Molecular and genetic basis of furocoumarin reactions

The psoralen-DNA photoreaction. Characterization of the monoaddition products from 8-methoxypsoralen and 4,5',8-trimethylpsoralen

“…The stereochemistry and product distribution of the adducts is determined in part by the constraints imposed by the DNA helix on the geometry of the non~covalent intercalation complex formed by psoralen and DNA prior to i-rradiation .. 4 Psoralens or furocoumarins are a class of compounds found in a wide variety of plants and fungi and have been used since ancient times as dermal photosensitizing agents for the treatment of various skin pigmentation disorders (Scott et al, 1976). Their photosensitizing activity is dependent upon subsequent exposure to near ultraviolet light {300-380 nm), and is now known to involve photochemical addition to the DNA of the target tissue (Song & Tapley, 1979) ..…”

Giant cell formation produced by laser microbeam irradiation of chromatin in Chinese hamster cells

“…In these experiments, we have observed giant cell formation when chromatin of V79 cells was microirradiated in interphase or mitosis with 365 nm laser I:\p Cell R,'I /341/98/) light in the presence of psoralen (PUV A microirradiation) [34]. By this treatment monofunctional and bifunctional psoralen photoadducts can be produced in DN A and RNA respectively [35]. The specificity of the photoadducts for the induction of giant cell formation was demonstrated by the fact that neither psoralen alone nor microirradiation of chromatin in the absence of psoralen prevented normal donal growth [34].…”

Lack of modifying potential of 8-methoxypsoralen in the promotion or progression stages of lung carcinogenesis in A/J female mice

“…8-Methoxypsoralen is a naturally occurring furanocoumarin derivative found in many fruits and vegetables (18), which has found application in the treatment of psoriasis and cutaneous T-cell lymphomas (19-21). Dunnick et al reported no clear dose-idependent toxicity with oral gavage 8-MOP at 25 and 50 mg/kg/day for 13 weeks in F344/N rats (22).…”