Development and Validation of the First Assay Method Coupling Liquid Chromatography with Chemiluminescence for the Simultaneous Determination of Menadione and Its Thioether Conjugates in Rat Plasma

详细信息    查看全文

• 作者：Mohamed Saleh Elgawish ; Chikako Shimomai ; Naoya Kishikawa ; Kaname Ohyama ; Mitsuhiro Wada ; Naotaka Kuroda
• 刊名：Chemical Research in Toxicology
• 出版年：2013
• 出版时间：September 16, 2013
• 年：2013
• 卷：26
• 期：9
• 页码：1409-1417
• 全文大小：324K
• 年卷期：v.26,no.9(September 16, 2013)
• ISSN：1520-5010

文摘

Menadione (2-methyl-1,4-naphthoquinone, MQ), a component of multivitamin drugs with antihemorrhagic, antineoplastic, and antimalarial activity, is frequently used to investigate quinone-induced cytotoxicity. The formation of MQ conjugates with glutathione (GSH) by Michael addition and subsequent biotransformation to yield N-acetyl-l-cysteine conjugates is believed to be an important detoxification process. However, the resulting conjugates, 2-methyl-3-(glutathione-S-yl)-1,4-naphthoquinone (MQ-GS) and 2-methyl-3-(N-acetyl-l-cysteine-S-yl)-1,4-naphthoquinone (MQ-NAC), retain the ability to redox cycle and to arylate cellular nucleophiles. Although the nephrotoxicity and hepatotoxicity of MQ-thiol conjugates have been reported in vitro, methods for their determination in vivo have yet to be published. Herein, a highly sensitive, simple, and selective HPLC-chemiluminescence (HPLC-CL) coupled method is reported, allowing for the first time the simultaneous determination of MQ, MQ-GS, and MQ-NAC in rat plasma after MQ administration. Our method exploits the unique redox characteristics of MQ, MQ-GS, and MQ-NAC to react with dithiothreitol (DTT) to liberate reactive oxygen species (ROS) which are detected by a CL assay using luminol as a CL probe. To verify the proposed mechanism, MQ-GS and MQ-NAC were synthetically prepared. Specimen preparation involved solid-phase extraction on an Oasis HLB cartridge followed by isocratic elution on an ODS column. No interference from endogenous substances was detected. Linearity was observed in the range of 5鈥?20 nM for MQ-GS and MQ-NAC and 10鈥?40 nM for MQ, with detection limits (S/N of 3) of 1.4, 0.8, and 128 fmol for MQ-GS, MQ-NAC, and MQ, respectively. The application of our method reported here is the first to extensively study the stability and reversibility of thiol-quinones.