Psoralen

Psoralen (also called psoralene) is the parent compound in a family of natural products known as furocoumarins. 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 (Psoralen + UVA) treatment for psoriasis, eczema, vitiligo, and cutaneous T-cell lymphoma. Many furocoumarins are extremely toxic to fish, and some are deposited in streams in Indonesia to catch fish.

Uses

Psoralen is a mutagen, and is used for this purpose in molecular biology research. Psoralen intercalates into the DNA and, on exposure to ultraviolet (UVA) radiation, can form monoadducts and covalent interstrand cross-links (ICL) with thymines preferentially at 5'-TpA sites in the genome, inducing apoptosis. Psoralen plus UVA (PUVA) therapy has shown considerable clinical efficacy. Unfortunately, a side effect of PUVA treatment is a higher risk of skin cancer.