concerns related to liver toxicity and possible carcinogenic activity reported inrats.[40] Anethole is associated with a slight increase inliver cancer in rats,[40] although the evidence is scant and generally regarded as evidence that anethole isnot acarcinogen.[40][41] An evaluation of anethole by theJoint FAO/WHO Expert Committee on Food Additives (JECFA) found its notablepharmacologic properties to be reduction in motor activity, lowering ofbody temperature, andhypnotic,analgesic, andanticonvulsant effects.[42] A subsequent evaluation by JECFA found some reason for concern regardingcarcinogenicity, but there is currently insufficient data to support this.[43] At this time, the JECFA summary of these evaluations is that anethole has "no safety concern at current levels of intake when used as a flavoring agent".[44]
In large quantities, anethole is slightlytoxic and may act as an irritant.[45]
That an oil could be extracted from anise and fennel had been known since theRenaissance by the German alchemistHieronymus Brunschwig (c. 1450 – c. 1512), the German botanistAdam Lonicer (1528–1586), and the German physicianValerius Cordus (1515–1544), among others.[46] Anethole was first investigated chemically by the Swiss chemistNicolas-Théodore de Saussure in 1820.[47] In 1832, the French chemistJean Baptiste Dumas determined that the crystallizable components of anise oil and fennel oil were identical, and he determined anethole's empirical formula.[48] In 1845, the French chemistCharles Gerhardt coined the termanethol – from the Latinanethum (anise) +oleum (oil) – for the fundamental compound from which a family of related compounds was derived.[49] Although the German chemistEmil Erlenmeyer proposed the correct molecular structure for anethole in 1866,[50] it was not until 1872, that the structure was accepted as correct.[46]
^Bodsgard, B. R.; Lien, N. R.; Waulters, Q. T. (2016). "Liquid CO2 Extraction and NMR Characterization of Anethole from Fennel Seed: A General Chemistry Laboratory".Journal of Chemical Education.93 (2):397–400.Bibcode:2016JChEd..93..397B.doi:10.1021/acs.jchemed.5b00689.
^Ryu, J.; Seo, J.; Lee, Y.; Lim, Y.; Ahn, J. H.; Hur, H. G. (2005). "Identification ofsyn- andanti-anethole-2,3-epoxides in the metabolism oftrans-anethole by the newly isolated bacteriumPseudomonas putida JYR-1".Journal of Agricultural and Food Chemistry.53 (15):5954–5958.Bibcode:2005JAFC...53.5954R.doi:10.1021/jf040445x.PMID16028980.
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^Camurça-Vasconcelos, A. L.; Bevilaqua, C. M.; Morais, S. M.; Maciel, M. V.; Costa, C. T.; Macedo, I. T.; Oliveira, L. M.; Braga, R. R.; Silva, R. A.; Vieira, L. S. (2007). "Anthelmintic activity ofCroton zehntneri andLippia sidoides essential oils".Veterinary Parasitology.148 (3–4):288–294.doi:10.1016/j.vetpar.2007.06.012.PMID17629623.
^Knio, K. M.; Usta, J.; Dagher, S.; Zournajian, H.; Kreydiyyeh, S. (2008). "Larvicidal activity of essential oils extracted from commonly used herbs in Lebanon against the seaside mosquito,Ochlerotatus caspius".Bioresource Technology.99 (4):763–768.Bibcode:2008BiTec..99..763K.doi:10.1016/j.biortech.2007.01.026.PMID17368893.
^Cheng, S. S.; Liu, J. Y.; Tsai, K. H.; Chen, W. J.; Chang, S. T. (2004). "Chemical composition and mosquito larvicidal activity of essential oils from leaves of differentCinnamomum osmophloeum provenances".Journal of Agricultural and Food Chemistry.52 (14):4395–4400.Bibcode:2004JAFC...52.4395C.doi:10.1021/jf0497152.PMID15237942.
^Morais, S. M.; Cavalcanti, E. S.; Bertini, L. M.; Oliveira, C. L.; Rodrigues, J. R.; Cardoso, J. H. (2006). "Larvicidal activity of essential oils from BrazilianCroton species againstAedes aegypti L.".Journal of the American Mosquito Control Association.22 (1):161–164.doi:10.2987/8756-971X(2006)22[161:LAOEOF]2.0.CO;2.PMID16646345.S2CID33429927.
^Park, I. K.; Choi, K. S.; Kim, D. H.; Choi, I. H.; Kim, L. S.; Bak, W. C.; Choi, J. W.; Shin, S. C. (2006). "Fumigant activity of plant essential oils and components from horseradish (Armoracia rusticana), anise (Pimpinella anisum) and garlic (Allium sativum) oils againstLycoriella ingenua (Diptera: Sciaridae)".Pest Management Science.62 (8):723–728.Bibcode:2006PMSci..62..723P.doi:10.1002/ps.1228.PMID16786497.
^Chang, K. S.; Ahn, Y. J. (2002). "Fumigant activity of (E)-anethole identified inIllicium verum fruit againstBlattella germanica".Pest Management Science.58 (2):161–166.Bibcode:2002PMSci..58..161C.doi:10.1002/ps.435.PMID11852640.
^Kim, D. H.; Ahn, Y. J. (2001). "Contact and fumigant activities of constituents ofFoeniculum vulgare fruit against three coleopteran stored-product insects".Pest Management Science.57 (3):301–306.Bibcode:2001PMSci..57..301K.doi:10.1002/ps.274.PMID11455661.
^Padilha de Paula, J.; Gomes-Carneiro, M. R.; Paumgartten, F. J. (2003). "Chemical composition, toxicity and mosquito repellency ofOcimum selloi oil".Journal of Ethnopharmacology.88 (2–3):253–260.doi:10.1016/s0378-8741(03)00233-2.PMID12963152.
^Sánchez Domínguez, M.; Rodríguez Abreu, C. (2016).Nanocolloids: A Meeting Point for Scientists and Technologists. Elsevier Science. p. 369.ISBN978-0-12-801758-6. Retrieved2018-08-02.O/W and W/O nano-emulsions can also be formed without a surfactant by self-emulsification, using the so-called Ouzo effect. The major components of Ouzo (a Greek drink) aretrans-anethole, ethanol, and water. Anethole is almost insoluble ...
^Spernath, A.; Aserin, A. (2006). "Microemulsions as carriers for drugs and nutraceuticals".Advances in Colloid and Interface Science.128–130:47–64.doi:10.1016/j.cis.2006.11.016.PMID17229398.
^Waumans, D.; Hermans, B.; Bruneel, N.; Tytgat, J. (2004). "A neolignan-type impurity arising from the peracid oxidation reaction of anethole in the surreptitious synthesis of 4-methoxyamphetamine (PMA)".Forensic Science International.143 (2–3):133–139.doi:10.1016/j.forsciint.2004.02.033.PMID15240033.
^Benoni, H.; Dallakian, P.; Taraz, K. (1996). "Studies on the essential oil from guarana".Zeitschrift für Lebensmittel-Untersuchung und -Forschung.203 (1):95–98.doi:10.1007/BF01267777.PMID8765992.S2CID45636969.
^Lachenmeier, D. W. (2008). "Thujon-Wirkungen von Absinth sind nur eine Legende—Toxikologie entlarvt Alkohol als eigentliche Absinthismus-Ursache" [Thujone-attributable effects of absinthe are only an urban legend—toxicology uncovers alcohol as real cause of absinthism].Medizinische Monatsschrift für Pharmazeuten (in German).31 (3):101–106.PMID18429531.
^Newberne, P.; Smith, R. L.; Doull, J.; Goodman, J. I.; Munro, I. C.; Portoghese, P. S.; Wagner, B. M.; Weil, C. S.; Woods, L. A.; Adams, T. B.; Lucas, C. D.; Ford, R. A. (1999). "The FEMA GRAS assessment oftrans-anethole used as a flavouring substance".Food and Chemical Toxicology.37 (7):789–811.doi:10.1016/S0278-6915(99)00037-X.PMID10496381.
^abcNewberne, P. M.; Carlton, W. W.; Brown, W. R. (1989). "Histopathological evaluation of proliferative liver lesions in rats fed trans-anethole in chronic studies".Food and Chemical Toxicology.27 (1):21–26.doi:10.1016/0278-6915(89)90087-2.PMID2467866.
^"Safety data for anethole". Physical & Theoretical Chemistry Laboratory Safety, Oxford University. Archived fromthe original on 2008-06-15. Retrieved2009-03-10.
Lippmann, Edmund Oskar von (1921)."§ 339. Anethol".Zeittafeln zur Geschichte der Organischen Chemie [Timeline of the history of organic chemistry] (in German). Berlin: Springer-Verlag. p. 1.ISBN9783662246665.{{cite book}}:ISBN / Date incompatibility (help)
Gildemeister, Eduard; Hoffmann, Friedrich (1900)."§ 307. Oil of anise".The Volatile Oils. Translated by Kremers, Edward. Milwaukee, Wisconsin: Review Publishing Co. pp. s558 –s563.
Dumas, J. (1832)."Mémoire sur les substances végétales qui se rapprochent du camphre, et sur quelques huiles essentielles" [Memoir on plant substances that resemble camphor, and on several essential oils].Annales de Chimie et de Physique. Série 2 (in French).50:225–240. On p. 234, Dumas provides anempirical formula C10H6O1/2 for anethol. If the subscripts are doubled and if the subscript for carbon is then halved (because Dumas, like many of his contemporaries, used the wrongatomic mass for carbon, 6 instead of 12), then Dumas' empirical formula is correct.
Dumas' finding that the crystallizable components of anise oil and fennel oil were identical was confirmed in 1833 by the team of Rodolphe Blanchet (1807–1864) and Ernst Sell (1808–1854). See:Blanchet, Sell (1833)."Ueber die Zusammensetzung einiger organischer Substanzen" [On the composition of some organic substances].Annalen der Pharmacie (in German).6 (3):259–313.doi:10.1002/jlac.18330060304. See especially pp. 287–288.
Dumas' empirical formula for anethole was confirmed in 1841 by the French chemistAuguste Cahours. See:Cahours, A. A. T. (1841)."Sur les essences de fenouil, de badiane et d'anis" [On the essential oils of fennel, star anise, and anise].Annales de Chimie et de Physique. Série 3 (in French).2:274–308. See pp. 278–279. Note that the subscripts of Cahours' empirical formula (C40H24O2) must be divided by 2 and then the subscript for carbon must be divided again by 2 (because, like many chemists of his time, Cahours used the wrong atomic mass for carbon, 6 instead of 12). If these changes are made, the resulting empirical formula is correct.
^Gerhardt, Charles (1845)."Ueber die Identität des Dragonöls und des Anisöls" [On the identity of tarragon oil and anise oil].Journal für praktische Chemie (in German).36:267–276.doi:10.1002/prac.18450360159.[From p. 269:] Ich werde keinen neuen Namen für jede einzelne Art der folgenden physisch verschiedenen Arten annehmen. In meinem Werke bezeichne ich sie als Varietäten der Gattung „Anethol". [I will adopt no new name for any individual species of the following physically different species. In my work, I designate them as varieties of the genusanethol.]
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