新型羟基和醌碳自由基产生的分子机理

波谱学杂志 ›› 2011, Vol. 28 ›› Issue (4): 479-489.

新型羟基和醌碳自由基产生的分子机理

朱本占*，覃浩，黄春华

中国科学院生态环境研究中心，环境化学与生态毒理学国家重点实验室, 北京 100085

收稿日期:2011-09-29 出版日期:2011-12-05 发布日期:2011-12-05
基金资助:
国家重点基础研究发展计划(“973”计划)资助项目(2008CB418106)；中国科学院“百人计划”资助项目；国家自然科学基金资助项目(20925724, 20777080, 20877081, 20890112, 20921063).

A Novel Mechanism for Metal-Independent Production of Hydroxyl Radicals and Carbon-Centered Quinone Ketoxy Radicals

ZHU Ben-Zhan*, QIN Hao, HUANG Chun-Hua

State Key Laboratory of Environmental Chemistry and Eco-toxocology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China

Received:2011-09-29 Online:2011-12-05 Published:2011-12-05
Supported by:
国家重点基础研究发展计划(“973”计划)资助项目(2008CB418106)；中国科学院“百人计划”资助项目；国家自然科学基金资助项目(20925724, 20777080, 20877081, 20890112, 20921063).

摘要/Abstract

摘要：

羟基自由基（·OH）被公认是生物系统中最具活性的活性氧物种，能导致生物体内DNA等生物大分子氧化损伤. 目前，最被广泛接受的·OH的产生机理是过渡金属离子催化的Fenton反应. 五氯酚(PCP)是一种重要的生物杀灭剂，主要用作木材保护. 采用电子自旋共振二级自旋捕获等分析手段，发现H₂O₂和五氯酚的代谢产物之一四氯苯醌（TCBQ）能通过不依赖于金属离子的途径产生·OH；进一步的研究发现是TCBQ，而非其相应的半醌自由基对·OH的产生极其重要. 基于这些数据和分析，提出以下新型·OH产生分子机理：H₂O₂对TCBQ进行亲核攻击形成不稳定的三氯氢过氧基苯醌中间产物，其可均裂产生·OH. 综合采用电子自旋共振自旋捕获和其他分析方法，第1次检测到一种新型的以碳为中心的醌自由基.

关键词: 电子自旋共振(ESR)自旋捕获, 羟基自由基, , 五氯酚, , 四氯苯醌, , 过氧化氢, , 以碳为中心的醌自由基

Abstract:

The hydroxyl radical (·OH) has been considered to be one of the most reactive oxygen species produced in biological systems. It has been shown that ·OH can cause oxidative damage to DNA and other macromolecules. One of the most widely accepted mechanisms for ·OH production is through the transition metal-catalyzed Fenton reaction. Pentachlorophenol (PCP) has been widely used as a wood preservative. Using electron spin resonance (ESR) secondary spin-trapping methods, we found that ·OH can be produced by H₂O₂ and tetrachloro-1,4-benzoquinone (TCBQ) (one of the major carcinogenic metabolites of PCP) independent of transition metal ions. Further studies showed that TCBQ, but not its corresponding semiquinone radical, the tetrachlorosemiquinone radical, is essential for ·OH production. Based on these data, we propose that ·OH production by H₂O₂ and TCBQ is through the following novel mechanism: a nucleophilic attack of H₂O₂ to TCBQ, forming a trichloro-hydroperoxyl-1,4-benzoquinone intermediate, which decomposes homolytically to produce ·OH. Through complementary application of ESR spin-trapping and other methods, we also detected and identified, for the first time, a novel carbon-centered quinone ketoxy radical.

Key words: electron spin resonance spin-trapping method, hydroxyl radical, pentachlorophenol, tetrachloro-1,4-benzoquinone, hydrogen peroxide, carbon-centered quinone ketoxy radical

中图分类号:

O482.53

朱本占, 覃浩, 黄春华. 新型羟基和醌碳自由基产生的分子机理[J]. 波谱学杂志, 2011, 28(4): 479-489.

ZHU Ben-Zhan, QIN Hao, HUANG Chun-Hua. A Novel Mechanism for Metal-Independent Production of Hydroxyl Radicals and Carbon-Centered Quinone Ketoxy Radicals[J]. Chinese Journal of Magnetic Resonance, 2011, 28(4): 479-489.

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