Mint and menthol: how freshness ingredients work!
Dr. Riccardo Matera
Menthol is one of the major components of mint essential oil: it has been used in therapy of respiratory disease to give relief to airways and provide a pleasant freshness sensation.
What benefits does mint brings?
Several benefits of Mint biocomponents are exploited in cosmetics, nutraceuticals and medicinal products. The majority of mint-based products are oral-care products (tooth paste, mouthwash) thanks to the antiseptic properties of mint actives and especially to the freshness sensation given to mouth and breath.
Which are the freshness ingredients in different mint species?
In the following table we show a different mint species and the corresponding essential oil varieties with their major compounds. Each one is related to various olfactory notes and boasts different biological properties. Table. Major compounds of mint essential oils from different Mint species
|ESSENTIAL OIL||SPECIES||MAIN COMPOUNDS|
|Peppermint oil||Peppermint||M. piperita||menthone, menthol|
|Spearmint oil, Native type |
Scotch Spearmint oil
|Spearmint|| M. spicata, M. viloso-nervata, |
M. gentilis nm. cardiaca
|Cornmint oil||Cornmint||M. arvensis var. piperascens||menthol|
|Pennyroyal oil||Pennyroyal||M. pulegium||pulegone|
|M. citrate oil||Citrata||M. citrata||linaool, linalyl acetate|
Menthol. How does it works?
Mentha piperita generally represents the most used species in health care products due to the high amount of menthol (30%) and menthone (20%).
In particular, menthol gives a freshness sensation not only on the skin but also on mucosa because it interacts with thermo-receptors such as the cold and menthol receptor. The activation of cold receptor originates several benefits:
- It increases the patency of airways (nasal flow)
- It reduces the sensation of dyspnoea
- At low concentration, it acts against cough
These important properties are very useful when seasonal illnesses appear with symptoms like cold, nasal congestion and cough. Some studies on menthol include also Eucalyptus essential oil, along with menthol, it has important properties against cough.
Menthol helps to clear respiratory tract: it gives temporary relief to upper airways and alleviates symptoms such as nasal congestion, sinusitis, cold and cough. Several expectorant balms contain a moderate percentage of mint essential oils or menthol since they revert congestion upon applying directly on chest.
A fundamental ingredient for BeC
Balsamo BeC, is very rich of typical terpenic balsamic components such as menthol and camphor along with the essential oils of Eucalyptus, Wintergreen and Peppermint, It provides beneficial effects and alleviate nasal congestion when applied by delicate massage on chest.
The special blend of essential oils named Sinergia SA by BeC, used in hot steam aerosol represents a real decongestant help thanks to the high content of mint essential oil along with pure menthol for a synergic action in calming cough. The balsamic blend of Mint, Chamomile, Lavender essential oils contribute to dilate bronchi.
Among the precious blend of essential oils, Idrobagno I.U. is one of the most interesting product for the balsamic and vasotonic effect.
The dermo-purifying and anti-inflammatory action of Clove, Cypress and Lemon essential oils which give a sensation of freshness when they are used in whirlpools or in the shower.Mint essential oils is very useful for hair wellness, indeed menthol provide a pleasant freshness sensation when applied on head scalp and help to remove dandruff. Moreover, antiseptic and regenerative properties is exploited also in hair care lotions by reinforcing scalp and providing a vivid and bright look to your hair.
 Mimica-Dukic and Bozin. Mentha L. Species (Lamiaceae) as Promising Sources of Bioactive Secondary Metabolites. Current Pharmaceutical Design, 2008, 14, 3141-3150
 Kenia, P.; Houghton, T.; Beardsmore, C. Does inhaling menthol affect nasal patency or cough? Pediatr. Pulmonol. 2008, 43, 532-7.
Cyclooxygenase, lipoxygenase and the inflammatory process
Cyclooxygenase and lipooxygenase are the two families of enzymes that are commonly involved in the inflammatory process, through a complex of reactions which is called arachidonic acid cascade. This complex of reactions develops as follows: a first enzyme, a phospholipase cleaves the phospholipids of biological membranes, releasing arachidonic acid, a polyunsaturated fatty acid with 20 carbon atoms (eicosa-5Z,8Z,11Z,14Z-tetraenoic acid ; C20:4; ω-6). The arachidonic acid is then transformed by two parallel enzymatic pathways, that is, by two families of enzymes: the cyclooxygenase which transforms it into prostaglandins and thromboxanes and the lipooxygenase which transforms it into hydroperoxides which in turn transform into leukotrienes .
There are two cyclooxygenase isoforms indicated with type 1 and type 2, briefly COX-1 and COX-2. COX-1 is the enzyme present in most cells (except red blood cells), and is constitutive, that is, it is always present. COX-2 is an inducible cyclooxygenase isoform: it is constitutively present in some organs such as brain, liver, kidney, stomach, heart and vascular system, while it can be induced (i.e. developed if necessary) following inflammatory stimuli on the skin, white blood cells and muscles.
There are various types of lipooxygenase that lead to different products, the most important in the inflammatory process is 5-lipooxygenase, 5-LOX.
Prostaglandins, Thromboxanes, and Leukotrienes
Prostaglandins, Thromboxanes, and Leukotrienes are chemical messengers or mediators, that is, molecules that bring a message to specific cells and activate or deactivate metabolic responses in these cells. They, therefore, have a function similar to hormones, only that, unlike what hormones do, the chemical message is carried only at a short distance, that is, only to the cells that are in the vicinity of the place where the mediators were produced. There are different prostaglandins, different thromboxanes and different leukotrienes that carry specific messages. In many cases these act as mediators of the inflammatory process , therefore they trigger all the events that are involved in inflammation:
– vasodilation with consequent blood supply (redness),
– increased capillary permeability with consequent fluid exudation (swelling or edema),
– stimulation of nociceptive nerve signals (pain),
– on-site recall of immune system cells that attack a possible invader (chemotactic action)
– activation of the biosynthesis of fibrous tissue to strengthen or repair the affected part (even if there is no need)
– generations of free radicals that can chemically destroy an invader (but also damage our tissues, i.e. they just “shoot in the middle”).
Prostaglandins and thromboxanes, however, also play important physiological roles in normal conditions, i.e. in the absence of inflammation. For example, they regulate the secretion of mucus that protects the walls of the stomach, they regulate the biosynthesis of cartilages and synovial fluid in the joints, they regulate vasodilation, hence the correct flow of blood in the various local districts, and more.
Triglycerides are the main components of most oils and fats. These are heavy, non-volatile and little polar molecules, insoluble in water, made up of glycerol (or glycerin) esterified with three molecules of fatty acids: therefore, it is a tri-ester of glycerin, from which the name derives. Each fatty acid contains 8 to 22 carbon atoms (commonly 16 to 18) and can be saturated, mono-unsaturated or poly-unsaturated. The size of the fatty acids and their saturation determines the physical and sensorial properties of the triglycerides, which can appear as oils (liquids at room temperature) or fats (solid or semi-solid) and can have greater or less greasiness and smoothness on the skin. Unsaturated triglycerides or with shorter fatty acids are more fluid and have greater flowability.
Fatty acids (saturated, mono-unsaturated and poly-unsaturated)
The name fatty acids is commonly used to indicate those organic acids that are found in the composition of lipids, that is, in animal and vegetable oils and fats, both in the free form and in the form of esters with glycerol (e.g. in triglycerides), or they are esterified with “fatty” alcohols, that is, long chain alcohols, to form waxes. Fatty acids are carboxylic acids (formula R-COOH) which have a long carbon chain (R), unlike common organic acids such as acetic acid and propionic acid, which have 2 or 3 carbon atoms in total, respectively. Fatty acids are defined as saturatedif they do not have double carbon-carbon bonds, (called “unsaturations”), they are defined mono-unsaturated if they have only one, they are defined mono-unsaturatedpoly-unsaturated if they have two or more double bonds (see figure). The term omega-3 (ω-3) or omega-6 (ω-3), refers to the position of the first double bond starting from the bottom of the chain of carbon atoms: if the first double bond is encountered after 3 carbon atoms the fatty acid is classified as omega-3 , if after six carbon atoms omega-6 , as shown in the figure. The most common saturated fatty acids are palmitic acid (16 carbon atoms and no double bond, C16: 0) and stearic acid (18 carbon atoms, 18: 0), the most common mono-unsaturated is the oleic acid, typical of olive oil (18 carbon atoms and 1 double bond in position 9, C18: 1; ω-9), while the most common poly-unsaturated are linoleic acid and linolenic acid, progenitors respectively omega-6 and omega-3 (see figure).
Terpenes and terpenoids
Terpenes or terpenoids are a large family of natural molecules, typically containing 10 to 30 carbon atoms, which are biosynthesized from a common “brick”, isopentenyl pyrophosphate (IPP), containing 5 carbon atoms (see figure). The discovery that the repetitive brick consists of 5 carbon atoms is relatively recent, while it was once assumed that the entire family was created by repeating a brick of 10 carbon atoms, which was called “terpene”. Therefore, the molecules with 10 carbon atoms (such as limonene, see figure) were called mono-terpenes, i.e. composed of a single brick, diterpenes those with 20 carbon atoms (e.g. the cafestol that gives the aroma to the coffee), triterpenes those with 30 carbon atoms (e.g. beta-carotene). Since molecules made from 15 carbon atoms were also found (such as bisabolol), it was thought they contained a terpene and a half, and were called sesquiterpenes (from the Latin semis = half + atque = and). Today it is known that the repetitive unit is composed of 5 carbon atoms, therefore it is easy to understand how mono-terpenes contain two (see figure), sesquiterpenes three, diterpenes four, triterpenes six.