Antioxidant reactions of beta-carotene: Identification of carotenoid-radical adducts
Antioxidant reactions of beta-carotene: Identification of carotenoid-radical adducts
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DOI：
10.1021/tx950151t
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发表时间：
1996-01-01
影响因子：
4.1
通讯作者：
McClure, TD
中科院分区：
文献类型：
--
作者：
Liebler, DC;McClure, TD
β-胡萝卜素和其它类胡萝卜素被认为通过清除活性自由基而发挥疾病预防作用，但这些反应的机制知之甚少。我们检测了β-胡萝卜素与偶氮二（2，4-二甲基戊腈）（AMVN）在苯中热分解产生的烷基、烷氧基和烷基过氧自由基反应形成的产物。通过大气压化学电离质谱分析确定了两种以前未知的β-胡萝卜素氧化产物。取代产物含有一个AMVN衍生的自由基加合物基团，并且是由类胡萝卜素多烯的氢转移接着自由基重组产生的。加成产物含有两个AMVN衍生的加合物基团，而不是从顺序的自由基加成到多烯的结果。这些产物结构为类胡萝卜素的自由基清除反应提供了第一个机理解释。
beta-Carotene and other carotenoids are thought to exert disease preventive actions by scavenging reactive free radicals, but the mechanisms of these reactions are poorly understood. We detected products formed by reaction of beta-carotene with alkyl, alkoxyl, and alkylperoxyl free radicals generated by thermolysis of azobis(2,4-dimethylvaleronitrile) (AMVN) in benzene. Analyses by atmospheric pressure chemical ionization mass spectrometry identified two previously unknown classes of beta-carotene oxidation products. Substitution products contain one AMVN-derived radical adduct group and result from hydrogen transfer from the carotenoid polyene followed by radical recombination. Addition products contain two AMVN-derived adduct groups and result instead from sequential radical additions to the polyene. These product structures provide the first mechanistic explanation for the radical scavenging reactions of carotenoids.