In humans, it is known that psoralens can behave as a general
competitor substrate or act as a suicide inhibitor reacting with the
heme group of the P450 proteins and therefore inactivating them. For
instance, the 8-methoxypsoralen (xanthotoxin), 5-methoxypsoralen
(Bergapten) and psoralen have been reported to act as suicide inactivators
of human-CYS2A6 protein in liver microsomes [6]. In addition,
bergapten is a suicide inhibitor of human CYP3A4, and
xanthotoxin competitively inhibits a variety of drug metabolites
catalyzed by CYP3A4 [7]. All the above mentioned compounds are
currently used as pharmaceuticals in the treatment of psoriasis [8,9],
vitiligo [10], and Tcell lymphoma [11].