Induction of cytochrome P450 3A by the Ginkgo biloba extract and bilobalides in human and rat primary hepatocytes.
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.
Deng
Ying
Y
Institute of Clinical Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, 74 Zhongshan Road II, Guangzhou 510080, PR China.
Bi
Hui-chang
HC
Zhao
Li-zi
LZ
Wang
Xue-ding
XD
Chen
Jie
J
Ou
Zhi-min
ZM
Ding
Liang
L
Xu
Le-jia
LJ
Guan
Su
S
Chen
Xiao
X
Zhou
Shu-Feng
SF
Huang
Min
M
D000328:Adult; D000368:Aged; D000818:Animals; D003517:Cyclopentanes / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology; D051544:Cytochrome P-450 CYP3A / Q000187:drug effects* / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D004790:Enzyme Induction / Q000187:drug effects; D005260:Female; D005663:Furans / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D020441:Ginkgo biloba / Q000737:chemistry*; D046934:Ginkgolides / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology; D022781:Hepatocytes / Q000187:drug effects / Q000201:enzymology; D006801:Humans; D007783:Lactones / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D009543:Nifedipine / Q000031:analogs & derivatives / Q000378:metabolism; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D003517:Cyclopentanes; D005663:Furans; D046934:Ginkgolides; D007783:Lactones; D010936:Plant Extracts; D012333:RNA, Messenger; C117802:dehydronifedipine; C045856:ginkgolide B; D051544:Cytochrome P-450 CYP3A; D009543:Nifedipine; C073710:bilobalide