Fate of [14C] 8-methoxypsoralen (xanthotoxin) in laying hens

The metabolism of 8-Methoxypsoralen (8-MOP), a naturally occurring furanocoumarin photosensitizer, was studied in laying hens treated with a single oral dose equivalent to 10 mg 8-MOP/kg of body weight. Greater than 99% of the administered radiocarbon was eliminated in the excreta within 48 hours after dosing. Of the different tissues collected, only the liver and kidney contained >.01% of the administered dose 7 days after treatment. Radiocarbon residues in the egg white, yolk, and shell were low. In the egg yolk and white, >95% of the radiocarbon present was identical in TLC behavior to 8-MOP. Twelve metabolites of 8-MOP were detected by 2 dimensional TLC analysis of the excreta, of which unmetabolized 8-MOP, 8-hydroxypsoralen and 6-(7-hydroxy-8-methoxycoumarly)-acetic acid were isolated and identified. 8-MOP is this metabolized in laying hens by o-demethylation, oxidation of the furan ring, an by unidentified mechanisms, and the compound shows very little tendency toward retention by body tissue or secretion into eggs