Hiramoto K, Ohkawa T, Kikugawa K
School of Pharmacy, Tokyo University of Pharmacy and Life Science, Hachioji, Japan.
Free Radic Res. 2001 Dec;35(6):803-13. doi: 10.1080/10715760100301301.
Solutions of N-nitrosamines, N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosomorpholine and N-nitrosopyrrolidine in phosphate buffer (pH 7.4) were irradiated by ultraviolet (UV) light at room temperature. The N-nitrosamines were extensively degraded due to irradiation for 120 min in a time-dependent fashion as monitored by UV-absorption or high performance liquid chromatographic analysis. Carbon-centered radicals were generated from four N-nitrosamines during the short time irradiation of 10-60 s as monitored by electron spin resonance (ESR) technique using 5,5-dimethyl-1-pyrroline N-oxide and N-tert-butyl-alpha-phenylnitrone as spin traps. Nitric oxide (NO) was generated during the short time irradiation as monitored by ESR technique using cysteine-Fe(II) complex, N-methyl-D-glucamine dithiocarbamate and 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide. Significant amounts of nitrite (4-16%) from four N-nitrosamines and also a significant amount of nitrate (4%) was produced from N-nitrosodimethylamine during the irradiation time of 120 min. Released NO from the N-nitrosamines must be converted into nitrite through intermediary reactive nitrogen oxide species including nitrogen dioxide and dinitrogen trioxide in contact with dissolved oxygen.
在室温下，用紫外线（UV）照射N-亚硝胺、N-亚硝基二甲胺、N-亚硝基二乙胺、N-亚硝基吗啉和N-亚硝基吡咯烷在磷酸盐缓冲液（pH 7.4）中的溶液。通过紫外吸收或高效液相色谱分析监测，N-亚硝胺在120分钟的照射时间内以时间依赖性方式被广泛降解。在10 - 60秒的短时间照射过程中，使用5,5-二甲基-1-吡咯啉N-氧化物和N-叔丁基-α-苯基硝酮作为自旋捕集剂，通过电子自旋共振（ESR）技术监测到四种N-亚硝胺产生了碳中心自由基。使用半胱氨酸-Fe(II)络合物、N-甲基-D-葡糖胺二硫代碳酸盐和2-(4-羧基苯基)-4,4,5,5-四甲基咪唑啉-1-氧基-3-氧化物，通过ESR技术监测到在短时间照射过程中产生了一氧化氮（NO）。在120分钟的照射时间内，四种N-亚硝胺产生了大量亚硝酸盐（4 - 16%），N-亚硝基二甲胺还产生了大量硝酸盐（4%）。N-亚硝胺释放的NO必须通过与溶解氧接触的包括二氧化氮和三氧化二氮在内的中间活性氮氧化物物种转化为亚硝酸盐。
