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

To evaluate the hepatotoxicity risks of physcion on the basis of the bilirubin metabolism mediated by glucuronidation of UDP-glucuronosyltransferases 1A1(UGT1A1 enzyme). The monomers were added into the rat liver microsomes to test the hepatotoxicity by using bilirubin as UGT1A1 enzyme substrate, with apparent inhibition constant K_i as the evaluation index. Liver microsome incubation in vitro was adopted to initiate phase Ⅱ metabolic reaction and investigate the inhibitory effect of physcion. Then the phase Ⅰ and Ⅱ metabolic reactions were initiated to investigate the comprehensive inhibition of metabolites and prototype components. The results showed that when only the phase Ⅱ reaction was initiated, physcion directly acted on the UGT1A1 enzyme in a prototype form, exhibited weak inhibition and the inhibition type was mixed inhibition; When the phase Ⅰ and Ⅱ reactions were initiated simultaneously, the inhibitory effects of physcion on UGT1A1 enzyme became strong and the inhibition type was mixed inhibition, suggesting that physcion had phase Ⅰ and Ⅱ metabolic processes, and the metabolites had strong inhibitory effect on UGT1A1 enzyme. This experiment preliminarily proved that the metabolites of physcion may be the main components to induce hepatotoxicity.
Animals ; Chemical and Drug Induced Liver Injury ; Emodin ; analogs & derivatives ; toxicity ; Glucuronosyltransferase ; metabolism ; Kinetics ; Microsomes, Liver ; drug effects ; Rats

This project is to investigate chemical compositions from the roots of Erythrina corallodendron. Through the methods of silica gel,ODS,Sephadex LH-20 column chromatography and preparative HPLC,15 compounds were isolated from the 95% ethanol extract of the roots of E. corallodendron. Based on spectroscopic techniques,the structures of these compounds were identified as 10,11-dioxoerythraline( 1),erythrinine( 2),erythraline( 3),11-methoxyerythraline( 4),cristanines B( 5),erythratine( 6),erysotrine( 7),medioresinol( 8),( ±)-ficusesquilignan A( 9),( +)-pinoresinol( 10),nicotinic acid( 11),dibutyl phthalate( 12),vanillic acid( 13),3-hydroxy-1-( 4-hydroxy-3-methoxyphenyl)-1-propanone( 14),and syringic acid( 15). Compounds 8-10 are isolated from genus Erythrina for the first time and all compounds are isolated from E. corallodendron for the first time. Furthermore,this paper screened the antioxidant and cytotoxic activities of the compounds using models of liver microsomal oxidation inhibition and MTT.
Antioxidants ; analysis ; Chromatography, High Pressure Liquid ; Erythrina ; chemistry ; Microsomes, Liver ; drug effects ; Phytochemicals ; analysis ; Plant Extracts ; analysis ; Plant Roots ; chemistry

The purpose of this study was to investigate the effect of apigenin on UGT1 A1 enzyme activity and to predict the potential drug-drug interaction of apigenin in clinical use. First,on the basis of previous experiments,the binding targets and binding strength of apigenin to UGT1 A1 enzyme were predicted by computer molecular docking method. Then the inhibitory effect of apigenin on UGT1 A1 enzyme was evaluated by in vitro human liver microsomal incubation system. Molecular docking results showed that apigenin was docked into the active region of UGT1 A1 enzyme protein F,consistent with the active region of bilirubin docking,with moderate affinity. Apigenin flavone mother nucleus mainly interacted with amino acid residues ILE343 and VAL345 to form hydrophobic binding Pi-Alkyl. At the same time,the hydroxyl group on the mother nucleus and the amino acid residue LYS346 formed an additional hydrogen bond,which increased the binding of the molecule to the protein. These results suggested that the flavonoid mother nucleus structure had a special structure binding to the enzyme protein UGT1 A1,and the introduction of hydroxyl groups into the mother nucleus can increase the binding ability. In vitro inhibition experiments showed that apigenin had a moderate inhibitory effect on UGT1 A1 enzyme in a way of competitive inhibition,which was consistent with the results of molecular docking. The results of two experiments showed that apigenin was the substrate of UGT1 A1 enzyme,which could inhibit the activity of UGT1 A1 enzyme competitively,and there was a risk of drug interaction between apigenin and UGT1 A1 enzyme substrate in clinical use.
Apigenin/chemistry* ; Bilirubin/chemistry* ; Drug Interactions ; Glucuronosyltransferase/metabolism* ; Humans ; Hydrogen Bonding ; Microsomes, Liver/drug effects* ; Molecular Docking Simulation

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

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

Animals ; Benzhydryl Compounds ; toxicity ; Biomarkers ; analysis ; blood ; Breast Neoplasms ; chemically induced ; Drug Synergism ; Endocrine Disruptors ; toxicity ; Estrone ; metabolism ; Genistein ; adverse effects ; Hydroxyestrones ; analysis ; Male ; Microsomes, Liver ; drug effects ; metabolism ; Oxidation-Reduction ; Phenols ; toxicity ; Rats, Wistar

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

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