por What is anethole?
He anethole It is an organic and aromatic compound, with the molecular formula C10H22O, derived from phenylpropene. It has a characteristic smell of anise oil and a sweet taste. It is found naturally in some essential oils.
Essential oils are liquid at room temperature, being responsible for the smell of plants. They are found mainly in plants of the family Labiatae (mint, lavender, thyme and rosemary) and Umbellifera (anise and fennel). Anethole is extracted from the latter by steam dragging.
Anise and fennel are plants that contain anethole, a phenolic ether, which in the case of anise is found in its fruit. This compound is used as a diuretic, carminative, and expectorant. In addition, it is added to foods to give them flavor.
It is synthesized by esterification of p-cresol with methyl alcohol, and subsequent condensation with aldehyde. Anethole can be extracted by distillation in a stream of steam.
Anethole has toxic effects, and can cause irritation to the skin, eyes, respiratory tract, or digestive tract, depending on the site of contact.
anethole structure
The structure of an anethole molecule in a ball and stick model is shown in the image above.
Here you can see why it is a phenolic ether: on the right is the methoxy group, -OCH3, and if you ignore CH3 for a moment, you will have the phenolic ring (with a propene substituent) without hydrogen, ArO- . Therefore, in summary, its structural formula could be visualized as ArOCH3.
It is a molecule whose carbon skeleton can be located in the same plane, since almost all of its atoms have sp2 hybridization.
Its intermolecular strength is of the dipole-dipole type, with the highest electron density located towards the region of the ring and the methoxy group. Also note the relatively amphiphilic character of anethole: -OCH3 is polar, and the rest of its structure is nonpolar and hydrophobic.
This fact explains its low solubility in water, behaving like any fat or oil. It also explains its affinity for other fats present in natural sources.
geometric isomers
Anethole can be present in two isomeric forms. The first image of the structure showed the trans form (E), the most stable and abundant. Again, this structure is shown in the top image, but accompanied by its cis (Z) isomer, at the top.
Note the difference between both isomers: the relative position of -OCH3 with respect to the aromatic ring. In the cis isomer of anethole, -OCH3 is closer to the ring, resulting in steric hindrance, which destabilizes the molecule.
In fact, such is the destabilization that some properties, such as the melting point, are altered. As a general rule, cis fats have lower melting points, and their intermolecular interactions are less efficient than those of trans fats.
Properties
Names: annexol and 1-methoxy-4-propenyl benzene
Molecular formula: C10h22EITHER
Physical Description: cwhite crystals or colorless liquid, sometimes pale yellow.
Boiling point: 454.1°F at 760mmHg (234°C).
Melting point: 704°F (21.3°C).
Ignition point: 195°F.
Solubility in water: eIt is practically insoluble in water (1.0 g/l) at 25 °C.
Solubility in organic solvents: en 1:8 ratio in 80% ethanol; 1:1 in 90% ethanol. Miscible with chloroform and ether. It reaches a concentration of 10 mM in dimethyl sulfoxide. Soluble in benzene, ethyl acetate, carbon disulfide, and petroleum ether.
Density: 0.9882 g/mL at 20°C.
Vapor pressure: 5.45 Pa at 294°K.
Goo: 2.45×10-3 Poise.
Refractive index: 1,561
Stability: estable, but it is a combustible compound. Incompatible with strong oxidizing agents.
Storage temperature: ebetween 2 and 8 °C.
pH: 7.0.
Applications
Pharmacological and therapeutic
Numerous functions are attributed to anethole trithione (ATT), including increasing salivary secretion, which helps in the treatment of xerostomia.
In anethole, and in the plants that contain it, an activity related to the respiratory system and the digestive system has been demonstrated, in addition to having an anti-inflammatory, anticholinesterase and chemopreventive action.
There is a relationship between the anethole content of a plant and its therapeutic action. Therefore, the therapeutic action is attributed to anethole.
The therapeutic activities of the plants that contain anethole make all of them antispasmodic, carminative, antiseptic and expectorant. They also have eupeptic, secretolytic, galactogogue properties and, at very high doses, emmenogogue activity.
Anethole presents a structural similarity with dopamine, which is why it is pointed out that it can interact with neurotransmitter receptors, inducing the secretion of the hormone prolactin, responsible for the galactogogue action attributed to anethole.
Star anise
Star anise, a culinary flavoring, is used in the treatment of stomach aches. In addition, analgesic, neurotropic and fever-reducing properties are attributed to it. It is used as a carminative and to relieve colic in children.
Insecticidal, antimicrobial and antiparasitic action
Anise is used against aphid insects (aphids), which suck on the leaves and shoots, producing their curling.
Anethole acts as an insecticide on the larvae of mosquito species Ochlerotatus caspices and Aedes egypti. In addition, it acts as a pesticide on the mite (arachnid). It has an insecticidal action on the species of cockroach blastella germanica.
It also acts on several adult weevil species. Finally, anethole is an insect repellent agent, especially mosquitoes.
Anethole acts on the bacteria enteric salmonella, acting in a bactericidal and bacteriostatic way. It presents antifungal activity, especially on species Saccharomyces cerevisiae and Candida albicans, the latter being an opportunistic species.
Anethole exerts an in vitro anthelmintic action on the eggs and larvae of the nematode species. Haemonchus contortuslocated in the digestive tract of sheep.
In food and drinks
Anethole, as well as plants that have a high content of the compound, is used as a flavoring in many foods, drinks and confectionery, due to its pleasant sweet taste. It is used in alcoholic beverages such as ouzo, raki, and Pernod.
Due to its low solubility in water, anethole is responsible for the ouzo effect. Adding water to ouzo liqueur forms tiny droplets of anethole that cloud the liqueur. This is proof of its authenticity.
Toxicity
It can cause, by contact, irritation of the eyes and skin, manifesting on the skin in erythema and edema causing desquamation. If swallowed, it can cause stomatitis, a sign that accompanies anethole toxicity. While by inhalation there is irritation of the respiratory tract.
Star anise (high anethole content) can cause allergies, especially in babies. Likewise, excessive consumption of anethole can induce the appearance of symptoms, such as muscle spasms, mental confusion and drowsiness due to its narcotic action.
Star anise poisoning increases when used intensively in the form of pure essential oils.
References
Anethole trithione. Retrieved from drugbank.ca.
Fennel & other essential oils with (E)-anethole. Retrieved from bkbotanicals.com.