RESUMO
A-series agent A-234 belongs to a new generation of nerve agents. The poisoning of a former Russian spy Sergei Skripal and his daughter in Salisbury, England, in March 2018 led to the inclusion of A-234 and other A-series agents into the Chemical Weapons Convention. Even though five years have already passed, there is still very little information on its chemical properties, biological activities, and treatment options with established antidotes. In this article, we first assessed A-234 stability in neutral pH for subsequent experiments. Then, we determined its inhibitory potential towards human recombinant acetylcholinesterase (HssAChE; EC 3.1.1.7) and butyrylcholinesterase (HssBChE; EC 3.1.1.8), the ability of HI-6, obidoxime, pralidoxime, methoxime, and trimedoxime to reactivate inhibited cholinesterases (ChEs), its toxicity in rats and therapeutic effects of different antidotal approaches. Finally, we utilized molecular dynamics to explain our findings. The results of spontaneous A-234 hydrolysis showed a slow process with a reaction rate displaying a triphasic course during the first 72 h (the residual concentration 86.2%). A-234 was found to be a potent inhibitor of both human ChEs (HssAChE IC50 = 0.101 ± 0.003 µM and HssBChE IC50 = 0.036 ± 0.002 µM), whereas the five marketed oximes have negligible reactivation ability toward A-234-inhibited HssAChE and HssBChE. The acute toxicity of A-234 is comparable to that of VX and in the context of therapy, atropine and diazepam effectively mitigate A-234 lethality. Even though oxime administration may induce minor improvements, selected oximes (HI-6 and methoxime) do not reactivate ChEs in vivo. Molecular dynamics implies that all marketed oximes are weak nucleophiles, which may explain the failure to reactivate the A-234 phosphorus-serine oxygen bond characterized by low partial charge, in particular, HI-6 and trimedoxime oxime oxygen may not be able to effectively approach the A-234 phosphorus, while pralidoxime displayed low interaction energy. This study is the first to provide essential experimental preclinical data on the A-234 compound.
Assuntos
Reativadores da Colinesterase , Compostos de Pralidoxima , Taurina/análogos & derivados , Ratos , Humanos , Animais , Reativadores da Colinesterase/farmacologia , Trimedoxima/farmacologia , Butirilcolinesterase , Acetilcolinesterase , Oximas/farmacologia , Compostos de Piridínio/farmacologia , Antídotos/farmacologia , Inibidores da Colinesterase/toxicidade , Fósforo , OxigênioRESUMO
"Novichok" refers to a new group of nerve agents called the A-series agents. Their existence came to light in 2018 after incidents in the UK and again in 2020 in Russia. They are unique organophosphorus-based compounds developed during the Cold War in a program called Foliant in the USSR. This review is based on original chemical entities from Mirzayanov's memoirs published in 2008. Due to classified research, a considerable debate arose about their structures, and hence, various structural moieties were speculated. For this reason, the scientific literature is highly incomplete and, in some cases, contradictory. This review critically assesses the information published to date on this class of compounds. The scope of this work is to summarize all the available and relevant information, including the physicochemical properties, chemical synthesis, mechanism of action, toxicity, pharmacokinetics, and medical countermeasures used to date. The environmental stability of A-series agents, the lack of environmentally safe decontamination, their high toxicity, and the scarcity of information on post-contamination treatment pose a challenge for managing possible incidents.
Assuntos
Contaminação de Medicamentos , Agentes Neurotóxicos , Agentes Neurotóxicos/toxicidade , Compostos OrganofosforadosRESUMO
Organophosphorus compounds (OPs) involving life-threatening nerve agents (NA) have been known for several decades. Despite a clear mechanism of their lethality caused by the irreversible inhibition of acetylcholinesterase (AChE) and manifested via overstimulation of peripheral nicotinic and muscarinic acetylcholine (ACh) receptors, the mechanism for central neurotoxicity responsible for acute or delayed symptoms of the poisoning has not been thoroughly uncovered. One of the reasons is the lack of a suitable model. In our study, we have chosen the SH-SY5Y model in both the differentiated and undifferentiated state to study the effects of NAs (GB, VX and A234). The activity of expressed AChE in cell lysate assessed by Ellman's method showed 7.3-times higher activity in differentiated SH-SY5Y cells in contrast to undifferentiated cells, and with no involvement of BuChE as proved by ethopropazine (20 µM). The activity of AChE was found to be, in comparison to untreated cells, 16-, 9.3-, and 1.9-times lower upon A234, VX, and GB (100 µM) administration respectively. The cytotoxic effect of given OPs expressed as the IC50 values for differentiated and undifferentiated SH-SY5Y, respectively, was found 12 mM and 5.7 mM (A234), 4.8 mM and 1.1 mM (VX) and 2.6 mM and 3.8 mM (GB). In summary, although our results confirm higher AChE expression in the differentiated SH-SY5Y cell model, the such higher expression does not lead to a more pronounced NA cytotoxic effect. On the contrary, higher expression of AChE may attenuate NA-induced cytotoxicity by scavenging the NA. Such finding highlights a protective role for cholinesterases by scavenging Novichoks (A-agents). Second, we confirmed the mechanism of cytotoxicity of NAs, including A-agents, can be ascribed rather to the non-specific effects of OPs than to AChE-mediated effects.
Assuntos
Antineoplásicos , Agentes Neurotóxicos , Neuroblastoma , Síndromes Neurotóxicas , Humanos , Acetilcolinesterase/metabolismo , Linhagem Celular Tumoral , Síndromes Neurotóxicas/etiologiaRESUMO
Alzheimer's disease (AD) is a complex disease with an unknown etiology. Available treatments, limited to cholinesterase inhibitors and N-methyl-d-aspartate receptor (NMDAR) antagonists, provide symptomatic relief only. As single-target therapies have not proven effective, rational specific-targeted combination into a single molecule represents a more promising approach for treating AD, and is expected to yield greater benefits in alleviating symptoms and slowing disease progression. In the present study, we designed, synthesized, and biologically evaluated 24 novel N-methylpropargylamino-quinazoline derivatives. Initially, compounds were thoroughly inspected by in silico techniques determining their oral and CNS availabilities. We tested, in vitro, the compounds' effects on cholinesterases and monoamine oxidase A/B (MAO-A/B), as well as their impacts on NMDAR antagonism, dehydrogenase activity, and glutathione levels. In addition, we inspected selected compounds for their cytotoxicity on undifferentiated and differentiated neuroblastoma SH-SY5Y cells. We collectively highlighted II-6h as the best candidate endowed with a selective MAO-B inhibition profile, NMDAR antagonism, an acceptable cytotoxicity profile, and the potential to permeate through BBB. The structure-guided drug design strategy applied in this study imposed a novel concept for rational drug discovery and enhances our understanding on the development of novel therapeutic agents for treating AD.
Assuntos
Doença de Alzheimer , Neuroblastoma , Humanos , Doença de Alzheimer/tratamento farmacológico , Inibidores da Monoaminoxidase/uso terapêutico , Neuroblastoma/tratamento farmacológico , Inibidores da Colinesterase/uso terapêutico , Monoaminoxidase/metabolismo , Desenho de Fármacos , Acetilcolinesterase/metabolismo , Relação Estrutura-AtividadeRESUMO
The search for novel and effective therapeutics for Alzheimer's disease (AD) is the main quest that remains to be resolved. The goal is to find a disease-modifying agent able to confront the multifactorial nature of the disease positively. Herewith, a family of huprineY-tryptophan heterodimers was prepared, resulting in inhibition of cholinesterase and neuronal nitric oxide synthase enzymes, with effect against amyloid-beta (Aß) and potential ability to cross the blood-brain barrier. Their cholinesterase pattern of behavior was inspected using kinetic analysis in tandem with docking studies. These heterodimers exhibited a promising pharmacological profile with strong implication in AD.
Assuntos
Acetilcolinesterase/metabolismo , Doença de Alzheimer/tratamento farmacológico , Aminoquinolinas/farmacologia , Inibidores da Colinesterase/farmacologia , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Fármacos Neuroprotetores/farmacologia , Triptofano/farmacologia , Doença de Alzheimer/metabolismo , Aminoquinolinas/química , Peptídeos beta-Amiloides/antagonistas & inibidores , Peptídeos beta-Amiloides/metabolismo , Inibidores da Colinesterase/síntese química , Inibidores da Colinesterase/química , Relação Dose-Resposta a Droga , Compostos Heterocíclicos de 4 ou mais Anéis/química , Humanos , Estrutura Molecular , Fármacos Neuroprotetores/síntese química , Fármacos Neuroprotetores/química , Relação Estrutura-Atividade , Triptofano/químicaRESUMO
Twenty known Amaryllidaceae alkaloids of various structural types, and one undescribed alkaloid of narcikachnine-type, named narcieliine (3), have been isolated from fresh bulbs of Zephyranthes citrina. The chemical structures of the isolated alkaloids were elucidated by a combination of MS, HRMS, 1D and 2D NMR, and CD spectroscopic techniques, and by comparison with literature data. The absolute configuration of narcieliine (3) has also been determined. Compounds isolated in a sufficient quantity were evaluated for their in vitro acetylcholinesterase (AChE; E.C. 3.1.1.7), butyrylcholinesterase (BuChE; E.C. 3.1.1.8), and prolyl oligopeptidase (POP; E.C. 3.4.21.26) inhibition activities. Significant human AChE/BuChE (hAChE/hBuChE) inhibitory activity was demonstrated by the newly described alkaloid narcieliine (3), with IC50 values of 18.7 ± 2.3 µM and 1.34 ± 0.31 µM, respectively. This compound is also predicted to cross the blood-brain barrier (BBB) through passive diffusion. The in vitro data were further supported by in silico studies of 3 in the active site of hAChE/hBuChE.
Assuntos
Alcaloides/química , Amaryllidaceae/química , Acetilcolinesterase/química , Acetilcolinesterase/metabolismo , Alcaloides/isolamento & purificação , Alcaloides/farmacologia , Alcaloides/uso terapêutico , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/patologia , Amaryllidaceae/metabolismo , Sítios de Ligação , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/metabolismo , Butirilcolinesterase/química , Butirilcolinesterase/metabolismo , Domínio Catalítico , Inibidores da Colinesterase/química , Inibidores da Colinesterase/metabolismo , Inibidores da Colinesterase/farmacologia , Inibidores da Colinesterase/uso terapêutico , Humanos , Cinética , Espectroscopia de Ressonância Magnética , Conformação Molecular , Simulação de Acoplamento Molecular , Relação Estrutura-AtividadeRESUMO
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-AtividadeRESUMO
The search for tacrine derivatives, as potential Alzheimer´s disease treatment, is still being at the forefront of scientific efforts. 7-MEOTA was found to be a potent, centrally active acetylcholinesterase inhibitor free of the serious side effects observed for tacrine. Unfortunately, a relevant argumentation about pharmacokinetics and potential toxicity is incomplete; information about tacrine derivatives absorption and especially CNS penetration are still rare as well as detailed toxicological profile in vivo. Although the structural changes between these compounds are not so distinctive, differences in plasma profile and CNS targeting were found. The maximum plasma concentration were attained at 18th min (tacrine; 38.20 ± 3.91 ng/ml and 7-MEOTA; 88.22 ± 15.19 ng/ml) after i.m. application in rats. Although the brain profiles seem to be similar; tacrine achieved 19.34 ± 0.71 ng/ml in 27 min and 7-MEOTA 15.80 ± 1.13 ng/ml in 22 min; the tacrine Kp (AUCbrain/AUCplasma) fit 1.20 and was significantly higher than 7-MEOTA Kp 0.10. Administration of tacrine and 7-MEOTA showed only mild elevation of some biochemical markers following single p.o. application in 24 hours and 7 days. Also histopathology revealed only mild-to-moderate changes following repeated p.o. administration for 14 days. It seems that small change in tacrine molecule leads to lower ability to penetrate through the biological barriers. The explanation that lower p.o. acute toxicity of 7-MEOTA depends only on differences in metabolic pathways may be now revised to newly described differences in pharmacokinetic and toxicological profiles.
Assuntos
Encéfalo/metabolismo , Inibidores da Colinesterase/administração & dosagem , Tacrina/análogos & derivados , Animais , Área Sob a Curva , Inibidores da Colinesterase/farmacocinética , Inibidores da Colinesterase/toxicidade , Masculino , Ratos , Ratos Wistar , Tacrina/administração & dosagem , Tacrina/farmacocinética , Tacrina/toxicidade , Fatores de Tempo , Distribuição TecidualRESUMO
Alzheimer's disease (AD) is a multifactorial neurodegenerative condition of the central nervous system (CNS) that is currently treated by cholinesterase inhibitors and the N-methyl-d-aspartate receptor antagonist, memantine. Emerging evidence strongly supports the relevance of targeting butyrylcholinesterase (BuChE) in the more advanced stages of AD. Within this study, we have generated a pilot series of compounds (1-20) structurally inspired from belladine-type Amaryllidaceae alkaloids, namely carltonine A and B, and evaluated their acetylcholinesterase (AChE) and BuChE inhibition properties. Some of the compounds exhibited intriguing inhibition activity for human BuChE (hBuChE), with a preference for BuChE over AChE. Seven compounds were found to possess a hBuChE inhibition profile, with IC50 values below 1 µM. The most potent one, compound 6, showed nanomolar range activity with an IC50 value of 72 nM and an excellent selectivity pattern over AChE, reaching a selectivity index of almost 1400. Compound 6 was further studied by enzyme kinetics, along with in-silico techniques, to reveal the mode of inhibition. The prediction of CNS availability estimates that all the compounds in this survey can pass through the blood-brain barrier (BBB), as disclosed by the BBB score.
Assuntos
Acetilcolinesterase/química , Alcaloides de Amaryllidaceae/química , Butirilcolinesterase/química , Inibidores da Colinesterase/farmacologia , Simulação de Acoplamento Molecular , Neuroblastoma/tratamento farmacológico , Tiramina/análogos & derivados , Proliferação de Células , Inibidores da Colinesterase/química , Simulação por Computador , Humanos , Neuroblastoma/patologia , Relação Estrutura-Atividade , Células Tumorais Cultivadas , Tiramina/químicaRESUMO
Human 17ß-hydroxysteroid dehydrogenase type 10 is a multifunctional protein involved in many enzymatic and structural processes within mitochondria. This enzyme was suggested to be involved in several neurological diseases, e.g., mental retardation, Parkinson's disease, or Alzheimer's disease, in which it was shown to interact with the amyloid-beta peptide. We prepared approximately 60 new compounds based on a benzothiazolyl scaffold and evaluated their inhibitory ability and mechanism of action. The most potent inhibitors contained 3-chloro and 4-hydroxy substitution on the phenyl ring moiety, a small substituent at position 6 on the benzothiazole moiety, and the two moieties were connected via a urea linker (4at, 4bb, and 4bg). These compounds exhibited IC50 values of 1-2 µM and showed an uncompetitive mechanism of action with respect to the substrate, acetoacetyl-CoA. These uncompetitive benzothiazolyl inhibitors of 17ß-hydroxysteroid dehydrogenase type 10 are promising compounds for potential drugs for neurodegenerative diseases that warrant further research and development.
Assuntos
3-Hidroxiacil-CoA Desidrogenases/antagonistas & inibidores , Benzotiazóis/química , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Ureia/química , Ureia/farmacologia , 3-Hidroxiacil-CoA Desidrogenases/química , Doença de Alzheimer/tratamento farmacológico , Ativação Enzimática , Humanos , Cinética , Estrutura Molecular , Proteínas Recombinantes , Relação Estrutura-AtividadeRESUMO
The major function of compounds with an oxime moiety attached to a quarternary nitrogen pyridinium ring is to reactivate acetylcholinesterase inhibited by organophosphorus agent (OP). However, other oxime mechanisms (e.g. modulation of cholinergic or glutamatergic receptor) may be involved in the recovery. The main disadvantage of positively charged reactivators is their low ability to penetrate into the brain although crossing the blood brain barrier could be supported via increasing the dose of administered oxime. Thus, this study presents maximal tolerated doses (MTD) for marketed oximes (TMB-4, MMB-4, LüH-6, HI-6, 2-PAM) and the most promising K-oximes (K027, K048, K203) which can be used in OP therapy in the future. No signs of sarin intoxication were observed in mice treated with 100% MTD of HI-6 in contrast to those treated with atropine and only 5% LD50 of HI-6. 100% MTD of HI-6 resulted in levels of 500⯵M and 12⯵M in plasma and brain, respectively. This concentration is by a far margin safe with respect to direct effects on neuronal cell viability and, on the other hand, does not have any effects on central NMDA receptors or central nACh receptors. However, a weak antimuscarinic activity in case of LüH-6 and a weak peripheral antinicotinic action in case of TMB-4 and 2-PAM could be observed at their respective 100% MTD dose. These high doses, represented by MTD, are, however, irrelevant to clinical practice since they led to mild to moderate toxic side effects. Therefore, we conclude that clinically used doses of marketed oxime reactivators have no significant direct pharmacological effect on the tested receptors.
Assuntos
Reativadores da Colinesterase/administração & dosagem , Dose Máxima Tolerável , Compostos Organofosforados/toxicidade , Oximas/administração & dosagem , Compostos de Piridínio/administração & dosagem , Animais , Células CHO , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Galinhas , Reativadores da Colinesterase/toxicidade , Cricetinae , Cricetulus , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Oximas/toxicidade , Compostos de Pralidoxima/administração & dosagem , Compostos de Pralidoxima/toxicidade , Compostos de Piridínio/toxicidadeRESUMO
Twelve derivatives 1a-1m of the ß-crinane-type alkaloid haemanthamine were developed. All the semisynthetic derivatives were studied for their inhibitory potential against both acetylcholinesterase and butyrylcholinesterase. In addition, glycogen synthase kinase 3ß (GSK-3ß) inhibition potency was evaluated in the active derivatives. In order to reveal the availability of the drugs to the CNS, we elucidated the potential of selected derivatives to penetrate through the blood-brain barrier (BBB). Two compounds, namely 11-O-(2-methylbenzoyl)-haemanthamine (1j) and 11-O-(4-nitrobenzoyl)-haemanthamine (1m), revealed the most intriguing profile, both being acetylcholinesterase (hAChE) inhibitors on a micromolar scale, with GSK-3ß inhibition properties, and predicted permeation through the BBB. In vitro data were further corroborated by detailed inspection of the compounds' plausible binding modes in the active sites of hAChE and hBuChE, which led us to provide the structural determinants responsible for the activity towards these enzymes.
Assuntos
Doença de Alzheimer/metabolismo , Alcaloides de Amaryllidaceae/química , Alcaloides de Amaryllidaceae/metabolismo , Amaryllidaceae/química , Amaryllidaceae/metabolismo , Fenantridinas/química , Fenantridinas/metabolismo , Barreira Hematoencefálica/metabolismo , Glicogênio Sintase Quinase 3 beta/metabolismo , Humanos , Ligantes , Modelos Moleculares , Conformação Molecular , Simulação de Acoplamento Molecular , Estrutura Molecular , Permeabilidade , Relação Estrutura-AtividadeRESUMO
In recent studies, several alkaloids acting as cholinesterase inhibitors were isolated from Corydalis cava (Papaveraceae). Inhibitory activities of (+)-thalictricavine (1) and (+)-canadine (2) on human acetylcholinesterase (hAChE) and butyrylcholinesterase (hBChE) were evaluated with the Ellman's spectrophotometric method. Molecular modeling was used to inspect the binding mode of compounds into the active site pocket of hAChE. The possible permeability of 1 and 2 through the bloodâ»brain barrier (BBB) was predicted by the parallel artificial permeation assay (PAMPA) and logBB calculation. In vitro, 1 and 2 were found to be selective hAChE inhibitors with IC50 values of 0.38 ± 0.05 µM and 0.70 ± 0.07 µM, respectively, but against hBChE were considered inactive (IC50 values > 100 µM). Furthermore, both alkaloids demonstrated a competitive-type pattern of hAChE inhibition and bind, most probably, in the same AChE sub-site as its substrate. In silico docking experiments allowed us to confirm their binding poses into the active center of hAChE. Based on the PAMPA and logBB calculation, 2 is potentially centrally active, but for 1 BBB crossing is limited. In conclusion, 1 and 2 appear as potential lead compounds for the treatment of Alzheimer's disease.
Assuntos
Acetilcolinesterase/efeitos dos fármacos , Alcaloides/química , Butirilcolinesterase/efeitos dos fármacos , Inibidores da Colinesterase/farmacologia , Acetilcolinesterase/química , Alcaloides/farmacologia , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/enzimologia , Berberina/análogos & derivados , Berberina/química , Berberina/farmacologia , Transporte Biológico/efeitos dos fármacos , Barreira Hematoencefálica/efeitos dos fármacos , Butirilcolinesterase/química , Inibidores da Colinesterase/química , Simulação por Computador , Corydalis/química , Dissacarídeos/química , Dissacarídeos/farmacologia , Humanos , Modelos Moleculares , Nitrocompostos/química , Nitrocompostos/farmacologia , Ligação Proteica/efeitos dos fármacosRESUMO
Nerve agents and oxon forms of organophosphorus pesticides act as strong irreversible inhibitors of two cholinesterases in the human body: acetylcholinesterase (AChE; EC 3.1.1.7) and butyrylcholinesterase (BChE; EC 3.1.1.8), and are therefore highly toxic compounds. For the recovery of inhibited AChE, antidotes from the group of pyridinium or bispyridinium aldoxime reactivators (pralidoxime, obidoxime, HI-6) are used in combination with anticholinergics and anticonvulsives. Therapeutic efficacy of reactivators (called "oximes") depends on their chemical structure and also the type of organophosphorus inhibitor. Three novel oximes (K131, K142, K153) with an oxime group in position four of the pyridinium ring were designed and then tested for their potency to reactivate human (Homo sapiens sapiens) AChE (HssACHE) and BChE (HssBChE) inhibited by the pesticide paraoxon (diethyl 4-nitrophenyl phosphate). According to the obtained results, none of the prepared oximes were able to satisfactorily reactivate paraoxon-inhibited cholinesterases. On the contrary, extraordinary activity of obidoxime in the case of paraoxon-inhibited HssAChE reactivation was confirmed. Additional docking studies pointed to possible explanations for these results.
Assuntos
Acetilcolinesterase/química , Antídotos/síntese química , Butirilcolinesterase/química , Inibidores da Colinesterase/química , Reativadores da Colinesterase/síntese química , Inseticidas/antagonistas & inibidores , Oximas/síntese química , Paraoxon/antagonistas & inibidores , Antídotos/farmacologia , Reativadores da Colinesterase/farmacologia , Ensaios Enzimáticos , Eritrócitos/efeitos dos fármacos , Eritrócitos/enzimologia , Humanos , Inseticidas/química , Inseticidas/toxicidade , Simulação de Acoplamento Molecular , Cloreto de Obidoxima/química , Cloreto de Obidoxima/farmacologia , Oximas/farmacologia , Paraoxon/química , Paraoxon/toxicidade , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Estrutura Secundária de Proteína , Relação Estrutura-Atividade , TermodinâmicaRESUMO
Alzheimer's disease is an age-related, neurodegenerative disorder, characterized by cognitive impairment and restrictions in activities of daily living. This disease is the most common form of dementia with complex multifactorial pathological mechanisms. Many therapeutic approaches have been proposed. Among them, inhibition of acetylcholinesterase, butyrylcholinesterase, and prolyl oligopeptidase can be beneficial targets in the treatment of Alzheimer's disease. Roots, along with aerial parts of Argemone platyceras, were extracted with ethanol and fractionated on an alumina column using light petrol, chloroform and ethanol. Subsequently, repeated preparative thin-layer chromatography led to the isolation of (+)-laudanosine, protopine, (-)-argemonine, allocryptopine, (-)-platycerine, (-)-munitagine, and (-)-norargemonine belonging to pavine, protopine and benzyltetrahydroisoquinoline structural types. Chemical structures of the isolated alkaloids were elucidated by optical rotation, spectroscopic and spectrometric analysis (NMR, MS), and comparison with literature data. (+)-Laudanosine was isolated from A. platyceras for the first time. Isolated compounds were tested for human blood acetylcholinesterase, human plasma butyrylcholinesterase and recombinant prolyl oligopeptidase inhibitory activity. The alkaloids inhibited the enzymes in a dose-dependent manner. The most active compound (-)-munitagine, a pavine alkaloid, inhibited both acetylcholinesterase and prolyl oligopeptidase with IC50 values of 62.3 ± 5.8 µM and 277.0 ± 31.3 µM, respectively.
Assuntos
Alcaloides/química , Doença de Alzheimer/tratamento farmacológico , Argemone/química , Colinesterases/efeitos dos fármacos , Serina Endopeptidases/efeitos dos fármacos , Alcaloides/isolamento & purificação , Alcaloides/farmacologia , Butirilcolinesterase/efeitos dos fármacos , Cromatografia em Camada Fina/métodos , Relação Dose-Resposta a Droga , Descoberta de Drogas , Ensaios Enzimáticos/métodos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Humanos , Concentração Inibidora 50 , Espectroscopia de Ressonância Magnética/métodos , Extratos Vegetais/química , Raízes de Plantas/química , Prolil OligopeptidasesRESUMO
A novel series of 6-chlorotacrine-scutellarin hybrids was designed, synthesized and the biological activity as potential anti-Alzheimer's agents was assessed. Their inhibitory activity towards human acetylcholinesterase (hAChE) and human butyrylcholinesterase (hBChE), antioxidant activity, ability to cross the blood-brain barrier (BBB) and hepatotoxic profile were evaluated in vitro. Among these compounds, hybrid K1383, bearing two methylene tether between two basic scaffolds, was found to be very potent hAChE inhibitor (IC50 = 1.63 nM). Unfortunately, none of the hybrids displayed any antioxidant activity (EC50 ≥ 500 µM). Preliminary data also suggests a comparable hepatotoxic profile with 6-Cl-THA (established on a HepG2 cell line). Kinetic studies performed on hAChE with the most active compound in the study, K1383, pointed out to a mixed, non-competitive enzyme inhibition. These findings were further corroborated by docking studies.
Assuntos
Apigenina/química , Inibidores da Colinesterase/química , Inibidores da Colinesterase/farmacologia , Glucuronatos/química , Tacrina/análogos & derivados , Acetilcolinesterase/metabolismo , Doença de Alzheimer/enzimologia , Barreira Hematoencefálica/metabolismo , Butirilcolinesterase/metabolismo , Inibidores da Colinesterase/síntese química , Desenho de Fármacos , Ativação Enzimática/efeitos dos fármacos , Humanos , Simulação de Acoplamento Molecular , Relação Estrutura-Atividade , Tacrina/químicaRESUMO
Tacrine (THA), the first clinically effective acetylcholinesterase (AChE) inhibitor and the first approved drug for the treatment of Alzheimer's disease (AD), was withdrawn from the market due to its side effects, particularly its hepatotoxicity. Nowadays, THA serves as a valuable scaffold for the design of novel agents potentially applicable for AD treatment. One such compound, namely 7-methoxytacrine (7-MEOTA), exhibits an intriguing profile, having suppressed hepatotoxicity and concomitantly retaining AChE inhibition properties. Another interesting class of AChE inhibitors represents Huprines, designed by merging two fragments of the known AChE inhibitors-THA and (-)-huperzine A. Several members of this compound family are more potent human AChE inhibitors than the parent compounds. The most promising are so-called huprines X and Y. Here, we report the design, synthesis, biological evaluation, and in silico studies of 2-methoxyhuprine that amalgamates structural features of 7-MEOTA and huprine Y in one molecule.
Assuntos
Aminoquinolinas/química , Aminoquinolinas/farmacologia , Descoberta de Drogas , Acetilcolinesterase , Doença de Alzheimer/tratamento farmacológico , Aminoquinolinas/síntese química , Sítios de Ligação , Barreira Hematoencefálica/metabolismo , Butirilcolinesterase , Domínio Catalítico , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Inibidores da Colinesterase/química , Inibidores da Colinesterase/farmacologia , Desenho de Fármacos , Ativação Enzimática/efeitos dos fármacos , Compostos Heterocíclicos de 4 ou mais Anéis/química , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Humanos , Hidrólise , Concentração Inibidora 50 , Modelos Moleculares , Conformação Molecular , Estrutura Molecular , Permeabilidade , Ligação Proteica , Relação Estrutura-Atividade , Tacrina/análogos & derivados , Tacrina/química , Tacrina/farmacologiaRESUMO
Two new isoquinoline alkaloids, named fumaranine (2) and fumarostrejdine (10), along with 18 known alkaloids were isolated from aerial parts of Fumaria officinalis. The structures of the isolated compounds were elucidated on the basis of spectroscopic analyses and by comparison with literature data. The absolute configuration of the new compound 2 was determined by comparing its circular dichroism spectra with those of known analogs. Compounds isolated in sufficient amounts were evaluated for their acetylcholinesterase, butyrylcholinesterase, prolyl oligopeptidase (POP), and glycogen synthase kinase-3ß inhibitory activities. Parfumidine (8) and sinactine (15) exhibited potent POP inhibition activities (IC50 99±5 and 53±2â µM, resp.).
Assuntos
Alcaloides/farmacologia , Doença de Alzheimer/tratamento farmacológico , Inibidores Enzimáticos/farmacologia , Fumaria/química , Isoquinolinas/farmacologia , Acetilcolinesterase/metabolismo , Alcaloides/química , Alcaloides/isolamento & purificação , Doença de Alzheimer/enzimologia , Butirilcolinesterase/metabolismo , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/química , Inibidores Enzimáticos/isolamento & purificação , Quinase 3 da Glicogênio Sintase/antagonistas & inibidores , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta , Humanos , Isoquinolinas/química , Isoquinolinas/isolamento & purificação , Estrutura Molecular , Prolil Oligopeptidases , Serina Endopeptidases/metabolismo , Relação Estrutura-AtividadeRESUMO
OBJECTIVES: Tacrine was the first acetylcholinesterase inhibitor approved for therapy of Alzheimer's disease. It has currently been withdrawn in some countries mostly due to the risk of hepatotoxicity and might be replaced by its derivate 7-methoxytacrine (7-MEOTA). The aim of this study was to assess the impact of these two compounds on gastric myoelectrical activity by means of surface cutaneous electrogastrography (EGG). METHODS: Twelve pigs (Sus scrofa f. domestica, weighing 30-35 kg) entered the study. A single dose of tacrine (200 mg i.m., n=6) or 7-MEOTA (200 mg i.m., n=6) was administrated. All EGG recordings were performed under general anaesthesia in the morning after 24 hours of fasting. Basal (30 minutes) and study recordings (150 minutes) were accomplished using an EGG stand (MMS, Enschede, the Netherlands). Results were expressed as dominant frequency of gastric slow waves, power analysis (areas of amplitudes) and power ratio assessment (ratio of the areas of amplitudes after and before study drug administration). RESULTS: Tacrine decreased EGG dominant frequency 10 minutes after its administration (from basal 3.1±0.6 to 2.8±0.6 cycles per minute; p=0.014). Tacrine induced a non-significant 60-minute increase of the power (with maximal value 493±533 µV2 at 20 minutes) and power ratio (with maximal value 2.04±3.4 at 10 minutes). Tacrine caused substantial gastric arrhythmia. 7-MEOTA did not influence dominant frequency of gastric slow waves significantly. 7-MEOTA caused a short-term late increase of the power ratio at 60 minutes (6.3±11.2; p=0.003). Blood cholinesterase activity did not correlate with any EGG parameter either after tacrine or 7-MEOTA at any time. CONCLUSIONS: Tacrine and 7-MEOTA have different impacts on EGG. Tacrine decreased dominant frequency and induced long-lasting gastric arrhythmia. 7-MEOTA caused a short-term late increase of the EGG power in experimental pigs.
Assuntos
Inibidores da Colinesterase/farmacologia , Músculo Liso/efeitos dos fármacos , Estômago/efeitos dos fármacos , Tacrina/análogos & derivados , Tacrina/farmacologia , Animais , Eletromiografia , Feminino , Sus scrofaRESUMO
Alzheimer's disease (AD) is a debilitating progressive neurodegenerative disorder that ultimately leads to the patient's death. Despite the fact that novel pharmacological approaches endeavoring to block the neurodegenerative process are still emerging, none of them have reached use in clinical practice yet. Thus, palliative treatment represented by acetylcholinesterase inhibitors (AChEIs) and memantine are still the only therapeutics used. Following the multi-target directed ligands (MTDLs) strategy, herein we describe the synthesis, biological evaluation and docking studies for novel 7-methoxytacrine-p-anisidine hybrids designed to purposely target both cholinesterases and the amyloid cascade. Indeed, the novel derivatives proved to be effective non-specific cholinesterase inhibitors showing non-competitive AChE inhibition patterns. This compounds' behavior was confirmed in the subsequent molecular modeling studies.