Stolze Klaus, Udilova Natascha, Rosenau Thomas, Hofinger Andreas, Nohl Hans
Research Institute of Pharmacology and Toxicology, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria.
Biochem Pharmacol. 2005 Jan 15;69(2):297-305. doi: 10.1016/j.bcp.2004.09.021. Epub 2004 Nov 24.
Free radicals are involved in the onset of many diseases, therefore the availability of adequate spin traps is crucial to the identification and localization of free radical formation in biological systems. In recent studies several hydrophilic compounds of 2-ethoxycarbonyl-2-methyl-pyrroline-N-oxide (EMPO) have been found to form rather stable superoxide spin adducts with half-lives up to twenty minutes at physiological pH. This is a major improvement over DMPO (t1/2=ca. 45 s), and even over DEPMPO (t1/2=ca. 14 min), the best commercially available spin trap for the unambiguous detection of superoxide radicals. In order to allow the detection of superoxide and also other radicals in lipid environment a series of more lipophilic derivatives of EMPO was synthesized and their structure unambiguously characterized by 1H and 13C NMR spectroscopy. In this way, six different compounds with a n-butyl group in position 5 and either an ethoxy- (EBPO), propoxy- (PBPO), iso-propoxy- (iPBPO), butoxy- (BBPO), sec-butoxy- (sBBPO) or tert-butoxycarbonyl group (tBBPO) in position 5 of the pyrroline ring were obtained and fully analytically characterized (NMR, IR). The stability of the superoxide adducts of all investigated spin traps were comparable with EMPO (t1/2=ca. 8 min), except for the two compounds bearing an additional methyl group in position 3 or 4 of the pyrroline ring, 5-butyl-5-ethoxycarbonyl-3-methyl-pyrroline-N-oxide (BEMPO-3) and 5-butyl-5-ethoxycarbonyl-4-methyl-pyrroline-N-oxide (BEMPO-4), of which the superoxide adducts were stable for more than 30 min. Spin adducts of other carbon- and oxygen-centered radicals were also investigated.
自由基参与多种疾病的发生，因此，有足够的自旋捕获剂对于在生物系统中识别和定位自由基的形成至关重要。在最近的研究中，发现几种2-乙氧羰基-2-甲基-吡咯啉-N-氧化物（EMPO）的亲水性化合物能形成相当稳定的超氧自旋加合物，在生理pH值下半衰期长达20分钟。这比DMPO（t1/2约为45秒）有了重大改进，甚至超过了DEPMPO（t1/2约为14分钟），DEPMPO是市售的用于明确检测超氧自由基的最佳自旋捕获剂。为了能够在脂质环境中检测超氧自由基以及其他自由基，合成了一系列EMPO的亲脂性更强的衍生物，并通过1H和13C NMR光谱对其结构进行了明确表征。通过这种方式，获得了六种不同的化合物，它们在吡咯啉环的5位带有正丁基，在吡咯啉环的5位分别带有乙氧基-（EBPO）、丙氧基-（PBPO）、异丙氧基-（iPBPO）、丁氧基-（BBPO）、仲丁氧基-（sBBPO）或叔丁氧羰基（tBBPO），并进行了全面的分析表征（NMR、IR）。除了在吡咯啉环的3位或4位带有额外甲基的两种化合物5-丁基-5-乙氧羰基-3-甲基-吡咯啉-N-氧化物（BEMPO-3）和5-丁基-5-乙氧羰基-4-甲基-吡咯啉-N-氧化物（BEMPO-4）外，所有研究的自旋捕获剂的超氧加合物的稳定性与EMPO相当（t1/2约为8分钟），其中BEMPO-3和BEMPO-4的超氧加合物稳定超过30分钟。还研究了其他以碳和氧为中心的自由基的自旋加合物。
