State Key Laboratory of Functions and Applications of Medicinal Plants & Guizhou Provincial Key Laboratory of Pharmaceutics, Guizhou Medical University, Guiyang, Guizhou 550004, PR China; School of Pharmacy, Guizhou Medical University, Guiyang, Guizhou 550004, PR China.
State Key Laboratory of Functions and Applications of Medicinal Plants & Guizhou Provincial Key Laboratory of Pharmaceutics, Guizhou Medical University, Guiyang, Guizhou 550004, PR China; First Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang 550001, PR China.
Toxicol Lett. 2023 Apr 15;379:20-34. doi: 10.1016/j.toxlet.2023.03.003. Epub 2023 Mar 10.
Columbin (CLB) is the most abundant (>1.0%) furan-containing diterpenoid lactone in herbal medicine Tinospora sagittate (Oliv.) Gagnep. The furano-terpenoid was found to be hepatotoxic, but the exact mechanisms remain unknown. The present study demonstrated that administration of CLB at 50 mg/kg induced hepatotoxicity, DNA damage and up-regulation of PARP-1 in vivo. Exposure to CLB (10 μM) induced GSH depletion, over-production of ROS, DNA damage, up-regulation of PARP-1 and cell death in cultured mouse primary hepatocytes in vitro. Co-treatment of mouse primary hepatocytes with ketoconazole (10 μM) or glutathione ethyl ester (200 μM) attenuated the GSH depletion, over-production of ROS, DNA damage, up-regulation of PARP-1, and cell death induced by CLB, while co-exposure to L-buthionine sulfoximine (BSO, 1000 μM) intensified such adverse effects resulting from CLB exposure. These results suggest that the metabolic activation of CLB by CYP3A resulted in the depletion of GSH and increase of ROS formation. The resultant over-production of ROS subsequently disrupted the DNA integrity and up-regulated the expression of PARP-1 in response to DNA damage, and ROS-induced DNA damage was involved in the hepatotoxicity of CLB.
葫芦巴碱（CLB）是草药三叶鬼针草（Oliv.）Gagnep 中含量最丰富（>1.0%）的呋喃型二萜内酯。该呋喃型萜烯被发现具有肝毒性，但确切的机制尚不清楚。本研究表明，50mg/kg 的 CLB 给药可在体内诱导肝毒性、DNA 损伤和 PARP-1 上调。暴露于 CLB（10μM）可在体外诱导培养的小鼠原代肝细胞中 GSH 耗竭、ROS 过度产生、DNA 损伤、PARP-1 上调和细胞死亡。用酮康唑（10μM）或谷胱甘肽乙酯（200μM）共同处理小鼠原代肝细胞可减轻 CLB 引起的 GSH 耗竭、ROS 过度产生、DNA 损伤、PARP-1 上调和细胞死亡，而同时暴露于 L-丁硫氨酸亚砜亚胺（BSO，1000μM）则加剧了 CLB 暴露引起的这些不良反应。这些结果表明，CLB 通过 CYP3A 的代谢激活导致 GSH 耗竭和 ROS 形成增加。由此产生的 ROS 过度产生随后破坏 DNA 完整性并上调 DNA 损伤时的 PARP-1 表达，ROS 诱导的 DNA 损伤参与了 CLB 的肝毒性。
