Cloves

This article is about the spice. For other uses, see Clove (disambiguation).
Clove
Scientific classification
Kingdom: Plantae
Phylum: Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Myrtales
Family: Myrtaceae
Genus: Syzygium
Species: S. aromaticum
Binomial name
Syzygium aromaticum
(L.) Merrill & Perry
Synonyms[1]
  • Caryophyllus aromaticus L.
  • Eugenia aromatica (L.) Baill.
  • Eugenia caryophyllata Thunb.
  • Eugenia caryophyllus (Spreng.) Bullock & S. G. Harrison

Cloves are the aromatic dried flower buds of a tree in the family Myrtaceae, Syzygium aromaticum. Cloves are native to the Maluku islands in Indonesia and used as a spice in cuisines all over the world. Cloves are harvested primarily in Indonesia, India, Madagascar, Zanzibar, Pakistan, and Sri Lanka. They have a numbing effect on mouth tissues.

The clove tree is an evergreen that grows to a height ranging from 8–12 m, having large leaves and sanguine flowers in numerous groups of terminal clusters. The flower buds are at first of a pale color and gradually become green, after which they develop into a bright red, when they are ready for collecting. Cloves are harvested when 1.5–2 cm long, and consist of a long calyx, terminating in four spreading sepals, and four unopened petals which form a small ball in the center.

Taxonomy and nomenclature

The scientific name of clove is Syzygium aromaticum. It belongs to the genus Syzygium, tribe Syzygieae, and subfamily Myrtoideae of the family Myrtaceae. It is classified in the order of Myrtales, which belong to superorder Rosids, under Eudicots of Dicotyledonae. Clove is an Angiospermic plant and belongs to division of Magnoliophyta in the kingdom Plantae.[1]

Uses



Cloves are often used in Asian, African, and Middle Eastern cooking in adding flavor to meats, curries, and meat marinades. They are also used to create sweet dishes, such as with fruits like apples, pears, or rhubarb.[2]

In Mexican cuisine, cloves are best known as clavos de olor, and often used together with cumin and cinnamon.[3]

Considered a very strong spice due to the eugenol chemical that makes up most of the clove's taste (85 percent), the quantity of clove used in recipes is usually small.[4] It pairs well with cinnamon, allspice, vanilla, red wine and basil, as well as with uncommon combinations like onion, citrus peel, star anise or peppercorns.[4]

Non-culinary uses

The spice is used in a type of cigarette called kretek in Indonesia.[1] Kreteks have been smoked throughout Europe, Asia and the United States. In 2009, clove cigarettes (as well as fruit and candy flavored cigarettes) were outlawed in the US. Cigarettes containing clove are now classified as cigars when sold in the US.[5]

Clove also works as an ant repellant.[6]

They can be used as to make a fragrant pomander when combined with an orange.

Traditional medicinal uses

Cloves are used in Indian Ayurvedic medicine, Chinese medicine, and western herbalism and dentistry where the essential oil is used as an anodyne (painkiller) for dental emergencies. Cloves are used as a carminative, to increase hydrochloric acid in the stomach and to improve peristalsis. Cloves are also said to be a natural anthelmintic.[7] The essential oil is used in aromatherapy when stimulation and warming are needed, especially for digestive problems. Topical application over the stomach or abdomen are said to warm the digestive tract. to a cavity in a decayed tooth, also relieves toothache.[8]

In Chinese medicine cloves or ding xiang are considered acrid, warm and aromatic, entering the kidney, spleen and stomach meridians, and are notable in their ability to warm the middle, direct stomach qi downward, to treat hiccough and to fortify the kidney yang.[9] Because the herb is so warming it is contraindicated in any persons with fire symptoms and according to classical sources should not be used for anything except cold from yang deficiency. As such it is used in formulas for impotence or clear vaginal discharge from yang deficiency, for morning sickness together with ginseng and patchouli, or for vomiting and diarrhea due to spleen and stomach coldness.[9]

Cloves may be used internally as a tea and topically as an oil for hypotonic muscles, including for multiple sclerosis. This is also found in Tibetan medicine.[10] Some recommend avoiding more than occasional use of cloves internally in the presence of pitta inflammation such as is found in acute flares of autoimmune diseases.[11]

Modern medicinal uses and pharmaceutical preparations

While it has been used historically in the West for dental pain, the U.S. Food and Drug Administration (FDA) has reclassified eugenol (one of the chemicals contained in Clove Oil), downgrading its effectiveness rating. The FDA now believes there isn’t enough evidence to rate eugenol as effective for toothache pain. Clove oil seems to be safe when applied to the skin, however frequent and repeated application of clove oil in the mouth on the gums can sometimes cause damage to the gums, tooth pulp, mucous membranes and skin.

Studies to determine its effectiveness for fever reduction, as a mosquito repellent and to prevent premature ejaculation have been inconclusive. Clove may reduce blood sugar levels.[12]

Tellimagrandin II is an ellagitannin found in S. aromaticum with anti-herpesvirus properties.[13]

The buds have anti-oxidant properties.[14]

Clove oil can be used to anesthetize fish, and prolonged exposure to higher doses (the recommended dose is 400 mg/l) is considered a humane means of euthanasia.[15]

In addition, clove oil is used in preparation of some toothpastes, laxative pills and Clovacaine solution which is a local anesthetic and used in oral ulceration and anti-inflammations. Eugenol (or clove oil generally) is mixed with Zinc oxide to be a temporary filling.[16]

Adulteration

Clove Stalks: They are slender stems of the inflorescence axis which show opposite decussate branching. Externally, they are brownish, rough and irregularly wrinkled longitudinally with short fracture and dry, woody texture.

Mother Cloves (Anthophylli): There are the ripe fruits of cloves which are ovoid, brown berries, unilocular and one-seeded. This can be detected by the presence of much starch in the seeds.

Brown Cloves: Expanded flowers from which both corolla and stamens have been detached.

Exhausted Cloves: Cloves from which almost or all of the oil has been removed by distillation. They yield no oil and are darker in color.[17]

History

Until modern times, cloves grew only on a few islands in the Maluku Islands (historically called the Spice Islands), including Bacan, Makian, Moti, Ternate, and Tidore.[18] In fact, it is believed that the oldest clove tree in the world, named "Afo," is found on Ternate—the tree being between 350 and 400 years old.[19] Seedlings from this Afo tree were stolen by a Frenchman named Poivre in 1770, transferred to France, and then later to Zanzibar which is today the world's largest producer of cloves.[19]

Until cloves were grown outside of the Maluku Islands, they were traded like oil, with a forced limit on exportation.[19] As the Dutch East India Company consolidated its control of the spice trade in the 17th century they sought to gain a monopoly in cloves as they had in nutmeg. However, "unlike nutmeg and mace, which were limited to the minute Bandas, clove trees grew all over the Moluccas, and the trade in cloves was way beyond the limited policing powers of the corporation."[20]

In the 3rd century BC, a Chinese leader in the Han Dynasty required those who addressed him to chew cloves so as to freshen their breath.[21] Cloves were traded by Muslim sailors and merchants during the Middle Ages in the profitable Indian Ocean trade, the clove trade is also mentioned by Ibn Battuta and even famous One Thousand and One Nights characters such Sinbad the Sailor is known to have bought and sold cloves.[22] Archeologists have also found cloves within a ceramic vessel in Syria along with evidence dating the find to within a few years of 1721 BC.[18]

Active compounds


Eugenol comprises 72-90% of the essential oil extracted from cloves, and is the compound most responsible for the cloves' aroma. Other important essential oil constituents of clove oil include acetyl eugenol, beta-caryophyllene and vanillin, crategolic acid, tannins such as bicornin,[23] gallotannic acid, methyl salicylate (painkiller), the flavonoids eugenin, kaempferol, rhamnetin, and eugenitin, triterpenoids like oleanolic acid, stigmasterol and campesterol and several sesquiterpenes.[24][25]

Eugenol can be toxic in relatively small quantities—as low as 5 ml.[26]

See also

References

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