Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan.
Chem Res Toxicol. 2010 Jan;23(1):134-41. doi: 10.1021/tx900314c.
Lucidin-3-O- primeveroside (LuP) is one of the components of madder root (Rubia tinctorum L.; MR) which is reported to be carcinogenic in the kidney and liver of rats. Since metabolism of LuP generates genotoxic compounds such as lucidin (Luc) and rubiadin (Rub), it is likely that LuP plays a key role in MR carcinogenesis. In the present study, the chemical structures of Luc-specific 2'-deoxyguanosine (dG) and 2'-deoxyadenosine (dA) adducts following the reactions of dG and dA with a Luc carbocation or quinone methide intermediate derived from Acetoxy-Luc were determined by liquid chromatography with photodiode array and electron spray ionizaion-mass spectrometry (LC-PDA-ESI/MS). The identification of the two measurable adducts as Luc-N(2)-dG and Luc-N(6)-dA was confirmed by NMR analysis. Subsequently, using a newly developed quantitative analytical method using LC-ESI/MS, the formation of Luc-N(2)-dG and Luc-N(6)-dA from the reaction of calf thymus DNA with Luc in the presence of S9 mixture was observed. The fact that this reaction with Rub also gave rise to the same dG and dA adducts strongly suggests that Rub genotoxicity involves a metabolic conversion to Luc. The precise determination of the modified DNA bases generated by LuP and the method for their analysis may contribute to further comprehension of the mode of action underlying carcinogenesis by MR and related anthraquinones.
毛蕊花糖苷（LuP）是茜草根（Rubia tinctorum L.；MR）的成分之一，据报道在大鼠的肾脏和肝脏中具有致癌性。由于 LuP 的代谢会生成遗传毒性化合物，如毛蕊花素（Luc）和茜草素（Rub），因此 LuP 很可能在 MR 致癌作用中发挥关键作用。在本研究中，通过液相色谱-光电二极管阵列-电喷雾离子化-质谱联用（LC-PDA-ESI/MS），确定了 Luc 碳正离子或 Acetoxy-Luc 衍生的醌甲醚中间体与 dG 和 dA 反应后形成的 Luc 特异性 2'-脱氧鸟苷（dG）和 2'-脱氧腺苷（dA）加合物的化学结构。通过 NMR 分析证实了两种可测量加合物为 Luc-N(2)-dG 和 Luc-N(6)-dA。随后，使用新开发的使用 LC-ESI/MS 的定量分析方法，观察到 Luc 在 S9 混合物存在下与小牛胸腺 DNA 的反应生成了 Luc-N(2)-dG 和 Luc-N(6)-dA。Rub 也产生相同的 dG 和 dA 加合物这一事实强烈表明，Rub 的遗传毒性涉及到代谢转化为 Luc。精确确定由 LuP 产生的修饰 DNA 碱基及其分析方法可能有助于进一步理解 MR 和相关蒽醌类物质致癌作用的作用模式。
