ESR Characterization of a Novel Spin-trapping Agent,<sup>15</sup>N-Labeled<i>N-tert</i>-Butyl-α-phenylnitrone, as a Nitric Oxide Donor
作者:Kieko SAITO、Hisashi YOSHIOKA
DOI:10.1271/bbb.66.2189
日期:2002.1
We previously found that one of the pharmacological effects of N-tert-butyl-α-phenylnitrone (PBN) is the release of nitric oxide (NO) under oxidative conditions. However, to confirm this hypothesis in vivo, NO released from PBN must be distinguished from NO produced in biological systems, and therefore we undertook the synthesis of PBN using labeled 15N to identify its corresponding 15NO in vivo. The properties were examined with an ESR spectrometer. To synthesize 15N-PBN, the starting material, ammonium-15N chloride, was converted to 2-amino-15N-2-methylpropane, oxidized to 2-methyl-2-nitropropane-15N, and finally reacted with benzaldehyde to give 15N-PBN. The final product was purified by repeated sublimation. With ferrous sulfate-methyl glucamine dithiocarbamate complex, Fe (MGD)2, as a trapping agent to measure the NO levels of 15N-PBN or 14N-PBN in vitro, the peak intensity of 15NO[Fe(MGD)2] was over 50% stronger than that of 14NO[Fe(MGD)2], and that 15NO and 14NO had the corresponding two-and three line hyperfine structures due to their nuclear spin quantum numbers. Subsequently, the ESR spectrum of 15NO derived from 15N-PBN was significantly different than that of lipopolysaccharide (LPS)-induced NO, which was derived from biological cells, and therefore we have demonstrated the possibility to distinguish 15NO from PBN and 14NO generated from cells. These results suggested that 15N-PBN is a useful molecule, not only as a spin-trapping agent, but also as an NO donor to explore the pharmacological mechanisms of PBN in vivo.
我们以前发现,N-叔丁基-α-苯基硝酮(PBN)的药理作用之一是在氧化条件下释放一氧化氮(NO)。然而,要在体内证实这一假设,必须将 PBN 释放的一氧化氮与生物系统中产生的一氧化氮区分开来,因此我们使用标记的 15N 合成了 PBN,以确定其在体内相应的 15NO。我们使用 ESR 光谱仪对其特性进行了检测。合成 15N-PBN 的起始原料是氯化铵-15N,将其转化为 2-氨基-15N-2-甲基丙烷,再氧化为 2-甲基-2-硝基丙烷-15N,最后与苯甲醛反应得到 15N-PBN。最终产物通过反复升华得到纯化。以硫酸亚铁-甲基葡糖胺二硫代氨基甲酸亚铁络合物 Fe (MGD)2 作为捕获剂,在体外测量 15N-PBN 或 14N-PBN 的 NO 含量时,15NO[Fe(MGD)2]的峰强度比 14NO[Fe(MGD)2] 强 50%以上,而且由于核自旋量子数的不同,15NO 和 14NO 具有相应的两线和三线超细结构。随后,从 15N-PBN 中得到的 15NO 的 ESR 光谱与从生物细胞中得到的脂多糖(LPS)诱导的 NO 的 ESR 光谱明显不同,因此我们证明了将 15NO 与从细胞中产生的 PBN 和 14NO 区分开来的可能性。这些结果表明,15N-PBN 是一种有用的分子,它不仅是一种自旋捕获剂,还是一种 NO 供体,可用于探索 PBN 在体内的药理机制。