Anethole

Anethole
IUPAC name

1-methoxy-4-(1-propenyl)benzene
Identifiers
CAS number 104-46-1 Y
PubChem 637563
ChemSpider 553166 Y
UNII 21C2F5E8RE Y
KEGG D02377 Y
ChEBI CHEBI:35616 Y
ChEMBL CHEMBL452630 Y
Jmol-3D images Image 1
Properties
Molecular formula C10H12O
Molar mass 148.2 g mol−1
Density 0.998 g/cm3
Melting point

20–21 °C
Boiling point

234 °C; 81 °C at 2 mmHg
Hazards
MSDS External MSDS
Related compounds
Related compounds Anisole; Estragole
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Anethole (also para-methoxyphenylpropene, p-propenylanisole, and isoestragole) is a phenylpropene, a type of aromatic compound that occurs widely in nature, in essential oils. It contributes a large component of the distinctive flavors of anise and fennel (both in the botanical family Apiaceae), anise myrtle (Myrtaceae), liquorice (Fabaceae), and star anise (Illiciaceae). Closely related to anethole is its double-bond isomer estragole, abundant in tarragon (Asteraceae) and basil (Lamiaceae), that has a flavor reminiscent of anise. Anethole has numerous commercial uses in multiple industries, and high potential for additional uses.

Contents

Structure and properties

In chemical terms, anethole is an aromatic, unsaturated ether. It has two cis-trans isomers (see also E-Z notation), involving the double bond outside the ring. The more abundant isomer, and the one preferred for use, is the trans or E isomer: trans-anethole, t-anethole, (E)-anethole, trans-para-methoxyphenylpropene. Its full chemical name is trans-1-methoxy-4-(prop-1-enyl)benzene.

Anethole is less soluble in water than in ethanol, which causes certain anise-flavored liqueurs to become opaque when diluted with water (see Ouzo effect). It is a clear, colorless liquid with boiling point 234 °C and congealing point (freezing point) 20 °C;[1] below its congealing point, anethole forms white crystals. The crystals will precipitate from an aqueous solution, which causes a "snow globe" effect when certain anise-flavored liqueurs are chilled. This effect is the basis of a patent for industrial purification of anethole from sources such as pine oil.[2] Anethole can be crystallized directly from a source essential oil by lowering the temperature of the oil; adding a crystal of anethole helps to start the process.[3] Historically, this was used to detect adulteration.[4]

Production

Commercial sources of anethole include some essential oils:[5]

Essential oil World production trans-anethole
Anise 8 tons (1999) 95%
Star anise 400 tons (1999), mostly from China 87%
Fennel 25 tons (1999), mostly from Spain 70%

Uses

Anethole is a flavoring substance of commercial value. In addition, it is distinctly sweet, measuring 13 times sweeter than sugar. It is perceived as being pleasant to the taste even at higher concentrations. It is unrelated to glycyrrhizic acid, which often co-occurs with it, and also is very sweet. Anethole is used in alcoholic drinks, seasoning and confectionery applications, oral hygiene products, and in small quantities in natural berry flavors.[5]

Anethole is an inexpensive chemical precursor for paramethoxyamphetamine (PMA),[6] and used in its clandestine manufacture.[7] Anethole is present in the essential oil from guarana, which is alleged to have a psychoactive effect; however, the absence of PMA or any other known psychoactive derivative of anethole leads to the conclusion that any purported psychoactive effect of guarana is not due to anethole.[8] Anethole is also present in absinthe, a liquor with a reputation for psychoactive effects; these effects however are attributed to ethanol[9] (see also Thujone).

Pharmaceutical drugs derived from or related to anethole include anisyldithiolthione,[10] anethole dithione (ADT), and anethole trithione (ATT).

Research

Anethole is responsible for the "ouzo effect", the spontaneous formation of a microemulsion[11][12] that gives many alcoholic beverages containing anethole and water their cloudy appearance. Such a spontaneous microemulsion has many potential commercial applications in the food and pharmaceutical industries.[13] A derivative of anethole, anethole trithione, is being investigated for use in self-microemulsifying drug delivery systems (SMEDDS).[14]

Bacterial strains capable of using trans-anethole as the sole carbon source include JYR-1 (Pseudomonas putida)[15] and TA13 (Arthrobacter aurescens).[16] Because they metabolize anethole into several aromatic chemical compounds, these bacteria are candidates for use in commercial bioconversion of these valuable compounds from anethole and other phenylpropanoids. Compared to other industrial processes, such bioconversion may be less costly and more friendly to the environment.[16]

Anethole has potent antimicrobial properties, against bacteria, yeast, and fungi.[17] Reported antibacterial properties include both bacteriostatic and bactericidal action against Salmonella enterica[18] but not when used against Salmonella via a fumigation method.[19] Antifungal activity includes increasing the effectiveness of some other phytochemicals (e.g. polygodial) against Saccharomyces cerevisiae and Candida albicans;[20] this synergistic effect has potential medical uses.[21]

In vitro, anethole has antihelmintic action on eggs and larvae of the sheep gastrointestinal nematode Haemonchus contortus.[22] Anethole also has nematicidal activity against the plant nematode Meloidogyne javanica in vitro and in pots of cucumber seedlings.[23]

Anethole also is a promising insecticide. Several essential oils consisting mostly of anethole have insecticidal action against larvae of the mosquitos Ochlerotatus caspius[24] and Aedes aegypti.[25][26] In similar manner, anethole itself is effective against the fungus gnat Lycoriella ingenua (Sciaridae)[27] and the mold mite Tyrophagus putrescentiae.[28] Against the mite, anethole is a slightly more effective pesticide than DEET but anisaldehyde, a related natural compound that occurs with anethole in many essential oils, is 14 times more effective.[28] The insecticidal action of anethole is greater as a fumigant than as a contact agent. (E)-anethole is highly effective as a fumigant against the cockroach Blattella germanica[29] and against adults of the weevils Sitophilus oryzae, Callosobruchus chinensis and beetle Lasioderma serricorne.[30]

As well as an insect pesticide, anethole is an effective insect repellent against mosquitos.[31]

Safety

Formerly generally recognized as safe (GRAS), after a hiatus anethole was reaffirmed by Flavor and Extract Manufacturers Association (FEMA) as GRAS.[32] The hiatus was due to concerns about liver toxicity and possible carcinogenic activity, reported in rats.[33] Anethole is associated with a slight increase in liver cancer in rats,[33] although the evidence is scant and generally regarded as evidence that anethole is not a carcinogen.[33][34] An evaluation of anethole by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) found its notable pharmacologic properties to be reduction in motor activity, lowering of body temperature, and hypnotic, analgesic, and anticonvulsant effects.[35] A subsequent evaluation by JECFA found some reason for concern re carcinogenicity but insufficient data.[36] 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.[37]

In large quantities, anethole is slightly toxic and may act as an irritant.[38]

See also

References

  1. ^ "Anethole USP". International Flavors & Fragrances. http://www.iff.com/Ingredients.nsf/0/025869D6ECC6B33180256990005F76F5. Retrieved March 10, 2009. 
  2. ^ "United States Patent 4902850: Purification of anethole by crystallization". Free Patents Online. http://www.freepatentsonline.com/4902850.html. Retrieved March 10, 2009. 
  3. ^ Ram Nath Chopra and I. C. Chopra and K. L. Handa and L. D. Kapur (1958). Chopra's Indigenous Drugs of India (2nd ed.). Academic Publishers. pp. 178–179. ISBN 9788185086804. http://books.google.com/?id=2HyC4-GJ50YC&pg=PA178&dq=anethole. 
  4. ^ S. Waldbott (1920). "Essential oils". Chemical Abstracts 14 (17): 3753–3755. http://books.google.com/?id=isq2AAAAIAAJ&pg=PA3753&dq=anethole+crystal. 
  5. ^ a b Philip R. Ashurst (1999). Food Flavorings. Springer. pp. 460. ISBN 9780834216211. http://books.google.com/?id=hrWuqmtwJiEC&dq=anethole&q=anethole#search_anchor. 
  6. ^ Waumans D, Bruneel N, Tytgat J (April 2003). "Anise oil as para-methoxyamphetamine (PMA) precursor". Forensic Sci. Int. 133 (1-2): 159–70. doi:10.1016/S0379-0738(03)00063-X. PMID 12742705. http://linkinghub.elsevier.com/retrieve/pii/S037907380300063X. 
  7. ^ Waumans D, Hermans B, Bruneel N, Tytgat J (July 2004). "A neolignan-type impurity arising from the peracid oxidation reaction of anethole in the surreptitious synthesis of 4-methoxyamphetamine (PMA)". Forensic Sci. Int. 143 (2-3): 133–9. doi:10.1016/j.forsciint.2004.02.033. PMID 15240033. http://linkinghub.elsevier.com/retrieve/pii/S0379073804002075. 
  8. ^ Benoni H, Dallakian P, Taraz K (July 1996). "Studies on the essential oil from guarana". Z Lebensm Unters Forsch 203 (1): 95–8. doi:10.1007/BF01267777. PMID 8765992. 
  9. ^ Lachenmeier DW (March 2008). "[Thujone-attributable effects of absinthe are only an urban legend--toxicology uncovers alcohol as real cause of absinthism]" (in German). Med Monatsschr Pharm 31 (3): 101–6. PMID 18429531. 
  10. ^ Mansuy D, Sassi A, Dansette PM, Plat M (March 1986). "A new potent inhibitor of lipid peroxidation in vitro and in vivo, the hepatoprotective drug anisyldithiolthione". Biochem. Biophys. Res. Commun. 135 (3): 1015–21. doi:10.1016/0006-291X(86)91029-6. PMID 3964266. http://linkinghub.elsevier.com/retrieve/pii/0006-291X(86)91029-6. 
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  12. ^ David Carteau, Dario Bassani, and Isabelle Pianet (April–May 2008). "The "Ouzo effect": Following the spontaneous emulsification of trans-anethole in water by NMR". Comptes Rendus Chimie 11 (4-5): 493–498. doi:10.1016/j.crci.2007.11.003. 
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  18. ^ Kubo I, Fujita K (December 2001). "Naturally occurring anti-Salmonella agents". J. Agric. Food Chem. 49 (12): 5750–4. doi:10.1021/jf010728e. PMID 11743758. 
  19. ^ Weissinger WR, McWatters KH, Beuchat LR (April 2001). "Evaluation of volatile chemical treatments for lethality to Salmonella on alfalfa seeds and sprouts". J. Food Prot. 64 (4): 442–50. PMID 11307877. 
  20. ^ Fujita K, Fujita T, Kubo I (January 2007). "Anethole, a potential antimicrobial synergist, converts a fungistatic dodecanol to a fungicidal agent". Phytother Res 21 (1): 47–51. doi:10.1002/ptr.2016. PMID 17078111. 
  21. ^ Marotta F, Barreto R, Kawakita S, Minelli E, Pavasuthipaisit K, Lorenzetti A, Nishiwaki M, Gelosa F, Fesce E, Okura R (2006). "Preventive strategy for Candida gut translocation during ischemia-reperfusion injury supervening on protein-calorie malnutrition". Chin J Dig Dis 7 (1): 33–8. doi:10.1111/j.1443-9573.2006.00241.x. PMID 16412035. http://www3.interscience.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=1443-9611&date=2006&volume=7&issue=1&spage=33. 
  22. ^ Camurça-Vasconcelos AL, Bevilaqua CM, Morais SM, Maciel MV, Costa CT, Macedo IT, Oliveira LM, Braga RR, Silva RA, Vieira LS (September 2007). "Anthelmintic activity of Croton zehntneri and Lippia sidoides essential oils". Vet. Parasitol. 148 (3-4): 288–94. doi:10.1016/j.vetpar.2007.06.012. PMID 17629623. http://linkinghub.elsevier.com/retrieve/pii/S0304-4017(07)00290-7. 
  23. ^ Oka Y, Nacar S, Putievsky E, Ravid U, Yaniv Z, Spiegel Y (July 2000). "Nematicidal activity of essential oils and their components against the root-knot nematode". Phytopathology 90 (7): 710–5. doi:10.1094/PHYTO.2000.90.7.710. PMID 18944489. http://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO.2000.90.7.710?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%3dncbi.nlm.nih.gov. 
  24. ^ Knio KM, Usta J, Dagher S, Zournajian H, Kreydiyyeh S (March 2008). "Larvicidal activity of essential oils extracted from commonly used herbs in Lebanon against the seaside mosquito, Ochlerotatus caspius". Bioresour. Technol. 99 (4): 763–8. doi:10.1016/j.biortech.2007.01.026. PMID 17368893. http://linkinghub.elsevier.com/retrieve/pii/S0960-8524(07)00102-2. 
  25. ^ Cheng SS, Liu JY, Tsai KH, Chen WJ, Chang ST (July 2004). "Chemical composition and mosquito larvicidal activity of essential oils from leaves of different Cinnamomum osmophloeum provenances". J. Agric. Food Chem. 52 (14): 4395–400. doi:10.1021/jf0497152. PMID 15237942. 
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  27. ^ Park IK, Choi KS, Kim DH, Choi IH, Kim LS, Bak WC, Choi JW, Shin SC (August 2006). "Fumigant activity of plant essential oils and components from horseradish (Armoracia rusticana), anise (Pimpinella anisum) and garlic (Allium sativum) oils against Lycoriella ingenua (Diptera: Sciaridae)". Pest Manag. Sci. 62 (8): 723–8. doi:10.1002/ps.1228. PMID 16786497. 
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  29. ^ Chang KS, Ahn YJ (February 2002). "Fumigant activity of (E)-anethole identified in Illicium verum fruit against Blattella germanica". Pest Manag. Sci. 58 (2): 161–6. doi:10.1002/ps.435. PMID 11852640. 
  30. ^ Kim DH, Ahn YJ (March 2001). "Contact and fumigant activities of constituents of Foeniculum vulgare fruit against three coleopteran stored-product insects". Pest Manag. Sci. 57 (3): 301–6. doi:10.1002/ps.274. PMID 11455661. 
  31. ^ Padilha de Paula J, Gomes-Carneiro MR, Paumgartten FJ (October 2003). "Chemical composition, toxicity and mosquito repellency of Ocimum selloi oil". J Ethnopharmacol 88 (2-3): 253–60. doi:10.1016/S0378-8741(03)00233-2. PMID 12963152. http://linkinghub.elsevier.com/retrieve/pii/S0378874103002332. 
  32. ^ Newberne P, Smith RL, Doull J, Goodman JI, Munro IC, Portoghese PS, Wagner BM, Weil CS, Woods LA, Adams TB, Lucas CD, Ford RA (July 1999). "The FEMA GRAS assessment of trans-anethole used as a flavouring substance. Flavour and Extract Manufacturer's Association". Food Chem. Toxicol. 37 (7): 789–811. doi:10.1016/S0278-6915(99)00037-X. PMID 10496381. http://linkinghub.elsevier.com/retrieve/pii/S027869159900037X. 
  33. ^ a b c Newberne PM, Carlton WW, Brown WR (January 1989). "Histopathological evaluation of proliferative liver lesions in rats fed trans-anethole in chronic studies". Food Chem. Toxicol. 27 (1): 21–6. doi:10.1016/0278-6915(89)90087-2. PMID 2467866. 
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  35. ^ Trans-anethole. WHO Food Additives Series. 14. International Program on Chemical Safety (IPCS). http://www.inchem.org/documents/jecfa/jecmono/v14je02.htm. 
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External links

Phenylpropenes