Singh V, Ahmad S, Rao G S
Industrial Toxicology Research Centre, Lucknow, India.
Toxicology. 1994 Mar 25;89(1):25-33. doi: 10.1016/0300-483x(94)90130-9.
Bleomycin-dependent degradation of DNA in bone marrow cells was studied in vitro in the presence of iron or iron polyphenol chelates which are formed during biotransformation of benzene. Iron polyphenol chelates markedly enhanced bleomycin-dependent DNA degradation in comparison to iron alone. About 1.5 and 2.5-fold increase was observed in the presence of iron hydroquinone (HQ) chelate and iron 1,2,4-benzenetriol (BT) chelate, respectively. Endogenous iron chelators such as glutamate, citrate, aspartate, glycine, cysteine, dithiothreitol, AMP, ADP and ATP did not enhance iron-catalysed bleomycin-dependent degradation of DNA. By bleomycin assay, the recovery of iron polyphenol chelate added externally to bone marrow lysate was complete. However, the presence of iron polyphenol chelate resulted in less thiobarbituric acid reactive products from glutamate or brain homogenate than with iron alone. The optical spectra of BT were modified in the presence of ferrous sulphate, revealing a new absorption peak at 259 nm indicating complexation with iron. Thus, the iron polyphenol chelate, on one hand, is a more potent DNA cleaving agent in the presence of bleomycin, and on the other hand, it is a less effective free radical generator as compared to iron alone.
在体外研究了骨髓细胞中博来霉素依赖的DNA降解情况，实验中存在铁或在苯的生物转化过程中形成的铁多酚螯合物。与单独的铁相比，铁多酚螯合物显著增强了博来霉素依赖的DNA降解。在存在对苯二酚（HQ）铁螯合物和1,2,4-苯三酚（BT）铁螯合物的情况下，分别观察到约1.5倍和2.5倍的增加。内源性铁螯合剂如谷氨酸、柠檬酸、天冬氨酸、甘氨酸、半胱氨酸、二硫苏糖醇、AMP、ADP和ATP并未增强铁催化的博来霉素依赖的DNA降解。通过博来霉素测定，添加到骨髓裂解物中的外部铁多酚螯合物的回收率是完全的。然而，与单独的铁相比，铁多酚螯合物导致谷氨酸或脑匀浆产生的硫代巴比妥酸反应产物较少。在硫酸亚铁存在的情况下，BT的光谱发生了改变，在259nm处出现了一个新的吸收峰，表明与铁形成了络合物。因此，铁多酚螯合物一方面在存在博来霉素的情况下是一种更有效的DNA切割剂，另一方面，与单独的铁相比，它是一种较不有效的自由基产生剂。
