title: UV-radiation protecting efficacy of thiols, studied with UVA-induced binding of 8-MOP and CPZ to rat epidermal biomacromolecules in vivo.
abstract: The following topically-applied thiols were investigated with regard to their possible UV-radiation protective properties: captopril, cysteamine, ergothioneine, mesna, mercaptopropionylglycine, N-acetyl-cysteine and penicillamine. As a measure for protection the inhibition of in vivo irreversible photobinding of the labelled phototoxic drugs chlorpromazine (CPZ) and 8-methoxypsoralen (8-MOP) to rat epidermal biomacromolecules was used. Ergothioneine, mesna and penicillamine did not show any effect; probably, as a result of their charge they are not able to enter the stratum corneum. Captopril, cysteamine, mercaptopropionylglycine and N-acetylcysteine showed a considerable inhibition of CPZ and 8-MOP photobinding. Captopril and N-acetylcysteine were clearly the most potent whereas cysteamine was the least effective. Captopril, mercaptopropionylglycine and N-acetylcysteine appeared to have a wider action range and to be a more effective protector than dl-alpha-tocopherol and di-butyl-hydroxytoluene. Cysteamine and mercaptopropionylglycine were only capable of protecting the stratum corneum. Captopril and N-acetylcysteine on the other hand showed an additional dose-dependent inhibition of photobinding to the viable epidermis. Gradually with increasing time after application, the protecting efficacy with regard to the viable layer of the epidermis decreased; the duration of protection depending on the dose.
authors.affiliation: Department of Medicinal Chemistry, Leiden University, The Netherlands.
authors.forename: L T
authors.initials: LT
authors.lastname: van den Broeke
authors.forename: G M
authors.initials: GM
authors.lastname: Beyersbergen van Henegouwen
mesh_terms: D000111:Acetylcysteine / Q000627:therapeutic use; D000818:Animals; D002216:Captopril / Q000627:therapeutic use; D002746:Chlorpromazine / Q000378:metabolism; D003543:Cysteamine / Q000627:therapeutic use; D004817:Epidermis / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D004880:Ergothioneine / Q000627:therapeutic use; D005260:Female; D015080:Mesna / Q000627:therapeutic use; D008730:Methoxsalen / Q000378:metabolism; D010396:Penicillamine / Q000627:therapeutic use; D011837:Radiation-Protective Agents / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar; D013438:Sulfhydryl Compounds / Q000627:therapeutic use*; D008625:Tiopronin / Q000627:therapeutic use; D014466:Ultraviolet Rays
chemical_list: D011837:Radiation-Protective Agents; D013438:Sulfhydryl Compounds; D003543:Cysteamine; D002216:Captopril; D004880:Ergothioneine; D008625:Tiopronin; D010396:Penicillamine; D015080:Mesna; D002746:Chlorpromazine; D008730:Methoxsalen; D000111:Acetylcysteine