Alternative names: peppermint, peppermint oil

Latin name: Mentha x piperita

Peppermint (Mentha × piperita) is a hybrid of mint, a cross between watermint and spearmint.Native to Europe and the Middle East, the plant is now widely spread and cultivated in many parts of the world.It is occasionally found in the wild with its parents.Although the genus Mentha includes more than 25 species, mint is the most commonly used.Western mint is derived from Mentha × piperita, while Chinese mint or peppermint is derived from the fresh leaves of M.haplocalyx. Both M. × piperita and M.haplocalyx are considered plant sources of menthol and menthone, and are among the oldest herbs used in culinary and medicinal products.

Botany:

Carl Linnaeus first described mint in 1753 from specimens collected in England; he recognized it as a species, but it is now generally accepted to be a hybrid.It is a rhizomatous perennial herb that grows to a height of 30-90 cm (12-35 in) and has smooth, square-shaped cross-sections.Rhizome widely distributed, fleshy, with fibrous roots. Leaves can be 4–9 cm (1+1⁄2–3+1⁄2 in) long and 1.5–4 cm (1⁄2–1+1⁄2 in) wide.They are dark green with reddish veins and have sharp tips and rough toothed edges.The leaves and stems are usually a little fuzzy.The flowers are purple, 6–8 mm (1⁄4–5⁄16 in) long, with a four-lobed corolla about 5 mm (3⁄16 in) in diameter; they form whorls (columbine verticillum) around the stem, Thick, blunt spikes form.The flowering season lasts from midsummer to late summer. Chromosome numbers were variable and 2n counts were recorded as 66, 72, 84 and 120. Mint is a fast growing plant; once sprouted, spreads very quickly.

Ecology:

Mint is commonly found in moist habitats, including streamsides and gutters.As a hybrid, it is usually sterile, does not produce seeds, and reproduces only vegetatively, spread by its runners.Outside its native range, areas formerly cultivated for oil often have large wild populations, and since 1843 it has been considered an invader in Australia, the Galapagos Islands of New Zealand, and the Great Lakes region of the United States.

Cultivation:

Mint usually grows best in moist, shady locations and expands by underground rhizomes.Take shoots from old seed and dig about 0.5 m (1.5 ft) into the ground.They grow quickly, and if the ground is permanently wet, they will overgrow with runners.For home gardeners, it is often planted in containers to limit rapid spread.It grows best with an adequate water supply, not under water, and when planted in partial sun to shade.Use the leaves and flowering tops; once the flowers start to open and are ready to dry, they are collected.The wild form of the plant is less suitable for this purpose and the cultivated plant has been selected for more and better oil content.They may be set and slightly withered before distillation, or they may be taken directly to the still.

Cultivars:

Several varieties have been selected for garden use:

• Mentha × piperita 'Candymint' has red stems.

• Mentha × piperita 'chocolate mint'. Its flowers open from the bottom up; its flavor is reminiscent of Andean chocolate mint, a popular dessert.

• Mentha × piperita 'Citrata' includes many varieties including 'eau de Cologne' mint, grapefruit mint, lemon mint and orange mint. Its leaves are fragrant and hairless.

• Mentha × piperita 'Crispa' has wrinkled leaves.

• Mentha × piperita 'Lavender Mint'.

• Mentha × piperita 'Lime Mint' has lime-scented leaves.

• Mentha × piperita 'Variegata' has mottled green and pale yellow leaves.

Commercial varieties may include:

• Dulgo rod

• Zephyr

• Population #2 in Bulgaria

• Clone 11-6-22

• Clone 80-121-33

• Meacham Digne 38

• Meacham Liebercourt 19

·'Todd's Mitcham', a verticillium wilt resistant variety bred at Brookhaven National Laboratory starting in the mid 50's through the Atomic Horticulture breeding and testing program.Refined Murray', also resistant to Verticillium wilt.Roberts Mitcham', also resistant to Verticillium wilt, is also the product of mutation breeding.

Production:

In 2020, world mint production was 48,437 tonnes, with Morocco accounting for 83% of the world total and Argentina 14% (table).

In the United States, the states of Oregon and Washington produce most of the country's peppermint,and the leaves are processed into an essential oil, mainly used as a flavoring in chewing gum and toothpaste. 

Chemical composition:

Peppermint is high in menthol.The essential oil also contains menthone and carboxylic acid esters, especially menthyl acetate.Dried mint typically contains 0.3–0.4% volatile oil, which contains menthol (7–48%), menthone (20–46%), menthyl acetate (3–10%), menthylfuran (1–17%), and 1,8-Cineole (3–6%).Peppermint oil also contains small amounts of many other compounds, including limonene, menthone, caryophyllene, and pinene.Mint contains eriocitrin, hesperidin, kaempferol 7-O-rutin and other terpenoids and flavonoids.

Oil:

Peppermint oil contains high concentrations of natural insecticides, mainly menthone (mainly found in M. arvensis var. piperascens (corn mint, peppermint or Japanese peppermint) and in small amounts (6,530 ppm) in Mentha × piperita subsp.notho and Menthone. It is known to repel some pests, including mosquitoes, and is used in organic gardening.It is also widely used to repel rodents.

Peppermint oil is also used as an effective remedy for nausea and digestive problems.Analysis of the Chemical Constituents of Peppermint Essential Oil (Mentha × piperita L.) by GC/FID and GC-MS. The main ingredients are menthol (40.7%) and menthone (23.4%). The other ingredients are (±)-menthyl acetate, 1,8-cineole, limonene, beta-pinene and beta-caryophyllene.

Research and Health Effects:

The potential of peppermint oil as a short-term treatment for irritable bowel syndrome is in preliminary research and is considered a traditional remedy for minor ailments.Peppermint oil and leaves have a cooling effect when used topically for muscle pain, nerve pain, itching, or as a perfume. Oral high doses of peppermint oil (500 mg) can cause mucous membrane irritation and heartburn-like symptoms.Peppermint roots bioaccumulate radium, so the plant may be effective for phytoremediation of radioactively contaminated soil.