ABSTRACT
Objective To study the inhibitory effects ofisorhamnetin on six kinds of CYPs of liver in vitro,and the toxic effect on rat hepatocytes Methods This report uses warm incubation of human liver microsomes in vitro to investigate the inhibition of isorhamnetin on 6 kinds of CYPs (CYP2C19,CYP2D6,CYP3A4,CYP2E1,CYP1A2 and CYP2C9),and using HPLC-MS/MS to detect product of metabolism as well as analysing of the pathways of metabolic.At the same time,using rat primary hepatocytes which has low CYPs activity in vitro to explore whether the use of isorhamnetin will cause effects on the ALT,AST and LDH of hepatocytes.Results Isorhamnetin has inhibition effects on CYP2E1 and CYP1A2,the inhibition rate were 59.48％ and 39.91％,respectively.Methylated metabolite is produced after incubating of isorhamnetin and HLMs.The isorhmnetin becomes high polarity and water solubility metabolite 3,3',4',5,7-hydroxyflavone.Isorhamnetin of 30,100 and 300 μmol/L cause a significant rise of ALT and LDH in primary cultured rat hepatocytes cultured (P ＜ 0.01).isorharnnetin of 100 μmol/L cause a rise of AST in primary cultured rat hepatocytes cultured (P ＜ 0.05) and 300 μmol/L cause a significant rise (P ＜ 0.01).It was a dose-dependent manner.Conclusion Isorhamnetin in vitro mainly metabolized by HLMs,and at the same time have a certain inhibitory effect on CYP2E1 and CYP1A2,which may cause the drugs which are metabolized by CYP2E1 and CYP1A2 in vivo accumulation that lead to a series of drug interactions.The results also indicate that heavy use of isorhamnetin cause some adverse effects on hepatocytes,and it was a dose-dependent manner.Individuals need to pay attention to the dose ofisorhamnetin and the potential drug interactions.
ABSTRACT
Aim Toinvestigatingtheinductionof CYPs in hepatocytes or HepG2 cells by triptolide(TP) andthepossiblemechanism.Methods AfterTPtreat-ment,the expression of CYPs in rat primary hepato-cytes or human HepG2 cells was detected by real-time PCR and Western blot assays.Specific inhibitors or gene knockdown method were employed to analyze the possiblemechanism.Results Theexpressionof CYP1A2,2C7,2C11,2C12,2D2,2E1 and 3A1 in rat primary hepatocytes was induced by TP.The fold was 19,2,31,3,21,88 and 34 at 50 nmol·L-1, respectively while at 100 nmol·L-1 it was 20,5,30,23,61,83 and 38,respectively.In HepG2 cells,the expression of human CYP1A1,2B6,2C9,2C19, 2D6,2E1 and 3A4 was also induced by TP.The ac-tivities of nuclear receptor PXR and CAR were inhibi-ted.TP upregulated p53 expression,and the induction of several CYPs caused by TP was blocked when p53 wasinhibited.Conclusions TPinducesCYPsexpres-sion in rat hepatocytes and HepG2 cells.Nuclear re-ceptors may not be involved in TP induced CYPs, while the mechanism may partly attribute to p53.