Stolze Klaus, Udilova Natascha, Nohl Hans
Institute of Pharmacology and Toxicology, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210.Vienna, Austria
Biochem Pharmacol. 2002 Apr 15;63(8):1465-70. doi: 10.1016/s0006-2952(02)00887-0.
Detection of oxygen-centered radicals was performed using the spin trap 1,3,3-trimethyl-6-azabicyclo[3.2.1]oct-6-ene-N-oxide (Trazon), a bicyclic nitrone spin trap that is easily synthesized from the corresponding amine via hydrogen peroxide mediated oxidation in the presence of the catalyst, sodium tungstate. Compared to monocyclic spin traps such as 5,5-dimethyl-1-pyrroline N-oxide (DMPO) or 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline N-oxide (DEPMPO), the ESR spectra of Trazon spin adducts provide additional structural information due to long-range hyperfine splitting constants and also due to the fact that different stereoisomers can be distinguished. This is especially helpful for the detection of lipid-derived alkoxyl radicals which can be identified according to their characteristic hyperfine splitting pattern. Due to the relatively high stability of the Trazon spin adducts with lipid alkoxyl radicals, which were formed from peroxidizing linoleic acid, ESR experiments could be performed using a stationary system, whereas a slow-flow system is recommended for DMPO. A series of structurally different alkoxyl radical adducts were synthesized by iron-catalyzed nucleophilic addition of the respective alcohol to the spin trap Trazon and the spectra were analyzed by computer simulation. Both the molecular weight of the alcohol and the position of the alcoholic hydroxyl group were of significant influence on the ESR spectra. Two stereochemically different spin adducts were formed in a ratio typical of the alcohol used, thus allowing structural classification of the alkoxyl radical trapped.
使用自旋捕获剂1,3,3-三甲基-6-氮杂双环[3.2.1]辛-6-烯-N-氧化物（Trazon）进行以氧为中心的自由基检测，Trazon是一种双环硝酮自旋捕获剂，可在催化剂钨酸钠存在下，通过过氧化氢介导的氧化反应，由相应的胺轻松合成。与单环自旋捕获剂如5,5-二甲基-1-吡咯啉N-氧化物（DMPO）或5-（二乙氧基磷酰基）-5-甲基-1-吡咯啉N-氧化物（DEPMPO）相比，Trazon自旋加合物的电子自旋共振（ESR）光谱由于远程超精细分裂常数以及不同立体异构体可被区分这一事实，提供了额外的结构信息。这对于检测脂质衍生的烷氧基自由基特别有帮助，这些自由基可根据其特征性超精细分裂模式进行识别。由于Trazon自旋加合物与由过氧化亚油酸形成的脂质烷氧基自由基具有相对较高的稳定性，因此可以使用固定系统进行ESR实验，而对于DMPO则建议使用慢流系统。通过铁催化将相应的醇亲核加成到自旋捕获剂Trazon上，合成了一系列结构不同的烷氧基自由基加合物，并通过计算机模拟分析了光谱。醇的分子量和醇羟基的位置对ESR光谱都有显著影响。形成了两种立体化学不同的自旋加合物，其比例与所用醇的典型比例相同，从而可以对捕获的烷氧基自由基进行结构分类。
