Names | |
---|---|
Preferred IUPAC name 1-Methoxy-4-[(E)-prop-1-enyl]benzene [1] | |
Other names (E)-1-Methoxy-4-(prop-1-en-1-yl)benzene (E)-1-Methoxy-4-(1-propenyl)benzene para-Methoxyphenylpropene p-Propenylanisole Isoestragole trans-1-Methoxy-4-(prop-1-enyl)benzene | |
Identifiers | |
| |
3D model (JSmol) | |
ChEBI | |
ChEMBL | |
ChemSpider | |
ECHA InfoCard | 100.002.914 |
KEGG | |
PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
| |
| |
Properties | |
C10H12O | |
Molar mass | 148.205 g/mol |
Density | 0.998 g/cm3 |
Melting point | 20 to 21 °C (68 to 70 °F; 293 to 294 K) |
Boiling point | 234 °C (453 °F; 507 K) 81 °C (178 °F; 354 K) at 2 mmHg |
−9.60×10−5 cm3/mol | |
Hazards | |
Safety data sheet (SDS) | External MSDS |
Related compounds | |
Related compounds | anisole estragole |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Anethole (also known as anise camphor) [2] is an organic compound that is widely used as a flavoring substance. It is a derivative of the aromatic compound allylbenzene and occurs widely in the essential oils of plants. It is in the class of phenylpropanoid organic compounds. It contributes a large component of the odor and flavor of anise and fennel (both in the botanical family Apiaceae), anise myrtle (Myrtaceae), liquorice (Fabaceae), magnolia blossoms, and star anise (Schisandraceae). Closely related to anethole is its isomer estragole, which is abundant in tarragon (Asteraceae) and basil (Lamiaceae), and has a flavor reminiscent of anise. It is a colorless, fragrant, mildly volatile liquid.[ clarification needed ] [3] Anethole is only slightly soluble in water but exhibits high solubility in ethanol. This trait causes certain anise-flavored liqueurs to become opaque when diluted with water; this is called the ouzo effect.
Anethole is an aromatic, unsaturated ether related to lignols. It exists as both 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. [4]
Like related compounds, anethole is poorly soluble in water. Historically, this property was used to detect adulteration in samples. [5]
Most anethole is obtained from turpentine-like extracts from trees. [3] [6] Of only minor commercial significance, anethole can also be isolated from essential oils. [7] [8] [9]
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, [4] [10] which is prepared from anisole. [3]
Anethole is distinctly sweet, measuring 13 times sweeter than sugar. It is perceived as being pleasant to the taste even at higher concentrations. It is used in alcoholic drinks ouzo, rakı, anisette and absinthe, among others. It is also used in seasoning and confectionery applications, such as German Lebkuchen, oral hygiene products, and in small quantities in natural berry flavors. [8]
Because they metabolize anethole into several aromatic chemical compounds, some bacteria are candidates for use in commercial bioconversion of anethole to more valuable materials. [11] Bacterial strains capable of using trans-anethole as the sole carbon source include JYR-1 ( Pseudomonas putida ) [12] and TA13 ( Arthrobacter aurescens ). [11]
Anethole has potent antimicrobial properties, against bacteria, yeasts, and fungi. [13] Reported antibacterial properties include both bacteriostatic and bactericidal action against Salmonella enterica [14] but not when used against Salmonella via a fumigation method. [15] Antifungal activity includes increasing the effectiveness of some other phytochemicals (such as polygodial) against Saccharomyces cerevisiae and Candida albicans ; [16]
In vitro , anethole has antihelmintic action on eggs and larvae of the sheep gastrointestinal nematode Haemonchus contortus . [17] Anethole also has nematicidal activity against the plant nematode Meloidogyne javanica in vitro and in pots of cucumber seedlings. [18]
Anethole also is a promising insecticide. Several essential oils consisting mostly of anethole have insecticidal action against larvae of the mosquito Ochlerotatus caspius [19] and Aedes aegypti . [20] [21] In a similar manner, anethole itself is effective against the fungus gnat Lycoriella ingenua (Sciaridae) [22] and the mold mite Tyrophagus putrescentiae. [23] 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. [23] The insecticidal action of anethole is greater as a fumigant than as a contact agent. trans-Anethole is highly effective as a fumigant against the cockroach Blattella germanica [24] and against adults of the weevils Sitophilus oryzae , Callosobruchus chinensis and beetle Lasioderma serricorne . [25]
As well as an insect pesticide, anethole is an effective insect repellent against mosquitos. [26]
Anethole is responsible for the "ouzo effect" (also "louche effect"), the spontaneous formation of a microemulsion [27] [28] that gives many alcoholic beverages containing anethole and water their cloudy appearance. [29] Such a spontaneous microemulsion has many potential commercial applications in the food and pharmaceutical industries. [30]
Anethole is an inexpensive chemical precursor for paramethoxyamphetamine (PMA), [31] and is used in its clandestine manufacture. [32] Anethole is present in the essential oil from guarana, 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. [33]
Anethole is also present in absinthe, a liquor with a reputation for psychoactive effects; these effects, however, are attributed to ethanol. [34] (See also thujone, anethole dithione (ADT), and anethole trithione (ATT).)
Anethole has estrogenic activity. [35] [36] [37] It has been found to significantly increase uterine weight in immature female rats. [38]
Fennel, which contains anethole, has been found to have a galactagogue effect in animals. Anethole bears a structural resemblance to catecholamines like dopamine and may displace dopamine from its receptors and thereby disinhibit prolactin secretion, which in turn may be responsible for the galactagogue effects. [39]
In the USA, anethole is generally recognized as safe (GRAS). After a hiatus due to safety concerns, anethole was reaffirmed by Flavor and Extract Manufacturers Association (FEMA) as GRAS. [40] The concerns related to liver toxicity and possible carcinogenic activity reported in rats. [41] Anethole is associated with a slight increase in liver cancer in rats, [41] although the evidence is scant and generally regarded as evidence that anethole is not a carcinogen. [41] [42] 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. [43] A subsequent evaluation by JECFA found some reason for concern regarding carcinogenicity, but there is currently insufficient data to support this. [44] 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". [45]
In large quantities, anethole is slightly toxic and may act as an irritant. [46]
That an oil could be extracted from anise and fennel had been known since the Renaissance by the German alchemist Hieronymus Brunschwig (c. 1450 – c. 1512), the German botanist Adam Lonicer (1528–1586), and the German physician Valerius Cordus (1515–1544), among others. [47] Anethole was first investigated chemically by the Swiss chemist Nicolas-Théodore de Saussure in 1820. [48] In 1832, the French chemist Jean Baptiste Dumas determined that the crystallizable components of anise oil and fennel oil were identical, and he determined anethole's empirical formula. [49] In 1845, the French chemist Charles Gerhardt coined the term anethol – from the Latin anethum (anise) + oleum (oil) – for the fundamental compound from which a family of related compounds was derived. [50] Although the German chemist Emil Erlenmeyer proposed the correct molecular structure for anethole in 1866, [51] it was not until 1872, that the structure was accepted as correct. [47]
Tarragon, also known as estragon, is a species of perennial herb in the family Asteraceae. It is widespread in the wild across much of Eurasia and North America and is cultivated for culinary and medicinal purposes.
Anise, also called aniseed or rarely anix, is a flowering plant in the family Apiaceae native to the eastern Mediterranean region and Southwest Asia.
Caraway, also known as meridian fennel and Persian cumin, is a biennial plant in the family Apiaceae, native to western Asia, Europe, and North Africa.
Fennel is a flowering plant species in the carrot family. It is a hardy, perennial herb with yellow flowers and feathery leaves. It is indigenous to the shores of the Mediterranean but has become widely naturalized in many parts of the world, especially on dry soils near the sea coast and on riverbanks.
Illicium verum is a medium-sized evergreen tree native to South China and northeast Vietnam. Its star-shaped pericarps harvested just before ripening is a spice that closely resembles anise in flavor. Its primary production country is China, followed by Vietnam and other Southeast Asian countries. Star anise oil is a highly fragrant oil used in cooking, perfumery, soaps, toothpastes, mouthwashes, and skin creams. Until 2012, when they switched to using genetically modified E. coli, Roche Pharmaceuticals used up to 90% of the world's annual star anise crop to produce oseltamivir (Tamiflu) via shikimic acid.
Ouzo is a dry anise-flavored aperitif that is widely consumed in Greece. It is made from rectified spirits that have undergone a process of distillation and flavoring. Its taste is similar to other anise liquors like pastis, sambuca, mastika, rakı, and arak.
Safrole is an organic compound with the formula CH2O2C6H3CH2CH=CH2. It is a colorless oily liquid, although impure samples can appear yellow. A member of the phenylpropanoid family of natural products, it is found in sassafras plants, among others. Small amounts are found in a wide variety of plants, where it functions as a natural antifeedant. Ocotea pretiosa, which grows in Brazil, and Sassafras albidum, which grows in eastern North America, are the main natural sources of safrole. It has a characteristic "sweet-shop" aroma.
Cinnamaldehyde is an organic compound with the formula or C₆H₅CH=CHCHO. Occurring naturally as predominantly the trans (E) isomer, it gives cinnamon its flavor and odor. It is a phenylpropanoid that is naturally synthesized by the shikimate pathway. This pale yellow, viscous liquid occurs in the bark of cinnamon trees and other species of the genus Cinnamomum. It is an essential oil. The bark of cinnamon tree contains high concentrations of cinnamaldehyde.
Thymol, C10H14O, is a natural monoterpenoid phenol derivative of p-Cymene, isomeric with carvacrol, found in oil of thyme, and extracted from Thymus vulgaris, ajwain, and various other plants as a white crystalline substance of a pleasant aromatic odor and strong antiseptic properties. Thymol also provides the distinctive, strong flavor of the culinary herb thyme, also produced from T. vulgaris. Thymol is only slightly soluble in water at neutral pH, but it is extremely soluble in alcohols and other organic solvents. It is also soluble in strongly alkaline aqueous solutions due to deprotonation of the phenol. Its dissociation constant (pKa) is 10.59±0.10. Thymol absorbs maximum UV radiation at 274 nm.
Linalool refers to two enantiomers of a naturally occurring terpene alcohol found in many flowers and spice plants. Together with geraniol, nerol, citronellol, linalool is one of the rose alcohols. Linalool has multiple commercial applications, the majority of which are based on its pleasant scent.
Carvone is a member of a family of chemicals called terpenoids. Carvone is found naturally in many essential oils, but is most abundant in the oils from seeds of caraway, spearmint, and dill.
Carvacrol, or cymophenol, C6H3(CH3)(OH)C3H7, is a monoterpenoid phenol. It has a characteristic pungent, warm odor of oregano.
Eucalyptol is a monoterpenoid colorless liquid, and a bicyclic ether. It has a fresh camphor-like odor and a spicy, cooling taste. It is insoluble in water, but miscible with organic solvents. Eucalyptol makes up about 70–90% of eucalyptus oil. Eucalyptol forms crystalline adducts with hydrohalic acids, o-cresol, resorcinol, and phosphoric acid. Formation of these adducts is useful for purification.
Myrcene, or β-myrcene, is a monoterpene. A colorless oil, it occurs widely in essential oils. It is produced mainly semi-synthetically from Myrcia, from which it gets its name. It is an intermediate in the production of several fragrances. An less-common isomeric form, having one of the three alkene units in a different position, is α-myrcene.
Caryophyllene, more formally (−)-β-caryophyllene (BCP), is a natural bicyclic sesquiterpene that occurs widely in nature. Caryophyllene is notable for having a cyclobutane ring, as well as a trans-double bond in a 9-membered ring, both rarities in nature.
Estragole is a phenylpropene, a natural organic compound. Its chemical structure consists of a benzene ring substituted with a methoxy group and an allyl group. It is an isomer of anethole, differing with respect to the location of the double bond. It is a colorless liquid, although impure samples can appear yellow. It is a component of various trees and plants, including turpentine, anise, fennel, bay, tarragon, and basil. It is used in the preparation of fragrances.
The ouzo effect, also known as the louche effect and spontaneous emulsification, is the phenomenon of formation of a milky oil-in-water emulsion when water is added to ouzo and other anise-flavored liqueurs and spirits, such as pastis, rakı, arak, sambuca and absinthe. Such emulsions occur with only minimal mixing and are highly stable.
Aromatherapy is a practice based on the use of aromatic materials, including essential oils and other aroma compounds, with claims for improving psychological well-being. It is used as a complementary therapy or as a form of alternative medicine, and typically is used via inhalation and not by ingestion.
Dianethole is a naturally occurring organic compound that is found in anise and fennel. It is a dimeric polymer of anethole. It has estrogenic activity, and along with anethole and photoanethole, may be responsible for the estrogenic effects of anise and fennel. These compounds bear resemblance to the estrogens stilbene and diethylstilbestrol, which may explain their estrogenic activity. In fact, it is said that diethylstilbestrol and related drugs were originally modeled after dianethole and photoanethole.
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) are trans-anethole, ethanol, and water. Anethole is almost insoluble ...
[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 genus anethol.]