Why does water with mints appear colder?


mentholDrug groupsAntipruriginosaMenthol is a monoterpene with a minty-fresh odor that is found naturally in the essential oil of plants of the genus Mentha occurs, for example in peppermint leaves. It has cooling, itching and pain-relieving effects and is contained in numerous medicinal products that are used, among other things, to treat skin diseases, colds, runny nose and sports injuries. Preparations with high menthol concentrations and pure menthol are irritating and should not get into the eyes.

synonymous: LevomentholumPhEur, Mentholum racemicumPhEur, MentholINCI, L-Menthol, Levomenthol

structure

As menthol (C.10H20O, M.r = 156.3 g / mol) the naturally occurring (-) - or L-menthol (levomenthol, levomentholum) is called. The European Pharmacopoeia contains two monographs:

Menthol is a cyclic monoterpene alcohol. It has three asymmetric carbon atoms and occurs in four diastereomeric pairs of enantiomers.

Stem plants

Menthol occurs in plants of the genus Mentha in front. It is the main component of peppermint essential oil (Mentha x piperita L., Lamiaceae). It is produced synthetically or from the Japanese mint (Mentha arvensis var. piperascens) won.

properties

Levomenthol (illustration) has a pleasant, minty-fresh smell and is in the form of colorless, shiny prisms or needle-shaped crystals. Racemic menthol is available as a free-flowing or agglomerated, crystalline powder or in the form of prismatic or needle-shaped, shiny crystals. Both substances are practically insoluble in water, very easily soluble in ethanol 96% and petroleum ether, easily soluble in fatty oils and liquid paraffin and very sparingly soluble in glycerol. Levomenthol melts at approx. 43 ° C, racemic menthol at 34 ° C. If menthol is mixed with camphor, thymol or borneol, liquid mixtures are created. Safety information: Xi irritant, R36: Irritating to eyes. Storage: Well closed at room temperature between 15-25 ° C.

Effects

Preparations in low concentrations (usually 1% dermal, 0.1% in nasal remedies) have a cooling effect. High concentrations produce a warming to burning, irritating and painful feeling and can lead to an increased sensitivity to cold.

Mechanism of action

The feeling of cold is not triggered physically, but by the binding of menthol to a cold receptor, which is activated physiologically by cool temperatures. This is the cation channel TRPM8 from the family of TRP channels. TRPM8 is located on free nerve endings of afferent A and C fibers and is of central importance for the sensation of cold. The same cold receptor is also activated by eucalyptol and icilin and leads to an increase in the intracellular calcium concentration and the triggering of an action potential. Capsaicin also binds to a TRP channel, namely to the heat-activated TRPV1 (transient receptor potential vanilloid subtype 1), but in contrast to menthol, it triggers a feeling of warmth.

Indications

For itchy skin diseases locally as a cooling and itch-relieving agent, for example for childhood diseases such as chickenpox, for cold sores, hemorrhoids, insect bites and eczema. The preparations usually contain 1% menthol.

For colds and nasal congestion in the form of inhalers, nasal remedies or cold balms. When inhaled, menthol triggers a feeling of freshness in the nose and has a subjectively (but not objectifiable) liberating effect. It should not be used on infants or young children as this can lead to respiratory failure.

For cold symptoms and inflammation in the mouth and throat, for example in the form of lozenges, bronchial lozenges, cold balms, baths and inhalants.

For sports injuries, joint and muscle pain, for example as a gel, cream, pad or cold spray.

For indigestion and flatulence orally in small doses. Internally, however, peppermint oil or tea is mostly used.

As a deodorant for bad breath (e.g. mints, Fisherman's Friend®).

For headaches, applied locally to the temples as a headache oil or balm.

Other uses: for example in cigarettes, food, sweets, chewing gum, perfumes, cosmetics and hygiene articles.

Contraindications

Use in infants and young children. Children, pregnancy and breastfeeding: According to specialist information. The preparations should not get into the eyes.

Interactions

Not known.

unwanted effects
  • Hypersensitivity reactions, allergic contact dermatitis
  • Eye irritation
  • Skin irritation with preparations with high concentration
  • Respiratory arrest and collapse in infants and young children
Preparations

Menthol powder (Talcum cum levomentholo) is a mixture of talc and menthol and is used for weeping skin diseases and childhood diseases such as chickenpox or measles.

Menthol shaking brush (Suspensio alba cutanea aquosa cum levomentholo) is a mixture of white shaking brushes with menthol and is used for acutely inflamed and itchy skin diseases.

Menthol cold cream (Ungentum leniens cum levomentholo) is a mixture of cold cream with menthol and is used as a cooling agent for inflammatory and itchy skin diseases.

Menthol alcohol (Levomentholi solutio ethanolica, Spiritus mentholi) is a mixture of menthol, ethanol and water and can also be used for itchy skin diseases. The disadvantage is that it burns in open areas and the skin dries out.

The corresponding recipes can be found in the DMS, for example. During production in the pharmacy, the menthol crystals can be crushed in a mortar or dissolved in a little ethanol 96% so that they can be better incorporated into the basics.

see also

Peppermint, peppermint oil capsules

literature
  • Medicinal product information (CH)
  • Bhatia S.P., McGinty D., Letizia C.S., Api A.M. Fragrance material review on l-menthol. Food Chem Toxicol, 2008, 46, Suppl 11 Pubmed
  • Croteau R.B., Davis E.M., Ringer K.L., Wildung M.R. (-) - Menthol biosynthesis and molecular genetics. Natural Sciences, 2005, 92 (12), 562-77 Pubmed
  • DMS
  • Eccles R. Role of cold receptors and menthol in thirst, the drive to breathe and arousal. Appetite, 2000, 34 (1), 29-35 Pubmed
  • Eccles R., Jones A.S. The effect of menthol on nasal resistance to air flow. J Laryngol Otol, 1983, 97 (8), 705-9 Pubmed
  • European Pharmacopoeia PhEur
  • Hansel R., Sticher O., Steinegger E. Pharmacognosy - Phytopharmacy. Berlin, Heidelberg: Springer, 1999
  • Burger A., ​​Wachter H. Hunnius. Pharmaceutical Dictionary. Berlin, New York: de Gruyter, 1998
  • Kenya P., Houghton T., Beardsmore C. Does inhaling menthol affect nasal patency or cough? Pediatr Pulmonol, 2008, 43 (6), 532-7 Pubmed
  • McKemy D.D. et al. Identification of a cold receptor reveals a general role for TRP channels in thermosensation. Nature, 2002, 416 (6876), 52-8 Pubmed
  • Patel T., Ishiuji Y., Yosipovitch G. Menthol: a refreshing look at this ancient compound. J Am Acad Dermatol, 2007, 57 (5), 873-8 Pubmed
  • Peier A.M. et al. A TRP channel that senses cold stimuli and menthol. Cell, 2002, 108 (5), 705-15 Pubmed
  • Samarasekera R., Weerasinghe I.S., Hemalal K.P. Insecticidal activity of menthol derivatives against mosquitoes. Pest Manag Sci, 2008, 64 (3), 290-5 Pubmed
  • Wasner G. et al. The effect of menthol on cold allodynia in patients with neuropathic pain. Pain Med, 2008, 9 (3), 354-8 Pubmed
  • Safety data sheet
author

Conflicts of Interest: None / Independent. The author has no relationships with the manufacturers and is not involved in the sale of the products mentioned.

additional Information
Support PharmaWiki with a donation!

© PharmaWiki 2007-2021 - PharmaWiki provides independent and reliable information about medication and health.
This article was last changed on 12/13/2019.
Imprint and data protection declaration
Show products for this page