Metabolic benefits of 1-(3-(4-(o-tolyl)piperazin-1-yl)propyl)pyrrolidin-2-one: a non-selective α-adrenoceptor antagonist.

PURPOSE: Previous studies have shown that several components of the metabolic syndrome, such as hypertension, obesity or imbalanced lipid and carbohydrate homeostasis, are associated with the sympathetic nervous system overactivity. Therefore, the inhibition of the adrenergic nervous system seems to be a reasonable and appropriate therapeutic approach for the treatment of metabolic disturbances. It has been suggested that non-selective adrenoceptor antagonists could be particularly beneficial, since α1-adrenoceptor antagonists can improve disrupted lipid and carbohydrate profiles, while the inhibition of the α2-adrenoceptor may contribute to body weight reduction. The aim of the present study was to investigate the metabolic benefits deriving from administration of a non-selective α-adrenoceptor antagonist from the group of pyrrolidin-2-one derivatives. The aim of the present study was to investigate the potential metabolic benefits deriving from chronic administration of a non-selective α-adrenoceptor antagonist, from the group of pyrrolidin-2-one derivatives. METHODS: The α1- and α2-adrenoreceptor affinities of the tested compound-1-(3-(4-(o-tolyl)piperazin-1-yl)propyl)pyrrolidin-2-one had been investigated previously by means of the radioligand binding assay. In the present study, we extended the pharmacological profile characteristics of the selected molecule by additional intrinistic activity assays. Next, we investigated the influence of the tested compound on body weight, hyperglycemia, hypertriglyceridemia, blood pressure in the animal model of obesity induced by a high-fat diet, and additionally we measured the spontaneous activity and body temperature. RESULTS: The intrinistic activity studies revealed that the tested compound is a potent, non-selective antagonist of α1B and α2A-adrenoceptors. After the chronic administration of the tested compound, we observed reduced level of triglycerides and glucose in the rat plasma. Interestingly, the tested did not reduce the body weight and did not influence the blood pressure in normotensive animals. Additionally, the administration of the tested compound did not change the animals' spontaneous activity and body temperature. CONCLUSION: Non-selective α-adrenoceptor antagonist seems to carry potential benefits in the improvement of the reduction of elevated glucose and triglyceride level. The lack of influence on blood pressure suggests that compounds with such a pharmacological profile may be particulary beneficial for the patients with disturbed lipid and carbohydrate profile, who do not suffer from hypertension. These results are particulary valuable, since currently there are no safe α2A-adrenoceptor antagonist drugs available in clinical use with the ability to modulate hyperglycemia that would not affect blood pressure.

α-Adrenoceptor antagonistic and hypotensive properties of novel arylpiperazine derivatives of pyrrolidin-2-one.

This study focused on a series of pyrrolidin-2-one derivatives connected via two or four methylene units to arylpiperazine fragment. The compounds obtained for α1- and α2-adrenoceptors were assessed. The compound with highest affinity for the α1-adrenoceptors was 1-{4-[4-(2-chloro-phenyl)-piperazin-1-yl]-butyl}-pyrrolidin-2-one (10 h) with pKi=7.30. Compound with pKi (α1) ⩾6.44 were evaluated in functional bioassays for intrinsic activity at α1A- and α1B-adrenoceptors. All compounds tested were antagonists of the α1B-adrenoceptors. Additionally, compounds 10e and 10h were α1A-adrenoceptors antagonist. The dual α1A-/α1B-adrenoceptors antagonists, compounds 10e and 10h were also tested in vivo for their hypotensive activity in rats. These compounds, when dosed of 1.0 mg/kg iv in normotensive, anesthetized rats, significantly decreased systolic and diastolic pressure and their hypotensive effects lasted for longer than one hour.

Antiarrhythmic and α-Adrenoceptor Antagonistic Properties of Novel Arylpiperazine Derivatives of Pyrrolidin-2-one.

In an effort to develop α-adrenoceptor antagonists with antiarrhythmic activity, we designed a series of pyrrolidin-2-one derivatives. The α1- and α2-adrenorecepor affinities of the new pyrrolidin-2-one derivatives were determined using a radioligand binding assay. The most active compound was then tested in vitro for intrinsic activity toward α(1A)- and α(1B)-adrenoceptors and in vitro for antiarrhythmic activity in epinephrine-induced arrhythmia in rats. The highest affinity for the α1-adrenoceptor (pK(i) = 7.01) was displayed by 1-{4-[4-(2-methoxy-5-chlorophenyl)-piperazin-1-yl]-methyl}-pyrrolidin-2-one (9). 1-[4-(2-Fluorophenyl)-piperazin-1-yl]-methyl-pyrrolidin-2-one (7) showed the highest affinity toward the α2-adrenoceptor (pK(i) = 6.52). Intrinsic activity studies of compound 9 showed that this compound is an antagonist of both α(1A)- (EC50 = 0.5 nM) and α(1B)- (EC50 = 51.0 nM) adrenoceptors. Compound 9 displayed antiarrhythmic activity in rats (ED50 = 5.0 mg/kg (3.13-7.99)). New derivatives of pyrrolidin-2-one with α1 -adrenoceptor affinity were identified. We propose that the antiarrhythmic activity of compound 9 is related to its antagonism of α(1A)- and α(1B)-adrenoceptors.

2-Substituted 4-hydroxybutanamides as potential inhibitors of γ-aminobutyric acid transporters mGAT1-mGAT4: synthesis and biological evaluation.

A series of 2-substituted 4-hydroxybutanamide derivatives has been synthesized by the aminolysis of appropriate 2-substituted dihydrofuran-2(3H)-one derivatives with various substituted benzylamines. The final compounds have been evaluated for their capability of inhibiting the GABA transport proteins GAT1-4 stably expressed in HEK-239 cell lines. The pIC50 values determined were in the range 4.21-5.14. Two compounds (16a and 16d), which displayed the most interesting profiles in in vitro tests, have also been subjected to further preliminary behavioral studies, evaluating their antinociceptive activity in hot-plate, writhing, and formalin tests. Their influence on motor coordination has also been assessed.

Application of NMR spectroscopy for assignment of the absolute configuration of 8-tert-butyl-2-hydroxy-7-methoxy-8-methyl-9-oxa-6-azaspiro[4.5]dec-6-en-10-one.

In order to assign the absolute configurations of 8-tert-butyl-2-hydroxy-7-methoxy-8-methyl-9-oxa-6-azaspiro[4.5]dec-6-en-10-one (2a,b), their esters (5a-d) with (R)- or (S)-2-methoxyphenylacetic acid (4a,b) have been synthesized. The absolute configurations of these compounds have been determined on the basis of NOESY correlations between the protons of the tert-butyl group and the cyclopentane fragment of the molecules. The crucial part of this analysis was assignment of the absolute configuration at C-5. Additionally, by calculation of the chemical shift anisotropy, δ(RS), for the relevant protons, it was also possible to confirm the absolute configurations at the C-2 centres of compounds 2a,b and 5a-d.

Discovery of novel multifunctional ligands targeting GABA transporters, butyrylcholinesterase, ß-secretase, and amyloid ß aggregation as potential treatment of Alzheimer's disease.

Alzheimer's disease (AD) is a global health problem in the medical sector that will increase over time. The limited treatment of AD leads to the search for a new clinical candidate. Considering the multifactorial nature of AD, a strategy targeting number of regulatory proteins involved in the development of the disease is an effective approach. Here, we present a discovery of new multi-target-directed ligands (MTDLs), purposely designed as GABA transporter (GAT) inhibitors, that successfully provide the inhibitory activity against butyrylcholinesterase (BuChE), ß-secretase (BACE1), amyloid ß aggregation and calcium channel blockade activity. The selected GAT inhibitors, 19c and 22a - N-benzylamide derivatives of 4-aminobutyric acid, displayed the most prominent multifunctional profile. Compound 19c (mGAT1 IC50 = 10 µM, mGAT4 IC50 = 12 µM and BuChE IC50 = 559 nM) possessed the highest hBACE1 and Aß40 aggregation inhibitory activity (IC50 = 1.57 µM and 99 % at 10 µM, respectively). Additionally, it showed a decrease in both the elongation and nucleation constants of the amyloid aggregation process. In contrast compound 22a represented the highest activity and a mixed-type of eqBuChE inhibition (IC50 = 173 nM) with hBACE1 (IC50 = 9.42 µM), Aß aggregation (79 % at 10 µM) and mGATs (mGAT1 IC50 = 30 µM, mGAT4 IC50 = 25 µM) inhibitory activity. Performed molecular docking studies described the mode of interactions with GATs and enzymatic targets. In ADMET in vitro studies both compounds showed acceptable metabolic stability and low neurotoxicity. Successfully, compounds 19c and 22a at the dose of 30 mg/kg possessed statistically significant antiamnesic properties in a mouse model of amnesia caused by scopolamine and assessed in the novel object recognition (NOR) task or the passive avoidance (PA) task.

Use of quantitative structure-enantioselective retention relationship for the liquid chromatography chiral separation prediction of the series of pyrrolidin-2-one compounds.

In this work, the enantioseparation of 15 structurally similar chiral solutes is studied, and analysis of the retention factors is performed using a genetic algorithm and multiple linear regression analysis technique. The present quantitative structure-enantioselective retention relationship model generated for retention factors' data has confirmed the importance of a number of descriptors altering the retention behavior and enantioselectivity of the studied compounds. Thus, fragment-based descriptor PSA, which encodes polar surface area, has confirmed the crucial role of heteroatoms in the retention behavior exhibited by pyrroliddin-2-ones. The presence of E(LUMO) descriptor, which represents a quantum-chemical property, has indicated the role of charge transfer interactions between the chiral stationary phase and enantiomers to retention factors, showing that lowest unoccupied molecular orbital energy is significantly different between enantiomers. The developed model exhibits a very good performance characterized by following statistical parameters: r(2) = 0.93 for training set and r(2) = 0.99 for the validation set. The selected three-variable model displays high predictive ability, catching the main factors affecting the enantioselectivity of studied chiral compounds, and therefore can be used for prediction of retention factors of other chiral compounds of similar structure to improve the separation process and so on.

QSAR studies on a number of pyrrolidin-2-one antiarrhythmic arylpiperazinyls.

The activity of a number of 1-[3-(4-arylpiperazin-1-yl)propyl]pyrrolidin-2-one antiarrhythmic (AA) agents was described using the quantitative structure-activity relationship model by applying it to 33 compounds. The molecular descriptors of the AA activity were obtained by quantum chemical calculations combined with molecular modeling calculations. The resulting model explains up to 91% of the variance and it was successfully validated by four tests (LOO, LMO, external test, and Y-scrambling test). Statistical analysis shows that the AA activity of the studied compounds depends mainly on the PCR and JGI4 descriptors. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00044-010-9540-x) contains supplementary material, which is available to authorized users.

Synthesis of novel N-benzyl substituted piperidine amides of 1H-indole-5-carboxylic acid as potential inhibitors of cholinesterases.

A series of novel N-benzyl substituted amides of 1H-indole-5-carboxylic acid were synthesized and evaluated for their ability to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). The target compounds (6b-6e) displayed moderate potency to inhibit BuChE. One of the compounds tested, i.e., 1-benzylpiperidine amide of 1H-indole-5-carboxylic acid (6a) was a weak, non-selective inhibitor for both enzymes. The highest inhibitory activity towards BuChE (30.06% [10 microM]) was determined for compound (6c) which is 1-(3-chloro)benzylpiperidine amide of 1H-indole-5-carboxylic acid.

Balloon aortic valvuloplasty in neonates: short- and long-term effects and predictors of successful outcome.

Introduction: Balloon aortic valvuloplasty (BAV) is a common treatment method of aortic valve (AV) stenosis in neonates. Long-term BAV effects are suboptimal, and their predictors are not well acknowledged. Aim: To identify predictors of suboptimal short- and long-term BAV results. Material and methods: The study group comprised forty-three neonates (8 females; weight 3.34 ±0.56 kg) who underwent BAV between 1998 and 2021. Seventeen patients (39.53%) had critical AV stenosis. AV was bicuspid in 22 patients, tricuspid in 12, unicuspid in 2, and undefined in 7 patients. The mean balloon/annulus ratio was 0.9 ±0.07. Catheterization, clinical, and follow-up data were analysed. Results: The peak-to-peak gradient decreased from 67.5 ±26.3 to 21.3 ±12.6 mm Hg. Twenty-eight patients (65.1%) had adequate early outcome. Aortic regurgitation (AR) occurred in 13 (30.2%) patients. No predictors of inadequate early outcome were found. Twenty-year survival was 90.7%. Eleven (35.5%) patients underwent reintervention at a median of 12 (1-215) months; BAV in 5 patients, surgical valvuloplasty in 2, Ross operation in 2, AV replacement in 1, and Norwood operation in 1 patient. Fifteen-year freedom from reintervention (FFR) was 48%. Adequate early outcome resulted in higher FFR (71% vs. 22%), and so did no significant AR (60% vs. 30%). Conclusions: BAV provides satisfying early results. AR remains a significant aftermath of BAV. Risk factors and procedural techniques improving the outcome of BAV are unclear. Further research is needed to improve FFR.

Novel Functionalized Amino Acids as Inhibitors of GABA Transporters with Analgesic Activity.

Neuropathic pain resistance to pharmacotherapy has encouraged researchers to develop effective therapies for its treatment. γ-Aminobutyric acid (GABA) transporters 1 and 4 (mGAT1 and mGAT4) have been increasingly recognized as promising drug targets for neuropathic pain (NP) associated with imbalances in inhibitory neurotransmission. In this context, we designed and synthesized new functionalized amino acids as inhibitors of GABA uptake and assessed their activities toward all four mouse GAT subtypes (mGAT1-4). According to the obtained results, compounds 2RS,4RS-39c (pIC50 (mGAT4) = 5.36), 50a (pIC50 (mGAT2) = 5.43), and 56a (with moderate subtype selectivity that favored mGAT4, pIC50 (mGAT4) = 5.04) were of particular interest and were therefore evaluated for their cytotoxic and hepatotoxic effects. In a set of in vivo experiments, both compounds 50a and 56a showed antinociceptive properties in three rodent models of NP, namely, chemotherapy-induced neuropathic pain models (the oxaliplatin model and the paclitaxel model) and the diabetic neuropathic pain model induced by streptozotocin; however compound 56a demonstrated predominant activity. Since impaired motor coordination is also observed in neuropathic pain conditions, we have pointed out that none of the test compounds induced motor deficits in the rotarod test.

Development of tricyclic N-benzyl-4-hydroxybutanamide derivatives as inhibitors of GABA transporters mGAT1-4 with anticonvulsant, antinociceptive, and antidepressant activity.

γ-Aminobutyric acid (GABA) neurotransmission has a significant impact on the proper functioning of the central nervous system. Numerous studies have indicated that inhibitors of the GABA transporters mGAT1-4 offer a promising strategy for the treatment of several neurological disorders, including epilepsy, neuropathic pain, and depression. Following our previous results, herein, we report the synthesis, biological evaluation, and structure-activity relationship studies supported by molecular docking and molecular dynamics of a new series of N-benzyl-4-hydroxybutanamide derivatives regarding their inhibitory potency toward mGAT1-4. This study allowed us to identify compound 23a (N-benzyl-4-hydroxybutanamide bearing a dibenzocycloheptatriene moiety), a nonselective GAT inhibitor with a slight preference toward mGAT4 (pIC50 = 5.02 ± 0.11), and compound 24e (4-hydroxy-N-[(4-methylphenyl)-methyl]butanamide bearing a dibenzocycloheptadiene moiety) with relatively high inhibitory activity toward mGAT2 (pIC50 = 5.34 ± 0.09). In a set of in vivo experiments, compound 24e successively showed predominant anticonvulsant activity and antinociception in the formalin model of tonic pain. In contrast, compound 23a showed significant antidepressant-like properties in mice. These results were consistent with the available literature data, which indicates that, apart from seizure control, GABAergic neurotransmission is also involved in the pathophysiology of several psychiatric diseases, however alternative mechanisms underlying this action cannot be excluded. Finally, it is worth noting that the selected compounds showed unimpaired locomotor skills that have been indicated to give reliable results in behavioral assays.

Novel mouse GABA uptake inhibitors with enhanced inhibitory activity toward mGAT3/4 and their effect on pain threshold in mice.

γ-Aminobutyric acid (GABA) uptake transporters are membrane transport proteins that are involved in the pathophysiology of a number of neurological disorders. Some types of chronic pain appear to result from the dysfunction of the GABAergic system. The deficiency of mouse GAT1 transporter (mGAT1) abolishes the nociceptive response, which means that mGAT1 inhibition is an appropriate medical approach to achieve analgesia. The mGAT4 transporter is the second most abundant GAT subtype in the brain; however, its physiological role has not yet been fully understood in the central nervous system. In this study, we examined whether the combination of mGAT1 and mGAT3/mGAT4 inhibition in a single molecule might lead to potentially synergistic effects improving analgesic activity to relieve neuropathic pain. To study this hypothesis, new GABA uptake inhibitors were designed, synthesized, and evaluated in terms of their activity and subtype selectivity for mGAT1-4. Among new functionalized amino acid derivatives of serine and GABA analogs, compounds with preferential mGAT3/4 inhibitory activity were discovered. Two selected hits (19b and 31c) were subjected to in vivo tests. We found a statistically significant antiallodynic activity in the von Frey test in diabetic and oxaliplatin-induced neuropathic pain model. The novel compounds (4-hydroxybutanoic, 4-hydroxypentanoic, and 4-aminobutanoic acid derivatives and serine analogs) provide new insights into the structure-activity relationship of mGAT3/mGAT4 inhibitors and indicate a new direction in the search for potential treatment of neuropathic pain of various origin.

Synthesis and pharmacological evaluation of new 1-[3-(4-phenylpiperazin-1-yl)-propyl]- and 1-[3-(4-phenylpiperidine)-propyl]- 3-aryl-3-alkyl-pyrrolidin-2-one derivatives with antiarrhythmic and antihypertensive activity.

A series of novel phenylpiperazine and phenylpiperidine derivatives bearing a 3,3-disubstituted pyrrolidin-2-one fragment were synthesized and evaluated for their binding affinity for alpha1-adrenoceptors (ARs) and for their antiarrhythmic and antihypertensive activities. The highest affinity for alpha1-ARs was displayed by 1-[2-hydroxy-3-(4-phenylpiperazin-l-yl)-propyl]-3-phenyl-3-n-propyl-pyrrolidin-2-one (10 a), which binds with pK(i) = 6.43. Among the compounds tested, 1-(2-hydroxy-3-(4-phenylpiperidin-1-yl)-propylpyrrolidin-2-one (5) was the most active in the prophylactic antiarrhythmic activity in adrenaline induced arrhythmia in anesthetized rats. Its ED50 value was 4.9 mg/kg intravenously (i.v.). Some of the compounds tested significantly decreased the systolic and diastolic pressure in normotensive anesthetized rats at a dose of 5.0 mg/kg i.v. and their hypotensive effects lasted for longer than an hour.

The role of structure activity relationship studies in the search for new GABA uptake inhibitors.

gamma-Aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the mammalian central nervous system (CNS). A decrease in GABAergic neurotransmission seems to be involved in neurological pathologies such as epilepsy, anxiety and pain. This review is focus on structure activity relationship studies aiming the search for new GABA uptake inhibitors.

Application of RP-TLC technique for the determination of dissociation constants of 1-substituted pyrrolidin-2-one derivatives.

The procedures for measuring dissociation constants (pK(a)) of twenty 1-substituted pyrrolidin-2-one derivatives are described. The dissociation constants of the compounds tested were determined using potentiometric titration, reversed-phase thin-layer chromatography (RP-TLC) and calculated using Pallas and Marvin programs. It was found that the RP-TLC method of determination of pK(a) could be considered as a feasible alternative to potentiometric titration. The Marvin program is a better tool for preliminary estimation of dissociation constant than the Pallas one.

Experimental Drugs for Neuropathic Pain.

BACKGROUND: Neuropathic pain (NP) is an important public health problem and despite recent progress in the understanding, diagnosis, pathophysiological mechanisms and the treatment of NP, many patients remain refractory to pharmacotherapy. OBJECTIVE: Currently used drugs have limited efficacy and dose-limiting adverse effects, and thus there is a substantial need for further development of novel medications for its treatment. Alternatively, drugs approved for use in diseases other than NP can be applied as experimental for NP conditions. This paper covers advances in the field of NP treatment. RESULTS: The prime focus of this paper is on drugs with well-established pharmacological activity whose current therapeutic applications are distinct from NP. These drugs could be a potential novel treatment of NP. Data from preclinical studies and clinical trials on these experimental drugs are presented. The development of advanced methods of genomics enabled to propose new targets for drugs which could be effective in the NP treatment. CONCLUSION: Experimental drugs for NP can be a treatment option which should be tailor-made for each individual on the basis of pain features, previous therapies, associated clinical conditions, recurrence of pain, adverse effects, contraindications and patients' preferences. At present, there are only some agents which may have potential as novel treatments. Increasing knowledge about mechanisms underlying NP, mechanisms of drug action, as well as available data from preclinical and clinical studies make botulinum toxin A, minocycline, ambroxol, statins and PPAR agonists (ATx086001) promising potential future treatment options.

Influence of the mobile phase composition on chiral recognition of some pyrrolidin-2-ones in the liquid chromatographic system with polysaccharide stationary phases.

Chiral separations of a series of 15 pyrrolidin-2-ones on polysaccharide stationary phases in the HPLC system have been reported. Three stationary phases have been applied: Chiralpak AD, Chiralpak IA and Chiralcel OD. The changes of retention and enantioselectivity have been examined depending on the organic modifier (ethanol or 2-propanol). The addition of a small amount of water has also been studied. Amylose columns exhibit better enantioselectivity (higher alpha values) than cellulose ones. All compounds can be enantiomerically separated on a Chiralpak IA column with EtOH as the organic modifier. The separation of all compounds on a Chiralpak AD and Chiralcel OD columns required changes of mobile phase composition. Depending on the structure of the compounds, the type of stationary phase, as well as the composition of the mobile phase, different intermolecular interactions can play a key role in chiral discrimination.

Carisbamate, a new carbamate for the treatment of epilepsy.

Carisbamate is a novel drug with neuromodulator activity that is currently under development for the treatment of epilepsy, diabetic neuropathy and neuralgia. The compound possessed a promising pharmacological profile in tests in vivo, and demonstrated broad anticonvulsant activity in preclinical studies, both elevating seizure threshold and preventing seizure spread. Carisbamate was also effective in protecting against spontaneous recurrent seizures in kainate-treated animals and in genetic models of epilepsy, and displayed antiepileptic and neuroprotective activity in the lithium-pilocarpine model of status epilepticus. In a phase I clinical trial, orally administered carisbamate demonstrated efficacy at high doses of 500 to 1000 mg. A phase II clinical trial confirmed that oral carisbamate was efficacious at a 300- to 1600-mg dose range. The preliminary evaluations of carisbamate in humans indicated complete absorption, extensive metabolism, and carbamate ester hydrolysis. The most frequently reported side effects associated with carisbamate are dizziness, headache, somnolence and nausea. In clinical trials, carisbamate did not display any significant interactions with commonly used antiepileptic drugs such as carbamazepine, valproate and lamotrigine. At the time of publication, a phase III clinical trial for carisbamate in the treatment of epilepsy was ongoing, as well as phase II trials in neuropathy and neuralgia. Data from preclinical brain injury studies with carisbamate and the analog RWJ-333369-A have also been reported. This drug profile will focus on the development of carisbamate in epilepsy.