Cyclic endoperoxides of beta-carotene, potential pro-oxidants, as products of chemical quenching of singlet oxygen.
Photoprotection by carotenoids is generally considered to be based on the photophysical quenching of triplets and singlet oxygen. There is also accumulating evidence of an alternative, chemical quenching of triplets and singlet oxygen by carotenoids. We report the identification of relatively stable cyclic mono- and diendoperoxides as first products of such an alternative reaction. Nevertheless, these species remain reactive and in the dark cause autooxidation of beta-carotene in our model system. Their formation could explain the intriguing pro-oxidant and cytotoxic activity of carotenoids.
Department of Plant Physiology and Biochemistry, Faculty of Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Cracow, Poland. lfiedor@mol.uj.edu.pl
Joanna
J
Fiedor
Leszek
L
Fiedor
Rainer
R
Haessner
Hugo
H
Scheer
D004355:Drug Stability; D016877:Oxidants; D010545:Peroxides; D017382:Reactive Oxygen Species; D026082:Singlet Oxygen; D019207:beta Carotene / Q000528:radiation effects
D016877:Oxidants; D010545:Peroxides; D017382:Reactive Oxygen Species; D019207:beta Carotene; D026082:Singlet Oxygen