Riboflavin as a sensitiser in the photodegradation of tetracyclines.: Kinetics, mechanism and microbiological implications
Riboflavin as a sensitiser in the photodegradation of tetracyclines.: Kinetics, mechanism and microbiological implications
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DOI：
10.1016/j.dyepig.2005.08.025
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发表时间：
2007-01-01
影响因子：
4.5
通讯作者：
Garcia, Norman A.
中科院分区：
文献类型：
--
作者：
Castillo, Carolina;Criado, Susana;Garcia, Norman A.
动力学、机理和微生物学研究集中在四环素衍生物（TccD）在核黄素（Rf）存在下可能发生的可见光促进的光反应，以及这些光转化的后果。我们发现TccD多西环素、甲他环素、金霉素、地美环素、土霉素和母体化合物四环素、淬灭核黄素在溶液中的单线态和三线态（（3）Rf*）激发态。在TccD浓度的亚mM范围内，仅（3）Rf* 的淬灭是显著的。结果，通过从TccD基态的电子转移事件产生物种Rf。此外，实验证据支持超氧阴离子自由基（O-2（-））的产生。在平行过程中，通过从（3）Rf* 到溶解氧的能量转移产生单线态分子氧（O-2（（1）Delta（g）。动力学证据表明，强力霉素、甲他环素、金霉素、地美环素和土霉素通过O-2（-）和O-2（（1）Delta（g））机制光降解，而四环素通过占主导地位的O（2）（-）介导的过程光降解相对较少。还观察到四环素的抗生素活性以与药物的光降解平行的方式降低。(c)2005爱思唯尔有限公司保留所有权利。
Kinetic, mechanistic and microbiological studies focus on the visible-light-promoted photoreactions that can take place when tetracycline derivatives (TccD) are in the presence of riboflavin (Rf), and on the consequences of these phototransformations. We found that the TccD doxycycline, methacycline, chlorotetracycline, demeclocycline, oxytetracycline and the parent compound tetracycline, quenched riboflavin singlet and triplet ((3)Rf*) excited states in solution. Within the sub-mM range of concentrations of TccD only the quenching of (3)Rf* was significant. As a result the species Rf was generated through an electron transfer event from TccD ground state. Further, experimental evidence supported the generation of superoxide radical anion (O-2(-)). In a parallel process singlet molecular oxygen (O-2((1)Delta(g))) was produced by energy transfer from (3)Rf* to dissolved oxygen. Kinetic evidence indicates that doxycycline, methacycline, chlorotetracycline, demeclocycline and oxytetracycline are photodegraded through both O-2(-) and O-2((1)Delta(g)) mechanisms, whereas tetracycline is comparatively less photodegradable through a dominant O(2)(-)mediated process. It was also observed that the antibiotic activity of tetracycline decreases in a parallel fashion with the photodegradation of the drug. (c) 2005 Elsevier Ltd. All rights reserved.