Organophosphorus compounds are highly toxic irreversible inhibitors of cholinesterases, causing the disruption of cholinergic functions. Treatment of poisoning includes causal antidotes (oximes) used as reactivators of inhibited cholinesterases, such as pralidoxime. In this work, new halogenated oxime reactivators derived from pralidoxime were developed. The oximes were designed with a halogen substituent that lowers the pK a and enhances oximate formation. Their synthesis, stability, physicochemical properties, inhibition of native cholinesterases, and in vitro reactivation of organophosphate-inhibited cholinesterases were investigated. A series of C4 and C6 halogenated oximes showed instability and their degradation products were identified, while C3 and C5 oximes exhibited sufficient stability for the evaluation. C3 oximes displayed overall low inhibition of cholinesterases and high reactivation ability of organophosphate-inhibited cholinesterases compared to pralidoxime, indicating the significant impact of halogen substitution on reactivation ability.

• Publikační typ
• časopisecké články MeSH

Six novel brominated bis-pyridinium oximes were designed and synthesized to increase their nucleophilicity and reactivation ability of phosphorylated acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Their pKa was valuably found lower to parent non-halogenated oximes. Stability tests showed that novel brominated oximes were stable in water, but the stability of di-brominated oximes was decreased in buffer solution and their degradation products were prepared and characterized. The reactivation screening of brominated oximes was tested on AChE and BChE inhibited by organophosphorus surrogates. Two mono-brominated oximes reactivated AChE comparably to non-halogenated analogues, which was further confirmed by reactivation kinetics. The acute toxicity of two selected brominated oximes was similar to commercially available oxime reactivators and the most promising brominated oxime was tested in vivo on sarin- and VX-poisoned rats. This brominated oxime showed interesting CNS distribution and significant reactivation effectiveness in blood. The same oxime resulted with the best protective index for VX-poisoned rats.

• Klíčová slova
• Cholinesterase, Nerve agent, Nucleophile, Organophosphate, Oxime, Reactivation,
• MeSH
• acetylcholinesterasa * metabolismus   účinky léků   MeSH
• butyrylcholinesterasa * metabolismus   MeSH
• chemické bojové látky toxicita   MeSH
• cholinesterasové inhibitory * toxicita   farmakologie   MeSH
• halogenace MeSH
• krysa rodu Rattus MeSH
• nervová bojová látka * toxicita   MeSH
• organothiofosforové sloučeniny * toxicita   MeSH
• oximy * farmakologie   chemie   MeSH
• potkani Wistar MeSH
• pyridinové sloučeniny farmakologie   MeSH
• reaktivátory cholinesterasy * farmakologie   chemie   MeSH
• sarin * toxicita   MeSH
• stabilita léku MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetylcholinesterasa * MeSH
• butyrylcholinesterasa * MeSH
• chemické bojové látky MeSH
• cholinesterasové inhibitory * MeSH
• nervová bojová látka * MeSH
• organothiofosforové sloučeniny * MeSH
• oximy * MeSH
• pyridinové sloučeniny MeSH
• reaktivátory cholinesterasy * MeSH
• sarin * MeSH
• VX MeSH Prohlížeč

The pyridinium-2-carbaldoximes with quinolinium carboxamide moiety were designed and synthesised as cholinesterase reactivators. The prepared compounds showed intermediate-to-high inhibition of both cholinesterases when compared to standard oximes. Their reactivation ability was evaluated in vitro on human recombinant acetylcholinesterase (hrAChE) and human recombinant butyrylcholinesterase (hrBChE) inhibited by nerve agent surrogates (NIMP, NEMP, and NEDPA) or paraoxon. In the reactivation screening, one compound was able to reactivate hrAChE inhibited by all used organophosphates and two novel compounds were able to reactivate NIMP/NEMP-hrBChE. The reactivation kinetics revealed compound 11 that proved to be excellent reactivator of paraoxon-hrAChE better to obidoxime and showed increased reactivation of NIMP/NEMP-hrBChE, although worse to obidoxime. The molecular interactions of studied reactivators were further identified by in silico calculations. Molecular modelling results revealed the importance of creation of the pre-reactivation complex that could lead to better reactivation of both cholinesterases together with reducing particular interactions for lower intrinsic inhibition by the oxime.

• Klíčová slova
• Organophosphate, acetylcholinesterase, butyrylcholinesterase, oxime, reactivator,
• MeSH
• acetylcholinesterasa metabolismus   MeSH
• butyrylcholinesterasa metabolismus   MeSH
• chinolinové sloučeniny chemická syntéza   chemie   farmakologie   MeSH
• cholinesterasové inhibitory chemická syntéza   chemie   farmakologie   MeSH
• lidé MeSH
• molekulární struktura MeSH
• pyridinové sloučeniny chemická syntéza   chemie   farmakologie   MeSH
• rekombinantní proteiny metabolismus   MeSH
• simulace molekulového dockingu MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetylcholinesterasa MeSH
• butyrylcholinesterasa MeSH
• chinolinové sloučeniny MeSH
• cholinesterasové inhibitory MeSH
• pyridinové sloučeniny MeSH
• rekombinantní proteiny MeSH

Organophosphorus poisoning caused by some pesticides and nerve agents is a life-threating condition that must be swiftly addressed to avoid casualties. Despite the availability of medical countermeasures, the clinically available compounds lack a broad spectrum, are not effective towards all organophosphorus toxins, and have poor pharmacokinetics properties to allow them crossing the blood-brain barrier, hampering cholinesterase reactivation at the central nervous system. In this work, we designed and synthesised novel isatin derivatives, linked to a pyridinium 4-oxime moiety by an alkyl chain with improved calculated properties, and tested their reactivation potency against paraoxon- and NEMP-inhibited acetylcholinesterase in comparison to the standard antidote pralidoxime. Our results showed that these compounds displayed comparable in vitro reactivation also pointed by the in silico studies, suggesting that they are promising compounds to tackle organophosphorus poisoning.

• Klíčová slova
• Isatin, antidotes, cholinesterase reactivators, nerve agents, organophosphorus poisoning, pyridine oximes,
• MeSH
• acetylcholinesterasa účinky léků   MeSH
• isatin farmakologie   MeSH
• počítačová simulace MeSH
• pyridiny farmakologie   MeSH
• reaktivátory cholinesterasy farmakologie   MeSH
• techniky in vitro MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetylcholinesterasa MeSH
• isatin MeSH
• pyridine MeSH Prohlížeč
• pyridiny MeSH
• reaktivátory cholinesterasy MeSH