scholarly journals In vitro inhibitory effect of obtusofolin on the activity of CYP3A4, 2C9, and 2E1

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Na Liu ◽  
Ping Chen ◽  
Xiaojun Du ◽  
Junxia Sun ◽  
Shasha Han
Keyword(s):  
Human Liver ◽  
Competitive Inhibition ◽  
Liver Microsomes ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Cytochrome P450 Enzymes ◽  
Inhibition Model ◽  
Dose Dependent

Abstract Background Obtusofolin is the major active ingredient of Catsia tora L., which possesses the activity of improving eyesight and protecting the optic nerve. Investigation on the interaction of obtusofolin with cytochrome P450 enzymes (CYP450s) could provide a reference for the clinical application of obtusofolin. Methods The effect of obtusofolin on the activity of CYP450s was investigated in the presence of 100 μM obtusofolin in pooled human liver microsomes (HLMs) and fitted with the Lineweaver–Burk plots to characterize the specific inhibition model and kinetic parameters. Results Obtusofolin was found to significantly inhibited the activity of CYP3A4, 2C9, and 2E1. In the presence of 0, 2.5, 5, 10, 25, 50, and 100 μM obtusofolin, the inhibition of these CYP450s showed a dose-dependent manner with the IC50 values of 17.1 ± 0.25, 10.8 ± 0.13, and 15.5 ± 0.16 μM, respectively. The inhibition of CYP3A4 was best fitted with the non-competitive inhibition model with the Ki value of 8.82 μM. While the inhibition of CYP2C9 and 2E1 was competitive with the Ki values of 5.54 and 7.79 μM, respectively. After incubating for 0, 5, 10, 15, and 30 min, the inhibition of CYP3A4 was revealed to be time-dependent with the KI value of 4.87 μM− 1 and the Kinact value of 0.0515 min− 1. Conclusions The in vitro inhibitory effect of obtusofolin implying the potential drug-drug interaction between obtusofolin and corresponding substrates, which needs further in vivo validations.

scholarly journals In vitro study on the effect of cornin on the activity of cytochrome P450 enzymes

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Qun Zhang ◽  
Zengqiang Qu ◽  
Yanqing Zhou ◽  
Jin Zhou ◽  
Junwei Yang ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Drug Interaction ◽  
Liver Microsomes ◽  
In Vitro Study ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Cytochrome P450 Enzymes ◽  
Drug Drug Interaction ◽  
Dose Dependent

Abstract Background Cornin is a commonly used herb in cardiology for its cardioprotective effect. The effect of herbs on the activity of cytochrome P450 enzymes (CYP450s) can induce adverse drug-drug interaction even treatment failure. Therefore, it is necessary to investigate the effect of cornin on the activity of CYP450s, which can provide more guidance for the clinical application of cornin. Methods Cornin (100 μM) was incubated with eight isoforms of CYP450s, including CYP1A2, 2A6, 3A4, 2C8, 2C9, 2C19, 2D6, and 2E1, in pooled human liver microsomes. The inhibition model and corresponding parameters were also investigated. Results Cornin exerted significant inhibitory effect on the activity of CYP3A4, 2C9, and 2E1 in a dose-dependent manner with the IC50 values of 9.20, 22.91, and 14.28 μM, respectively (p < 0.05). Cornin inhibited the activity of CYP3A4 non-competitively with the Ki value of 4.69 μM, while the inhibition of CYP2C9 and 2E1 by cornin was competitive with the Ki value of 11.31 and 6.54 μM, respectively. Additionally, the inhibition of CYP3A4 by cornin was found to be time-dependent with the KI/Kinact value of 6.40/0.055 min− 1·μM− 1. Conclusions The inhibitory effect of cornin on the activity of CYP3A4, 2C9, and 2E1 indicated the potential drug-drug interaction between cornin and drugs metabolized by these CYP450s, which needs further investigation and validation.

The effect of d,l-4-hydroxypropranolol on the thyroxine to 3,5,3'-triiodothyronine conversion in rat renal and liver microsomes

1984 ◽  
Vol 105 (2) ◽  
pp. 205-210 ◽  
Author(s):  
Preben Holme Jørgensen ◽  
lb Bo Lumholtz ◽  
Jens Faber ◽  
Carsten Kirkegaard ◽  
Kaj Siersbæk-Nielsen ◽  
...  
Keyword(s):  
Competitive Inhibition ◽  
Liver Microsomes ◽  
Parent Drug ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Beta Adrenoceptor ◽  
Adrenoceptor Agonist ◽  
Vitro Effect ◽  
Dose Dependent

Abstract. The in vitro effect of d,l-4-hydroxypropranolol, a major pharmacological active metabolite of the beta adrenoceptor blocking drug d,l-propranolol, on the thyroxine (T4) to 3,5,3'-triiodothyronine (T3) conversion has been studied using rat renal and liver microsomal fractions. The results showed, that primarily the metabolite, but also the parent drug inhibits the T3-production in a dose dependent manner. The potency, expressed as the 50% inhibition of the T3-production, was reached using 65 ± 12 (sd) μm d,l-4-OH-propranolol and 1000 ± 22 (sd) μm d,l-propranolol, respectively in both tissues. The efficacy of 4-OH-propranolol corresponded to a maximal inhibition of 86 ± 7% while it for d,l-propranolol corresponded to 58 ± 6% (P < 0.001). The beta adrenoceptor agonist isoprenaline itself did not effect the T4 to T3 conversion but considerably opposed the inhibitory effect of d,l-4-OH-propranolol but not of d,l-propranolol. The D-isomer form of propranolol, which is without beta receptor blocking activity inhibited the T3-production in the same degree as d,l-propranolol. Evaluation of the enzyme kinetic data suggested that 4-OH-propranolol caused a competitive inhibition of both T4 and DTT. It is concluded, that the metabolite d,l-4-OH-propranolol is a much more potent and efficacious inhibitor of the T4-5'-deiodination than d,l-propranolol.

Immunomodulatory activities of whey fractions in efferent prefemoral lymph of sheep

1996 ◽  
Vol 63 (2) ◽  
pp. 257-267 ◽  
Author(s):  
Chun W. Wong ◽  
Geoffrey O. Regester ◽  
Geoffrey L. Francis ◽  
Dennis L. Watson
Keyword(s):  
Immune Responses ◽  
Bovine Milk ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Milk Whey ◽  
Significant Difference ◽  
Lymphocyte Phenotypes ◽  
Dose Dependent

SummaryStudies on the immunomodulatory activities of ruminant milk and colostral whey fractions were undertaken. By comparing with boiled colostral whey in a preliminary experiment, a putative heat-labile immunostimulatory factor for antibody responses was found to be present in ovine colostral whey. Studies were then undertaken in sheep in which the efferent prefemoral lymphatic ducts were cannulated bilaterally, and immune responses in the node were measured following subcutaneous injection in the flank fold of whey protein preparations of various purities. A significant sustained decline of efferent lymphocyte output was observed following injection with autologous crude milk whey or colostral whey preparations, but no changes were observed in interferon-gamma levels in lymph plasma. Two bovine milk whey fractions (lactoperoxidase and lactoferrin) of high purity were compared in bilaterally cannulated sheep. A transient decline over the first 6 h was seen in the efferent lymphocyte output and lymph flow rate after injection of both fractions. A significant difference was seen between the two fractions in interferongamma levels in lymph at 6 h after injection. However, no significant changes in the proportion of the various efferent lymphocyte phenotypes were seen following either treatment. Whereas both fractions showed a significant inhibitory effect in a dose-dependent manner on the proliferative response of T lymphocytes, but not B lymphocytes, to mitogenic stimulation in vitro, no similar changes were seen following in vivo stimulation with these two fractions.

scholarly journals Inhibition of murine erythroid colony formation in vitro by interferon gamma and correction by interferon receptor immunoadhesin

Blood ◽  
1994 ◽  
Vol 83 (4) ◽  
pp. 911-915 ◽  
Author(s):  
RT Jr Means ◽  
SB Krantz ◽  
J Luna ◽  
SA Marsters ◽  
A Ashkenazi
Keyword(s):  
Animal Model ◽  
Interferon Gamma ◽  
Colony Formation ◽  
Interleukin 1 ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Ifn Gamma ◽  
Dose Dependent

It has been previously reported that inhibition of human erythroid colony-forming units (CFU-E) in vitro by interleukin-1 (IL-1) is an indirect effect, occurring through the production of interferon gamma (IFN gamma). IFN gamma, in turn, inhibits CFU-E colony formation directly, and its inhibitory effect can be overcome by exposure to high concentrations of erythropoietin (EPO). To develop an in vitro animal model for investigating inhibition of erythropoiesis by IFN gamma, the effects of recombinant murine (rm) IFN gamma on highly purified CFU-E from the spleens of mice infected with the anemia strain of the Friend virus (FVA) were studied. rmIFN gamma inhibited CFU-E colony formation in a dose-dependent manner. This inhibition occurred with large (> or = 8 cell) colonies only; smaller colonies were not affected. The inhibitory effect was corrected to 72% of control by high EPO concentrations of 64 U/mL. Murine CFU-E were then cultured with rmIFN gamma in the presence of a soluble murine IFN gamma receptor fused to the hinge and Fc domains of the human IgG1 heavy chain (mIFN gamma R-IgG). Inhibition of CFU-E colony formation by rmIFN gamma (100 U/mL) was corrected by mIFN gamma R-IgG in a dose-dependent manner, with an approximate IC50 of 0.05 nmol/L, and complete or near complete correction at 0.5 nmol/L. Similarly, a human IFN gamma R-IgG greatly reduced the inhibitory effect of recombinant human IFN gamma on human CFU-E. These experiments provide an in vitro animal model for studying the inhibitory effects of IFN gamma on erythropoiesis and indicate that IFN gamma R-IgG may be a useful agent for reducing the toxicity of IFN gamma in vivo.

3,3′,5′-Triiodothyronine inhibits ontogenetic development of iodothyronine-5′-deiodinase in the liver of the neonatal mouse

1988 ◽  
Vol 119 (2) ◽  
pp. 181-188 ◽  
Author(s):  
Doo Chol Han ◽  
Kanji Sato ◽  
Yuko Fujii ◽  
Minoru Ozawa ◽  
Hidehito Imamura ◽  
...  
Keyword(s):  
Single Injection ◽  
Inhibitory Effect ◽  
Antagonistic Effect ◽  
Time Dependent ◽  
Dependent Manner ◽  
Neonatal Mice ◽  
Dose Dependent Decrease ◽  
Dose Dependent

Abstract. To elucidate the effect of rT3 on iodothyronine-5′-deiodinating activity (I-5′-DA) in the liver of neonatal mice, rT3 was injected sc on the 5–8th day after birth and I-5′-DA in the liver was determined. A single injection of rT3 (0.01–1 μg/g) inhibited the ontogenetically developing I-5′-DA in a dose- and time-dependent manner. The inhibitory effect was reversible and specific for I-5′-DA. Lineweaver-Burk analysis revealed that the time- and dose-dependent decrease in the enzyme activity was due to a decrease in Vmax with no alteration in Km values (5 × 10−8 mol/l). The maximal inhibitory effect was observed at a dose of 1 μg rT3/g, whereas the inhibitory effect was diminished at greater doses (4–10 μg/g), probably owing to a contamination with T4 of the rT3 preparation administered. Furthermore, consistent with our previous in vitro findings, rT3 inhibited the I-5′-DA induced by T3 in the liver of neonatal mice. These findings suggest that rT3 inhibited I-5′-DA in the liver of neonatal mice by decreasing the amount of enzyme available to the substrate and that rT3 also elicited an antagonistic effect against T3 in the induction of I-5′-DA in vivo.

scholarly journals Inhibition of murine erythroid colony formation in vitro by interferon gamma and correction by interferon receptor immunoadhesin

Blood ◽  
1994 ◽  
Vol 83 (4) ◽  
pp. 911-915 ◽  
Author(s):  
RT Jr Means ◽  
SB Krantz ◽  
J Luna ◽  
SA Marsters ◽  
A Ashkenazi
Keyword(s):  
Animal Model ◽  
Interferon Gamma ◽  
Colony Formation ◽  
Interleukin 1 ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Ifn Gamma ◽  
Dose Dependent

Abstract It has been previously reported that inhibition of human erythroid colony-forming units (CFU-E) in vitro by interleukin-1 (IL-1) is an indirect effect, occurring through the production of interferon gamma (IFN gamma). IFN gamma, in turn, inhibits CFU-E colony formation directly, and its inhibitory effect can be overcome by exposure to high concentrations of erythropoietin (EPO). To develop an in vitro animal model for investigating inhibition of erythropoiesis by IFN gamma, the effects of recombinant murine (rm) IFN gamma on highly purified CFU-E from the spleens of mice infected with the anemia strain of the Friend virus (FVA) were studied. rmIFN gamma inhibited CFU-E colony formation in a dose-dependent manner. This inhibition occurred with large (> or = 8 cell) colonies only; smaller colonies were not affected. The inhibitory effect was corrected to 72% of control by high EPO concentrations of 64 U/mL. Murine CFU-E were then cultured with rmIFN gamma in the presence of a soluble murine IFN gamma receptor fused to the hinge and Fc domains of the human IgG1 heavy chain (mIFN gamma R-IgG). Inhibition of CFU-E colony formation by rmIFN gamma (100 U/mL) was corrected by mIFN gamma R-IgG in a dose-dependent manner, with an approximate IC50 of 0.05 nmol/L, and complete or near complete correction at 0.5 nmol/L. Similarly, a human IFN gamma R-IgG greatly reduced the inhibitory effect of recombinant human IFN gamma on human CFU-E. These experiments provide an in vitro animal model for studying the inhibitory effects of IFN gamma on erythropoiesis and indicate that IFN gamma R-IgG may be a useful agent for reducing the toxicity of IFN gamma in vivo.

scholarly journals Effects of DU-6859a, a New Quinolone Antimicrobial, on Theophylline Metabolism in In Vitro and In Vivo Studies

1998 ◽  
Vol 42 (7) ◽  
pp. 1751-1755 ◽  
Author(s):  
Yoshihito Niki ◽  
Kenichi Itokawa ◽  
Osamu Okazaki
Keyword(s):  
Healthy Subjects ◽  
Human Liver ◽  
Liver Microsomes ◽  
Urinary Metabolites ◽  
Inhibitory Effect ◽  
In Vivo Studies ◽  
Metabolite Formation ◽  
Theophylline Metabolism

ABSTRACT In vitro and in vivo studies were conducted to investigate the drug interaction between a new quinolone antimicrobial, DU-6859a, and theophylline (TP). The effect of DU-6859a on TP metabolism was evaluated in vitro by measuring the rate of TP metabolite formation by using human liver microsomes. DU-6859a inhibited the metabolism of TP, especially the formation of 1-methylxanthine, in vitro, but to a lesser extent than other drugs that are known to interact with TP. TP was administered alone (200 mg twice a day [b.i.d.] for 9 days) or in combination with DU-6859a (50 or 100 mg b.i.d. for 5 days) to six healthy subjects. DU-6859a administered at a dose of 50 mg resulted in no changes in serum TP concentrations, and slight increases in serum TP concentrations were observed at a dose of 100 mg. Moreover, the administration of 100 mg of DU-6859a resulted in decreases in all urinary TP metabolites, with significant differences. It appears that although DU-6859a has a weak inhibitory effect on TP metabolism in vitro, its concomitant use with TP at clinical dosage levels does not cause any adverse effects, showing only a slight increase in blood TP concentrations and a decrease in urinary metabolites.

scholarly journals Effects of thia-substituted fatty acids on mitochondrial and peroxisomal β-oxidation. Studies in vivo and in vitro

1990 ◽  
Vol 270 (1) ◽  
pp. 167-173 ◽  
Author(s):  
R Hovik ◽  
H Osmundsen ◽  
R Berge ◽  
A Aarsland ◽  
S Bergseth ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Competitive Inhibition ◽  
Inhibitory Effect ◽  
Inhibitory Effects ◽  
Duration Of Treatment ◽  
Acyl Coa Oxidase ◽  
Dose Dependent

1. The effects of 3-, 4- and 5-thia-substituted fatty acids on mitochondrial and peroxisomal β-oxidation have been investigated. When the sulphur atom is in the 4-position, the resulting thia-substituted fatty acid becomes a powerful inhibitor of β-oxidation. 2. This inhibition cannot be explained in terms of simple competitive inhibition, a phenomenon which characterizes the inhibitory effects of 3- and 5-thia-substituted fatty acids. The inhibitory sites for 4-thia-substituted fatty acids are most likely to be the acyl-CoA dehydrogenase in mitochondria and the acyl-CoA oxidase in peroxisomes. 3. The inhibitory effect of 4-thia-substituted fatty acids is expressed both in vitro and in vivo. The effect in vitro is instantaneous, with up to 95% inhibition of palmitoylcarnitine oxidation. The effect in vivo, in contrast, is dose-dependent and increases with duration of treatment. 4. Pretreatment of rats with a 3-thia-substituted fatty acid rendered mitochondrial β-oxidation less sensitive to inhibition by 4-thia-substituted fatty acids.

Probenecid Inhibits Platelet Responses to Aggregating Agents in Vitro and Has a Synergistic Inhibitory Effect with Penicillin G

1996 ◽  
Vol 76 (02) ◽  
pp. 239-244 ◽  
Author(s):  
M A Packham ◽  
M L Rand ◽  
D W Perry ◽  
D H Ruben ◽  
R L Kinlough-Rathbone
Keyword(s):  
Platelet Activating Factor ◽  
Anion Channel ◽  
Inhibitory Effect ◽  
Penicillin G ◽  
Dependent Manner ◽  
Fura 2 ◽  
Synergistic Inhibitory Effect ◽  
Dose Dependent

SummaryProbenecid is an anion channel blocker and uricosuric agent, originally developed to slow the rate of excretion of penicillin. It is now also administered with many other drugs to reduce their required dosages. Recently, probenecid (2.5 mM) has been used to prevent leakage of fura-2 or fluo-3 when these indicators of cytosolic Ca2+ levels have been introduced into cells. However, we found that probenecid markedly inhibited the increases in cytosolic Ca2+ caused by ADP, thrombin, the thrombin receptor-activating peptide (SFLLRN, TRAP), ADP, sodium arachidonate, the thromboxane A2 (TXA2) mimetic U46619, and platelet-activating factor (PAF). This finding precluded the use of probenecid with platelets in measurements of cytosolic Ca2+ with indicators such as fura-2. We then investigated the effects of probenecid on aggregation and release of 14C-serotonin from prelabeled platelets. Responses to all the agonists were inhibited by 2.5 mM probenecid, but concentrations as low as 0.25-0.5 mM inhibited responses to agonists that act largely via TXA2 (collagen, sodium arachidonate and U46619). Collagen-induced TXA2 formation was inhibited in a dose-dependent manner. Responses of aspirin-pretreated platelets to thrombin, SFLLRN, U46619 and PAF were also inhibited by probenecid, indicating that prevention of TXA2 formation does not account for all the inhibitory effects. The combination of probenecid with penicillin G produced additive or synergistic inhibition of platelet responses; responses dependent on TXA2 were synergistically inhibited by concentrations of the drugs that are reached in vivo. The synergistic inhibitory effect of probenecid on platelet functions could further impair hemostasis if it has already been partially compromised by the administration of other drugs.

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