Oxime reactivators of acetylcholinesterase (AChE) are used as causal antidotes for intended and unintended poisoning by organophosphate nerve agents and pesticides. Despite all efforts to develop new AChE reactivators, none of these drug candidates replaced conventional clinically used oximes. In addition to the therapeutic efficacy, determining the safety profile is crucial in preclinical drug evaluation. The exact mechanism of oxime toxicity and the structure-toxicity relationship are subjects of ongoing research, with oxidative stress proposed as a possible mechanism. In the present study, we investigated four promising bispyridinium oxime AChE reactivators, K048, K074, K075, and K203, and their ability to induce oxidative stress in vitro. Cultured human hepatoma cells were exposed to oximes at concentrations corresponding to their IC50 values determined by the MTT assay after 24 h. Their potency to generate reactive oxygen species, interfere with the thiol antioxidant system, and induce lipid peroxidation was evaluated at 1, 4, and 24 h of exposure. Reactivators without a double bond in the four-carbon linker, K048 and K074, showed a greater potential to induce oxidative stress compared with K075 and K203, which contain a double bond. Unlike oximes with a three-carbon-long linker, the number of aldoxime groups attached to the pyridinium moieties does not determine the oxidative stress induction for K048, K074, K075, and K203 oximes. In conclusion, our results emphasize that the structure of oximes plays a critical role in inducing oxidative stress, and this relationship does not correlate with their cytotoxicity expressed as the IC50 value. However, it is important to note that oxidative stress cannot be disregarded as a potential contributor to the side effects associated with oximes.
- MeSH
- Acetylcholinesterase metabolism MeSH
- Antidotes pharmacology MeSH
- Hep G2 Cells MeSH
- Cholinesterase Inhibitors toxicity MeSH
- Humans MeSH
- Organophosphates toxicity MeSH
- Oxidative Stress MeSH
- Oximes pharmacology chemistry MeSH
- Pyridinium Compounds pharmacology chemistry MeSH
- Cholinesterase Reactivators * pharmacology chemistry MeSH
- Carbon MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Oxime reactivators are causal antidotes for organophosphate intoxication. Herein, the toxicity, pharmacokinetics, and reactivation effectiveness of o-chlorinated bispyridinium oxime K870 are reported. Oxime K870 was found to have a safe profile at a dose of 30 mg/kg in rats. It exhibited rapid absorption and renal clearance similar to those of other charged oximes after intramuscular administration. Its isoxazole-pyridinium degradation product was identified in vivo. Although it showed some improvement in brain targeting, it was nevertheless rapidly effluxed from the central nervous system. Its reactivation effectiveness was evaluated in rats and mice intoxicated with sarin, tabun, VX, and paraoxon and compared with pralidoxime and asoxime. K870 was found to be less effective in reversing tabun poisoning compared to its parent unchlorinated oxime K203. However, K870 efficiently reactivated blood acetylcholinesterase for all tested organophosphates in rats. In addition, K870 significantly protected against intoxication by all tested organophosphates in mice. For these reasons, oxime K870 seems to have a broader reactivation spectrum against multiple organophosphates. It seems important to properly modulate the oximate forming properties (pKa) to obtain more versatile oxime reactivators.
- MeSH
- Acetylcholinesterase metabolism MeSH
- Antidotes MeSH
- Cholinesterase Inhibitors metabolism toxicity MeSH
- Rats MeSH
- Mice MeSH
- Organophosphates MeSH
- Oximes * MeSH
- Pyridinium Compounds toxicity MeSH
- Cholinesterase Reactivators * therapeutic use MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
The authors report on the synthesis and biological evaluation of new compounds whose structure combines tacrine and indole moieties. Tacrine-indole heterodimers were designed to inhibit cholinesterases and β-amyloid formation, and to cross the blood-brain barrier. The most potent new acetylcholinesterase inhibitors were compounds 3c and 4d (IC50 = 25 and 39 nM, respectively). Compound 3c displayed considerably higher selectivity for acetylcholinesterase relative to human plasma butyrylcholinesterase in comparison to compound 4d (selectivity index: IC50 [butyrylcholinesterase]/IC50 [acetylcholinesterase] = 3 and 0.6, respectively). Furthermore, compound 3c inhibited β-amyloid-dependent amyloid nucleation in the yeast-based prion nucleation assay and displayed no dsDNA destabilizing interactions with DNA. Compounds 3c and 4d displayed a high probability of crossing the blood-brain barrier. The results support the potential of 3c for future development as a dual-acting therapeutic agent in the prevention and/or treatment of Alzheimer's disease.
- MeSH
- Acetylcholinesterase metabolism MeSH
- Alzheimer Disease drug therapy MeSH
- Amyloid beta-Peptides metabolism MeSH
- Cholinesterase Inhibitors chemistry pharmacology MeSH
- Molecular Targeted Therapy MeSH
- Dimerization MeSH
- DNA chemistry MeSH
- Blood-Brain Barrier MeSH
- Indoles chemistry pharmacology MeSH
- Inhibitory Concentration 50 MeSH
- Humans MeSH
- Ligands MeSH
- Neuroprotective Agents chemistry pharmacology MeSH
- Drug Evaluation, Preclinical MeSH
- Molecular Dynamics Simulation MeSH
- Molecular Docking Simulation MeSH
- Tacrine chemistry pharmacology MeSH
- Protein Binding MeSH
- Structure-Activity Relationship MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Research Support, N.I.H., Extramural MeSH
A series of novel C4-C7-tethered biscoumarin derivatives (12a-e) linked through piperazine moiety was designed, synthesized, and evaluated biological/therapeutic potential. Biscoumarin 12d was found to be the most effective inhibitor of both acetylcholinesterase (AChE, IC50 = 6.30 μM) and butyrylcholinesterase (BChE, IC50 = 49 μM). Detailed molecular modelling studies compared the accommodation of ensaculin (well-established coumarin derivative tested in phase I of clinical trials) and 12d in the human recombinant AChE (hAChE) active site. The ability of novel compounds to cross the blood-brain barrier (BBB) was predicted with a positive outcome for compound 12e. The antiproliferative effects of newly synthesized biscoumarin derivatives were tested in vitro on human lung carcinoma cell line (A549) and normal colon fibroblast cell line (CCD-18Co). The effect of derivatives on cell proliferation was evaluated by MTT assay, quantification of cell numbers and viability, colony-forming assay, analysis of cell cycle distribution and mitotic activity. Intracellular localization of used derivatives in A549 cells was confirmed by confocal microscopy. Derivatives 12d and 12e showed significant antiproliferative activity in A549 cancer cells without a significant effect on normal CCD-18Co cells. The inhibition of hAChE/human recombinant BChE (hBChE), the antiproliferative activity on cancer cells, and the ability to cross the BBB suggest the high potential of biscoumarin derivatives. Beside the treatment of cancer, 12e might be applicable against disorders such as schizophrenia, and 12d could serve future development as therapeutic agents in the prevention and/or treatment of Alzheimer's disease.
- MeSH
- Enzyme Activation drug effects MeSH
- Alzheimer Disease drug therapy MeSH
- Antineoplastic Agents chemical synthesis chemistry pharmacology MeSH
- Cell Cycle drug effects MeSH
- A549 Cells MeSH
- Cholinesterase Inhibitors chemical synthesis chemistry pharmacology MeSH
- Blood-Brain Barrier drug effects metabolism MeSH
- Coumarins chemical synthesis chemistry pharmacology MeSH
- Humans MeSH
- Models, Molecular * MeSH
- Molecular Structure MeSH
- Chemistry Techniques, Synthetic * MeSH
- Cell Survival drug effects MeSH
- Dose-Response Relationship, Drug MeSH
- Structure-Activity Relationship MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Acetylcholinesterase cysteine-targeted insecticides against malaria vector Anopheles gambia and other mosquitos have already been introduced. We have applied the olefin metathesis for the preparation of cysteine-targeted insecticides in high yields. The prepared compounds with either a succinimide or maleimide moiety were evaluated on Anopheles gambiae and human acetylcholinesterase with relatively high irreversible inhibition of both enzymes but poor selectivity. The concept of cysteine binding was not proved by several methods, and poor stability was observed of the chosen most potent/selective compounds in a water/buffer environment. Thus, our findings do not support the proposed concept of cysteine-targeted selective insecticides for the prepared series of succinimide or maleimide compounds.
- Publication type
- Journal Article MeSH
S ohledem na události posledních let není riziko vojenského či teroristického zneužití vysoce toxických látek včetně zakázaných bojových otravných látek zanedbatelné. Katedra toxikologie a vojenské farmacie Fakulty vojenského zdravotnictví Univerzity obrany tudíž zavedla analytické metody a postupy úprav biologických vzorků (plasma, moč) pro stanovení identifikačních znaků (biomarkerů) vystavení nervově paralytickým látkám (sarinu, cyklosarinu, somanu, tabunu a V-látkám) a yperitu, čímž přináší do Armády České republiky schopnost potvrdit jejich zneužití vůči živé síle. Metody popsané v článku jsou založeny na průkazu metabolitů (O-alkyl methylfosfonových kyselin pro nervově paralytické látky a thiodiglykolu pro yperit) a produktů jejich reakcí s přítomnými biomolekulami (tyrosinových aduktů nervově paralytických látek a peptidových aduktů sirného yperitu) pomocí kapalinové a plynové chromatografie spojené s hmotnostní spektrometrií. Funkčnost těchto metod je ověřována a diskutována v rámci testu odborné způsobilosti pro biomedicínskou analýzu s mezinárodní účastí, který každoročně pořádá Organizace pro zákaz chemických zbraní. Katedra se těchto testů účastní od roku 2016, kdy se konal první ročník.
Taking into account the events of recent years, a risk of exposure to high toxic substances including chemical weapons is not negligible. Therefore the Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence introduced analytical and biological samples (plasma, urine) preparation methods for determination of biomarkers of exposure to nerve agent (sarin, cyclosarin, soman, tabun, VX and VR agent) and sulphur mustard. Evidence of chemical weapon use is based on detection of their metabolites (Alkyl methylphosphonic acids as metabolites of the organophosphorus nerve agents, thiodiglycol as a metabolite of sulphur mustard) and products of their reactions with biomolecules (tyrosine adducts of organophosphorus nerve agents, sulphur mustard-albumin adducts). Gas chromatography tandem mass spectrometry and liquid chromatography tandem mass spectrometry are used for determination of biomarkers. Functionality of described methods is validated and discussed participating in Biomedical proficiency test, which is organized by The Organisation for the Prohibition of Chemical Weapons every year.
In this communication, we report the synthesis and cholinesterase (ChE)/monoamine oxidase (MAO) inhibition of 19 quinolinones (QN1-19) and 13 dihydroquinolinones (DQN1-13) designed as potential multitarget small molecules (MSM) for Alzheimer's disease therapy. Contrary to our expectations, none of them showed significant human recombinant MAO inhibition, but compounds QN8, QN9, and DQN7 displayed promising human recombinant acetylcholinesterase (hrAChE) and butyrylcholinesterase (hrBuChE) inhibition. In particular, molecule QN8 was found to be a potent and quite selective non-competitive inhibitor of hrAChE (IC50 = 0.29 μM), with Ki value in nanomolar range (79 nM). Pertinent docking analysis confirmed this result, suggesting that this ligand is an interesting hit for further investigation.
- MeSH
- Acetylcholinesterase metabolism MeSH
- Alzheimer Disease drug therapy MeSH
- Quinolones pharmacology MeSH
- Cholinesterase Inhibitors pharmacology MeSH
- Inhibitory Concentration 50 MeSH
- Monoamine Oxidase Inhibitors pharmacology MeSH
- Kinetics MeSH
- Humans MeSH
- Ligands MeSH
- Magnetic Resonance Spectroscopy MeSH
- Monoamine Oxidase metabolism MeSH
- Drug Evaluation, Preclinical MeSH
- Drug Design MeSH
- Recombinant Proteins metabolism MeSH
- Molecular Docking Simulation MeSH
- Structure-Activity Relationship MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
The series of symmetrical and unsymmetrical isoquinolinium-5-carbaldoximes was designed and prepared for cholinesterase reactivation purposes. The novel compounds were evaluated for intrinsic acetylcholinesterase (AChE) or butyrylcholinesterase (BChE) inhibition, when the majority of novel compounds resulted with high inhibition of both enzymes and only weak inhibitors were selected for reactivation experiments on human AChE or BChE inhibited by sarin, VX, or paraoxon. The AChE reactivation for all used organophosphates was found negligible if compared to the reactivation ability of obidoxime. Importantly, two compounds were found to reactivate BChE inhibited by sarin or VX better to obidoxime at human attainable concentration. One compound resulted as better reactivator of NEMP (VX surrogate)-inhibited BChE than obidoxime. The in vitro results were further rationalized by molecular docking studies showing future directions on designing potent BChE reactivators.
- MeSH
- Acetylcholinesterase drug effects MeSH
- Butyrylcholinesterase drug effects MeSH
- Cholinesterase Inhibitors pharmacology MeSH
- Isoquinolines chemical synthesis chemistry pharmacology MeSH
- Humans MeSH
- Cholinesterase Reactivators pharmacology MeSH
- Molecular Docking Simulation MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
