Peppermint

Peppermint
Peppermint (Mentha x piperita)
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Lamiales
Family: Lamiaceae
Genus: Mentha
Binomial name
Mentha × piperita
L.

Peppermint (Mentha × piperita, also known as M. balsamea Willd.[1]) is a hybrid mint, a cross between the watermint (Mentha aquatica) and spearmint (Mentha spicata). The plant, indigenous to Europe, is now widespread in cultivation throughout all regions of the world.[2] It is found wild occasionally with its parent species.[2][3]

Contents

Botany

Peppermint flowers

Peppermint was first described by Carolus Linnaeus from specimens that had been collected in England; he treated it as a species,[4] but it is now universally agreed to be a hybrid.[5]

It is a herbaceous rhizomatous perennial plant growing to 30–90 cm (12–35 in) tall, with smooth stems, square in cross section. The rhizomes are wide-spreading, fleshy, and bare fibrous roots. The leaves are from 4–9 cm (1.6–3.5 in) long and 1.5–4 cm (0.59–1.6 in) cm broad, dark green with reddish veins, and with an acute apex and coarsely toothed margins. The leaves and stems are usually slightly hairy. The flowers are purple, 6–8 mm (0.24–0.31 in) long, with a four-lobed corolla about 5 mm (0.20 in) diameter; they are produced in whorls (verticillasters) around the stem, forming thick, blunt spikes. Flowering is from mid to late summer. The chromosome number is variable, with 2n counts of 66, 72, 84, and 120 recorded.[3][6][7]

Ecology

Peppermint typically occurs in moist habitats, including stream sides and drainage ditches. Being a hybrid, it is usually sterile, producing no seeds and reproducing only vegetatively, spreading by its rhizomes. If placed, it can grow anywhere, with a few exceptions.[3][7]

It is an invasive species in the Great Lakes region, noted since 1843.[8]

Uses

1887 illustration

Peppermint has a long tradition of medicinal use, with archaeological evidence placing its use at least as far back as ten thousand years ago.

Peppermint has a high menthol content, and is often used as tea and for flavouring ice cream, confectionery, chewing gum, and toothpaste. The oil also contains menthone and menthyl esters, particularly menthyl acetate.[9] It is the oldest and most popular flavour of mint-flavoured confectionery. Peppermint can also be found in some shampoos and soaps, which give the hair a minty scent and produce a cooling sensation on the skin.

Freeze-dried leaves

In 2007, Italian investigators reported that 75% of the patients in their study who took peppermint oil capsules for four weeks had a major reduction in irritable bowel syndrome (IBS) symptoms, compared with just 38% of those who took a placebo.[10]

Similarly, some poorly designed earlier trials found that peppermint oil has the ability to reduce colicky abdominal pain due to IBS with an NNT (number needed to treat) around 3.1,[11] but the oil is an irritant to the stomach in the quantity required and therefore needs wrapping for delayed release in the intestine. This could also be achieved by using the whole herb or leaves rather than the volatile components alone. Peppermint relaxes the gastro-esophageal sphincter, thus promoting belching.

Peppermint flowers are large nectar producers and honey bees as well as other nectar harvesting organisms forage them heavily. A mild, pleasant varietal honey can be produced if there is a sufficient area of plants.

Peppermint oil is used by commercial pesticide applicators, in the EcoSmart Technologies line of products, as a natural insecticide.[12]

Outside of its native range, areas where peppermint was formerly grown for oil often have an abundance of feral plants, and it is considered invasive in Australia, the Galápagos Islands, New Zealand,[13] and in the United States.[14]

Cultivation

Peppermint generally thrives in moist, shaded locations, and expands quickly by underground stolons. It is often grown in containers to restrict rapid spreading. It grows best with a good supply of water, and is often planted in areas with part-sun to shade.

The leaves and flowering tops are used, they are collected as soon as the flowers begin to open and then are carefully dried. The wild form of the plant is less suitable for this purpose, with cultivated plants having been selected for more and better oil content. Seeds sold at stores labelled peppermint generally will not germinate into true peppermint, but often produce a less intensely scented spearmint-like plant. The true peppermint rarely produce seeds, and only by fertilization from a spearmint plant, which contributes only their own spearmint genes that dilutes down the scent and flavour.

Toxicology

The toxicity studies of the plant have received controversial results. Some authors reported that the plant may induce hepatic diseases, while others found that it is of protective functions against the liver damages which are caused by heavy metal inductions.[15], [16] In addition to that, the toxicities of the plant seem to vary from one cultivar to another[17] and are dose dependent.[15], [18] This is probably attributed from the content level of pulegone.[19] Some of the toxic components may come from herbicides.[20], [21]

List of the cultivars

A number of cultivars have been selected for garden use:[6]

Commercial cultivars may include

Standardization of its products and services

See also

Notes

  1. ↑ World Health Organization. "WHO monographs on selected medicinal plants Volume 2". http://whqlibdoc.who.int/publications/2002/9241545372.pdf. Retrieved 3 June 2009. 
  2. ↑ 2.0 2.1 Euro+Med Plantbase Project: Mentha × piperita
  3. ↑ 3.0 3.1 3.2 Flora of NW Europe: Mentha × piperita
  4. ↑ Linnaeus, C. (1753). Species Plantarum 2: 576–577.
  5. ↑ Harley, R. M. (1975). Mentha L. In: Stace, C. A., ed. Hybridization and the flora of the British Isles page 387.
  6. ↑ 6.0 6.1 Huxley, A., ed. (1992). New RHS Dictionary of Gardening. Macmillan ISBN 0-333-47494-5.
  7. ↑ 7.0 7.1 Blamey, M. & Grey-Wilson, C. (1989). Flora of Britain and Northern Europe. ISBN 0-340-40170-2
  8. ↑ "List of invasive species in the Great Lakes Great Lakes United / Union Saint-Laurent Grands Lacs". http://www.glu.org/en/node/199. Retrieved 2009-02-07. 
  9. ↑ PDR for Herbal Medicines, 4th Edition, Thomson Healthcare, page 640. ISBN 978-1563636783
  10. ↑ Cappello, G.; et al. (2007). "Peppermint oil (Mintoil) in the treatment of irritable bowel syndrome: A prospective double blind placebo-controlled randomized trial". Digestive and Liver Disease 39 (6): 530–536. doi:10.1016/j.dld.2007.02.006. 
  11. ↑ Bandolier Journal: Peppermint oil for irritable bowel syndrome
  12. ↑ EcoSMART Product label
  13. ↑ Pacific Island Ecosystems at Risk: Mentha x piperita
  14. ↑ USDA Plants Profile: Mentha x piperita
  15. ↑ 15.0 15.1 Akdogan, Mehmet (2004). "Investigation of biochemical and histopathological effects of Mentha piperitaLabiatae and Mentha spicata Labiatae on liver tissue in rats". Human & Experimental Toxicology 23 (1): 21–28. http://het.sagepub.com/cgi/content/abstract/23/1/21. Retrieved 3 June 2009. 
  16. ↑ Sharma, Ambika et al. (2007). "Protective Effect of Mentha piperita against Arsenic-Induced Toxicity in Liver of Swiss Albino Mice". Basic & Clinical Pharmacology & Toxicology 100 (4): 249–257. http://www3.interscience.wiley.com/journal/118500486/abstract. Retrieved 3 June 2009. 
  17. ↑ Akdogan, Mehmet (2003). "Investigation of biochemical and histopathological effects of Mentha piperita L. and Mentha spicata L. on kidney tissue in rats". Human & Experimental Toxicology 22 (4): 213–219. http://het.sagepub.com/cgi/content/abstract/22/4/213. Retrieved 3 June 2009. 
  18. ↑ Akdogan, Mehmet et al. (2004). "Effect of Mentha piperita (Labiatae) and Mentha spicata (Labiatae) on iron absorption in rats". Toxicology and Industrial Health 20 (6 - 10): 119–122. http://tih.sagepub.com/cgi/content/abstract/20/6-10/119. Retrieved 3 June 2009. 
  19. ↑ Farley, Derek R.; Valerie Howland (2006). "The natural variation of the pulegone content in various oils of peppermint". Journal of the Science of Food and Agriculture 31 (11): 1143–1151. doi:10.1002/jsfa.2740311104. 
  20. ↑ Edwards, J.; F.E. Bienvenu (1999). "Investigations into the use of flame and the herbicide, paraquat, to control peppermint rust in north-east Victoria, Australia". Australasian Plant Pathology 28 (3): 212–224. doi:10.1071/AP99036. 
  21. ↑ Adamovic, D.S. et al.. "Variability of herbicide efficiency and their effect upon yield and quality of peppermint (Mentha X Piperital L.)". http://www.actahort.org/books/249/249_8.htm. Retrieved 6 June 2009. 
  22. ↑ Mountain Valley Growers: Mentha piperita cv. Chocolate Mint
  23. ↑ 23.0 23.1 23.2 23.3 23.4 Stanev, S.; V.D. Zheljazkov. "Study on essential oil and free menthol accumulation in 19 cultivars, populations, and clones of peppermint (Mentha X Piperita)". http://www.actahort.org/books/629/629_21.htm. Retrieved 6 June 2009. 
  24. ↑ 24.0 24.1 24.2 Jullien, Frédéric et al.; F.E. Bienvenu (1998). "An optimising protocol for protoplast regeneration of three peppermint cultivars ( Mentha x piperita)". Plant Cell, Tissue and Organ Culture 54 (3): 153–159. doi:10.1023/A:1006185103897. 
  25. ↑ International Organization for Standardization. "ISO 676:1995 Spices and condiments -- Botanical nomenclature". http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=4844. Retrieved 8 June 2009. 
  26. ↑ International Organization for Standardization. "ISO 5563:1984 Dried peppermint (Mentha piperita Linnaeus) -- Specification". http://www.iso.org/iso/catalogue_detail.htm?csnumber=11633. Retrieved 7 June 2009. 
  27. ↑ International Organization for Standardization. "ISO 856:2008 Oil of peppermint (Mentha x piperita L.)". http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=32041. Retrieved 7 June 2009. 

External links