Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.277
Filtrar
1.
Molecules ; 27(3)2022 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-35164361

RESUMO

A family of novel efficient non-oxime compounds exhibited promising reactivation efficacy for VX and sarin inhibited human acetylcholinesterase was discovered. It was found that aromatic groups coupled to Mannich phenols and the introduction of imidazole to the ortho position of phenols would dramatically enhance reactivation efficiency. Moreover, the in vivo experiment was conducted, and the results demonstrated that Mannich phenol L10R1 (30 mg/kg, ip) could afford 100% 48 h survival for mice of 2*LD50 sarin exposure, which is promising for the development of non-oxime reactivators with central efficiency.


Assuntos
Acetilcolinesterase/metabolismo , Antídotos/farmacologia , Reativadores da Colinesterase/farmacologia , Síndromes Neurotóxicas/tratamento farmacológico , Compostos de Piridínio/farmacologia , Sarina/toxicidade , Animais , Substâncias para a Guerra Química/toxicidade , Humanos , Camundongos , Síndromes Neurotóxicas/etiologia , Síndromes Neurotóxicas/patologia , Oximas
2.
Med Chem ; 18(2): 273-287, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-33563155

RESUMO

AIM: To synthesize and evaluate the fused heterocyclic imidazo[1,2-a]pyridine based oxime as a reactivator against paraoxon inhibited acetylcholinesterase. BACKGROUND: Organophosphorus compounds (OPs) include parathion, malathion, chlorpyrifos, monocrotophos, and diazinon, which are commonly used in agriculture for enhancing agricultural productivity via killing crop-damaging pests. However, people may get exposed to OPs pesticides unintentionally/intentionally via ingestion, inhalation, or dermal. The current treatment regimen includes reactivator such as mono or bis-pyridinium oximes along with anticholinergic and anticonvulsant drugs that are recommended for the treatment of OP poisoning. Unfortunately, the drawback of the existing reactivator is the permanent charge present on the pyridinium, making them inefficient to cross the blood-brain barrier (BBB) and reactivate OP-inhibited central nervous system (CNS) acetylcholinesterase. Therefore, there is a need of a reactivator that could cross the BBB and reactivate the OP inhibited acetylcholinesterase. OBJECTIVE: The objectives of the study were synthesis, molecular docking, BSA binding, and in-vitro estimation of oximes of various substituted imidazo [1,2-a]pyridine against paraoxon inhibited acetylcholinesterase. METHODS: The reactivators were synthesized in three steps and characterized using various spectroscopic techniques. The molecular docking study was performed on 2WHP and 3ZLV PDB using the Glide-XP software. The acid dissociation constant (pKa) of oximes was calculated experimentally, and the drug-likeness properties of the oximes were calculated in silico using Molinspiration and Swiss ADME software. The binding of oximes with bovine serum albumin (BSA) was also investigated using a Fluorescence spectrophotometer. The reactivation potential of the oximes was determined by in vitro enzymatic assay. RESULTS: The In-silico study inferred that the synthesized molecules fulfilled the parameters required for a successful CNS drug candidate. Furthermore, in-vitro enzymatic assay indicated reasonable reactivation potential of the oximes against paraoxon-inhibited AChE. The binding of oximes with bovine serum albumin (BSA) revealed that there was a static quenching of intrinsic fluorescence of BSA by the oxime. The binding constant value and number of binding sites were found to be 0.24 x 104 mol-1 and 1, respectively. CONCLUSION: The results of the study concluded that this scaffold could be used for further designing of more efficient uncharged reactivators.


Assuntos
Acetilcolinesterase , Reativadores da Colinesterase , Reativadores da Colinesterase/farmacologia , Humanos , Imidazóis , Simulação de Acoplamento Molecular , Oximas/farmacologia , Paraoxon/toxicidade , Piridinas , Soroalbumina Bovina
3.
Acta Medica (Hradec Kralove) ; 64(3): 145-152, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34779379

RESUMO

AIM: The comparison of neuroprotective and central reactivating effects of the oxime K870 in combination with atropine with the efficacy of standard antidotal treatment in tabun-poisoned rats. METHODS: The neuroprotective effects of antidotal treatment were determined in rats poisoned with tabun at a sublethal dose using a functional observational battery 2 h and 24 h after tabun administration, the tabun-induced brain damage was investigated by the histopathological evaluation and central reactivating effects of oximes was evaluated by the determination of acetylcholinesterase activity in the brain using a standard spectrophotometric method. RESULTS: The central reactivating efficacy of a newly developed oxime K870 roughly corresponds to the central reactivating efficacy of pralidoxime while the ability of the oxime HI-6 to reactivate tabun-inhibited acetylcholinesterase in the brain was negligible. The ability of the oxime K870 to decrease tabun-induced acute neurotoxicity was slightly higher than that of pralidoxime and similar to the oxime HI-6. These results roughly correspond to the histopathological evaluation of tabun-induced brain damage. CONCLUSION: The newly synthesized oxime K870 is not a suitable replacement for commonly used oximes in the antidotal treatment of acute tabun poisonings because its neuroprotective efficacy is only slightly higher or similar compared to studied currently used oximes.


Assuntos
Substâncias para a Guerra Química , Reativadores da Colinesterase , Organofosfatos , Oximas , Venenos , Compostos de Piridínio , Acetilcolinesterase , Animais , Antídotos/farmacologia , Substâncias para a Guerra Química/toxicidade , Inibidores da Colinesterase/farmacologia , Reativadores da Colinesterase/farmacologia , Oximas/farmacologia , Compostos de Pralidoxima , Compostos de Piridínio/farmacologia , Ratos , Ratos Wistar
4.
ACS Chem Neurosci ; 12(15): 2865-2877, 2021 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-34284583

RESUMO

Organophosphorus (OP) cholinesterase inhibitors, which include insecticides and chemical warfare nerve agents, are very potent neurotoxicants. Given that the actual treatment has several limitations, the present study provides a general method, called the zebrafish-OP-antidote test (ZOAT), and basic scientific data, to identify new antidotes that are more effective than the reference pyridinium oximes after acute OP poisoning. The reactivation capacity of a chemical compound can be measured using in vivo and ex vivo acetylcholinesterase (AChE) assays. We demonstrated that it is possible to differentiate between chemical compound protective efficacies in the central and peripheral nervous system via the visual motor response and electric field pulse motor response tests, respectively. Moreover, the ability to cross the brain-blood barrier can be estimated in a physiological context by combining an AChE assay on the head and trunk-tail fractions and the cellular and tissue localization of AChE activity in the whole-mount animal. ZOAT is an innovative method suitable for the screening and rapid identification of chemicals and mixtures used as antidote for OP poisoning. The method will make it easier to identify more effective medical countermeasures for chemical threat agents, including combinatorial therapies.


Assuntos
Reativadores da Colinesterase , Intoxicação por Organofosfatos , Acetilcolinesterase , Animais , Antídotos/farmacologia , Inibidores da Colinesterase/farmacologia , Reativadores da Colinesterase/farmacologia , Larva , Intoxicação por Organofosfatos/tratamento farmacológico , Oximas , Peixe-Zebra
5.
J Enzyme Inhib Med Chem ; 36(1): 1370-1377, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34148470

RESUMO

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.


Assuntos
Acetilcolinesterase/efeitos dos fármacos , Reativadores da Colinesterase/farmacologia , Isatina/farmacologia , Piridinas/farmacologia , Simulação por Computador , Técnicas In Vitro
6.
Mol Pharm ; 18(6): 2416-2427, 2021 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-34019427

RESUMO

Oxime-based molecules are used for the treatment of patients to reactivate acetylcholinesterase (AChE) function after organophosphate intoxication. However, their efficacy is limited by low penetration through the blood-brain barrier and fast elimination. In this work, the cucurbit[7]uril (CB[7]) carrier was used for the encapsulation of the clinical agent asoxime to enhance brain bioavailability and the treatment window. We present a pharmacokinetic study of asoxime and the asoxime-CB[7] complex in an in vivo mouse model. Ultrahigh-performance liquid chromatography with electrospray ionization-mass spectrometry detection was developed to determine asoxime and CB[7] in biological fluids and tissues after thorough optimization of chromatographic conditions. The dihydroxypropane-silica stationary phase using hydrophilic interaction liquid chromatography conditions provided the best chromatographic performance. The final method was validated and applied for the pharmacokinetic study of mouse plasma, urine, bile, liver, kidney, and brain samples at different times after administration of asoxime and the asoxime-CB[7] complex. The results showed a greater than 3-fold increase in the area under the curve (AUC) in the brain for asoxime administered as a complex with CB[7] relative to that for the administration of asoxime alone. The effectiveness of the treatment strategy was evaluated using a reactivation study and a functional observatory battery. Protection of brain AChE activity is crucial for saving human lives or reducing the consequences of poisoning. The asoxime administered as a complex increased the brain activity by approximately 30% compared to that with atropine alone. CB[7] coadministration improved the AChE activity by 11%, which agrees with the higher asoxime AUC assessed in the pharmacokinetic study.


Assuntos
Hidrocarbonetos Aromáticos com Pontes/química , Reativadores da Colinesterase/administração & dosagem , Portadores de Fármacos/química , Imidazóis/química , Intoxicação por Organofosfatos/tratamento farmacológico , Oximas/farmacocinética , Compostos de Piridínio/farmacocinética , Acetilcolinesterase/metabolismo , Animais , Área Sob a Curva , Barreira Hematoencefálica/metabolismo , Inibidores da Colinesterase/administração & dosagem , Inibidores da Colinesterase/toxicidade , Reativadores da Colinesterase/farmacocinética , Cromatografia Líquida de Alta Pressão , Modelos Animais de Doenças , Ensaios Enzimáticos , Humanos , Interações Hidrofóbicas e Hidrofílicas , Espectrometria de Massas , Camundongos , Oximas/administração & dosagem , Compostos de Piridínio/administração & dosagem , Sarina/administração & dosagem , Sarina/toxicidade
7.
PLoS One ; 16(4): e0249794, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33822820

RESUMO

Several studies have suggested that sympathetic overstimulation causes deleterious effects in septic shock. A previous study suggested that pralidoxime exerted a pressor effect through a mechanism unrelated to the sympathetic nervous system; this effect was buffered by the vasodepressor action of pralidoxime mediated through sympathoinhibition. In this study, we explored the effects of pralidoxime on hemodynamics and survival in rats with peritonitis-induced sepsis. This study consisted of two sub-studies: survival and hemodynamic studies. In the survival study, 66 rats, which survived for 10 hours after cecal ligation and puncture (CLP), randomly received saline placebo, pralidoxime, or norepinephrine treatment and were monitored for up to 24 hours. In the hemodynamic study, 44 rats were randomly assigned to sham, CLP-saline placebo, CLP-pralidoxime, or CLP-norepinephrine groups, and hemodynamic measurements were performed using a conductance catheter placed in the left ventricle. In the survival study, 6 (27.2%), 15 (68.1%), and 5 (22.7%) animals survived the entire 24-hour monitoring period in the saline, pralidoxime, and norepinephrine groups, respectively (log-rank test P = 0.006). In the hemodynamic study, pralidoxime but not norepinephrine increased end-diastolic volume (P <0.001), stroke volume (P = 0.002), cardiac output (P = 0.003), mean arterial pressure (P = 0.041), and stroke work (P <0.001). The pressor effect of norepinephrine was short-lived, such that by 60 minutes after the initiation of norepinephrine infusion, it no longer had any significant effect on mean arterial pressure. In addition, norepinephrine significantly increased heart rate (P <0.001) and the ratio of arterial elastance to ventricular end-systolic elastance (P = 0.010), but pralidoxime did not. In conclusion, pralidoxime improved the hemodynamics and 24-hour survival rate in rats with peritonitis-induced sepsis, but norepinephrine did not.


Assuntos
Peritonite/tratamento farmacológico , Compostos de Pralidoxima/farmacologia , Sepse/tratamento farmacológico , Animais , Reativadores da Colinesterase/farmacologia , Modelos Animais de Doenças , Hemodinâmica/efeitos dos fármacos , Masculino , Norepinefrina/farmacologia , Peritonite/complicações , Peritonite/patologia , Ratos , Ratos Wistar , Sepse/etiologia , Sepse/patologia , Choque Séptico/tratamento farmacológico , Choque Séptico/patologia , Vasoconstritores/farmacologia
8.
J Biochem Mol Toxicol ; 35(6): 1-10, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33682265

RESUMO

Past assassinations and terrorist attacks demonstrate the need for a more effective antidote against nerve agents and other organophosphates (OP) that cause brain damage through inhibition of acetylcholinesterase (AChE). Our lab has invented a platform of phenoxyalkyl pyridinium oximes (US patent 9,277,937) that demonstrate the ability to cross the blood-brain barrier in in vivo rat tests with a sarin surrogate nitrophenyl isopropyl methylphosphonate (NIMP) and provide evidence of brain penetration by reducing cessation time of seizure-like behaviors, accumulation of glial fibrillary acidic protein (GFAP), and hippocampal neuropathology, as opposed to the currently approved oxime, 2-pyridine aldoxime methyl chloride (2-PAM). Using two of the novel oximes (Oximes 1 and 20), this project examined whether gene expression changes might help explain this protection. Expression changes in the piriform cortex were examined using polymerase chain reaction arrays for inflammatory cytokines and receptors. The hippocampus was examined via quantitative polymerase chain reaction for the expression of immediate-early genes involved in brain repair (Bdnf), increasing neurotoxicity (Fos), and apoptosis control (Jdp2, Bcl2l1, Bcl2l11). In the piriform cortex, NIMP significantly stimulated expression for the macrophage inflammatory proteins CCL4, IL-1A, and IL-1B. Oxime 20 by itself elicited the most changes. When it was given therapeutically post-NIMP, the largest change occurred: a 310-fold repression of the inflammatory cytokine, CCL12. In the hippocampus, NIMP increased the expression of the neurotoxicity marker Fos and decreased the expression of neuroprotective Bdnf and antiapoptotic Bcl2l1. Compared with 2-PAM, Oxime 20 stimulated Bcl2l1 expression more and returned expression closer to the vehicle control values.


Assuntos
Acetilcolinesterase , Encéfalo/metabolismo , Reativadores da Colinesterase , Regulação da Expressão Gênica/efeitos dos fármacos , Oximas , Sarina/toxicidade , Acetilcolinesterase/metabolismo , Animais , Encéfalo/patologia , Reativadores da Colinesterase/química , Reativadores da Colinesterase/farmacocinética , Reativadores da Colinesterase/farmacologia , Proteínas Ligadas por GPI/antagonistas & inibidores , Proteínas Ligadas por GPI/metabolismo , Masculino , Oximas/química , Oximas/farmacocinética , Oximas/farmacologia , Ratos , Ratos Sprague-Dawley
9.
Toxicol Appl Pharmacol ; 415: 115443, 2021 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-33548273

RESUMO

The brain is a critical target for the toxic action of organophosphorus (OP) inhibitors of acetylcholinesterase (AChE) such as the nerve agent sarin. However, the available oxime antidote 2-PAM only reactivates OP-inhibited AChE in peripheral tissues. Monoisonitrosoacetone (MINA), a tertiary oxime, reportedly reactivates AChE in the central nervous system (CNS). The current study investigated whether MINA would be beneficial as a supplemental oxime treatment in preventing lethality and reducing morbidity following lethal sarin exposure, MINA supplement would improve AChE recovery in the body, and MINA would be detectable in the CNS. Guinea pigs were exposed to sarin and treated with atropine sulfate and 2-PAM at one minute. Additional 2-PAM or MINA was administered at 3, 5, 15, or 30 min after sarin exposure. Survival and morbidity were assessed at 2 and 24 h. AChE activity in brain and peripheral tissues was evaluated one hour after MINA and 2-PAM treatment. An in vivo microdialysis technique was used to determine partitioning of MINA into the brain. A liquid chromatography-tandem mass spectrometry method was developed for the analysis of MINA in microdialysates. MINA-treated animals exhibited significantly higher survival and lower morbidity compared to 2-PAM-treated animals. 2-PAM was significantly more effective in reactivating AChE in peripheral tissues, but only MINA reactivated AChE in the CNS. MINA was found in guinea pig brain microdialysate samples beginning at ~10 min after administration in a dose-related manner. The data strongly suggest that a centrally penetrating oxime could provide significant benefit as an adjunct to atropine and 2-PAM therapy for OP intoxication.


Assuntos
Acetilcolinesterase/metabolismo , Antídotos/farmacologia , Encéfalo/efeitos dos fármacos , Reativadores da Colinesterase/farmacologia , Intoxicação por Organofosfatos/prevenção & controle , Oximas/farmacologia , Sarina , Animais , Antídotos/metabolismo , Encéfalo/enzimologia , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Ativação Enzimática , Cobaias , Masculino , Microdiálise , Intoxicação por Organofosfatos/enzimologia , Oximas/metabolismo , Permeabilidade , Compostos de Pralidoxima/metabolismo , Compostos de Pralidoxima/farmacologia , Distribuição Tecidual
10.
J Pharm Sci ; 110(4): 1842-1852, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33545185

RESUMO

Oxime reactivators of acetylcholinesterase (AChE) represent an integral part of standard antidote treatment of organophosphate poisoning. Oxime K869 is a novel bisquaternary non-symmetric pyridinium aldoxime with two pyridinium rings connected by a tetramethylene bridge where two chlorines modify the pyridinium ring bearing the oxime moiety. Based on in vitro assays, K869 is a potent AChE and butyrylcholinesterase (BChE) reactivator. For the investigation of the basic pharmacokinetic properties of K869 after its intramuscular application, new HPLC-UV and LC-MS/MS methods were developed and validated for its determination in rat body fluids and tissues. In this study, the SPE procedure for sample pretreatment was optimized as an alternative to routine protein precipitation widely used in oxime pharmacokinetics studies. K869 oxime is quickly absorbed into the central compartment reaching its maximum in plasma (39 ± 4 µg/mL) between 15 and 20 min. The majority of K869 was eliminated by kidneys via urine when compared with biliary excretion. However, only a limited amount of K869 (65 ± 4 ng/g of brain tissue) was found in the brain 30 min after oxime administration. Regarding the brain/plasma ratio calculated (less than 1%), the penetration of K869 into the brain did not exceed conventionally used oximes.


Assuntos
Líquidos Corporais , Reativadores da Colinesterase , Acetilcolinesterase , Animais , Inibidores da Colinesterase , Cromatografia Líquida , Oximas , Ratos , Espectrometria de Massas em Tandem
11.
J Neurochem ; 158(6): 1217-1222, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33638151

RESUMO

We detail here distinctive departures from lead classical cholinesterase re-activators, the pyridinium aldoximes, to achieve rapid CNS penetration and reactivation of AChE in the CNS (brain and spinal cord). Such reactivation is consistent with these non-canonical re-activators enhancing survival parameters in both mice and macaques following exposure to organophosphates. Thus, the ideal cholinesterase re-activator should show minimal toxicity, limited inhibitory activity in the absence of an organophosphate, and rapid CNS penetration, in addition to its nucleophilic potential at the target, the conjugated AChE active center. These are structural properties directed to reactivity profiles at the conjugated AChE active center, reinforced by the pharmacokinetic and tissue disposition properties of the re-activator leads. In the case of nicotinic acetylcholine receptor (nAChR) agonists and antagonists, with the many existing receptor subtypes in mammals, we prioritize subtype selectivity in their design. In contrast to nicotine and its analogues that react with panoply of AChR subtypes, the substituted di-2-picolyl amine pyrimidines possess distinctive ionization characteristics reflecting in selectivity for the orthosteric site at the α7 subtypes of receptor. Here, entry to the CNS should be prioritized for the therapeutic objectives of the nicotinic agent influencing aberrant CNS activity in development or in the sequence of CNS ageing (longevity) in mammals, along with general peripheral activities controlling inflammation.


Assuntos
Acetilcolinesterase/química , Reativadores da Colinesterase/química , Desenho de Fármacos , Agonistas Nicotínicos/química , Antagonistas Nicotínicos/química , Receptores Nicotínicos/química , Acetilcolinesterase/metabolismo , Animais , Reativadores da Colinesterase/metabolismo , Humanos , Ligantes , Agonistas Nicotínicos/metabolismo , Antagonistas Nicotínicos/metabolismo , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Receptores Nicotínicos/metabolismo
12.
Chem Res Toxicol ; 34(3): 699-703, 2021 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-33566584

RESUMO

Oxime cholinesterase reactivators (oximes) are used to counteract organophosphate intoxication. Charged oximes are administered via intramuscular or intravenous injection when the majority of dose is unmetabolized and is excreted as urine. In this study, the effects of selected double charged oximes were determined in the HK-2 cell line as a model for renal toxicity screening. Some effects on dehydrogenase activity were found for obidoxime, asoxime (syn. HI-6), K027, and K203. The effects of K868 and K869 were found to be unreliable due to rapid degradation of both chlorinated oximes in the assay medium, resulting for K868 in an isoxazole-pyridinium product.


Assuntos
Reativadores da Colinesterase/efeitos adversos , Rim/efeitos dos fármacos , Oximas/efeitos adversos , Linhagem Celular , Reativadores da Colinesterase/administração & dosagem , Reativadores da Colinesterase/química , Relação Dose-Resposta a Droga , Humanos , Rim/metabolismo , Estrutura Molecular , Oximas/administração & dosagem , Oximas/química
13.
Eur J Med Chem ; 215: 113286, 2021 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-33611189

RESUMO

Covalent drugs have been intensively studied in some very important fields such as anti-tumor and anti-virus, including the currently global-spread SARS-CoV-2. However, these drugs may interact with a variety of biological macromolecules and cause serious toxicology, so how to reactivate the inhibited targets seems to be imperative in the near future. Organophosphate was an extreme example, which could form a covalent bound easily with acetylcholinesterase and irreversibly inhibited the enzyme, causing high toxicology. Some nucleophilic oxime reactivators for organophosphate poisoned acetylcholinesterase had been developed, but the reactivation process was still less understanding. Herein, we proposed there should be a pre-reactivated pose during the reactivating process and compounds whose binding pose was easy to transfer to the pre-reactivated pose might be efficient reactivators. Then we refined the previous reactivators based on the molecular dynamic simulation results, the resulting compounds L7R3 and L7R5 were proven as much more efficient reactivators for organophosphate inhibited acetylcholinesterase than currently used oximes. This work might provide some insights for constructing reactivators of covalently inhibited targets by using computational methods.


Assuntos
Acetilcolinesterase/química , Reativadores da Colinesterase/química , Acetilcolinesterase/metabolismo , Inibidores da Colinesterase/química , Reativadores da Colinesterase/metabolismo , Humanos , Cinética , Simulação de Dinâmica Molecular , Compostos Organofosforados/química , Estudo de Prova de Conceito , Ligação Proteica
14.
Arch Toxicol ; 95(3): 985-1001, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33517499

RESUMO

To date, the only treatments developed for poisoning by organophosphorus compounds, the most toxic chemical weapons of mass destruction, have exhibited limited efficacy and versatility. The available causal antidotes are based on reactivation of the enzyme acetylcholinesterase (AChE), which is rapidly and pseudo-irreversibly inhibited by these agents. In this study, we developed a novel series of monoquaternary reactivators combining permanently charged moieties tethered to position 6- of 3-hydroxypyridine-2-aldoxime reactivating subunit. Highlighted representatives (21, 24, and 27; also coded as K1371, K1374, and K1375, respectively) that contained 1-phenylisoquinolinium, 7-amino-1-phenylisoquinolinium and 4-carbamoylpyridinium moieties as peripheral anionic site ligands, respectively, showed efficacy superior or comparable to that of the clinically used standards. More importantly, these reactivators exhibited wide-spectrum efficacy and were minutely investigated via determination of their reactivation kinetics in parallel with molecular dynamics simulations to study their mechanisms of reactivation of the tabun-inhibited AChE conjugate. To further confirm the potential applicability of these candidates, a mouse in vivo assay was conducted. While K1375 had the lowest acute toxicity and the most suitable pharmacokinetic profile, the oxime K1374 with delayed elimination half-life was the most effective in ameliorating the signs of tabun toxicity. Moreover, both in vitro and in vivo, the versatility of the agents was substantially superior to that of clinically used standards. Their high efficacy and broad-spectrum capability make K1374 and K1375 promising candidates that should be further investigated for their potential as nerve agents and insecticide antidotes.


Assuntos
Acetilcolinesterase/efeitos dos fármacos , Antídotos/farmacologia , Reativadores da Colinesterase/farmacologia , Acetilcolinesterase/metabolismo , Animais , Antídotos/síntese química , Antídotos/química , Reativadores da Colinesterase/síntese química , Reativadores da Colinesterase/química , Feminino , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Simulação de Dinâmica Molecular , Oximas/síntese química , Oximas/química , Oximas/farmacologia , Relação Estrutura-Atividade
15.
Biomolecules ; 11(2)2021 01 27.
Artigo em Inglês | MEDLINE | ID: mdl-33513955

RESUMO

Poisoning with organophosphorus compounds used as pesticides or misused as chemical weapons remains a serious threat to human health and life. Their toxic effects result from irreversible blockade of the enzymes acetylcholinesterase and butyrylcholinesterase, which causes overstimulation of the cholinergic system and often leads to serious injury or death. Treatment of organophosphorus poisoning involves, among other strategies, the administration of oxime compounds. Oximes reactivate cholinesterases by breaking the covalent bond between the serine residue from the enzyme active site and the phosphorus atom of the organophosphorus compound. Although the general mechanism of reactivation has been known for years, the exact molecular aspects determining the efficiency and selectivity of individual oximes are still not clear. This hinders the development of new active compounds. In our research, using relatively simple and widely available molecular docking methods, we investigated the reactivation of acetyl- and butyrylcholinesterase blocked by sarin and tabun. For the selected oximes, their binding modes at each step of the reactivation process were identified. Amino acids essential for effective reactivation and those responsible for the selectivity of individual oximes against inhibited acetyl- and butyrylcholinesterase were identified. This research broadens the knowledge about cholinesterase reactivation and demonstrates the usefulness of molecular docking in the study of this process. The presented observations and methods can be used in the future to support the search for new effective reactivators.


Assuntos
Acetilcolinesterase/metabolismo , Butirilcolinesterase/metabolismo , Inibidores da Colinesterase/farmacologia , Reativadores da Colinesterase/farmacologia , Simulação de Acoplamento Molecular , Animais , Domínio Catalítico , Análise por Conglomerados , Ativação Enzimática , Humanos , Ligantes , Camundongos , Modelos Moleculares , Organofosfatos/química , Oximas/química , Fósforo/química , Ligação Proteica , Biossíntese de Proteínas , Conformação Proteica , Teoria Quântica , Sarina/química
16.
Curr Med Chem ; 28(7): 1422-1442, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32334495

RESUMO

BACKGROUND: Neurotoxic chemical warfare agents can be classified as some of the most dangerous chemicals for humanity. The most effective of those agents are the Organophosphates (OPs) capable of restricting the enzyme Acetylcholinesterase (AChE), which in turn, controls the nerve impulse transmission. When AChE is inhibited by OPs, its reactivation can be usually performed through cationic oximes. However, until today, it has not been developed one universal defense agent, with complete effective reactivation activity for AChE inhibited by any of the many types of existing neurotoxic OPs. For this reason, before treating people intoxicated by an OP, it is necessary to determine the neurotoxic compound that was used for contamination, in order to select the most effective oxime. Unfortunately, this task usually requires a relatively long time, raising the possibility of death. Cationic oximes also display a limited capacity of permeating the Blood-Brain Barrier (BBB). This fact compromises their capacity to reactivating AChE inside the nervous system. METHODS: We performed a comprehensive search on the data about OPs available on the scientific literature today in order to cover all the main drawbacks still faced in the research for the development of effective antidotes against those compounds. RESULTS: Therefore, this review about neurotoxic OPs and the reactivation of AChE, provides insights for the new agents' development. The most expected defense agent is a molecule without toxicity and effective to reactivate AChE inhibited by all neurotoxic OPs. CONCLUSION: To develop these new agents, the application of diverse scientific areas of research, especially theoretical procedures as computational science (computer simulation, docking and dynamics), organic synthesis, spectroscopic methodologies, biology, biochemical and biophysical information, medicinal chemistry, pharmacology and toxicology, is necessary.


Assuntos
Acetilcolinesterase , Reativadores da Colinesterase , Inibidores da Colinesterase/toxicidade , Reativadores da Colinesterase/farmacologia , Simulação por Computador , Humanos , Compostos Organofosforados/toxicidade , Oximas/farmacologia
17.
J Control Release ; 329: 1117-1128, 2021 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-33096123

RESUMO

Effective intracerebral delivery acetylcholinesterase (AChE) reactivator is key for the acute organophosphorus (OPs) poison treatment. However, the blood-brain barrier (BBB) restricts the transport of these drugs from blood into the brain. Herein, we developed transferrin receptor (TfR) aptamer-functionalized liposomes (Apt-LP) that could deliver AChE reactivator (obidoxime) across the BBB to act against paraoxon (POX) poisoning. The aptamer had strong affinity for TfR and was modified with 3'-inverted deoxythymidine (dT) to improve serum stability. The uptake of Apt-LP by bEnd.3 cells was significantly higher than that of non-targeting liposomes. The ability of Apt-LP to penetrate intact BBB was confirmed in in vitro BBB mice model and in vivo biodistribution studies. Treatment of POX-poisoned mice with Apt-LP-LuH-6 reactivated 18% of the brain AChE activity and prevented brain damage to some extent. Taken together, these results showed that Apt-LP may be used as a promising brain-targeted drug delivery system against OPs toxicity.


Assuntos
Reativadores da Colinesterase , Cloreto de Obidoxima , Animais , Encéfalo , Lipossomos , Camundongos , Compostos Organofosforados , Distribuição Tecidual
18.
Regul Toxicol Pharmacol ; 119: 104823, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33212192

RESUMO

Nerve agent exposure is generally treated by an antidote formulation composed of a muscarinic antagonist, atropine sulfate (ATR), and a reactivator of acetylcholinesterase (AChE) such as pralidoxime, obidoxime (OBI), methoxime, trimedoxime or HI-6 and an anticonvulsant. Organophosphates (OPs) irreversibly inhibit AChE, the enzyme responsible for termination of acetylcholine signal transduction. Inhibition of AChE leads to overstimulation of the central and peripheral nervous system with convulsive seizures, respiratory distress and death as result. The present study evaluated the efficacy and pharmacokinetics (PK) of ATR/OBI following exposure to two different VX dose levels. The PK of ATR and OBI administered either as a single drug, combined treatment but separately injected, or administered as the ATR/OBI co-formulation, was determined in plasma of naïve guinea pigs and found to be similar for all formulations. Following subcutaneous VX exposure, ATR/OBI-treated animals showed significant improvement in survival rate and progression of clinical signs compared to untreated animals. Moreover, AChE activity after VX exposure in both blood and brain tissue was significantly higher in ATR/OBI-treated animals compared to vehicle-treated control. In conclusion, ATR/OBI has been proven to be efficacious against exposure to VX and there were no PK interactions between ATR and OBI when administered as a co-formulation.


Assuntos
Atropina , Substâncias para a Guerra Química/toxicidade , Inibidores da Colinesterase/toxicidade , Reativadores da Colinesterase , Antagonistas Muscarínicos , Cloreto de Obidoxima , Compostos Organotiofosforados/toxicidade , Acetilcolinesterase/sangue , Acetilcolinesterase/metabolismo , Animais , Atropina/sangue , Atropina/farmacocinética , Atropina/uso terapêutico , Encéfalo/metabolismo , Reativadores da Colinesterase/sangue , Reativadores da Colinesterase/farmacocinética , Reativadores da Colinesterase/uso terapêutico , Modelos Animais de Doenças , Combinação de Medicamentos , Cobaias , Masculino , Antagonistas Muscarínicos/sangue , Antagonistas Muscarínicos/farmacocinética , Antagonistas Muscarínicos/uso terapêutico , Cloreto de Obidoxima/sangue , Cloreto de Obidoxima/farmacocinética , Cloreto de Obidoxima/uso terapêutico , Resultado do Tratamento
19.
Int J Mol Sci ; 21(21)2020 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-33114215

RESUMO

Antidotes against organophosphates often possess physicochemical properties that mitigate their passage across the blood-brain barrier. Cucurbit[7]urils may be successfully used as a drug delivery system for bisquaternary oximes and improve central nervous system targeting. The main aim of these studies was to elucidate the relationship between cucurbit[7]uril, oxime K027, atropine, and paraoxon to define potential risks or advantages of this delivery system in a complex in vivo system. For this reason, in silico (molecular docking combined with umbrella sampling simulation) and in vivo (UHPLC-pharmacokinetics, toxicokinetics; acetylcholinesterase reactivation and functional observatory battery) methods were used. Based on our results, cucurbit[7]urils affect multiple factors in organophosphates poisoning and its therapy by (i) scavenging paraoxon and preventing free fraction of this toxin from entering the brain, (ii) enhancing the availability of atropine in the central nervous system and by (iii) increasing oxime passage into the brain. In conclusion, using cucurbit[7]urils with oximes might positively impact the overall treatment effectiveness and the benefits can outweigh the potential risks.


Assuntos
Atropina/química , Hidrocarbonetos Aromáticos com Pontes/química , Imidazóis/química , Oximas/química , Paraoxon/toxicidade , Compostos de Piridínio/química , Animais , Barreira Hematoencefálica , Reativadores da Colinesterase/química , Reativadores da Colinesterase/toxicidade , Simulação por Computador , Camundongos , Simulação de Acoplamento Molecular , Paraoxon/química
20.
Int J Mol Sci ; 21(18)2020 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-32899591

RESUMO

Organophosphorus (OP) compounds are used as both chemical weapons and pesticides. However, these agents are very dangerous and toxic to humans, animals, and the environment. Thus, investigations with reactivators have been deeply developed in order to design new antidotes with better efficiency, as well as a greater spectrum of action in the acetylcholinesterase (AChE) reactivation process. With that in mind, in this work, we investigated the behavior of trimedoxime toward the Mus musculus acetylcholinesterase (MmAChE) inhibited by a range of nerve agents, such as chemical weapons. From experimental assays, reactivation percentages were obtained for the reactivation of different AChE-OP complexes. On the other hand, theoretical calculations were performed to assess the differences in interaction modes and the reactivity of trimedoxime within the AChE active site. Comparing theoretical and experimental data, it is possible to notice that the oxime, in most cases, showed better reactivation percentages at higher concentrations, with the best result for the reactivation of the AChE-VX adduct. From this work, it was revealed that the mechanistic process contributes most to the oxime efficiency than the interaction in the site. In this way, this study is important to better understand the reactivation process through trimedoxime, contributing to the proposal of novel antidotes.


Assuntos
Reativadores da Colinesterase/química , Trimedoxima/farmacologia , Trimedoxima/uso terapêutico , Acetilcolinesterase/metabolismo , Animais , Antídotos/farmacologia , Inibidores da Colinesterase/metabolismo , Inibidores da Colinesterase/farmacologia , Reativadores da Colinesterase/farmacologia , Biologia Computacional/métodos , Humanos , Camundongos , Agentes Neurotóxicos/química , Compostos Organofosforados/química , Oximas/química , Ratos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...