title: Dichloro-4-quinolinol-3-carboxylic acid: synthesis and antioxidant abilities to scavenge radicals and to protect methyl linoleate and DNA.
abstract: 5,7-, 5,8-, 6,8-, 7,8-dichloro-4-quinolinol-3-carboxylic acid (5,7-, 5,8-, 6,8-, 7,8-DCQA) together with 7-chloro-4-quinolinol-3-carboxylic acid (7-CQA) and 4-quinolinol-3-carboxylic acid (QA) were synthesized to investigate the antioxidant properties. 5,7-DCQA exhibited the highest ability to scavenge 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS+.), 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and galvinoxyl radicals. 6,8-DCQA possessed the highest efficacy to protect methyl linoleate against 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH)-induced oxidation. 5,7-, 5,8-DCQA and QA were able to retard the beta-carotene-bleaching in beta-carotene-linoleic acid emulsion. In addition, 5,8- and 6,8-DCQA efficiently protected DNA against hydroxyl radical (.OH)-mediated oxidation, and 5,8-DCQA and 7-CQA were active to protect DNA against AAPH-induced oxidation. Furthermore, only 7-CQA can protect DNA against Cu2+/glutathione (GSH)-mediated oxidation. Dichloro-4-quinolinol-3-carboxylic acids were potent to be antiradical drugs, and were worthy to be researched pharmacologically.
authors.affiliation: Department of Organic Chemistry, College of Chemistry, Jilin University, Changchun 130021, China.
authors.forename: Guo-Xiang
authors.initials: GX
authors.lastname: Li
authors.forename: Zai-Qun
authors.initials: ZQ
authors.lastname: Liu
authors.forename: Xu-Yang
authors.initials: XY
authors.lastname: Luo
mesh_terms: D000975:Antioxidants / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D004247:DNA / Q000737:chemistry / Q000187:drug effects*; D016166:Free Radical Scavengers / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D008041:Linoleic Acids / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D015125:Oxyquinoline / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D008041:Linoleic Acids; C005575:methyl linoleate; D015125:Oxyquinoline; D004247:DNA