Synthesis of new 4-butyl-arylpiperazine-3-(1H-indol-3-yl)pyrrolidine-2,5-dione derivatives and evaluation for their 5-HT1A and D2 receptor affinity and serotonin transporter inhibition

Development of heterocyclic-based frameworks as potential scaffold of 5-HT1A receptor agonist and future perspectives: A review

As a subtype of the 5-hydroxytryptamine (5-HT) receptor, 5-HT1A receptors are involved in the pathological process of psychiatric disorders and is an important target for antidepressants. The research groups focus on these area have tried to design novel compounds to alleviate depression by targeting 5-HT1A receptor. The heterocyclic structures is an important scaffold to enhance the antidepressant activity of ligands, including piperazine, piperidine, benzothiazole, and pyrrolidone. The current review highlights the function and significance of nitrogen-based heterocyclics 5-HT1AR represented by piperazine, piperidine, benzothiazole, and pyrrolidone in the development of antidepressant.

Advances in drug design and therapeutic potential of selective or multitarget 5-HT1A receptor ligands

5-HT1A receptor (5-HT1A-R) is a serotoninergic G-protein coupled receptor subtype which contributes to several physiological processes in both central nervous system and periphery. Despite being the first 5-HT-R identified, cloned and studied, it still represents a very attractive target in drug discovery and continues to be the focus of a myriad of drug discovery campaigns due to its involvement in numerous neuropsychiatric disorders. The structure-activity relationship studies (SAR) performed over the last years have been devoted to three main goals: (i) design and synthesis of 5-HT1A-R selective/preferential ligands; (ii) identification of 5-HT1A-R biased agonists, differentiating pre- versus post-synaptic agonism and signaling cellular mechanisms; (iii) development of multitarget compounds endowed with well-defined poly-pharmacological profiles targeting 5-HT1A-R along with other serotonin receptors, serotonin transporter (SERT), D2-like receptors and/or enzymes, such as acetylcholinesterase and phosphodiesterase, as a promising strategy for the management of complex psychiatric and neurodegenerative disorders. In this review, medicinal chemistry aspects of ligands acting as selective/preferential or multitarget 5-HT1A-R agonists and antagonists belonging to different chemotypes and developed in the last 7 years (2017-2023) have been discussed. The development of chemical and pharmacological 5-HT1A-R tools for molecular imaging have also been described. Finally, the pharmacological interest of 5-HT1A-R and the therapeutic potential of ligands targeting this receptor have been considered.

Nitrogen-containing heterocyclic compounds: A ray of hope in depression?

Depression is not similar to daily mood fluctuations and temporary emotional responses to day-to-day activities. Depression is not a passing problem; it is an ongoing problem. It deals with different episodes consisting of several symptoms that last for at least 2 weeks. It can be seen for several weeks, months, or years. At its final stage, or can say, in its worst condition, it can lead to suicide. Antidepressants are used to inhibit the reuptake of the neurotransmitters by some selective receptors, which increase the concentration of specific neurotransmitters around the nerves in the brain. Drugs that are currently being used for the management of various types of depression include selective serotonin reuptake inhibitors, tricyclic antidepressants, atypical antidepressants, serotonin, noradrenaline reuptake inhibitors, etc. In this review, we have outlined different symptoms, causes, and recent advancements in nitrogen-containing heterocyclic drug candidates for the management of depression. This article highlights the various structural features along with the structure-activity relationship (SAR) of nitrogen-containing heterocyclics that play a key role in binding at target sites for potential antidepressant action. The in silico studies were carried out to determine the binding interactions of the target ligands with the receptor site to determine the potential role of substitution patterns at core pharmacophoric features. This article will help medicinal chemists, biochemists, and other interested researchers in identifying the potential pharmacophores as lead compounds for further development of new potent antidepressants.

A Review on the Arylpiperazine Derivatives as Potential Therapeutics for the Treatment of Various Neurological Disorders

Abstract:

Neurological disorders are disease conditions related to the neurons and central nervous system (CNS). Any kind of structural, electrical, biochemical and functional abnormalities in neurons can lead to various types of disorders like Alzheimer’s disease (AD), depression, Parkinson’s disease (PD), epilepsy, stroke, etc. Currently available medicines are symptomatic and do not treat the disease state. Thus, novel CNS active agents with the potential of complete treatment of an illness are highly desired. A range of small organic molecules are being explored as potential drug candidates for the cure of different neurological disorders. In this context, arylpiperazine has been found to be a versatile scaffold and indispensable pharmacophore in many CNS active agents. A number of molecules with arylpiperazine nucleus have been developed as potent leads for the treatment of AD, PD, depression and other disorders. The arylpiperazine nucleus can be optionally substituted at different chemical structures and offer flexibility for the synthesis of large number of derivatives. In the current review article, we have explored the role of various arylpiperazine containing scaffolds against different neurological disorders, including AD, PD, and depression. The structure-activity relationship studies were conducted for recognizing potent lead compounds. This review article may provide important clues on the structural requirements for the design and synthesis of effective molecules as curative agents for different neurological disorders.

Design Strategies, Chemistry and Therapeutic Insights of Multi-target Directed Ligands as Antidepressant Agents

Depression is one of the major disorders of the central nervous system worldwide and causes disability and functional impairment. According to the World Health Organization, around 265 million people worldwide are affected by depression. Currently marketed antidepressant drugs take weeks or even months to show anticipated clinical efficacy but remain ineffective in treating suicidal thoughts and cognitive impairment. Due to the multifactorial complexity of the disease, single-target drugs do not always produce satisfactory results and lack the desired level of therapeutic efficacy. Recent literature reports have revealed improved therapeutic potential of multi-target directed ligands due to their synergistic potency and better safety. Medicinal chemists have gone to great extents to design multitarget ligands by generating structural hybrids of different key pharmacophores with improved binding affinities and potency towards different receptors or enzymes. This article has compiled the design strategies of recently published multi-target directed ligands as antidepressant agents. Their biological evaluation, structural-activity relationships, mechanistic and in silico studies have also been described. This article will prove to be highly useful for the researchers to design and develop multi-target ligands as antidepressants with high potency and therapeutic efficacy.

Identification of New Compounds with Anticonvulsant and Antinociceptive Properties in a Group of 3-substituted (2,5-dioxo-pyrrolidin-1-yl)(phenyl)-Acetamides

We report herein a series of water-soluble analogues of previously described anticonvulsants and their detailed in vivo and in vitro characterization. The majority of these compounds demonstrated broad-spectrum anticonvulsant properties in animal seizure models, including the maximal electroshock (MES) test, the pentylenetetrazole-induced seizure model (scPTZ), and the psychomotor 6 Hz (32 mA) seizure model in mice. Compound 14 showed the most robust anticonvulsant activity (ED₅₀ MES = 49.6 mg/kg, ED₅₀ 6 Hz (32 mA) = 31.3 mg/kg, ED₅₀scPTZ = 67.4 mg/kg). Notably, it was also effective in the 6 Hz (44 mA) model of drug-resistant epilepsy (ED₅₀ = 63.2 mg/kg). Apart from favorable anticonvulsant properties, compound 14 revealed a high efficacy against pain responses in the formalin-induced tonic pain, the capsaicin-induced neurogenic pain, as well as in the oxaliplatin-induced neuropathic pain in mice. Moreover, compound 14 showed distinct anti-inflammatory activity in the model of carrageenan-induced aseptic inflammation. The mechanism of action of compound 14 is likely complex and may result from the inhibition of peripheral and central sodium and calcium currents, as well as the TRPV1 receptor antagonism as observed in the in vitro studies. This lead compound also revealed beneficial in vitro ADME-Tox properties and an in vivo pharmacokinetic profile, making it a potential candidate for future preclinical development. Interestingly, the in vitro studies also showed a favorable induction effect of compound 14 on the viability of neuroblastoma SH-SY5Y cells.

The Structural Determinants for α1-Adrenergic/Serotonin Receptors Activity among Phenylpiperazine-Hydantoin Derivatives

Several studies confirmed the reciprocal interactions between adrenergic and serotoninergic systems and the influence of these phenomena on the pathogenesis of anxiety. Hence, searching for chemical agents with a multifunctional pharmacodynamic profile may bring highly effective therapy for CNS disorders. This study presents a deep structural insight into the hydantoin-arylpiperazine group and their serotonin/α-adrenergic activity. The newly synthesized compounds were tested in the radioligand binding assay and the intrinsic activity was evaluated for the selected derivatives. The computer-aided SAR analysis enabled us to answer questions about the influence of particular structural fragments on selective vs. multifunctional activity. As a result of the performed investigations, there were two leading structures: (a) compound 12 with multifunctional adrenergic-serotonin activity, which is a promising candidate to be an effective anxiolytic agent; (b) compound 14 with high α_1A/α_1D affinity and selectivity towards α_1B, which is recommended due to the elimination of probable cardiotoxic effect. The structural conclusions of this work provide significant support for future lead optimization in order to achieve the desired pharmacodynamic profile in searching for new CNS-modulating agents.

Piperazine, a Key Substructure for Antidepressants: Its Role in Developments and Structure-Activity Relationships

Depression is the single largest contributor to global disability with a huge economic and social burden on the world. There are a number of antidepressant drugs on the market, but treatment-resistant depression and relapse of depression in a large number of patients have increased problems for clinicians. One peculiarity observed in most of the marketed antidepressants is the presence of a piperazine substructure. Although piperazine is also used in the optimization of other pharmacological agents, it is almost extensively used for the development of novel antidepressants. One common understanding is that this is due to its favorable CNS pharmacokinetic profile; however, in the case of antidepressants, piperazine plays a much bigger role and is involved in specific binding conformations of these agents. Therefore, in this review, a critical analysis of the significance of the piperazine moiety in the development of antidepressants has been performed. An overview of current developments in the designing and synthesis of piperazine-based antidepressants (2015 onwards) along with SAR studies is also provided. The various piperazine-based therapeutic agents in early- or late-phase human testing for depression are also discussed. The preclinical compounds discussed in this review will help researchers understand how piperazine actually influences the design and development of novel antidepressant compounds. The SAR studies discussed will provide crucial clues about the structural features and optimizations required to enhance the efficacy and potency of piperazine-based antidepressants.

Research progress in biological activities of succinimide derivatives

Succinimides are well recognized heterocyclic compounds in drug discovery which produce diverse therapeutically related applications in pharmacological practices. Researches in medicinal chemistry field have isolated and synthesized succinimide derivatives with multiple medicinal properties including anticonvulsant, anti-inflammatory, antitumor and antimicrobial agents, 5-HT receptor ligands and enzyme inhibitors. Simultaneously, SAR (Structure-Activity Relationship) analysis has been gradually possessed, along with a great deal of derivatives have been derived for potential targets. In this article, we comprehensively summarize the biological activities and SAR for succinimide derivatives, along with the featuring bioactive molecules reported in patents, wishing to provide an overall retrospect and prospect on the succinimide analogues.

Multi-targeted drug design strategies for the treatment of schizophrenia

INTRODUCTION

Schizophrenia is a complex psychiatric disease (or a conglomeration of disorders) manifesting with positive, negative and cognitive symptoms. The pathophysiology of schizophrenia is not completely known; however, it involves many neurotransmitters and their receptors. In order to treat schizophrenia, drugs need to be multi-target drugs. Indeed, the action of second and third generation antipsychotics involves interactions with many receptors, belonging mainly to aminergic GPCRs.

AREAS COVERED

In this review, the authors summarize current concepts of schizophrenia with the emphasis on the modern dopaminergic, serotoninergic, and glutamatergic hypotheses. Next, they discuss treatments of the disease, stressing multi-target antipsychotics. They cover different aspects of design of multi-target ligands, including the application of molecular modeling approaches for the design and benefits and limitations of multifunctional compounds. Finally, they present successful case studies of multi-target drug design against schizophrenia.

EXPERT OPINION

Treatment of schizophrenia requires the application of multi-target drugs. While designing single target drugs is relatively easy, designing multifunctional compounds is a challenge due to the necessity to balance the affinity to many targets, while avoiding promiscuity and the problems with drug-likeness. Multi-target drugs bring many benefits: better efficiency, fewer adverse effects, and drug-drug interactions and better patient compliance to drug regime.

Recent advances in multitarget-directed ligands targeting G-protein-coupled receptors

Mounting evidence indicates that single-target drugs might be inadequate to achieve satisfactory therapeutic effects on complex diseases. Recently, increasing attention has been paid to developing drugs that can manipulate multiple targets to generate beneficial effects through potential synergy. G-protein-coupled receptors (GPCRs) become desirable targets for developing multitarget-directed ligands (MTDLs) because of their crucial roles in the pathophysiology of various human diseases and the accessibility of druggable sites at the cell surface. Herein, we review the most recent advances in the development of GPCR-targeted MTDLs in treating complex diseases, and discuss their potential therapeutic strategies to reveal current trends and shed insights into the utility of GPCR-targeted MTDLs for future drug design and development.