Kim Ji In, Lee Jun Hyun, Choi Dong Seong, Won Bo Mi, Jung Mun Yhung, Park Jiyong
Dept. of Biomaterials Science and Engineering, Yonsei Univ., Seoul, Republic of Korea.
J Food Sci. 2009 Jun;74(5):C362-9. doi: 10.1111/j.1750-3841.2009.01160.x.
Effects of synthetic phenolic antioxidants (BHA, BHT, and TBHQ) on the methylene blue (MB) sensitized photooxidation of linoleic acid as compared with that of alpha-tocopherol have been studied. Their antioxidative mechanism was studied by both ESR spectroscopy in a 2,2,6,6-tetramethylpiperidone (TMPD)-methylene blue (MB) system and spectroscopic analysis of rubrene oxidation induced by a chemical source of singlet oxygen. Total singlet oxygen quenching rate constants (k(ox-Q)+k(q)) were determined using a steady state kinetic equation. TBHQ showed the strongest protective activity against the MB sensitized photooxidation of linoleic acid, followed by BHA and BHT. TBHQ (1 x 10(-3) M) exhibited 86.5% and 71.4% inhibition of peroxide and conjugated diene formations, respectively, in linoleic acid photooxidation after 60-min light illumination. The protective activity of TBHQ against the photosensitized oxidation of linoleic acid was almost comparable to that of alpha-tocopherol. The data obtained from ESR and rubrene oxidation studies clearly showed the strong singlet oxygen quenching ability of TBHQ. The k(ox-Q)+k(q) of BHA, BHT, and TBHQ were determined to be 3.37 x 10(7), 4.26 x 10(6), and 1.67 x 10(8) M(-1) s(-1), respectively. The k(ox-Q)+k(q) of TBHQ was within the same order of magnitude of that of alpha-tocopherol, a known efficient singlet oxygen quencher. There was a high negative correlation (r(2) = -0.991) between log (k(ox-Q)+k(q)) and reported oxidation potentials for the synthetic antioxidants, indicating their charge-transfer mechanism for singlet oxygen quenching. This is the 1st report on the kinetic study on k(ox-Q)+k(q) of TBHQ in methanol as compared with other commonly used commercial synthetic antioxidants and alpha-tocopherol.
研究了合成酚类抗氧化剂（丁基羟基茴香醚、二丁基羟基甲苯和叔丁基对苯二酚）与α-生育酚相比，对亚油酸亚甲基蓝敏化光氧化的影响。通过在2,2,6,6-四甲基哌啶酮（TMPD）-亚甲基蓝（MB）体系中的电子自旋共振光谱和由单线态氧化学源诱导的红荧烯氧化的光谱分析，研究了它们的抗氧化机制。使用稳态动力学方程测定了总单线态氧猝灭速率常数（k(ox-Q)+k(q)）。叔丁基对苯二酚对亚油酸亚甲基蓝敏化光氧化表现出最强的保护活性，其次是丁基羟基茴香醚和二丁基羟基甲苯。在光照60分钟后，叔丁基对苯二酚（1×10⁻³ M）分别对亚油酸光氧化中过氧化物和共轭二烯形成的抑制率为86.5%和71.4%。叔丁基对苯二酚对亚油酸光敏氧化的保护活性几乎与α-生育酚相当。从电子自旋共振和红荧烯氧化研究获得的数据清楚地表明了叔丁基对苯二酚具有很强的单线态氧猝灭能力。丁基羟基茴香醚、二丁基羟基甲苯和叔丁基对苯二酚的k(ox-Q)+k(q)分别测定为3.37×10⁷、4.26×10⁶和1.67×10⁸ M⁻¹ s⁻¹。叔丁基对苯二酚的k(ox-Q)+k(q)与已知有效的单线态氧猝灭剂α-生育酚处于同一数量级。合成抗氧化剂的log (k(ox-Q)+k(q))与报道的氧化电位之间存在高度负相关（r² = -0.991），表明它们的单线态氧猝灭电荷转移机制。这是第一篇关于与其他常用商业合成抗氧化剂和α-生育酚相比，叔丁基对苯二酚在甲醇中k(ox-Q)+k(q)的动力学研究报告。
