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The Journal of Toxicological Sciences 2019A high incidence of positive results is obtained with in vitro genotoxicity tests, which do not correlate with the in vivo negative results in many cases. To address...
A high incidence of positive results is obtained with in vitro genotoxicity tests, which do not correlate with the in vivo negative results in many cases. To address this issue, the metabolic profile of rat liver 9000 × g supernatant fraction (S9) pretreated with phenobarbital (PB) and 5,6-benzoflavone (BNF) was characterized. Furthermore, the in vitro micronucleus tests of 10 compounds were performed with PB-BNF-induced rat S9. PB-BNF increased cytochrome P450 (CYP) activity and CYP1A1, CYP1A2, CYP2B1/2, CYP2C6, CYP3A1, and CYP3A2 expression in rat S9, whereas it decreased CYP2C11 and CYP2E1 expression. PB-BNF-induced S9 enhanced the micronucleus induction (MI) of benzo[a]pyrene (BaP), cyclophosphamide (CPA), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine hydrochloride (PhIP), which are metabolized by CYP1A1, CYP2C6, and CYP1A2, respectively. In contrast, coumarin and chlorpheniramine showed MI with PB-BNF-induced S9 despite the fact that they show negative results in the in vivo studies. Furthermore, diclofenac, piroxicam, lansoprazole, and caffeine showed MI regardless of the enzyme induction by PB-BNF, whereas phenacetin did not show MI. These results indicate that PB-BNF-induced rat S9 is effective in detecting the genotoxic potential of promutagens, such as BaP, CPA, and PhIP, but not of coumarin and chlorpheniramine, probably due to the differences in the in vitro and in vivo metabolic profile and its exposure levels of the drugs.
Topics: Animals; Cell Line; Cricetulus; Cytochrome P-450 Enzyme System; Liver; Male; Micronucleus Tests; Mutagens; Phenobarbital; Rats, Sprague-Dawley; beta-Naphthoflavone
PubMed: 30842367
DOI: 10.2131/jts.44.145 -
BioMed Research International 2019, a Traditional Chinese Medicine, has been widely used for the alternative and/or complementary therapy of hypertension, arrhythmias rheumatoid arthritis, sciatica,...
, a Traditional Chinese Medicine, has been widely used for the alternative and/or complementary therapy of hypertension, arrhythmias rheumatoid arthritis, sciatica, stroke, hemiplegia, paraplegia, and vascular embolism. The aim of this study was to determinate the potential effects of on the five cytochrome P450 (CYP) enzyme activities (CYP1A2, CYP3A4, CYP2C9, CYP2C19, and CYP2D6) by cocktail approach. To evaluate whether concurrent use of interferes with the effect of several prescription drugs, saline (control group) or (XTW group) were administrated via gavage for 7 successive days. A probe cocktail solution (phenacetin, omeprazole, metoprolol, tolbutamide, and midazolam) was given 24 h after the last dose of saline or . A specific and sensitive UHPLC-MS/MS method was validated for the determination of five substrates and their metabolites in control group and XTW group. Our results indicated that could have inductive effects of CYP2C19 and inhibit the activities of CYP1A2 and CYP3A4. However, had no significant influence on CYP2C9 and CYP2D6. The herb-drug interaction should require more attention by careful monitoring and appropriate drug dosing adjustments to the concurrent use of western medications which were metabolized by CYP1A2, CYP2C19, and CYP3A4 in human-, Cytochrome P450, Cocktail, Pharmacokinetics, herb-drug interactions.
Topics: Animals; Corydalis; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Drugs, Chinese Herbal; Herb-Drug Interactions; Male; Midazolam; Omeprazole; Phenacetin; Rats; Rats, Sprague-Dawley; Tolbutamide
PubMed: 30800683
DOI: 10.1155/2019/9614781 -
Forensic Science International Nov 2018Nyaope, a street drug commonly found in South Africa, is a mixture of low grade heroin, cannabis products, antiretroviral drugs and other materials added as cutting...
Nyaope, a street drug commonly found in South Africa, is a mixture of low grade heroin, cannabis products, antiretroviral drugs and other materials added as cutting agents. It is a highly physiologically addictive substance which is smoked by users. Little work has been published on the chemical analysis and profiling of nyaope. Sample preparation prior to chromatographic or spectrometric analysis normally involves dissolution of the sample in an organic solvent. This study determined the most suitable organic solvent in which the common components of nyaope, namely Δ-tetrahydrocannabinol, diamorphine, caffeine, dextromethorphan, phenacetin and the antiretrovirals efavirenz and nevirapine, which have different chemical characteristics, are stable during extraction and prior to analysis of nyaope samples i.e. autosampler stability. Street samples of cannabis (Δ-tetrahydrocannabinol), heroin (diamorphine) and antiretrovirals were mixed to mimic a nyaope sample and dissolved in the organic solvents dichloromethane, ethanol, ethyl acetate, hexane, isopropanol and tertiary butyl alcohol. Analysis was performed after intervals of 0, 1, 6, 8, 24, 48 and 72h, prior to analysis by gas chromatography-mass spectrometry. Tertiary butyl alcohol resulted in the most stable extracts of the main nyaope components after 72h of storage. The analysis was also repeated on actual street samples of nyaope. These results show that tertiary butyl alcohol is a suitable solvent for sample preparation for the identification, comparison and profiling of nyaope samples.
PubMed: 30296627
DOI: 10.1016/j.forsciint.2018.08.001 -
International Journal of Hepatology 2018Both paracetamol (PA) and phenacetin (PH) are analgesic and antipyretic agents. Part of phenacetin therapeutic activity is attributed to its metabolism into paracetamol....
Comparative Protective Effects of N-Acetylcysteine, N-Acetyl Methionine, and N-Acetyl Glucosamine against Paracetamol and Phenacetin Therapeutic Doses-Induced Hepatotoxicity in Rats.
BACKGROUND AND AIMS
Both paracetamol (PA) and phenacetin (PH) are analgesic and antipyretic agents. Part of phenacetin therapeutic activity is attributed to its metabolism into paracetamol. Paracetamol causes direct hepatic oxidative stress damage. The present study aimed to investigate the possible damaging effects of both PA and PH, when used in therapeutic doses, on rat liver and to compare the antioxidant and hepatoprotective effects of N-acetylcysteine (NAC), N-acetyl-methionine (NAM), and N-acetylglucosamine (NAG) against PA- or PH-induced hepatic damage.
METHODS
90 male Wistar albino rats (120-140 gm) were undertaken, categorized randomly into 9 groups of 10 rats each, and administered by gavage for 2 weeks with DMSO 1% (controls), PA, PA+NAC, PA+NAM, PA+NAG, PH, PH+NAC, PH+NAM, and PH+NAG. Biochemical assays of malondialdehyde (MDA), nitric oxide (NO), reduced glutathione (GSH), total thiols, and alpha-fetoprotein (AFP) in liver homogenates and serum assays of ALT, AST, 8-hydroxy guanine (8-OH-Gua), and AFP were done. Also histopathological examinations of liver tissues in various groups were done.
RESULTS
PA and PH cause significant increase in hepatic levels of MDA, NO, and AFP and serum ALT, AST, and 8-OH-Gua levels, with significant decrease in hepatic GSH and total thiols. NAG and NAC significantly improve the PA- and PH-induced hepatic and blood, biochemical, and histopathological disturbances, respectively.
CONCLUSIONS
Both PA and PH induce oxidative stress in rat liver within their therapeutic doses. NAG and NAC in pharmacological doses can antagonize the oxidative damaging effect of both PA and PH.
PubMed: 30245889
DOI: 10.1155/2018/7603437 -
Biomedicine & Pharmacotherapy =... Dec 2018Worldwide, aspirin and ibuprofen are the most commonly used non-steroidal anti-inflammatory drugs (NSAIDs). Some adverse reactions, including gastrointestinal reactions,...
Worldwide, aspirin and ibuprofen are the most commonly used non-steroidal anti-inflammatory drugs (NSAIDs). Some adverse reactions, including gastrointestinal reactions, have been concerned extensively. Nevertheless, the mechanism of liver injury remains unclear. In the present study, we focused on the metabolism of liver cytochrome P450 (CYP450) and ultrastructural morphology of liver cells. A total of thirty rats were divided into three groups of 10. Rats in the aspirin and ibuprofen groups were given enteric-coated aspirin (15 mg/kg) and ibuprofen (15 mg/kg), respectively by gavage for four weeks. The body weights were recorded every two days. Liver function and metabolic capacity of CYP450 were studied on days 14 and 28. We then conducted ultrastructural examinations. Body weights in the Ibuprofen group were lower than those of the Control group, and ALT and AST levels were significantly higher (P < 0.05). There were no significant differences in terms of body weight, ALT or AST between the Aspirin and Control groups. The metabolic capacity of CYP450 was evaluated using five probe drugs, phenacetin, tolbutamide, metoprolol, midazolam, and bupropion. We found that ibuprofen and aspirin induced metabolism of the probe drugs. Moreover, according to the pharmacokinetic data, the Control, Aspirin and Ibuprofen groups could be discriminated accurately. Ultrastructural examination showed that the number of mitochondria was increased in both the Ibuprofen and Aspirin groups. Long-term administration of enteric-coated aspirin and ibuprofen induced the metabolic activity of the CYP450 enzyme. Aspirin had better tolerability than did ibuprofen, as reflected by pharmacokinetic data of probe drug metabolism.
Topics: Animals; Aspirin; Body Weight; Cytochrome P-450 Enzyme System; Discriminant Analysis; Ibuprofen; Liver; Male; Rats, Sprague-Dawley
PubMed: 30219678
DOI: 10.1016/j.biopha.2018.08.162 -
Saudi Pharmaceutical Journal : SPJ :... Jul 2018The aim of the present study was to investigate the potential effect of thymoquinone (TQ) on the metabolic activity of four major drug metabolizing enzymes in human...
The aim of the present study was to investigate the potential effect of thymoquinone (TQ) on the metabolic activity of four major drug metabolizing enzymes in human liver microsomes, namely cytochrome P450 (CYP) 1A2, CYP2C9, CYP2D6 and CYP3A4. The inhibition of CYP enzymatic activities by TQ was evaluated by incubating typical substrates (phenacetin for CYP1A2, tolbutamide for CYP2C9, dextromethorphan for CYP2D6, and testosterone for CYP3A4) with human liver microsomes and NADPH in the absence or presence of TQ (1, 10 and 100 µM). The respective metabolite of the substrate that was formed was measured by HPLC. Results of the presented study presented that the metabolic activities of all the investigated CYP enzymes, viz. CYP1A2, CYP2C9, CYP2D6 and CYP3A4, were inhibited by TQ. At 1 µM TQ, CYP2C9 enzyme activity was maximally inhibited by 46.35%, followed by CYP2D6 (20.26%) > CYP1A2 (13.52%) > CYP3A4 (12.82%). However, at 10 µM TQ, CYP2C9 enzyme activity was maximally inhibited by 69.69%, followed by CYP3A4 (23.59%) > CYP1A2 (23.51%) > CYP2D6 (11.42%). At 100 µM TQ, CYP1A2 enzyme activity was maximally inhibited by 81.92%, followed by CYP3A4 (79.24%) > CYP2C9 (69.22%) > CYP2D6 (28.18%). The IC (mean ± SE) values for CYP1A2, CYP2C9, CYP2D6 and CYP3A4 inhibition were 26.5 ± 2.9 µM, 0.5 ± 0.4 µM, >500 µM and 25.2 ± 3.1 µM, respectively. These findings suggest that there is a high probability of drug interactions resulting from the co-administration of TQ or herbs containing TQ with drugs that are metabolized by the CYP enzymes, particularly CYP2C9.
PubMed: 29989011
DOI: 10.1016/j.jsps.2018.02.024 -
Journal of Pharmaceutical and... Sep 2018Neobavaisoflavone (NBIF), a phenolic compound isolated from Psoralea corylifolia L., possesses several significant biological properties. However, the pharmacokinetic... (Comparative Study)
Comparative Study
In vitrometabolic mapping of neobavaisoflavone in human cytochromes P450 and UDP-glucuronosyltransferase enzymes by ultra high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry.
Neobavaisoflavone (NBIF), a phenolic compound isolated from Psoralea corylifolia L., possesses several significant biological properties. However, the pharmacokinetic behaviors of NBIF have been characterized as rapid oral absorption, high clearance, and poor oral bioavailability. We found that NBIF underwent massive glucuronidation and oxidation by human liver microsomes (HLM) in this study with the intrinsic clearance (CL) values of 12.43, 10.04, 2.01, and 6.99 μL/min/mg for M2, M3, M4, and M5, respectively. Additionally, the CL values of G1 and G2 by HLM were 271.90 and 651.38 μL/min/mg, respectively, whereas their respective parameters were 59.96 and 949.01 μL/min/mg by human intestine microsomes (HIM). Reaction phenotyping results indicated that CYP1A1, 1A2, 2C8, and 2C19 were the main contributors to M4 (34.96 μL/min/mg), M3 (29.45 μL/min/mg), M3 (13.16 μL/min/mg), and M2 (63.42 μL/min/mg), respectively. UGT1A1, 1A7, 1A8, and 1A9 mainly catalyzed the formation of G1 (250.87 μL/min/mg), G2 (438.15 μL/min/mg), G1 (92.68 μL/min/mg), and G2 (1073.25 μL/min/mg), respectively. Activity correlation analysis assays showed that phenacetin-N-deacetylation was strongly correlated to M3 (r = 0.860, p = 0.003) and M4 (r = 0.775, p = 0.014) in nine individual HLMs, while significant activity correlations were detected between paclitaxel-6-hydroxylation and M2 (r = 0.675, p = 0.046) and M3 (r = 0.829, p = 0.006). There was a strong correlation between β-estradiol-3-O-glucuronide and G1 (r = 0.822, p = 0.007) and G2 (r = 0.689, p = 0.040), as well as between propofol-O-glucuronidation and G1 (r = 0.768, p = 0.016) and G2 (r = 0.860, p = 0.003). Moreover, the phase I metabolism and glucuronidation of NBIF revealed marked species differences, and mice are the best animal model for investigating the metabolism of NBIF in humans. Taken together, characterization of NBIF-related metabolic pathways involving in CYP1A1, 1A2, 2C8, 2C19, and UGT1A1, 1A7, 1A8, 1A9 are helpful for understanding the pharmacokinetic behaviors and conducting in-depth pharmacological studies.
Topics: Animals; Chromatography, High Pressure Liquid; Cytochrome P-450 Enzyme System; Enzyme Assays; Glucuronides; Glucuronosyltransferase; Haplorhini; Humans; Hydroxylation; Intestinal Mucosa; Intestines; Isoflavones; Liver; Mice; Microsomes, Liver; Oxidation-Reduction; Rabbits; Rats; Species Specificity; Tandem Mass Spectrometry
PubMed: 29933228
DOI: 10.1016/j.jpba.2018.06.022 -
Molecules (Basel, Switzerland) Jun 2018Honokiol (2-(4-hydroxy-3-prop-2-enyl-phenyl)-4-prop-2-enyl-phenol) and magnolol (4-Allyl-2-(5-allyl-2-hydroxy-phenyl)phenol) are the major active polyphenol constituents...
Honokiol (2-(4-hydroxy-3-prop-2-enyl-phenyl)-4-prop-2-enyl-phenol) and magnolol (4-Allyl-2-(5-allyl-2-hydroxy-phenyl)phenol) are the major active polyphenol constituents of (Magnoliaceae) bark, which has been widely used in traditional Chinese medicine (Houpu Tang) for the treatment of various diseases, including anxiety, stress, gastrointestinal disorders, infection, and asthma. The aim of this study was to investigate the direct effects of honokiol and magnolol on hepatic CYP1A and 2C-mediated metabolism in vitro using rat liver microsomes and in vivo using the Sprague-Dawley rat model. Honokiol and magnolol inhibited in vitro CYP1A activity (probe substrate: phenacetin) more potently than CYP2C activity (probe substrate: diclofenac): The mean IC values of honokiol for the metabolism of phenacetin and diclofenac were 8.59 μM and 44.7 μM, while those of magnolol were 19.0 μM and 47.3 μM, respectively. Notably, the systemic exposure (AUC and C) of phenacetin, but not of diclofenac, was markedly enhanced by the concurrent administration of intravenous honokiol or magnolol. The differential effects of the two phytochemicals on phenacetin and diclofenac in vivo pharmacokinetics could at least be partly attributed to their lower IC values for the inhibition of phenacetin metabolism than for diclofenac metabolism. In addition, the systemic exposure, CL, and V of honokiol and magnolol tended to be similar between the rat groups receiving phenacetin and diclofenac. These findings improve our understanding of CYP-mediated drug interactions with and its active constituents.
Topics: Administration, Intravenous; Animals; Biphenyl Compounds; Chromatography, High Pressure Liquid; Cytochrome P-450 CYP1A1; Cytochrome P-450 Enzyme System; Diclofenac; Drug Interactions; Gene Expression Regulation; Lignans; Liver; Microsomes, Liver; Molecular Structure; Phenacetin; Rats; Rats, Sprague-Dawley
PubMed: 29914211
DOI: 10.3390/molecules23061470 -
Biochemistry Research International 2018has been used to treat various cancers. Cytochrome P450, a drug metabolic enzyme, might be influenced by herbal medicine. Currently, the problem that remains is the...
has been used to treat various cancers. Cytochrome P450, a drug metabolic enzyme, might be influenced by herbal medicine. Currently, the problem that remains is the effective treatment in drug-drug interaction situation. Potential influences of were elucidated on the CYP450 activities in rats using a cocktail method. Blood samples were precipitated by acetonitrile. Quantitative determination of target test object was done by ultra-performance liquid chromatography tandem mass spectrometry detection. Influences of on the activities of five CYP450 subtypes in rats were evaluated by five specific probe drugs (phenacetin for CYP1A2, omeprazole for CYP2C19, tolbutamide for CYP2C9, metoprolol for CYP2D6, and midazolam for CYP3A4) according to the pharmacokinetic parameters changes. No statistically significant difference ( > 0.05) in pharmacokinetic behaviors can be observed in the five probe drugs. There is a potential guidance on clinical drug combination with . in compound preparation showed well security.
PubMed: 29850248
DOI: 10.1155/2018/1467143 -
International Journal of Molecular... May 2018Leucine382 of cytochrome P450 1A2 (CYP1A2) plays an important role in binding and -dealkylation of phenacetin, with the L382V mutation increasing substrate oxidation...
Leucine382 of cytochrome P450 1A2 (CYP1A2) plays an important role in binding and -dealkylation of phenacetin, with the L382V mutation increasing substrate oxidation (Huang and Szklarz, 2010, . 38:1039⁻1045). This was attributed to altered substrate binding orientation, but no direct experimental evidence had been available. Therefore, in the current studies, we employed nuclear magnetic resonance (NMR) longitudinal (T₁) relaxation measurements to investigate phenacetin binding orientations within the active site of CYP1A2 wild type (WT) and mutants. Paramagnetic relaxation time (T) for each proton of phenacetin was calculated from the T₁ value obtained from the enzymes in ferric and ferrous-CO state in the presence of phenacetin, and used to model the orientation of phenacetin in the active site. All aromatic protons of phenacetin were nearly equidistant from the heme iron (6.34⁻8.03 Å). In contrast, the distance between the proton of the ⁻OCH₂⁻ group, which is abstracted during phenacetin oxidation, and the heme iron, was much shorter in the L382V (5.93 Å) and L382V/N312L (5.96 Å) mutants compared to the N312L mutant (7.84 Å) and the wild type enzyme (6.55 Å), consistent with modeling results. These studies provide direct evidence for the molecular mechanism underlying increased oxidation of phenacetin upon the L382V mutation.
Topics: Amino Acid Substitution; Catalytic Domain; Cloning, Molecular; Cytochrome P-450 CYP1A2; Escherichia coli; Gene Expression; Genetic Vectors; Humans; Kinetics; Models, Molecular; Mutation; Oxidation-Reduction; Phenacetin; Protein Binding; Protein Conformation, alpha-Helical; Protein Conformation, beta-Strand; Protein Interaction Domains and Motifs; Recombinant Fusion Proteins; Substrate Specificity; Thermodynamics
PubMed: 29799514
DOI: 10.3390/ijms19061580