title: Protection of UV-radiation induced skin toxicity by reactive oxygen scavengers.
abstract: Although, photoaddition reactions of psoralens with DNA and membrane lipid are regarded as the major photochemical events responsible for skin-photosensitization and photochemotherapeutic properties, their O2-dependent reactive oxygen specie (ROS) generating potential is also responsible for biologic photooxidation reactions and cutaneous phototoxicity. We have investigated the skin-sensitization reactions of psoralen in presence of selected free radical scavengers. The results confirm that sodium azide, DABCO and beta-carotene inhibited considerably the 1O2 generation reactions in a chemical system (determined by monitoring the bleaching of N,N-dimethyl-p-nitrosoaniline in the presence of histidine used as a selective acceptor of 1O2) as well as skin sensitization in vivo (epilated guinea pig skin). These observation suggest that the O2-dependent photodynamic action of psoralen contributes significantly to the development of cutaneous toxicity which can be inhibited by selective scavengers of 1O2.
authors.affiliation: Photobiology Laboratory, Industrial Toxicology Research Centre, Lucknow, India.
authors.forename: R S
authors.initials: RS
authors.lastname: Ray
authors.forename: P C
authors.initials: PC
authors.lastname: Joshi
mesh_terms: D000818:Animals; D017484:Dermatitis, Phototoxic / Q000517:prevention & control*; D005260:Female; D016166:Free Radical Scavengers; D006168:Guinea Pigs; D017382:Reactive Oxygen Species
chemical_list: D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species