title: The protective role of carotenoids against 7-keto-cholesterol formation in solution.
abstract: The antioxidant activity of beta-carotene and oxygenated carotenoids lutein, canthaxanthin, and astaxanthin was investigated during spontaneous and peroxyl-radical-induced cholesterol oxidation. Cholesterol oxidation, measured as generation of 7-keto-cholesterol (7-KC), was evaluated in a heterogeneous solution with cholesterol, AAPH, and carotenoids solubilized in tetrahydrofuran and in water, and in a homogeneous solution of chlorobenzene, with AIBN as a prooxidant. The formation of 7-KC was dependent on temperature and on cholesterol and prooxidant concentrations. All the carotenoids tested, exhibited significant antioxidant activity by inhibiting spontaneous, AAPH- and AIBN-induced formation of 7-KC, although the overall order of efficacy of these compounds was astaxanthin > canthaxanthin > lutein = beta-carotene. The finding that carotenoids exert protective effects on spontaneous and free radical-induced cholesterol oxidation may have important beneficial effects on human health, by limiting the formation of atheroma and by inhibiting cholesterol oxidation in food processing or storage.
authors.affiliation: Institute of General Pathology, Catholic University School of Medicine, Largo F. Vito 1, 00168 Rome, Italy. p.palozza@rm.unicatt.it
authors.forename: Paola
authors.initials: P
authors.lastname: Palozza
authors.forename: Eugenio
authors.initials: E
authors.lastname: Barone
authors.forename: Cesare
authors.initials: C
authors.lastname: Mancuso
authors.forename: Nevio
authors.initials: N
authors.lastname: Picci
mesh_terms: D000578:Amidines / Q000494:pharmacology; D000975:Antioxidants / Q000378:metabolism; D016644:Canthaxanthin / Q000494:pharmacology; D002338:Carotenoids / Q000494:pharmacology*; D007653:Ketocholesterols / Q000378:metabolism*; D014975:Lutein / Q000494:pharmacology; D010084:Oxidation-Reduction / Q000187:drug effects; D010545:Peroxides / Q000494:pharmacology; D020011:Protective Agents / Q000494:pharmacology*; D012996:Solutions; D013696:Temperature; D024341:Xanthophylls / Q000494:pharmacology; D019207:beta Carotene / Q000494:pharmacology
chemical_list: D000578:Amidines; D000975:Antioxidants; D007653:Ketocholesterols; D010545:Peroxides; D020011:Protective Agents; D012996:Solutions; D024341:Xanthophylls; D019207:beta Carotene; C049375:perhydroxyl radical; D002338:Carotenoids; D016644:Canthaxanthin; C046728:2,2'-azobis(2-amidinopropane); C005948:astaxanthine; C003001:7-ketocholesterol; D014975:Lutein