Lewandowski Marcin, Gwoździński Krzysztof
Katedra Biofizyki Molekularnej Uniwersytetu Łódzkiego.
Postepy Hig Med Dosw (Online). 2016 Oct 14;70(0):1101-1111. doi: 10.5604/17322693.1222099.
Nitroxides are a group of stable organic radicals of low molecular weight having a nitroxyl group > N-.O, which has an unpaired electron. The presence of this group allows a nitroxide to participate in redox reactions. They serve as mimics of superoxide dismutase (SOD) and have stimulative properties towards haemoproteins with catalase-like activity. Nitroxides oxidize Fe (II) to Fe (III) preventing the Fenton and Haber-Weiss reactions. As the radicals have the ability to scavenge other free radicals. Nitroxides are not immunogenic, and mutagenic and do not show toxicity to the human cells. The review discusses the use of nitroxide in protecting cells and tissues from the effects of UVA radiation. Preliminary studies indicate that they are more effective than conventionally used vitamins C and E and UV filters. They also protect the biological material from the effects of ionizing radiation. Nitroxides protect healthy cells and simultaneously they do not protect cancer cells from ionizing radiation. The differences in the nitroxide activity are associated with conditions prevailing in the oxidizing environment of the tumor as opposed to reducing conditions in normal cells. Nitroxides can be used as contrast agents in the magnetic resonance imaging (MR). They have ability of detection of subtle changes in redox equilibrium in the tumor tissue. Application of nitroxides in MR method allow to distinguish normal and pathological state of tissue. Successful investigations using this technique were conducted in mice with colon and brain cancer.
氮氧化物是一类分子量较低的稳定有机自由基，含有一个硝酰基＞N-.O，该基团有一个未成对电子。这个基团的存在使氮氧化物能够参与氧化还原反应。它们可作为超氧化物歧化酶（SOD）的模拟物，对具有过氧化氢酶样活性的血红蛋白具有刺激特性。氮氧化物将Fe（II）氧化为Fe（III），从而防止芬顿反应和哈伯-维西反应。由于这些自由基有能力清除其他自由基。氮氧化物不具有免疫原性、致突变性，对人体细胞也无毒性。这篇综述讨论了氮氧化物在保护细胞和组织免受紫外线A辐射影响方面的应用。初步研究表明，它们比传统使用的维生素C和E以及紫外线滤过剂更有效。它们还能保护生物材料免受电离辐射的影响。氮氧化物能保护健康细胞，同时不会保护癌细胞免受电离辐射。氮氧化物活性的差异与肿瘤氧化环境中普遍存在的条件有关，与正常细胞中的还原条件相反。氮氧化物可用作磁共振成像（MR）中的造影剂。它们有能力检测肿瘤组织中氧化还原平衡的细微变化。在磁共振成像方法中应用氮氧化物可以区分组织的正常和病理状态。使用该技术在患有结肠癌和脑癌的小鼠身上进行了成功的研究。
