Free radical reactions of curcumin in membrane models.
Free radical reactions of curcumin in membrane models.
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DOI：
10.1016/s0891-5849(97)00026-9
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发表时间：
1997
影响因子：
7.4
通讯作者：
K. Priyadarsini
中科院分区：
文献类型：
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作者：
K. Priyadarsini
以TX-100胶束为模型膜，研究了姜黄脂溶性抗氧化剂姜黄素与多种氧化剂的自由基反应。在乙腈-水混合物和TX-100胶束中，单电子氧化叠氮自由基生成的姜黄素的苯氧基自由基表现出非常相似的光谱行为。然而，在膜模型中，自由基寿命和摩尔消光系数与均相溶液有很大的不同。胶束化的姜黄素与卤代过氧化氢自由基、超氧阴离子自由基和过氧化脂质自由基的反应速率常数分别为5×10~8、4.6×10~4和5.3×10~5M−1S−1。姜黄素衍生的苯氧基自由基在均相溶液中通过自由基反应衰减，而在胶束中，当胶束的平均占有率小于1时，自由基的衰减大多为一级。讨论了这些结果对评价姜黄素作为抗氧化剂的意义。
Free radical reactions of curcumin, a lipid soluble antioxidant from turmeric (Curcuma longa), have been studied with a variety of oxidants using TX 100 micelle as a model membrane. The phenoxyl radicals of curcumin generated by one electron oxidizing azide radicals in acetonitrile-water mixture and TX 100 micelles show very similar spectral behavior. However, in membrane models the radical lifetimes and the molar extinction coefficients are significantly different from the homogeneous solutions. Micellized curcumin reacts with haloperoxyl radicals, superoxide, and lipid peroxyl radicals with rate constants of 5 × 108, 4.6 × 104, and 5.3 × 105M−1s−1, respectively. Curcumin derived phenoxyl radicals decay by radical-radical reactions in homogeneous solutions, while in the micelles, radical decay is mostly first order when the average occupancy of the micelle is less than 1. Implications of these results in evaluating curcumin as an antioxidant is discussed.