...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemical research in toxicology >Fractionation of aqueous cigarette tar extracts: fractions that contain the tar radical cause DNA damage.
【24h】

Fractionation of aqueous cigarette tar extracts: fractions that contain the tar radical cause DNA damage.

机译：分馏含水香烟焦油提取物：含有焦油自由基的馏分会引起DNA损伤。

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Previously, we have shown that aqueous cigarette tar (ACT) extracts contain a long-lived tar radical that associates with DNA in isolated rat alveolar macrophages and causes DNA damage in isolated rat thymocytes. These ACT solutions reduce oxygen to produce superoxide and, ultimately, hydrogen peroxide. In this study, we report the fractionation of ACT solutions prepared from the tar from five cigarettes using Sephadex columns. The fractions were analyzed by UV and electron paramagnetic resonance (EPR) spectroscopy and gas chromatography/mass spectrometry (GC/MS). The fractions containing polyphenolic species (principally catechol and hydroquinone, as determined by MS) caused most of the observed DNA damage in rat thymocytes. These DNA-damaging fractions produced superoxide, H2O2, and hydroxyl radicals. Stable free radicals were identified as o- and p-benzosemiquinone radicals by EPR spectroscopy. Hydroxyl radicals were detected by EPR spin-trapping with 5, 5-dimethyl-1-pyrroline N-oxide (DMPO). Catalase inhibited the EPR signal of the DMPO-OH adduct, indicating that H2O2 is the precursor of the hydroxyl radical spin adduct. The Sephadex separation resulted in a 90-fold concentration of the hydrogen peroxide-generating capacity of the fractions that contained polyphenols, relative to the unfractionated ACT solution. Another fraction, which contained nicotine, caused some DNA damage, but this damage was 28-fold less than the damage caused by the most damaging phenolic fraction. These results support our hypothesis that the tar radical system is an equilibrium mixture of semiquinones, hydroquinones, and quinones. The tar radical associates with DNA, causes DNA damage, and very likely is involved in the toxicity associated with cigarette smoking.
机译：以前，我们已经证明含水香烟焦油（ACT）提取物含有长寿命的焦油自由基，该自由基与分离的大鼠肺泡巨噬细胞中的DNA缔合，并在分离的大鼠胸腺细胞中引起DNA损伤。这些ACT溶液可还原氧气以产生超氧化物，并最终产生过氧化氢。在这项研究中，我们报告了使用Sephadex色谱柱从五支香烟的焦油中制备的ACT溶液的分级分离。通过UV和电子顺磁共振（EPR）光谱和气相色谱/质谱（GC / MS）分析级分。含有多酚类物质（主要是邻苯二酚和对苯二酚，由MS测定）的馏分引起了大鼠胸腺细胞中观察到的大多数DNA损伤。这些破坏DNA的馏分产生超氧化物，过氧化氢和羟​​基自由基。通过EPR光谱将稳定的自由基鉴定为邻-和对-苯并半醌醌。通过使用5、5-二甲基-1-吡咯啉N-氧化物（DMPO）进行EPR旋转捕集，可检测到羟基自由基。过氧化氢酶抑制了DMPO-OH加合物的EPR信号，表明H2O2是羟基自由基自旋加合物的前体。相对于未分级的ACT溶液，Sephadex分离可将含有多酚的馏分的过氧化氢生成能力浓缩90倍。另一个含有尼古丁的馏分造成了一些DNA损伤，但是这种破坏比最具破坏性的酚类馏分引起的破坏少28倍。这些结果支持了我们的假设，即焦油自由基体系是半醌，对苯二酚和醌的平衡混合物。焦油自由基与DNA结合，引起DNA损伤，很可能与吸烟相关的毒性有关。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号