scholarly journals Synthesis, in Vitro Covalent Binding Evaluation, and Metabolism of14C-Labeled Inhibitors of 11β-HSD1

2014 ◽  
Vol 5 (11) ◽  
pp. 1245-1250 ◽  
Author(s):  
Daqing Sun ◽  
Qiuping Ye ◽  
Xuelei Yan ◽  
Yosup Rew ◽  
Peter Fan ◽  
...  
Keyword(s):  
Covalent Binding

Novel Iodinated Hydrazide-hydrazones and their Analogues as Acetyl- and Butyrylcholinesterase Inhibitors

2020 ◽  
Vol 20 (23) ◽  
pp. 2106-2117
Author(s):  
Martin Krátký ◽  
Šárka Štěpánková ◽  
Michaela Brablíková ◽  
Katarína Svrčková ◽  
Markéta Švarcová ◽  
...  
Keyword(s):  
Biological Activities ◽  
Structural Parameters ◽  
Covalent Binding ◽  
Docking Studies ◽  
Potent Inhibition ◽  
Brain Barrier Permeability ◽  
Electric Eel ◽  
Ic50 Values ◽  
Ellman’S Method

Background: Hydrazide-hydrazones have been known as scaffold with various biological activities including inhibition of acetyl- (AChE) and butyrylcholinesterase (BuChE). Cholinesterase inhibitors are mainstays of dementias’ treatment. Objective: Twenty-five iodinated hydrazide-hydrazones and their analogues were designed as potential central AChE and BuChE inhibitors. Methods: Hydrazide-hydrazones were synthesized from 4-substituted benzohydrazides and 2-/4- hydroxy-3,5-diiodobenzaldehydes. The compounds were investigated in vitro for their potency to inhibit AChE from electric eel and BuChE from equine serum using Ellman’s method. We calculated also physicochemical and structural parameters for CNS delivery. Results: The derivatives exhibited a moderate dual inhibition with IC50 values ranging from 15.1-140.5 and 35.5 to 170.5 μmol.L-1 for AChE and BuChE, respectively. Generally, the compounds produced a balanced or more potent inhibition of AChE. N'-[(E)-(4-Hydroxy-3,5-diiodophenyl)methylidene]-4- nitrobenzohydrazide 2k and 4-fluoro-N'-(2-hydroxy-3,5-diiodobenzyl)benzohydrazide 3a were the most potent inhibitors of AChE and BuChE, respectively. Structure-activity relationships were established, and molecular docking studies confirmed interaction with enzymes. Conclusion: Many novel hydrazide-hydrazones showed lower IC50 values than rivastigmine against AChE and some of them were comparable for BuChE to this drug used for the treatment of dementia. They interact with cholinesterases via non-covalent binding into the active site. Based on the BOILEDEgg approach, the majority of the derivatives met the criteria for blood-brain-barrier permeability.

Role of Phase II Enzymes in the Bioactivation of 1,4-Dichlorobenzene and 1,4-Dibromobenzene

1996 ◽  
Vol 24 (4) ◽  
pp. 603-608
Author(s):  
Moreno Paolini ◽  
Laura Pozzetti ◽  
Renata Mesirca ◽  
Andrea Sapone ◽  
Paola Silingardi ◽  
...  
Keyword(s):  
Dna Binding ◽  
Phase I ◽  
Phase Ii ◽  
Covalent Binding ◽  
Fold Increase ◽  
Test System ◽  
Oxidative Enzymes ◽  
Transferase Activity ◽  
Genetic Toxicology

The use of sodium phenobarbital (PB, CYP2B1 inducer) combined with β-naphthoflavone (β-NF, 1A1) to induce certain Phase I reactions in S9 liver fractions is a standard method for conducting short-term bioassays for genotoxicity. However, because post-oxidative enzymes are also able to activate many precarcinogens, we tested the possibility of adapting S9 liver fractions derived from Phase II-induced rodents to the field of genetic toxicology. In this study, S9 liver fractions derived from Swiss albino CD1 mice fed 7.5g/kg 2-(3)-tert-butyl-4-hydroxyanisole (BHA; a monofunctional Phase II-inducer) for 3 weeks, show a clear pattern of induction with an approximately 3.5–9.5-fold increase in glutathione S-transferase activity. In vitro DNA binding of the promutagenic agents, [14C]-l,4-dichlorobenzene (DCB) and [14C]-1,4-dibromobenzene (DBB), is mediated by such metabolic liver preparations and showed a significant increase in covalent binding capability. In some instances, enzyme activity was more elevated when compared to that obtained with traditional (Phase I-induced) S9. Together with DNA binding, the genetic response of these chemicals in the diploid D7 strain of Saccharomyces cerevisiae used as a biological test system, revealed the ability of the BHA-derived preparations to activate the promutagenic agents, as exemplified by the significant enhancement of mitotic gene-conversion (up to 5.2-fold for DCB and 3.4-fold for DBB) and reverse point mutation (up to 3.6-fold for DCB and 2.5-fold for DBB) at a 4mM concentration. This novel metabolising biosystem, with enhanced Phase II activity, is recommended together with a traditional S9, for detecting unknown promutagens in genotoxicity studies. The routine use of either oxidative or post-oxidative S9 increases the responsiveness of the test and can contribute to the identification of promutagens not detected when using traditional protocols.

scholarly journals Investigating the Mechanism of Trimethoprim-Induced Skin Rash and Liver Injury

2021 ◽  
Author(s):  
Yanshan Cao ◽  
Ahsan Bairam ◽  
Alison Jee ◽  
Ming Liu ◽  
Jack Uetrecht
Keyword(s):  
Liver Injury ◽  
Skin Rash ◽  
Covalent Binding ◽  
Reactive Metabolites ◽  
Important Data ◽  
Drug Induced ◽  
Interindividual Differences ◽  
Immune Mediated ◽  
Sulfate Conjugate

Abstract Trimethoprim (TMP)-induced skin rash and liver injury are likely to involve the formation of reactive metabolites. Analogous to nevirapine-induced skin rash, one possible reactive metabolite is the sulfate conjugate of α-hydroxyTMP, a metabolite of TMP. We synthesized this sulfate and found that it reacts with proteins in vitro. We produced a TMP-antiserum and found covalent binding of TMP in the liver of TMP-treated rats. However, we found that α-hydroxyTMP is not a substrate for human sulfotransferases, and we did not detect covalent binding in the skin of TMP-treated rats. Although less reactive than the sulfate, α-hydroxyTMP was found to covalently bind to liver and skin proteins in vitro. Even though there was covalent binding to liver proteins, TMP did not cause liver injury in rats or in our impaired immune tolerance mouse model that has been able to unmask the ability of other drugs to cause immune-mediated liver injury. This is likely because there was much less covalent binding of TMP in the livers of TMP-treated mice than TMP-treated rats. It is possible that some patients have a sulfotransferase that can produce the reactive benzylic sulfate; however, α-hydroxyTMP, itself, has sufficient reactivity to covalently bind to proteins in the skin and may be responsible for TMP-induced skin rash. Interspecies and interindividual differences in TMP metabolism may be one factor that determines the risk of TMP-induced skin rash. This study provides important data required to understand the mechanism of TMP-induced skin rash and drug-induced skin rash in general.

Chloroethyl urea derivatives block tumour growth and thioredoxin-1 nuclear translocation

2010 ◽  
Vol 88 (11) ◽  
pp. 1102-1114 ◽  
Author(s):  
Alexandre Patenaude ◽  
Jessica S. Fortin ◽  
Réna Deschenes ◽  
Marie-France Côté ◽  
Jacques Lacroix ◽  
...  
Keyword(s):  
Anticancer Activity ◽  
Nuclear Translocation ◽  
Human Cancer ◽  
Alkylating Agents ◽  
Covalent Binding ◽  
Intracellular Localization ◽  
Site Directed Mutagenesis ◽  
Loss Of Function ◽  
Thioredoxin 1

Aryl chloroethyl ureas (CEUs) are new protein alkylating agents exhibiting anticancer activity both in vitro and in vivo. We report herein that 14C-labeled CEU derivatives, designated CEU-025 and CEU-027, covalently bind to thioredoxin-1 (TRX1). Covalent binding of these molecules slightly decreases the disulfide-reducing activity of recombinant TRX1, when compared with the effect of strong thioalkylating agents such as N-ethylmaleimide. Moreover, site-directed mutagenesis and diamide competition assays demonstrated that TRX1 cysteinyl residues are not the prime targets of CEUs. CEU-025 abrogates the nuclear translocation of TRX1 in human cancer cells. In addition, we show that CEU-025 can block TRX1 nuclear translocation induced by cisplatin. Unexpectedly, pretreatment with sublethal CEU-025 concentrations that block TRX1 nuclear translocation protected the cells against cisplatin cytotoxicity. Overexpression of TRX1 in HT1080 fibrosarcoma cells attenuated CEU-025 cytotoxicity, while its suppression using TRX1-specific siRNA increased the effects of CEU-025, suggesting that loss of function of TRX1 is involved, at least in part, in the cytotoxic activity of CEU-025. These results suggest that CEU-025 and CEU-027 exhibit anticancer activity through a novel, unique mechanism of action. The importance of TRX1 and the dependence of the cytotoxicity of CEU-025 and CEU-027 on TRX1 intracellular localization are also discussed.

COVALENT BINDING OF STYRENE OXIDE TO RAT LIVER MACROMOLECULES IN VIVO AND IN VITRO

1977 ◽  
pp. 698-702 ◽  
Author(s):  
Jukka Marniemi ◽  
Else-Maj Suolinna ◽  
Niilo Kaartinen ◽  
Harri Vainio
Keyword(s):  
Rat Liver ◽  
Styrene Oxide ◽  
Covalent Binding
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