The bilirubin metabolism mediated by the phase Ⅱ metabolizing enzyme UGT1A1 in the liver was evaluated to study the potential hepatotoxicity risk based on investigation on the inhibitory effect of rhein and its metabolites on the UGT1A1 enzyme in Rhei Radix et Rhizoma. Firstly, in vitro liver microsomes incubation was used to initiate the phase Ⅱ metabolic reaction to investigate the inhibitory effect of rheinon UGT1A1 enzyme. Secondly, the phase Ⅰ and phase Ⅱ metabolic reactions were initiated to investigate the hepatotoxicity risk of rhein metabolites. It was found that the rhein and its phase Ⅱ metabolites had no significant inhibitory effect on UGT1A1 enzyme, but its phase Ⅰ metabolites significantly reduced UGT1A1 enzyme activity. Based on the metabolites analysis, it is speculated that the rhein phase Ⅰ metabolite rheinhydroxylate and its tautomers have certain hepatotoxicity risks, while the toxicity risk induced by the prototype and phase Ⅱ metabolites of rheinglucoside, rheinglucuronic acid and rhein sulfate is small.
Anthraquinones/toxicity* ; Chemical and Drug Induced Liver Injury ; Drugs, Chinese Herbal/toxicity* ; Glucuronosyltransferase/metabolism* ; Humans ; Liver/enzymology* ; Microsomes, Liver/drug effects* ; Rhizome

Pharmacological activities and adverse side effects of ginkgolic acids (GAs), major components in extracts from the leaves and seed coats of Ginkgo biloba L, have been intensively studied. However, there are few reports on their hepatotoxicity. In the present study, the metabolism and hepatotoxicity of GA (17 : 1), one of the most abundant components of GAs, were investigated. Kinetic analysis indicated that human and rat liver microsomes shared similar metabolic characteristics of GA (17 : 1) in phase I and II metabolisms. The drug-metabolizing enzymes involved in GA (17 : 1) metabolism were human CYP1A2, CYP3A4, UGT1A6, UGT1A9, and UGT2B15, which were confirmed with an inhibition study of human liver microsomes and recombinant enzymes. The MTT assays indicated that the cytotoxicity of GA (17 : 1) in HepG2 cells occurred in a time- and dose-dependent manner. Further investigation showed that GA (17 : 1) had less cytotoxicity in primary rat hepatocytes than in HepG2 cells and that the toxicity was enhanced through CYP1A- and CYP3A-mediated metabolism.
Animals ; Cells, Cultured ; Cytochrome P-450 CYP1A2 ; metabolism ; Cytochrome P-450 CYP3A ; metabolism ; Ginkgo biloba ; chemistry ; Glucuronosyltransferase ; metabolism ; Hepatocytes ; chemistry ; drug effects ; enzymology ; metabolism ; Humans ; Kinetics ; Liver ; chemistry ; drug effects ; enzymology ; metabolism ; Microsomes, Liver ; chemistry ; drug effects ; enzymology ; metabolism ; Plant Extracts ; chemistry ; metabolism ; toxicity ; Rats ; Rats, Sprague-Dawley ; Salicylates ; chemistry ; metabolism ; toxicity

This study was carried out to investigate the effect of oral administration of Dendrobium huoshanense on the expressions and activities of hepatic microsomal cytochrome P450s in mice, and to provide a reference for the evaluation of drug-drug interactions between D. huoshanense and clinical drugs. The C57BL/6 mice were randomly divided into blank control group, D. huoshanense low dose group (crude drug 1.25 g·kg⁻¹), D. huoshanense high dose group (crude drug 7.5 g·kg⁻¹), and phenobarbital positive control group (0.08 g·kg⁻¹). Each group was intragastrically administered with drugs for 2 weeks. The mice were sacrificed and their liver microsomes were prepared. The expressions of major subtypes of P450 enzyme were determined by Western blot and the probe drugs were used to detect the enzyme activities of P450 subtypes with protein expression changes. Western blot analysis showed that the protein expressions of CYP1A1, CYP1A2 and CYP2B in liver tissues were up-regulated in D. huoshanense-treated group. In vitro enzyme activity tests showed that there were no significant difference in metabolism of 7-ethoxyresorufin (a probe drug for CYP1A1) and bupropion (a probe drug for CYP2B) between D. huoshanense group and control group. The metabolism of phenacetin (a probe drug for CYP1A2) showed a statistical difference in rate Vmax, and it was significantly increased by approximately 20% in D. huoshanense group as compared with the blank control group, and the clearance CLint in treated group was also increased by about 32%. Therefore, oral administration of D. huoshanense had no effects on the activities of most hepatic P450 enzymes in mice, with no drug-drug interaction related to the P450 enzyme system in most clinical drugs theoretically. However, oral administration of D. huoshanense may accelerate the metabolism of CYP1A2-catalyzed drugs, which needs to be considered in clinical practice.
Animals ; Cytochrome P-450 CYP1A1 ; metabolism ; Cytochrome P-450 CYP1A2 ; metabolism ; Cytochrome P-450 Enzyme System ; metabolism ; Dendrobium ; chemistry ; Drugs, Chinese Herbal ; pharmacology ; Mice ; Mice, Inbred C57BL ; Microsomes, Liver ; drug effects ; enzymology ; Random Allocation

Ferulic acid (FA) is an active component of herbal medicines. One of the best documented activities of FA is its antioxidant property. Moreover, FA exerts antiallergic, anti-inflammatory, and hepatoprotective effects. However, the metabolic pathways of FA in humans remain unclear. To identify whether human CYP or UGT enzymes are involved in the metabolism of FA, reaction phenotyping of FA was conducted using major CYP-selective chemical inhibitors together with individual CYP and UGT Supersomes. The CYP- and/or UGT-mediated metabolism kinetics were examined simultaneously or individually. Relative activity factor and total normalized rate approaches were used to assess the relative contributions of each major human CYPs towards the FA metabolism. Incubations of FA with human liver microsomes (HLM) displayed NADPH- and UDPGA-dependent metabolism with multiple CYP and UGT isoforms involved. CYPs and UGTs contributed equally to the metabolism of FA in HLM. Although CYP1A2 and CYP3A4 appeared to be the major contributors in the CYP-mediated clearance, their contributions to the overall clearance are still minor (< 25%). As a constitute of many food and herbs, FA poses low drug-drug interaction risk when co-administrated with other herbs or conventional medicines because multiple phase I and phase II enzymes are involved in its metabolism.
Coumaric Acids ; chemistry ; metabolism ; Cytochrome P-450 Enzyme System ; chemistry ; metabolism ; Drugs, Chinese Herbal ; metabolism ; Glucuronosyltransferase ; chemistry ; metabolism ; Humans ; Kinetics ; Medicine, Chinese Traditional ; Microsomes, Liver ; chemistry ; enzymology

Isochlorogenic acid A (ICQA), which has anti-inflammatory, hepatoprotective, and antiviral properties, is commonly presented in fruits, vegetables, coffee, plant-based food products, and herbal medicines. These herbal medicines are usually used in combination with other medicines in the clinic. However, little is known about the regulatory effects of ICQA on drug-metabolizing enzymes and the herb-drug interactions. In the present study, we evaluated the inhibitory potentials of ICQA on CYP1A2, CYP2C9, CYP2C19, CYP3A4, CYP2D6, and CYP2E1 in vitro based on a cocktail approach. The P450 and UGT activities in mice treated with ICQA for a prolonged period were also determined. Our results demonstrated that ICQA exhibited a weak inhibitory effect on CYP2C9 in human liver microsomes with IC being 57.25 μmol·L and Ki being 26.77 μmol·L. In addition, ICQA inhibited UGT1A6 activity by 25%, in the mice treated with ICQA (i.p.) at 30 mg·kg for 14 d, compared with the control group. Moreover, ICQA showed no mechanism-based inhibition on CYP2C9 or UGT1A6. In conclusion, our results further confirm a safe use of ICQA in clinical practice.
Animals ; Chlorogenic Acid ; analogs & derivatives ; chemistry ; Cytochrome P-450 Enzyme Inhibitors ; chemistry ; Cytochrome P-450 Enzyme System ; chemistry ; metabolism ; Glucuronosyltransferase ; chemistry ; metabolism ; Humans ; Kinetics ; Mice ; Mice, Inbred C57BL ; Microsomes, Liver ; chemistry ; enzymology

Effect of ginsenoside total saponin (GTS) on the regulation of P450 of livers of rats after γ-ray irradiation was studied. Rats were irradiated by the ⁶⁰Coγ-ray for one-time dose of 5.5 Gy, dose rate of 117.1-119.2 cGy. The cocktail probe, qPCR and Western blot were used to detect expression of enzymatic activites, mRNA and protein of rats. Contrasted with blank group, expression of CYP1A2, 2B1, 2E1, 3A4 of irradiation group showed a up-regulated (P < 0.05). Contrasted with irradiation group, exprression of CYP1A2, 2B1, 2E1, 3A4 of GTS group showed a downward trend. GTS had negative agonistic action against expression of P450 of rats by irradiatied.
Animals ; Cytochrome P-450 Enzyme System ; genetics ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Gamma Rays ; Ginsenosides ; pharmacology ; Liver ; drug effects ; enzymology ; radiation effects ; Male ; Microsomes, Liver ; drug effects ; enzymology ; Panax ; chemistry ; Rats ; Rats, Wistar

To research the influence of Reduning injection on the activity and mRNA expression of cytochrome P450 (CYP450) system in rat liver microsomes. Rat liver microsomes were prepared after a seven-days continuous administration of Reduning injection. An HPLC-MS method was applied to determine the specific metabolites of CYP450 probe substrates in rat liver microsomal incubations. The activity of CYP450 isozymes were represented by the formation of metabolites. The Real-time quantitative polymerase chain reaction (Q-PCR) was applied to determine the mRNA expression levels of CYP450. Reduning injection significantly reduced the activity of CYP2B1, 2C12, 2C13 (P < 0.01), but did not affect CYPlA2; low dose and high dose of Reduning injection had an inhibition trend on the activity of CYP2D2, but did not statistically differ from control group; low dose of Reduning injection significantly induced the activity of CYP3A1 (P < 0.01), high dose of Reduning injection had an induce trend on the activity of CYP3A1, but did not statistically differ from control. At the mRNA level, low and high dose of Reduning injection had an induce trend on the expression of CYP1A2, 2C11, 2D1, 2E1, 3A1, but did not statistically differ from control. Reduning injection significantly induced the activity of CYP2B1. Reduning injection significantly induced the activity of CYP3A1 in mRNA expression and enzyme activity levels, which may result adverse drug reaction after being combined with macrolides antibiotics. Reduning injection significantly reduced the activity of CYP2B1, 2C12, 2C13, 2D2 in enzyme activity levels, when combined with other drugs, it should be fully taken into account of the possible drug-drug interaction in order to avoid adverse side effects.
Animals ; Cytochrome P-450 Enzyme System ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Injections ; Isoenzymes ; metabolism ; Male ; Microsomes, Liver ; drug effects ; enzymology ; Rats ; Rats, Sprague-Dawley

To investigate the effect of Jiawei Foshou San and its various combined administration on hepatic P450 enzyme activity and hepatocyte morphology in rats. Rats were orally administered with drugs for four weeks and then sacrificed to prepare liver microsomes. The liver microsomes were incubated with the cocktail method; The metabolites were determined with the rapid liquid chromatography with tandem mass spectrometry (LC-MS/MS) to investigate the hepatocyte P450 enzyme activity. In addition, the hepatic pathological changes were observed by using the hematoxylin and eosin (HE) staining. Compared with the control group, the enzyme activity of CYP1A2 and CYP3A4 in the Jiawei Foshou san group showed a significant rise (P < 0.05); the enzyme activity of CYP1A2, CYP2C9, CYP2D6, CYP2E1 and CYP3A4 in the ferulic acid + ligustrazine group and the ligustrazine + tetrahydropalmatine group showed a significant rise (P < 0.05) ; the enzyme activity of CYP1A2, CYP2D6 and CYP2E1 in the ligustrazine group showed a significant rise (P < 0.05); the enzyme activity of CYP3A4 in the ferulic acid group showed a significant reduction (P < 0.05). After the administration with various drugs, the hepatocyte morphologies in the ferulic acid group and the ligustrazine group were normal. The pathological changes were observed in the tetrahydropalmatine group, such as unclear boundary of hepatic lobules, disordered hepatic cell arrangement, blurred edge, anisokaryosis and infiltration of inflammatory cells. The ferulic acid + tetrahydropalmatine group, the ligustrazine + tetrahydropalmatine group and the Jiawei Foshou San group also showed inflammatory infiltration, but with less pathological changes, particularly the Jiawei Foshou San group. The study result shows that Jiawei Foshou San can induce the enzyme activity of CYP1A2 and CYP3A4, and ligustrazine may be the effective substance for inducing CYP1A2. Its combination with ferulic acid and ligustrazine can significantly reduce the liver toxicity of tetrahydropalmatine.
Animals ; Cytochrome P-450 Enzyme System ; metabolism ; Drugs, Chinese Herbal ; administration & dosage ; Female ; Hepatocytes ; drug effects ; enzymology ; Microsomes, Liver ; drug effects ; enzymology ; Rats ; Rats, Sprague-Dawley

Rats were continuously given different doses of water extract of Polygonum multiflorum (1, 10 g x kg(-1)) for 7 days to prepare liver microsomes. Cocktail in vitro incubation approach and Real-time quantitative PCR technology were used to observe the effect of water extract of P. multiflorum on CYP450 enzymatic activities and mRNA expressions in rat liver. Compared with the blank control group, both 1, 10 g x kg(-1) water extract of P. multiflorum treated groups showed significant inhibitions in CYP2E1 enzymatic activities and mRNA expressions (enzymatic activities of CYP2E1, P < 0.01; mRNA expression of CYP2E1, P < 0.05 in 1 g x kg(-1) group, P < 0.01 in 10 g x kg(-1) group). They revealed a significant increase in the enzymatic activity of CYP3A1 (P < 0.01), but without significant change in mRNA expressions. The 10 g x kg(-1) group showed a significant inhibition in CYP1A2 enzymatic activities and mRNA expressions in rat livers (P < 0.01).
Animals ; Cytochrome P-450 CYP1A2 ; genetics ; metabolism ; Cytochrome P-450 CYP2E1 ; genetics ; metabolism ; Cytochrome P-450 Enzyme Inhibitors ; administration & dosage ; isolation & purification ; Drugs, Chinese Herbal ; administration & dosage ; isolation & purification ; Liver ; drug effects ; enzymology ; Male ; Microsomes, Liver ; drug effects ; enzymology ; Polygonum ; chemistry ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley

Tangcao pill is commonly applied in adjuvant and even alternative therapy for patients with AIDS. However, the herb contains complex ingredients, but with unknown effect against anti-HIV drug and unknown function. Because CYP450 emzyme is the main metabolic enzymes of the drug, it is of important significance to study the regulation of CYP450 enzymes before and after the combined administration of Tangcao pill and EFV. Proteomics, due to its high throughout and high sensitivity, has been widely applied in CYP450 enzyme study. In this paper, liver microsomes were separated through differential centrifugation. Their proteins were separated through SDS-PAGE. The three protein bands that CYP450 enzymes were located were cut and identified by liquid chromatography tandem mass spectrometry. Totally 16 CYP450 isoenzymes were identified. Furthermore, in order to make a quantitative analysis on the effect of tang herb on CYP450 emzyme, the multiple reaction monitoring (MRM) technology based on MS was adopted. The CYP2C11 was selected based on the results of the mass spectrum identification of proteins. The characteristic polypeptides were obtained through searching Expasy blast database. The m/z of the fragment ions was less than 800. In the paper, the m/z of ion pairs of CYP2C11 were 711.5/232.1, 711.5/319.2, 711.5/466.2 and 711.5/595.3, and the m/z of ESAT-6 (internal standard, IS) were 735.5/215.3, 735.5/389.3, 735.5/460.3 and 735.5/524.3. The relative peak (analyte/IS) area was adopted for the relative quantitative analysis. Compared with the EFV single administration group, the EFV and Tangcao pill combined administration group showed a 1.6-fold increase in CYP2C11. The results of the paper indicated that Tangcao pill may affect drug metabolism by regulating metabolic enzymes such as CYP2C11, but the specific mechanism still unknown.
Animals ; Cytochrome P-450 Enzyme System ; chemistry ; genetics ; metabolism ; Drugs, Chinese Herbal ; administration & dosage ; Electrophoresis, Polyacrylamide Gel ; Male ; Microsomes, Liver ; chemistry ; drug effects ; enzymology ; Proteomics ; Rats ; Rats, Sprague-Dawley