title: Detection of vitamin C-induced singlet oxygen formation in oxidized LDL using MCLA as a chemiluminescence probe.
abstract: In this study, it was observed that addition of vitamin C (vit C) to oxidized low-density lipoprotein (Ox-LDL) by cupric ions (Cu2+) could result in the formation of singlet oxygen (1O2). In experiments, 1O2 was detected by chemiluminescence method using a Cypridina luciferin analog, 2-methyl-6-(p-methoxyphenyl)-3, 7-dihydroimidazo [1, 2-a] pyrazin-3-one (MCLA), as a selective and sensitive chemiluminescence probe. Additional experimental evidence for the formation of 1O2 came from the quenching effect of sodium azide (NaN3) on vit C-induced chemiluminescence in the reaction mixture of LDL-Cu(2+)-MCLA. Analysis based on the experimental results demonstrated the plausible reaction mechanism is that vit C first converts Cu2+ to its reduced state and vit C becomes vit C radical itself, thereby stimulating the formation of peroxyl and alkoxyl radicals, and bimolecular reaction of peroxyl radicals results in 1O2 production in the systems studied.
authors.affiliation: Institute of Laser Life Science, South China Normal University, Guangzhou 510631, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Wang
authors.forename: Da
authors.initials: D
authors.lastname: Xing
mesh_terms: D001205:Ascorbic Acid / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D008077:Lipoproteins, LDL / Q000032:analysis*; D008163:Luminescent Measurements; D010100:Oxygen / Q000378:metabolism*; D011719:Pyrazines / Q000737:chemistry*
chemical_list: D007093:Imidazoles; D008077:Lipoproteins, LDL; D011719:Pyrazines; C099252:oxidized low density lipoprotein; C063412:2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo(1,2-alpha)pyrazin-3-one; D001205:Ascorbic Acid; D010100:Oxygen