2.3.3.1 Psoralen
Synonyms Ficusin; 6-Hydroxy-5-Benzofuranacrylic acid d-lactone; Furo (3, 2-d)-coumarin.
Biological Source Psoralen belongs to one of a group of furanocoumarins occurring naturally in more than two dozen different plant sources, for instance: Rutaceae (e.g., Bergamot, Limes, Cloves); Umbelliferae (Celery; Parsnips); Leguminosae (e.g., Psoralen coryfolia); and Moraceae (e.g., Figs). It is also found in the Rue Oil obtained from Ruta graveolens L. (Rutaceae)-known as Rue, Garden Rue or German Rue. It is obtained from the leaves of Ficus carica Linn. (Moraceae)-Figs, Anjir.
Chemical Structure
Characteristic Features Psoralen crystals from ether have two sets of melting points e.g., 163-164°C and 169-179°C (Spath). It is very soluble in chloroform, less soluble in alcohol, sparingly soluble in ether and practically insoluble in petroleum ether (60-80°C).
Identification Tests
1. Dissolve 1 mg of psoralen is 5 ml of ethanol and add to it 15 ml of a mixture made up of 3 parts of propylene glycol, 5 parts of acetic acid and 43 parts of water. The resulting mixture on being exposed to the uv-light in a uv-chamber, gives a distinct blue-fluorescence.
2. When 1 mg is dissolved in 2 ml ethanol, mixed with two drops of NaOH solution (0.1 M) and the resulting solution is subjected to uv-light, it emits a yellow fluorescence.
Uses
1. It is used in the treatment of leucoderma patches.
2. Psoralens have also exhibited photosensitizing and phototoxic effects in animals and human beings and, hence have been employed extensively in photochemotherapy for the treatment and management of vitiligo*, psoriasis** and mycosis fungoides.***
