Mint / Pudina

General features – The word ‘Mint’ originates from Mentha which is a splintered Greek word, Mintha. The species is not so defined. It exists possibly in eighteen or more variations that arises due the process of natural hybridization. All of them belong to the lamiaceae family and grow in all continents, Asia, Europe, America, Africa and Australia. They are perennial and highly aromatic by nature. Normally, the plants are 12 to 80 cm tall and have the tendency to spread indiscriminately which is often considered as being invasive. The majority of the species possess high level of Menthol compared to other components. Among the members, Mentha Avensis, the wild type or Corn mint is called Pudina in Hindi, heavily used in Indian and other South Asian cooking and also in many household remedies. It grows in temperate climate of America, Siberia, Central Asia and Northern India. It is herbaceous and perennial. The leaves are 3 – 6 cm long and 1- 2 cm wide and somewhat hairy bearing pink or purple colored flowers, 3 – 4 mm in size. It also bears tiny fruits. Among the commonly used mints, the famous ones are Spearmint, Peppermint, Lemon balm, Lemon mint and water mint. They are largely known for their medicinal, culinary and cosmetic use. All are hybrid by nature and also used for numerous household purposes like in, mouth wash, chewing gums, confectioneries, ice creams and tooth pastes etc. Additionally, the mint oils act as insect or rodent repellants. It is well known for the aromatherapy since mint oil or mint-candles provide soothing smell that helps alleviate the depression or anxiety and subsequently bringing good mood. The chemical ingredients among the species vary significantly although some are common. For example, they all have the high level of Menthol which provides soothing and enjoyable smell. In addition, they have different level of other terpenes, vitamins and minerals.

Table showing various uses of different categories of mints

Mints	Culinary uses	Medicinal uses	Other uses
Peppermint	Soups, salads, salad dressings, cooked foods & drinks.	Upset stomach, Relieving cold, cough and enhancing mood.	Mouthwash, tooth paste, ointments, cosmetics.
Spearmint	Tea, beverages, salads, salad dressings, ice creams, confectionaries etc.	Treatment for nausea, anti-spasmodic, flue and fever, digestive help.	Tooth paste, shower gels, mouthwash, anti-fungal, insecticidal sprays.
Lemon mint / Bergamot	Salads, salad dressings, drinks for citrus flavor, marmalades, jellies, cooked sea foods or sea food salads and chicken.	Aromatherapy, anti-depressant, anxiolytic.	Cosmetics, creams having lemony smell.
Lemon balm (Citronella)	Flavoring teas hot and iced, ice creams, candies and making pesto for cooking fish and chicken.	Natural anti-histamine, carminative, anti-bacterial, effective against flu, cold, high blood pressure and insomnia.	Cosmetics, aromatherapy, anti-oxidants.
Water mint	Used in teas, salads, drinks, cooking hot foods.	Helps digestive problems, fevers, headaches, sore throats, anti-depressant and age related illness.	Cosmetics or aromatherapy.
Corn mint / Pudina	Herbal tea, various Indian cooking, cigarettes, ice creams, foods.	Appetizer, help for gastric trouble, flatulence, gall bladder problems, coughs and fevers.	Various cosmetics, creams, powder, cand

History of mint use: The use of mint is started to be around 1000 B.C. The plant received its name from the Greek mythical character, Minthe who happened to be the lustful river nymph. According to the Greek mythology, the underworld God, Hades fell in love with her that raised anger in his wife, Persephone. Out of anger, she turned that nymph into a plant so that anyone can crush it according to the will. But out of love, Hades gave her marvelous aroma so that anyone would get a soothing smell if walking near her. When crushed then more aroma will come out of it. But that enticing aroma, as it is known today is due to the large presence of Menthol and other terpenes. Earlier, both Romans and Greeks used mints for flavoring the foods, drinks and even their baths especially with the spearmint. Customarily, the Jews used to scatter the mint leaves on the synagogue floor for spreading its beautiful aroma during congregations. It was spread or grown on the tombs of Egyptians. Greek elites used to aromatize the body by dipping into the bath containing crushed leaves. Romans practiced to chew it after the dinner as mouth freshener.

Uses: The herb has immense medicinal values as noticed from the ancient times thus introduced for the very same reason. Either the herb or essential oil extracted from it are used in most purposes. Due to magnificent aroma and physiological compatibility it finds uses in culinary, cosmetic, insecticidal, fungicidal and anti-bacterial purposes. It was once introduced against the stomach ache, pains, heart burn as a result of indigestion or cough, cold and flu but that practice is still continuing. Additionally, due to its sensational cooling ability and anti-inflammatory effect it is also applied to treat minor burns or skin irritation. Further, it enables to unlock breathing passages helping the respiratory troubles. It can relieve headaches if sipped as mint-tea. Some of its kinds also have the anti-depressant effect so its essential oils are also often used in aromatherapy or body massaging.

Chemical components: The essential oil level varies ~ 0.3 – 0.4 %. Among the common mints, major compound is always menthol ~ 30 % on an average level. In addition there are other components also. Below is the few commonly known mints and their major chemical ingredients.

Peppermint – It is a hybrid of spearmint and water mint. The average Menthol content ~ 30 – 48 %, Menthone ~ 20 – 46 %, Menthyl acetate ~ 3 – 10 %, Menthofuran ~ 2 – 17 %, 1-8 Cineol ~ 3 – 6 %. In addition it has Limonene, Pulegone, Caryophyllene and Pinenes. Pulegone is a monoterpene and acts as emmenagogue and abortifacient.

Spearmint – The major io mahngredients of its essential oil are, Carvone ~ 75 %, d – Limonene ~ 8 %, dihydro-Carvone ~ 4 %. Carvone occurs in two isoforms of (S) – (+) – and (R) – (-) conformations. The herb has high level of Carvone instead of Menthol. The (S) – (+) enantiomer is used for the preservation and storage of vegetables like potatoes whereas (R) – (-) conformer has the insect repellant property like mosquitos thus acting as natural pesticide. Additionally, it has beneficial effects on respiratory and cardiovascular system.

Corn mint / Pudina – It has high level of Menthol ~ 45 – 75 %, Menthone ~ 8 – 22 %, Iso-Menthone ~ 6 %, p – Menthone ~ 8 %, neo – Menthol ~ 3 %. These are major ingredients of Pudina in addition to other minor components.

Water mint – It has traceable level of Menthol but high in Limonene ~ 44 %, Linalool ~ 36 % and Linalyl acetate ~ 20 – 30 %. In some cases the Piperitone content is extremely high ~ 69 %. But in most cases it is low. Uniquely it has good amount of Naringenin ~ 2 – 3 % whereas in others its existence is extremely low. This polyphenol has wide range of biologic effect.

Pharmacologic and medicinal effects: One of the widely known effects of peppermint is to create cooling sensation. It is the major reason why Peppermint finds its so many uses. The cooling sensation is provided by the naturally occurring enantiomer, (-) – Menthol. The compound works by interacting with Transient receptor potential cation channel subfamily M (8^th member) (TRPM8). It is a transmembrane ion channel receptor with six helices often defined as cold receptor expressed in the sensory neurons. It is a molecular transducer that can be activated also by lowering the temperature. A set of four helices together on the outer membrane binds to (-) – Menthol allowing the entry of Na⁺ and Ca⁺² ions inside cells causing its depolarization that in turn generates the action potential. The signal is then conducted through C & A – δ fibers of the afferent neurons producing cold sensation. Besides Menthol there are few natural and synthetic agonists able to activate the receptor. Surprisingly, TRPM8 also expresses in the prostate, bladder and lung but the exact functions are yet to be revealed.

Menthol also blocks voltage sensitive Na⁺ channels thereby lowers the neural actions while stimulating the muscle activity. Simultaneously, it creates allosteric modulation of the GABA_A receptor offering low level anesthetic and analgesic effects. Further, the compound has strong cytotoxic actions on many cancer cells that enable to reduce the malignant growth. The other action of Peppermint is to relax the gastrointestinal muscle including stomach. That event reduces the colonic motility but helps digestion relieving flatulence. It is claimed that Peppermint oil help those suffering from the Irritable bowel syndrome (IBS). Further, Menthol is anti-ulcerative. It protects stomach lining from the effect of Indomethacin or Aspirin. The anti-inflammatory action of Menthol is due to reduced production of PGE₂, LTB₄ and IL-1β.The lowering of LDL-cholesterol by Peppermint occurs due to the anti-oxidant role of Rosmarinic acid. The compound also has anxiolytic property while inhibiting the GABA transaminase.

The major ingredient (~ 74 %) of Spearmint oil is R – (-) – Carvone which provides the minty smell whereas S – (+) – enantiomer exists mainly in the Carraway oil with different smell having different biological role. R – (-) – Carvone has the properties of decongestant, diuretic, anti-viral and tonic effects. The recent animal studies by National Cancer Institute in US also show that R – (-) – Carvone has strong anti-tumorigenic ability. Its anti-spasmodic action occurs by the blocking of Ca⁺² channels like that in case of Verapamil. Due to its strong anti-fungal property, Carvone is often used in the agriculture especially for cultivating potatoes. Another component exists at reasonably high level (~ 8 %) is d – Limonene which is a proven anti-stress compound that works on para-sympathetic neurons through the olfactory stimulation providing physiological and psychological relaxation. Its inhalation lowers the heart rate and the subjects feel more comfortable. The enzymatic formation of Perillyl alcohol is proven to be behind the relaxation role. d – Limonene also offers ant-inflammatory and anti-oxidant role. Water mint has high level of both Limonene, Linalool and almost equally significant amount of Linalyl acetate (~ 34 %). Linalool offers lavender like smell. Both Linalool and Linalyl acetate provide sedative and local anesthetic effects. They modulate the nicotinic receptor at neuro-muscular junctions. It also modulate the NMDA receptor in cerebral cortex inhibiting any excitatory seizure actions. Linalool also blocks the Ca⁺² channels. But it does not exert any effect on the GABA_A receptor. Experimentally it does not even provide any anxiolytic action although many claim on its behalf. The water mint has other physiological and medicinal roles. It acts as anti-inflammatory, anti-headaches and lowering coughs, colic, muscle pain and bacterial infections. The compound Naringenin of this mint is a potent MAO inhibitor and binds with high affinity to the GABA_A receptor and weakly to κ – opiate receptor. So it offers anxiolytic, anti-depressant and partial analgesic effect. Further it protects the liver from Hepatitis C virus also.

Summarizing the medicinal effects of mints: A great many medicinal effects are offered by the members of mint family which are summarized below.

• Anti-allergic – The presence of Rosmarinic acid, a strong anti-oxidant compound prevents any seasonal allergy.
• Effect on breast feeding – In case of first time mothers, breast feeding often causes nipple crack which is prevented by consuming Peppermint or applying its extract on nipple.
• Effective on pain relief – Menthol in mints is effective in lowering any pain caused by inflammation. So menthol containing ointment is often used during the massage.
• Effect on common cold – Menthol breaks up phlegm and mucus helping its ejection also.
• Effect on stomach and digestion – It sooths stomach and indigestion. It also enhances bile secretion and flow that essentially helps the digestion process. Peppermint particularly relieves discomfort, bloating and flatulence. It is very effective against gastric ulcers also.
• Effect on IBS – Very effective against IBS offering comfort.
• Anti-microbial effect – It acts as strong microbial agent thus often used in dental wash and breath fresheners.

Conclusion: Although historically introduced for its medicinal role but the family of mints finds too many other uses, from culinary to the aromatherapy and confectioneries. The major component of most categories is Menthol, which displays great many effects but the role of accompanying ingredients also have large impact. All the family members have large beneficial role in human health.