In this study, 3-hydroxymethyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, and 5-hydroxy-1,1,3,3-tetramethylisoindoline-2-oxyl O-galactosides (PG, TG, and IG) were synthesized. Moreover, their reduction reactivity (RR) for ascorbic acid and hydrolysis reactivity (HR) for β-galactosidase were measured via electron paramagnetic resonance (EPR) spectroscopy and high-performance liquid chromatography (HPLC), respectively. The both rate constants for these two reactions were found to exhibit the following order: RR: TG > IG > PG, and HR: IG > PG > TG. Based on the results of the in vitro assay, IG was selected as the candidate for the bioassay. The bioassay of IG by HeLa cells (cancer cells) and PC12 cells (normal cells) indicated that after 20 min of IG addition, more nitroxide radicals were located in the cancer cells than in the normal cells, while their EPR intensity was low.

中文翻译：

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靶向β-半乳糖苷酶的旋转标签探针的合成与评价：5-

在这项研究中，3-羟基甲基-2,2,5,5-四甲基吡咯烷-1-氧基，4-羟基-2,2,6,6-四甲基哌啶-1-氧基和5-羟基-1,1,3合成了3-3-四甲基异吲哚啉-2-氧基O-半乳糖苷（PG，TG和IG）。此外，它们对抗坏血酸的还原反应（RR）和对β的水解反应（HR）-半乳糖苷酶分别通过电子顺磁共振（EPR）光谱和高效液相色谱（HPLC）测定。发现这两个反应的两个速率常数均显示以下顺序：RR：TG> IG> PG，HR：IG> PG> TG。根据体外测定的结果，选择IG作为生物测定的候选者。HeLa细胞（癌细胞）和PC12细胞（正常细胞）对IG的生物分析表明，添加IG 20分钟后，癌细胞中的一氧化氮自由基比正常细胞中的多，而它们的EPR强度却很低。