Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan; Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan.
Department of Nutrition, China Medical University, No. 91, Hsueh-Shih Road, Taichung 404, Taiwan.
J Ethnopharmacol. 2018 Apr 24;216:18-25. doi: 10.1016/j.jep.2018.01.026. Epub 2018 Feb 3.
Shikonin, a naphthoquinone pigment abundant in the root of the Chinese herb Lithospermum erythrorhizon, has been widely used to treat inflammatory diseases for thousands of years. Whether shikonin changes drug metabolism remains unclear.
We investigated whether shikonin modulates the expression of hepatic drug-metabolizing enzymes and transporters as well as the possible mechanisms of this action.
Primary hepatocytes isolated from Sprague-Dawley rats were treated with 0-2 μM shikonin and the protein and mRNA levels of drug-metabolizing enzymes and transporters as well as the activation of aryl hydrocarbon receptor (AhR) and NF-E2-related factor 2 (Nrf2) were determined.
Shikonin dose-dependently increased the protein and RNA expression of phase I enzymes, i.e., cytochrome P450 (CYP) 1A1/2, CYP3A2, CYP2D1, and CYP2C6; phase II enzymes, i.e., glutathione S-transferase (GST), NADP(H) quinone oxidoreductase 1 (NQO1), and UDP glucuronosyltransferase 1A1; and phase III drug transporters, i.e., P-glycoprotein, multidrug resistance-associated protein 2/3, organic anion transporting polypeptide (OATP) 1B1, and OATP2B1. Immunoblot analysis and EMSA revealed that shikonin increased AhR and Nrf2 nuclear contents and DNA binding activity. AhR and Nrf2 knockdown by siRNA attenuated the ability of shikonin to induce drug-metabolizing enzyme expression. In addition, shikonin increased p38, JNK, and ERK1/2 phosphorylation, and inhibitors of the respective kinases inhibited shikonin-induced Nrf2 nuclear translocation.
Shikonin effectively upregulates the transcription of CYP isozymes, phase II detoxification enzymes, and phase III membrane transporters and this function is at least partially through activation of AhR and Nrf2. Moreover, Nrf2 activation is dependent on mitogen-activated protein kinases.
紫草素是一种萘醌色素，大量存在于中国草药紫草的根部，几千年来一直被广泛用于治疗炎症性疾病。然而，紫草素是否会改变药物代谢仍不清楚。
本研究旨在探讨紫草素是否调节肝药物代谢酶和转运体的表达及其可能的作用机制。
采用 Sprague-Dawley 大鼠原代肝细胞，用 0-2μM 紫草素处理，测定药物代谢酶和转运体的蛋白和 mRNA 水平以及芳香烃受体 (AhR) 和核因子 E2 相关因子 2 (Nrf2) 的激活情况。
紫草素呈剂量依赖性地增加了 I 相酶（细胞色素 P450（CYP）1A1/2、CYP3A2、CYP2D1 和 CYP2C6）、II 相酶（谷胱甘肽 S-转移酶（GST）、NADP（H）醌氧化还原酶 1（NQO1）和 UDP 葡萄糖醛酸转移酶 1A1）和 III 相药物转运体（P-糖蛋白、多药耐药相关蛋白 2/3、有机阴离子转运多肽 1B1 和 OATP2B1）的蛋白和 RNA 表达。免疫印迹分析和 EMSA 显示，紫草素增加了 AhR 和 Nrf2 的核含量和 DNA 结合活性。用 siRNA 敲低 AhR 和 Nrf2 可减弱紫草素诱导药物代谢酶表达的能力。此外，紫草素增加了 p38、JNK 和 ERK1/2 的磷酸化，相应激酶的抑制剂抑制了紫草素诱导的 Nrf2 核易位。
紫草素能有效上调 CYP 同工酶、II 相解毒酶和 III 相膜转运体的转录，其功能至少部分通过激活 AhR 和 Nrf2 实现。此外，Nrf2 的激活依赖于丝裂原活化蛋白激酶。
