烟草去甲基尼古丁产生的机理

烟叶的采收后处理和加工过程中，大量的尼古丁经去甲基化作用生成了去甲基尼古丁，后者是烟草特有的亚硝胺类（tobacco-specific nitrosamines，TSNAs）致癌物——亚硝基去甲基尼古丁（nitrosonomicoline，NNN）的前体，与人类健康息息相关。由于尼古丁去甲基化反应在基础理论研究和商业上的重要价值，长期以来关于这个反应的机制研究一直是学术界的热点。本文讨论了尼古丁去甲基化反应研究的历史概况、反应机制假说的演变及影响该反应的因素，期望通过对烟草尼古丁去甲基化反应研究的总结，为烟草品质提高和低毒害烟草制品的研究与开发提供一定的参考。

Mechanism of Nicotine N-demethylation to Nornicotine in Tobacco

Nornicotine is produced by the N-demethylation of nicotine during the post-harvest treatment of tobacco leaves. Nornicotine in tobacco serves as the precursor in synthesis of the well-characterized carcinogen N'-nitrosonornicotine (NNN), one of the tobacco-specific nitrosamines (TSNAs), and consequently damages the health of tobacco smokers and passive smokers. Studies of the mechanism of nicotine N-demethylation have, over the last decades, attracted serious attention because of its importance in plant physiological research and commerce. In this review, we discuss the history and mechanisms of nicotine N-demethylation and the factors that affect this enzymatic reaction. The current advances in nicotine N-demethylation in tobacco provide important insights into improving the quality of tobacco and developing hazard-reduced tobacco products.