Rao G S, Pandya K P
Industrial Toxicology Research Centre, Mahatma Gandhi Marg, Lucknow India.
Toxicology. 1989 Nov;59(1):59-65. doi: 10.1016/0300-483x(89)90156-x.
Cytotoxic effects of various quinone compounds are thought to be due to the formation of semiquinone free radicals. Hydroquinone and 1,2,4-benzenetriol in the presence of copper ions release from glutamate or DNA aldehydic products capable of reacting with 2-thiobarbituric acid (TBA). The formation of TBA reactive products (TBAR) was greater in the presence of 1,2,4-benzenetriol in comparison with hydroquinone. Complete inhibition of formation of TBAR from glutamate by 1,2,4-benzenetriol and copper was observed in the presence of catalase, thiourea and mannitol. Albumin and superoxide dismutase offered substantial protection. Complete protection of formation of TBAR from DNA was observed in the presence of catalase and thiourea. Presence of albumin, mannitol and superoxide dismutase caused only partial inhibition. The formation of TBAR from glutamate or DNA is dependent on copper ion concentration. The present data indicate that hydroquinone and 1,2,4-benzenetriol in the presence of copper ions can lead to the formation of reactive hydroxyl radicals which can release TBAR from glutamate or DNA.
各种醌类化合物的细胞毒性作用被认为是由于半醌自由基的形成。对苯二酚和1,2,4 -苯三酚在铜离子存在下会从谷氨酸或DNA中释放出能够与2 -硫代巴比妥酸（TBA）反应的醛类产物。与对苯二酚相比，在1,2,4 -苯三酚存在下，TBA反应性产物（TBAR）的形成更多。在过氧化氢酶、硫脲和甘露醇存在的情况下，观察到1,2,4 -苯三酚和铜完全抑制了谷氨酸形成TBAR。白蛋白和超氧化物歧化酶提供了显著的保护作用。在过氧化氢酶和硫脲存在的情况下，观察到DNA形成TBAR受到完全保护。白蛋白、甘露醇和超氧化物歧化酶的存在仅导致部分抑制。谷氨酸或DNA形成TBAR取决于铜离子浓度。目前的数据表明，对苯二酚和1,2,4 -苯三酚在铜离子存在下可导致活性羟基自由基的形成，这些自由基可从谷氨酸或DNA中释放出TBAR。
