Furanocoumarin

Furanocoumarins are a class of organic chemical compounds produced by a variety of plants. They are a type of coumarin with a furan ring fused to the coumarin. The furan may be fused in different ways producing several isomers.

Chemistry

Furanocoumarins are made of a furan ring fused with coumarin. The different isomers, including psoralen, are defined by the fusion of the furan ring and the position of the carbonyl group. They are colorless, crystalline compounds which occur abundantly in nature.

Biosynthesis

Furanocoumarins are biosynthesized from phenylalanine and malonyl-CoA by a series of enzymes. The process involves the conversion of phenylalanine into umbelliferone through a series of steps involving trans-cinnamate and p-coumarate. Umbelliferone then undergoes a series of transformations to yield the final furanocoumarin product.

Biological effects

Furanocoumarins have the ability to absorb ultraviolet light, which leads to a variety of biological effects. They are known to cause phytophotodermatitis, a severe skin inflammation in humans. When the skin containing the furanocoumarins is exposed to UVA light, the compounds are excited to an active state and can form covalent bonds with DNA, leading to skin cell death.

Medical uses

Some furanocoumarins are used in the treatment of psoriasis and vitiligo. Psoralen, a type of furanocoumarin, is used in PUVA therapy for the treatment of psoriasis, eczema, and vitiligo. It is applied topically or taken orally, followed by exposure to UVA light to activate the compound.

Food sources

Furanocoumarins are found in many species of plants. They are particularly high in the families Apiaceae (including carrots, parsley, and celery) and Rutaceae (including grapefruit and oranges). They are also found in some fungi and bacteria.

File:Furanocoumarin.png

Chemical structure of a furanocoumarin

See also

• Coumarin
• Psoralen
• Phytophotodermatitis
• Psoriasis
• Vitiligo