Deng Ying, Bi Hui-chang, Zhao Li-zi, Wang Xue-ding, Chen Jie, Ou Zhi-min, Ding Liang, Xu Le-jia, Guan Su, Chen Xiao, Zhou Shu-Feng, Huang Min
Institute of Clinical Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, 74 Zhongshan Road II, Guangzhou 510080, PR China.
Drug Metab Lett. 2008 Jan;2(1):60-6. doi: 10.2174/187231208783478489.
Ginkgo biloba is one of the most popular herbal medicines in the world, due to its purported pharmacological effects, including memory-enhancing, cognition-improving, and antiplatelet effects. The study aimed to investigate the activity and expression of cytochrome P450 (CYP) 3A in human and rat primary hepatocytes treated with standardized G. biloba extract (100, 500, and 2500 ng/ml) for 72 hr, and to measure the protein expression of CYP3A in human and rat primary hepatocytes treated with bilobalide (2, 10, and 50 ng/ml) and ginkgolides B (2, 10, and 50 ng/ml). The activity of CYP3A was measured by the quantification of dehydronifedipine formation using a validated tandem liquid chromatography mass spectrometry (LC/MS/MS) method. The levels of mRNA and protein of CYP3A were determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western-blotting analysis, respectively. The G. biloba extract at 100-2,500 ng/ml significantly induced the activity, protein and mRNA expression of CYP3A in a dose-dependent manner in human and rat primary hepatocytes. Bilobalide at 2-50 ng/ml significantly increased CYP3A protein expression in a dose-dependent manner in human and rat primary hepatocytes. However, ginkgolide B did not affect CYP3A protein expression in vitro. The results indicate that G. biloba extract pretreatment significantly induced the expression of CYP3A protein and mRNA and increased CYP3A activity, and there was no significant species difference between human and rat. G. biloba may cause potential interactions with substrate drugs of CYP3A. Bilobalide might play a key role in the enzyme-inducing effects of G. biloba extract. Further study is needed to identify the substances in GBE that induce CYPs in vivo, and elucidate the molecular mechanism of CYP3A induction by GBE and bilobalides.
银杏是世界上最受欢迎的草药之一，因其具有所谓的药理作用，包括增强记忆力、改善认知和抗血小板作用。该研究旨在调查用标准化银杏提取物（100、500和2500纳克/毫升）处理72小时的人及大鼠原代肝细胞中细胞色素P450（CYP）3A的活性和表达，并测量用白果内酯（2、10和50纳克/毫升）和银杏内酯B（2、10和50纳克/毫升）处理的人及大鼠原代肝细胞中CYP3A的蛋白表达。使用经过验证的串联液相色谱质谱（LC/MS/MS）方法通过定量脱氢硝苯地平的形成来测量CYP3A的活性。CYP3A的mRNA和蛋白水平分别通过逆转录聚合酶链反应（RT-PCR）和蛋白质印迹分析来测定。100 - 2500纳克/毫升的银杏提取物在人及大鼠原代肝细胞中以剂量依赖的方式显著诱导CYP3A的活性、蛋白和mRNA表达。2 - 50纳克/毫升的白果内酯在人及大鼠原代肝细胞中以剂量依赖的方式显著增加CYP3A蛋白表达。然而，银杏内酯B在体外不影响CYP3A蛋白表达。结果表明，银杏提取物预处理显著诱导了CYP3A蛋白和mRNA的表达并增加了CYP3A活性，且人和大鼠之间没有显著的物种差异。银杏可能会与CYP3A的底物药物发生潜在相互作用。白果内酯可能在银杏提取物的酶诱导作用中起关键作用。需要进一步研究以确定银杏叶提取物中在体内诱导细胞色素P450的物质，并阐明银杏叶提取物和白果内酯诱导CYP3A的分子机制。
