Furanocoumarin

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Two furanocoumarin isomers

The furanocoumarins, or furocoumarins, are a class of organic chemical compounds produced by a variety of plants. Most of the plant species found to contain furanocoumarins belong to a handful of plant families. The families Apiaceae and Rutaceae include the largest numbers of plant species that contain furanocoumarins. The families Moraceae and Fabaceae include a few widely distributed plant species that contain furanocoumarins. [1]

Contents

Generally furanocoumarins are most abundant in plants that have flowered and in ripe seeds and fruits. [1] (An exception is the common fig where furanocoumarins are found chiefly in the milky sap of the leaves and shoots but not the fruits. [2] ) During the early stages of plant growth, their presence is not easily detected.

Structure

The chemical structure of furanocoumarins consists of a furan ring fused with a coumarin. The furan ring may be fused in various ways producing several different isomers. The parent compounds of the most common isomers are psoralen and angelicin. Derivatives of these two compounds are referred to respectively as linear and angular furanocoumarins, [3] so called since they exhibit a linear or angular chemical structure.

Biosynthesis

The compounds are biosynthesized partly through the phenylpropanoid pathway and the mevalonate pathway, which is biosynthesized by a coupling of dimethylallyl pyrophosphate (DMAPP) and 7-hydroxycoumarin (umbelliferone).

Effects

Direct toxicity

Many furanocoumarin compounds are toxic. The phytochemicals enter the nucleus of epithelial cells and form a bond (crosslinking) with the DNA when exposed to UV, which causes cell death and causes inflammation via activation of the arachidonic acid cascade. The result is known as phytophotodermatitis, a serious skin inflammation. [4]

Furanocoumarins produced by plants may serve as a defense mechanism against predators such as insects and mammals. [5] [6] It is also likely that furanocoumarins are related to a plant's natural defense against fungal attack. [7] In particular, the linear furanocoumarins (psoralen, bergapten, and methoxsalen), which occur naturally in Apiaceae, Rutaceae, and other plant families, are known to be toxic to fungi. [8] Plants that cause phytophotodermatitis usually contain linear furanocoumarins. [7]

Furanocoumarins are found in the sap of plants such as Ammi majus , parsnip, and giant hogweed. At least 36 species of the genus Heracleum in the family Apiaceae are known to contain one or more furanocoumarin compounds. [9]

Medication interactions

Furanocoumarins have other biological effects as well. For example, in humans, bergamottin and 6',7'-dihydroxybergamottin are responsible for the "grapefruit juice effect", in which these furanocoumarins affect certain P450 liver and gut enzymes, such as the inhibition of CYP3A4 which either activates or deactivates many drugs, thus leading to higher or lower levels in the bloodstream. [10] Furanocoumarins have various effects which can specifically increase or decrease (depending on the drug) the blood levels of many pharmaceuticals in ways that can be life-threatening, so FDA-approved drugs include warnings for grapefruit.

See also

Related Research Articles

<span class="mw-page-title-main">Apiaceae</span> Family of flowering plants

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, with more than 3,800 species in about 446 genera, including such well-known and economically important plants as ajwain, angelica, anise, asafoetida, caraway, carrot, celery, chervil, coriander, cumin, dill, fennel, lovage, cow parsley, parsley, parsnip and sea holly, as well as silphium, a plant whose identity is unclear and which may be extinct.

<span class="mw-page-title-main">Heterocyclic compound</span> Molecule with one or more rings composed of different elements

A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic organic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and applications of organic heterocycles.

<i>Citrus</i> Genus of flowering plants

Citrus is a genus of flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, lemons, grapefruits, pomelos, and limes. The genus Citrus is native to South Asia, East Asia, Southeast Asia, Melanesia, and Australia. Various citrus species have been used and domesticated by indigenous cultures in these areas since ancient times. From there its cultivation spread into Micronesia and Polynesia by the Austronesian expansion ; and to the Middle East and the Mediterranean via the incense trade route, and onwards to Europe and the Americas.

<span class="mw-page-title-main">Enantiomer</span> Stereoisomers which are non-superposable mirror images of each other

In chemistry, an enantiomer – also called optical isomer, antipode, or optical antipode – is one of two stereoisomers that are non-superposable onto their own mirror image. Enantiomers are much like one's right and left hands; without mirroring one of them, hands cannot be superposed onto each other. No amount of reorientation in three spatial dimensions will allow the four unique groups on the chiral carbon to line up exactly. The number of stereoisomers a molecule has can be determined by the number of chiral carbons it has. Stereoisomers include both enantiomers and diastereomers.

<span class="mw-page-title-main">Open-chain compound</span> Type of organic molecule with a linear structure

In chemistry, an open-chain compound or acyclic compound is a compound with a linear structure, rather than a cyclic one. An open-chain compound having no side groups is called a straight-chain compound. Many of the simple molecules of organic chemistry, such as the alkanes and alkenes, have both linear and ring isomers, that is, both acyclic and cyclic. For those with 4 or more carbons, the linear forms can have straight-chain or branched-chain isomers. The lowercase prefix n- denotes the straight-chain isomer; for example, n-butane is straight-chain butane, whereas i-butane is isobutane. Cycloalkanes are isomers of alkenes, not of alkanes, because the ring's closure involves a C-C bond. Having no rings, all open-chain compounds are aliphatic.

<i>Heracleum</i> (plant) Genus of flowering plants in the celery family

Heracleum is a genus of biennial and perennial herbs in the carrot family Apiaceae. They are found throughout the temperate northern hemisphere and in high mountains as far south as Ethiopia. Common names for the genus or its species include hogweed and cow parsnip.

<span class="mw-page-title-main">Photodermatitis</span> Skin condition

Photodermatitis, sometimes referred to as sun poisoning or photoallergy, is a form of allergic contact dermatitis in which the allergen must be activated by light to sensitize the allergic response, and to cause a rash or other systemic effects on subsequent exposure. The second and subsequent exposures produce photoallergic skin conditions which are often eczematous. It is distinct from sunburn.

<span class="mw-page-title-main">Benzofuran</span> Heterocyclic compound consisting of fused benzene and furan rings

Benzofuran is the heterocyclic compound consisting of fused benzene and furan rings. This colourless liquid is a component of coal tar. Benzofuran is the "parent" of many related compounds with more complex structures. For example, psoralen is a benzofuran derivative that occurs in several plants.

<span class="mw-page-title-main">Methoxsalen</span> Chemical compound

Methoxsalen, sold under the brand name Oxsoralen among others, is a medication used to treat psoriasis, eczema, vitiligo, and some cutaneous lymphomas in conjunction with exposing the skin to ultraviolet (UVA) light from lamps or sunlight. Methoxsalen modifies the way skin cells receive the UVA radiation, allegedly clearing up the disease. Levels of individual patient PUVA exposure were originally determined using the Fitzpatrick scale. The scale was developed after patients demonstrated symptoms of phototoxicity after oral ingestion of methoxsalen followed by PUVA therapy. Chemically, methoxsalen belongs to a class of organic natural molecules known as furanocoumarins. They consist of coumarin annulated with furan. It can also be injected and used topically.

<span class="mw-page-title-main">Psoralen</span> Chemical compound

Psoralen is the parent compound in a family of naturally occurring organic compounds known as the linear furanocoumarins. It is structurally related to coumarin by the addition of a fused furan ring, and may be considered as a derivative of umbelliferone. Psoralen occurs naturally in the seeds of Psoralea corylifolia, as well as in the common fig, celery, parsley, West Indian satinwood, and in all citrus fruits. It is widely used in PUVA treatment for psoriasis, eczema, vitiligo, and cutaneous T-cell lymphoma; these applications are typically through the use of medications such as Methoxsalen. Many furanocoumarins are extremely toxic to fish, and some are deposited in streams in Indonesia to catch fish.

<i>Ammi majus</i> Species of plant

Ammi majus, commonly called bishop's flower, false bishop's weed, laceflower, bullwort, etc., is a member of the carrot family Apiaceae. The plant, which has white lace-like flower clusters, has a large distribution through Southern Europe, North Africa and West and Central Asia, though it is hypothesized to be native to the Nile River Valley.

<span class="mw-page-title-main">Bergamottin</span> Chemical compound

Bergamottin (5-geranoxypsoralen) is a natural furanocoumarin found in the pulp of pomelos and grapefruits. It is also found in the peel and pulp of the bergamot orange, from which it was first isolated and from which its name is derived.

<span class="mw-page-title-main">Phytophotodermatitis</span> Medical condition

Phytophotodermatitis, also known as berloque dermatitis or margarita photodermatitis, is a cutaneous phototoxic inflammatory reaction resulting from contact with a light-sensitizing botanical agent followed by exposure to ultraviolet light. Symptoms include erythema, edema, blisters, and delayed hyperpigmentation. Heat and moisture tend to exacerbate the reaction.

<span class="mw-page-title-main">Bergapten</span> Chemical compound

Bergapten (5-methoxypsoralen) is a naturally-occurring organic chemical compound produced by numerous plant species, especially from the carrot family Apiaceae and the citrus family Rutaceae. For example, bergapten has been extracted from 24 species of the genus Heracleum in the family Apiaceae. In the family Rutaceae, various Citrus species contain significant amounts of bergapten, especially the bergamot orange, the micrantha, and certain varieties of lime and bitter orange.

<span class="mw-page-title-main">Denticity</span> Number of atoms in a ligand that bond to the central atom of a coordination complex

In coordination chemistry, denticity refers to the number of donor groups in a given ligand that bind to the central metal atom in a coordination complex. In many cases, only one atom in the ligand binds to the metal, so the denticity equals one, and the ligand is said to be monodentate. Ligands with more than one bonded atom are called polydentate or multidentate. The denticity of a ligand is described with the Greek letter κ ('kappa'). For example, κ6-EDTA describes an EDTA ligand that coordinates through 6 non-contiguous atoms.

<span class="mw-page-title-main">Angelicin</span> Chemical compound

Angelicin is the parent compound in a family of naturally occurring organic compounds known as the angular furanocoumarins. Structurally, it can be considered as benzapyra-2-one fused with a furan moiety in the 7,8-position. Angelicin is commonly found in certain Apiaceae and Fabaceae plant species such as Bituminaria bituminosa. It has a skin permeability coefficient (LogKp) of -2.46. The maximum absorption is observed at 300 nm. The 1HNMR spectrum is available; the infrared and mass spectra of angelicin can be found in this database. The sublimation of angelicin occurs at 120 °C and the pressure of 0.13 Pa. Angelicin is a coumarin.

<span class="mw-page-title-main">Bergamot essential oil</span> Cold-pressed essential oil

Bergamot essential oil is a cold-pressed essential oil produced by cells inside the rind of a bergamot orange fruit. It is a common flavoring and top note in perfumes. The scent of bergamot essential oil is similar to a sweet light orange peel oil with a floral note.

<span class="mw-page-title-main">6',7'-Dihydroxybergamottin</span> Chemical compound

6',7'-Dihydroxybergamottin is a natural furanocoumarin found in pomelos, grapefruits, and sour oranges, in both the peel and the pulp. Along with the chemically related compound bergamottin, it is believed to be responsible for a number of grapefruit–drug interactions, in which the consumption of citrus containing one or both of these compounds affects the metabolism of a variety of pharmaceutical drugs.

<span class="mw-page-title-main">Marmesin</span> Chemical compound

Marmesin (nodakenetin) is a chemical compound precursor in psoralen and linear furanocoumarins biosynthesis.

In chemical nomenclature, a descriptor is a notational prefix placed before the systematic substance name, which describes the configuration or the stereochemistry of the molecule. Some listed descriptors are only of historical interest and should not be used in publications anymore as they do not correspond with the modern recommendations of the IUPAC. Stereodescriptors are often used in combination with locants to clearly identify a chemical structure unambiguously.

References

  1. 1 2 Pathak, M. A.; Daniels Jr., Farrington; Fitzpatrick, T. B. (September 1962). "The Presently Known Distribution of Furocoumarins (Psoralens) in Plants". Journal of Investigative Dermatology. 39 (3): 225–239. doi: 10.1038/jid.1962.106 . PMID   13941836.
  2. Zaynoun, S. T.; Aftimos, B. G.; Abi Ali, L.; Tenekjian, K. K.; Khalidi, U.; Kurban, A. K. (July 1984). "Ficus carica; isolation and quantification of the photoactive components". Contact Dermatitis. 11 (1): 21–25. doi:10.1111/j.1600-0536.1984.tb00164.x. PMID   6744838. Cited in McGovern and Barkley 2000, section  Phytophotodermatitis.
  3. IUPAC , Compendium of Chemical Terminology , 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006) " furanocoumarins ". doi : 10.1351/goldbook.F02558 IUPAC , Compendium of Chemical Terminology , 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006) " furocoumarins ". doi : 10.1351/goldbook.F02562
  4. Baugh WP (September 8, 2016). "Phytophotodermatitis". Medscape. Retrieved February 19, 2020.
  5. Berenbaum, May (June 14, 2010). "Furanocoumarins as potent chemical defenses".
  6. Cox, George W. (2004). Alien species and evolution: the evolutionary ecology of exotic plants, animals, microbes, and interacting native species. Island Press. p.  125. ISBN   978-1-55963-009-2.
  7. 1 2 McGovern, Thomas W.; Barkley, Theodore M. (2000). "Botanical Dermatology". The Electronic Textbook of Dermatology. Internet Dermatology Society. Section  Phytophotodermatitis . Retrieved November 29, 2018.
  8. Camm, E. L.; Wat, C. K.; Towers, G. H. N. (1976). "An assessment of the roles of furanocoumarins in Heracleum lanatum". Can. J. Bot. 54 (22): 2562–2566. doi:10.1139/b76-275.
  9. Mitchell, John; Rook, Arthur (1979). Botanical Dermatology: Plants and Plant Products Injurious to the Skin. Vancouver: Greengrass. pp. 692–699.
  10. Kakar, SM; Paine, MF; Stewart, PW; Watkins, PB (2004). "6',7'-Dihydroxybergamottin contributes to the grapefruit juice effect". Clinical Pharmacology and Therapeutics. 75 (6): 569–579. doi:10.1016/j.clpt.2004.02.007. hdl: 2027.42/109773 . PMID   15179411.