Reszka K J, Chignell C F
Laboratory of Molecular Biophysics, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709.
Photochem Photobiol. 1994 Nov;60(5):450-4. doi: 10.1111/j.1751-1097.1994.tb05132.x.
Compounds possessing a pyridine-2-thione moiety show antimicrobial, antifungal and anticancer activities. Some of them are also photochemically active and upon UV irradiation generate free radicals. In this work, employing EPR and the spin traps 2-methyl-2-nitrosopropane (MNP) and aci-nitromethane (NM), we investigated the photochemistry in aqueous solutions of N-hydroxypyridine-2-thione (used here as a sodium salt, 2-S-PyrNONa), and pyridine-2-thione (2-S-PryH), as well as photochemistry of the respective disulfides, 2,2'-dithiobis(pyridine N-oxide) [(2-S-PyrN-->O)2] and 2,2'-dithiodipyridine [(2-S-Pyr)2]. We found that UV irradiation of 2-S-PyrNONa and of 2-S-PyrH in the presence of MNP and NM generates EPR signals of reduced spin traps in addition to signals of MNP and NM adducts with aryl-thiyl radicals, 2-.S-PyrN-->O and 2-.S-Pyr. The identification of the aromatic thiyl radicals was based on comparison of EPR spectra of spin adducts generated by irradiation of 2-S-PyrNONa and 2-S-PyrH with those produced by UV photolysis of the respective disulfides (2-S-PyrN-->O)2 and (2-S-Pyr)2. It is concluded that pyridine-2-thione and N-hydroxypyridine-2-thione possess a photoreducing capacity and generate aromatic thiyl radicals upon UV activation. This property may be relevant to biological action of agents containing the pyridine-2-thione moiety.
含有吡啶 -2-硫酮部分的化合物具有抗菌、抗真菌和抗癌活性。其中一些还具有光化学活性，在紫外线照射下会产生自由基。在这项工作中，我们使用电子顺磁共振（EPR）以及自旋捕获剂2-甲基-2-亚硝基丙烷（MNP）和酸式硝基甲烷（NM），研究了N-羟基吡啶-2-硫酮（此处用作钠盐，2-S-PyrNONa）和吡啶-2-硫酮（2-S-PryH）水溶液中的光化学，以及各自二硫化物2,2'-二硫代双（吡啶N-氧化物）[（2-S-PyrN→O）2]和2,2'-二硫代二吡啶[（2-S-Pyr）2]的光化学。我们发现，在MNP和NM存在下，紫外线照射2-S-PyrNONa和2-S-PryH除了产生MNP和NM与芳基硫自由基2-S-PyrN→O和2-S-Pyr的加合物信号外，还产生还原自旋捕获剂的EPR信号。芳香硫自由基的鉴定是基于将2-S-PyrNONa和2-S-PryH照射产生的自旋加合物的EPR光谱与相应二硫化物（2-S-PyrN→O）2和（2-S-Pyr）2的紫外线光解产生的光谱进行比较。得出的结论是，吡啶-2-硫酮和N-羟基吡啶-2-硫酮具有光还原能力，在紫外线激活后会产生芳香硫自由基。这一特性可能与含有吡啶-2-硫酮部分的试剂的生物作用有关。
