Stiborová Marie, Simánek Vilím, Frei Eva, Hobza Pavel, Ulrichová Jitka
Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 2 Prague, Czech Republic.
Chem Biol Interact. 2002 Aug 15;140(3):231-42. doi: 10.1016/s0009-2797(02)00038-8.
Using the 32P-postlabeling assay, we investigated the ability of quaternary benzo[c]phenanthridine alkaloids, sanguinarine, chelerythrine and fagaronine, to form DNA adducts in vitro. Two enhanced versions of the assay (enrichment by nuclease P1 and 1-butanol extraction) were utilized in the study. Hepatic microsomes of rats pre-treated with beta-naphthoflavone or those of uninduced rats, used as metabolic activators, were incubated in the presence of calf thymus DNA and the alkaloids, with NADPH used as a cofactor. Under these conditions sanguinarine and chelerythrine, but not fagaronine, formed DNA adducts detectable by 32P-postlabeling. DNA adduct formation by both alkaloids was found to be concentration dependent. When analyzing different atomic and bond indices of the C11-C12 bond (ring B) in alkaloid molecules we found that fagaronine behaved differently from sanguinarine and chelerythrine. While sanguinarine and chelerythrine showed a preference for electrophilic attack indicating higher potential to be activated by cytochrome P450, fagaronine exhibited a tendency for nucleophilic attack. Our results demonstrate that sanguinarine and chelerythrine are metabolized by hepatic microsomes to species, which generate DNA adducts.
我们使用³²P后标记分析法，研究了季铵型苯并[c]菲啶生物碱血根碱、白屈菜红碱和吴茱萸次碱在体外形成DNA加合物的能力。本研究采用了该分析法的两种改进版本（通过核酸酶P1富集和正丁醇萃取）。将经β-萘黄酮预处理的大鼠肝微粒体或未诱导的大鼠肝微粒体用作代谢激活剂，在小牛胸腺DNA和生物碱存在的情况下进行孵育，并使用NADPH作为辅助因子。在这些条件下，血根碱和白屈菜红碱可形成³²P后标记法可检测到的DNA加合物，而吴茱萸次碱则不能。发现这两种生物碱形成DNA加合物均呈浓度依赖性。在分析生物碱分子中C11 - C12键（B环）的不同原子和键指标时，我们发现吴茱萸次碱的行为与血根碱和白屈菜红碱不同。血根碱和白屈菜红碱表现出亲电攻击的倾向，表明其被细胞色素P450激活的潜力更高，而吴茱萸次碱则表现出亲核攻击的倾向。我们的结果表明，血根碱和白屈菜红碱可被肝微粒体代谢为能产生DNA加合物的物质。
