mint

mint, (genus Mentha), genus of 25 species of fragrant herbs of the mint family (Lamiaceae). Native to Eurasia, North America, southern Africa, and Australia, mints are widely distributed throughout the temperate areas of the world and have naturalized in many places. A number of species, particularly peppermint and spearmint, are used as flavorings for foods (including candy and gum) and for liqueur and dentifrices. The essential oils of mints are used as scents in perfumery. Some species are commonly used in herbal medicine and as food additives.

Physical description

Mints have square stems and opposite aromatic leaves. These hardy plants can grow on many different soil types under full sun or partial shade. Many can spread vegetatively by stolons and can be aggressive in gardens. The small flowers are usually pale purple, pink, or white in color and are arranged in clusters, either forming whorls or crowded together in a terminal spike. The flowers are not typical of other members of the family, having four rather than five united petals. The volatile oils are concentrated in resinous dots in the leaves and stems.

Major species

Spearmint (Mentha spicata) grows to about 90 cm (3 feet) in height, with open spikes of pink or lilac flowers and stalkless leaves; it has the characteristic mint fragrance. Peppermint (Mentha ×piperita), a hybrid between spearmint and water mint, has a heavy scent, stalked leaves, and reddish lilac flowers in dense spikes. Water mint (M. aquatica) commonly grows in ditches and has rounded flower spikes and stalked hairy leaves. Wild mint (M. arvensis), native in North America and Eurasia, reaches about 1 meter (about 3.3 feet) in height.

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Pennyroyal (M. pulegium) has small oval obtuse leaves and flowers in axillary whorls and is remarkable for its creeping habit and pungent odor. It has been used in folk medicine to induce perspiration and menstruation. The plant has also been used as an herbal abortifacient, though such preparations are unlikely to terminate a pregnancy. Pennyroyal can induce potentially lethal reactions such as vomiting, hemorrhages, and organ failure in people who ingest it. Pennyroyal oil in particular is highly toxic and should not be ingested.

Related species

Other members of the family Lamiaceae are also known as mints: the bergamots, or bee balms (genus Monarda), are sometimes called horsemint; members of the genus Pycnanthemum are called mountain mints; catnip (Nepeta cataria) is also known as catmint; dittany (Cunila origanoides) is called stonemint; and plants of the Australian genus Prostanthera are called mint bushes.

Mint essential oil

The monoterpene alcohols menthol and neomenthol and the monoterpene ketones menthone and isomenthone are the major constituents of mint essential oil. Several other chemical compounds, including ethers such as menthofuran and 1,8-cineole, esters such as menthyl acetate and dihydrocarvyl acetate, and hydrocarbons such as limonene and β-caryophyllene, are also found in mint. The proportions of the different chemicals in mint essential oil varies depending on the species and cultivar planted, fertilizers used, region where the plant is cultivated, as well as the method of extraction used. Traditionally, mint essential oil has been extracted through steam distillation and solvent extraction. To improve extraction efficiency, however, modern time- and energy-efficient methods such as microwave-assisted, ohmic-assisted, ultrasound-assisted, pulsed electric field, and super and subcritical fluid extraction are now increasingly applied.

Mint essential oil has antibacterial, antifungal, antiviral, antioxidant, anti-inflammatory, and possible anticancer properties. It has been traditionally used to treat oral mucositis, enteritis, gastritis, irritable bowel syndrome, and respiratory tract disorders. The oil is also used to kill insect pests of cereals such as wheat and rice.

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