Menthol, extracted from the essential oil of mint, is useful in the treatment of diseases affecting the respiratory and digestive systems. Let’s find out better.
What is menthol
Menthol is an alcohol extracted from Mentha sp. Isolate appears as a potentially irritating white solid.
Within the phytocomplex of the plant (i.e. considering all the active ingredients contained in the extract and essential oil of the mint plant), menthol is useful as a fragrance, as well as a drug for digestive and respiratory problems.
Where is menthol found
Menthol is contained in the essential oil of Mint sp. in quantities between 30-40%; in addition to menthol, mint essential oil also contains menton, mentofuran, 1-8 cineole (chemically it belongs to the group of oxides and also takes the name of eucalyptol, present, as the name implies, also in eucalyptus, a plant indicated for respiratory problems), limonene and d-pulegone.
Plants belonging to the Mentha sp. they are many and distributed all over the world. They are aromatic herbs that propagate by stolons (creeping stems transformed with a reserve function); the leaves are sessile or with petioles depending on the species. Each species has numerous varieties, strains or chemotypes that produce essential oils that differ widely in chemical composition.
Let’s clarify what is meant by chemotype, given that the concept in aromatherapy is fundamental. As mentioned, the phytocomplex of the essential oil of the mint plant is composed of many molecules, the concentration of the same varies depending on environmental factors.
Therefore the same species of mint that grows in full sun, or a little in the shade; or even that grows at 500 m asl or at 30 m asl, etc., will have different concentrations of active ingredients. The essential oils of mint present on the market can be distinguished by the relative content of menthol and carvone.
Properties of menthol
For internal use, menthol is present in many products to relieve sore throats and respiratory congestion.
Mint essential oil is widely used as a flavoring, antiseptic and local anesthetic agent in products for colds, coughs and other preparations (candies, syrups, ointments, etc.).
Furthermore, menthol is useful for reducing gastric spasms and pains; has an eupeptic action, that is, it improves digestion; and carminative (reduces the air in the belly); moreover, it has a stimulating action on the biliary secretion by the gallbladder.
The enteric-coated peppermint oil capsules have been designed to break through the stomach barrier and reach the colon where they can act to relieve spasms due to irritable bowel syndrome.
Finally, it has an antibacterial action, a feature common to all essential oils.
For external use, menthol plays an important refreshing and tonic action on the muscles, so much so that it is present in creams and ointments useful in promoting circulation and giving freshness to tired and swollen legs.
Menthol is present in many formulations such as: ointments and creams, capsules, syrups and throat sprays; it is also present in food preparations such as chewing gum, candies, sweets and chocolates and in alcoholic and non-alcoholic beverages, sweets, cheeses, sauces and packaged fruit, where it is used for flavoring. Lastly, no less important is the use of menthol in the perfume industry.
Mint is also a tonic, therefore, its use in high dosages in the evening, especially as an essential oil, and therefore as menthol, is not recommended, as it can lead to hyperexcitability.
Contraindications
Menthol is contraindicated in the case of gastroesophageal reflux diseases, as it reduces the tone of the lower esophageal sphincter (LES); in people with severe liver problems; for those suffering from occlusions in the biliary tract, because, as mentioned above, it stimulates bile secretion; in pregnancy and in pediatrics.
In addition, the essential oil of Mentha sp. it is not recommended in subjects suffering from favism, as menthol is metabolized by the glucose-6-phosphate dehydrogenase enzyme system, which is genetically deficient in these subjects.
Administration of high doses of peppermint essential oil can cause severe kidney problems or severe kidney failure.
The lethal dose in humans is estimated at 3-8 g of menthol.
