Xanthotoxin

Xanthotoxin, also known as Methoxsalen, is a furocoumarin and a psoralen derivative. It is a natural product found in several plants, including Parsnip and Amni majus. Xanthotoxin is used in the treatment of psoriasis, eczema, vitiligo, and some cutaneous lymphomas in conjunction with exposing the skin to sunlight.

Chemistry

Xanthotoxin is a member of the class of compounds known as furocoumarins. It is a psoralen derivative, which means it is a type of organic compound that is based on the structure of psoralen. Psoralens are a type of coumarin, a class of phenolic compounds that have a 2H-chromen-2-one skeleton.

Pharmacology

Xanthotoxin is used in a therapy called PUVA therapy (psoralen and ultraviolet A radiation). In this therapy, the patient takes xanthotoxin orally or applies it to the skin, then the affected skin is exposed to ultraviolet A (UVA) light. The xanthotoxin absorbs the UVA radiation and initiates a reaction that leads to the death of the skin cells. This can help to slow the rapid growth of skin cells that occurs in conditions like psoriasis.

Side Effects

Like all medications, xanthotoxin can cause side effects. These can include nausea, itching, and redness of the skin. In rare cases, it can cause serious burns if the skin is exposed to too much sunlight or UVA light after taking the medication.

History

Xanthotoxin was first isolated from the plant Amni majus in the 1940s. It was later found in other plants, including parsnip and celery. The use of xanthotoxin in PUVA therapy was first proposed in the 1970s.

See Also

• Psoralen
• Furocoumarin
• PUVA therapy