Kinetic Study of the Aroxyl-Radical-Scavenging Activity of Five Fatty Acid Esters and Six Carotenoids in Toluene Solution: Structure: Activity Relationship for the Hydrogen Abstraction Reaction
Kinetic Study of the Aroxyl-Radical-Scavenging Activity of Five Fatty Acid Esters and Six Carotenoids in Toluene Solution: Structure: Activity Relationship for the Hydrogen Abstraction Reaction
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五种脂肪酸酯和六种类胡萝卜素在甲苯溶液中芳氧基自由基清除活性的动力学研究：夺氢反应的结构：活性关系
DOI：
10.1021/acs.jpcb.7b04570
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发表时间：
2017
期刊：
影响因子：
3.3
通讯作者：
Nagaoka Shin-ichi
中科院分区：
文献类型：
--
作者：
Mukai Kazuo;Yoshimoto Maya;Ishikura Masaharu;Nagaoka Shin-ichi
本文研究了芳氧基自由基（ArO·）与脂肪酸酯（LHS 1 -5、硬脂酸乙酯1、油酸乙酯2、亚油酸乙酯3、亚麻酸乙酯4和花生四烯酸乙酯5）反应的动力学。本文用化学计量法测定了25.0 °C甲苯中ArO·与LHS_（1 - 5）反应的二级速率常数（ks）。Ks值按LH_（1）<2<3<4<5的顺序增加，即随LH_（1 -5）中双键数目的增加而增加。LH 5的K_s值为2.93 × 10 ~（-3）M ~（-1）s ~（-1）。结果表明，ArO·与LHs 1 - 5的反应是烯丙基夺氢反应。对ArO·与6种类胡萝卜素（Car-Hs 1 -6、astaxanthin 1、β-carotene 2、lyce 3、capsanthin 4、zeaxanthin 5和lute 6）的反应进行了类似的动力学研究。结果表明，在不同的温度下，Ks值按Car-H_1 <2<3<4<5<6的顺序增加。Car-H6的K_s值为8.4 × 10 ~（-4）M ~（-1）s ~（-1）。Car-Hs 1 - 6的kS值与LHs 1 -5的kS值的顺序相同。对上述反应的kS值进行了详细的分析，结果表明该反应也可用烯丙基夺氢反应来解释。结合Martinez和巴博萨的密度泛函理论计算结果，讨论了反应的构效关系.
A kinetic study of the reaction between an aroxyl radical (ArO•) and fatty acid esters (LHs1–5, ethyl stearate1, ethyl oleate2, ethyl linoleate3, ethyl linolenate4, and ethyl arachidonate5) has been undertaken. The second-order rate constants (ks) for the reaction of ArO•with LHs1–5in toluene at 25.0 °C have been determined spectrophotometrically. Theksvalues obtained increased in the order of LH1<2<3<4<5, that is, with increasing the number of double bonds included in LHs1–5. Theksvalue for LH5was 2.93 × 10–3M–1s–1. From the result, it has been clarified that the reaction of ArO•with LHs1–5was explained by an allylic hydrogen abstraction reaction. A similar kinetic study was performed for the reaction of ArO•with six carotenoids (Car-Hs1–6, astaxanthin1, β-carotene2, lycopene3, capsanthin4, zeaxanthin5, and lutein6). Theksvalues obtained increased in the order of Car-H1<2<3<4<5<6. Theksvalue for Car-H6was 8.4 × 10–4M–1s–1. Theksvalues obtained for Car-Hs1–6are in the same order as that of the values for LHs1–5. The results of detailed analyses of theksvalues for the above reaction indicated that the reaction was also explained by an allylic hydrogen abstraction reaction. Furthermore, the structure–activity relationship for the reaction was discussed by taking the result of density functional theory calculation reported by Martinez and Barbosa into account.