Sesquiterpene lactones (SLs) are a class of

sesquiterpenoid Sesquiterpenes are a class of terpenes that consist of three isoprene units and often have the molecular formula C15H24. Like monoterpenes, sesquiterpenes may be cyclic or contain rings, including many unique combinations. Biochemical modificatio ...

s that contain a

lactone Lactones are cyclic carboxylic esters, containing a 1-oxacycloalkan-2-one structure (), or analogues having unsaturation or heteroatoms replacing one or more carbon atoms of the ring. Lactones are formed by intramolecular esterification of the co ...

ring. They are most often found in plants of the family

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

(daisies, asters). Other plant families with SLs are

Umbelliferae Apiaceae or Umbelliferae is a family of mostly aromatic flowering plants named after the type genus ''Apium'' and commonly known as the celery, carrot or parsley family, or simply as umbellifers. It is the 16th-largest family of flowering plants ...

(celery, parsley, carrots) and

Magnoliaceae The Magnoliaceae () are a flowering plant family, the magnolia family, in the order Magnoliales. It consists of two genera: ''Magnolia'' and '' Liriodendron'' (tulip trees). Unlike most angiosperms, whose flower parts are in whorls (rings), t ...

(magnolias). A collection of colorless, lipophilic solids, SLs are a rich source of drugs. They can be allergenic and toxic in grazing livestock causing severe

neurological Neurology (from el, νεῦρον (neûron), "string, nerve" and the suffix -logia, "study of") is the branch of medicine dealing with the diagnosis and treatment of all categories of conditions and disease involving the brain, the spinal c ...

problems in horses. Some are also found in corals such as '' Maasella edwardsi''.

Types

Sesquiterpene lactones can be divided into several main classes including germacranolides, heliangolides,

guaianolide In organic chemistry, a guaianolide is a type of sesquiterpene lactone consisting of a gamma-lactone and either a cyclopentane or cyclopentene, both fused to a central cycloheptane or cycloheptene structure. There are two subclasses, structural ...

s, pseudoguaianolides, hypocretenolides, and eudesmanolides.

Examples

Artemisinin Artemisinin () and its semisynthetic derivatives are a group of drugs used in the treatment of malaria due to '' Plasmodium falciparum''. It was discovered in 1972 by Tu Youyou, who shared the 2015 Nobel Prize in Physiology or Medicine for her ...

, a new, highly-effective anti-

malaria Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. S ...

l compound, is a sesquiterpene lactone found in ''

Artemisia annua ''Artemisia annua'', also known as sweet wormwood, sweet annie, sweet sagewort, annual mugwort or annual wormwood (), is a common type of wormwood native to temperate Asia, but naturalized in many countries including scattered parts of North Am ...

''.

Lactucin Lactucin is a bitter substance that forms a white crystalline solid and belongs to the group of sesquiterpene lactones. It is found in some varieties of lettuce and is an ingredient of lactucarium. It has been shown to have analgesic and sedati ...

, desoxylactucin,

lactucopicrin Lactucopicrin (Intybin) is a bitter substance that has a sedative and analgesic effect, acting on the central nervous system. It is a sesquiterpene lactone, and is a component of lactucarium, derived from the plant '' Lactuca virosa'' (wild lettu ...

, lactucin-15-oxalate, lactucopicrin-15-oxalate are some of the most prominent found in

lettuce Lettuce (''Lactuca sativa'') is an annual plant of the family Asteraceae. It is most often grown as a leaf vegetable, but sometimes for its stem and seeds. Lettuce is most often used for salads, although it is also seen in other kinds of food, ...

and spinach, giving most of the bitter taste to these crops. One eudesmanolide, 3-oxo-5αH,8βH-eudesma-1,4(15),7(11)-trien-8,12-olide, can work with

vernolic acid Vernolic acid (leukotoxin) is a long chain fatty acid that is monounsaturated and contains an epoxide. It is the R,R-''cis'' epoxide derived from the C12–C13 alkene of linoleic acid. Vernolic acid was first definitively characterized in 1954. I ...

and other compounds in plants to reduce inflammation.

Sesquiterpene lactone-containing plants

Some plants containing these compounds include: *

Artichoke The globe artichoke ('' Cynara cardunculus'' var. ''scolymus'' ),Rottenberg, A., and D. Zohary, 1996: "The wild ancestry of the cultivated artichoke." Genet. Res. Crop Evol. 43, 53–58. also known by the names French artichoke and green artich ...

*Boneset

Eupatorium perfoliatum ''Eupatorium perfoliatum'', known as common boneset or just boneset, is a North American perennial plant in the family Asteraceae. It is a common native to the Eastern United States and Canada, widespread from Nova Scotia to Florida, west as far ...

* Burdock *'' Calea ternifolia'' *

Chamomile Chamomile (American English) or camomile (British English; see spelling differences) ( or ) is the common name for several plants of the family Asteraceae. Two of the species, ''Matricaria recutita'' and ''Anthemis nobilis'', are commonly us ...

*'' Chrysanthemum'' * Cocklebur * Feverfew *'' Gaillardia'' *''

Ginkgo biloba ''Ginkgo biloba'', commonly known as ginkgo or gingko ( ), also known as the maidenhair tree, is a species of tree native to China. It is the last living species in the order Ginkgoales, which first appeared over 290 million years ago. Fossil ...

'' *''

Laurus nobilis ''Laurus nobilis'' is an aromatic evergreen tree or large shrub with green, glabrous (smooth) leaves. It is in the flowering plant family Lauraceae. It is native to the Mediterranean region and is used as bay leaf for seasoning in cooking. ...

'' *

Lettuce Lettuce (''Lactuca sativa'') is an annual plant of the family Asteraceae. It is most often grown as a leaf vegetable, but sometimes for its stem and seeds. Lettuce is most often used for salads, although it is also seen in other kinds of food, ...

(''

Lactuca ''Lactuca'', commonly known as lettuce, is a genus of flowering plants in the family Asteraceae. The genus includes at least 50 species, distributed worldwide, but mainly in temperate Eurasia. Its best-known representative is the garden lettuce ...

'') * Marsh elder *

Mugwort Mugwort is a common name for several species of aromatic flowering plants in the genus '' Artemisia.'' In Europe, mugwort most often refers to the species ''Artemisia vulgaris'', or common mugwort. In East Asia the species ''Artemisia argyi'' is ...

*'' Parthenium'' * Poverty weed *

Pyrethrum ''Pyrethrum'' was a genus of several Old World plants now classified as ''Chrysanthemum'' or ''Tanacetum'' which are cultivated as ornamentals for their showy flower heads. Pyrethrum continues to be used as a common name for plants formerly inclu ...

Ragweed Ragweeds are flowering plants in the genus ''Ambrosia'' in the aster family, Asteraceae. They are distributed in the tropical and subtropical regions of the Americas, especially North America,Sagebrush Sagebrush is the common name of several woody and herbaceous species of plants in the genus '' Artemisia''. The best known sagebrush is the shrub '' Artemisia tridentata''. Sagebrushes are native to the North American west. Following is an al ...

Sneezeweed Sneezeweed is a common name for several plants in the family Asteraceae and may refer to: *'' Achillea ptarmica'', with white flowers *'' Hymenoxys hoopesii'', with long yellow petals, native to western North America *Various species of ''Helenium ...

* Spinach * Star anise * Sunflower * Ironweed * Wormwood * Yellow star thistle *

bitter leaf ''Vernonia amygdalina'', a member of the daisy family, is a small shrub that grows in tropical Africa. ''V. amygdalina'' typically grows to a height of . The leaves are elliptical and up to long. Its bark is rough. ''V. amygdalina'' is commonl ...

Quorum sensing inhibitors Sesquiterpene lactones have been found to possess the ability to inhibit

quorum sensing In biology, quorum sensing or quorum signalling (QS) is the ability to detect and respond to cell population density by gene regulation. As one example, QS enables bacteria to restrict the expression of specific genes to the high cell densities at ...

in bacteria.

References

External links

* {{Commons category-inline, Sesquiterpene lactones