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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., (© 2024 John Wiley & Sons Ltd.)

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., (© 2021 Wiley-VCH GmbH.)

Depression is declared the second leading cause of disability worldwide. Recently, cases of depression have increased significantly in adolescents, young adults as well as in elder population. Monoamine oxidase‐A (MAO‐A) is considered one of the major targets for the treatment of depression. In the current study, we have designed and synthesized various indole functionalized piperazinyl derivatives and evaluated them for in vitro MAO‐A inhibitory activity and in vivo antidepressant‐like activity. Most of the compounds were found to possess potent MAO‐A inhibitory activity with IC50 values in the sub‐micromolar range along with significant selectivity over MAO‐B. Compounds RP1 and RP9 emerged as the most promising reversible MAO‐A inhibitors with IC50 values of 0.11±0.03 μM and 0.14±0.02 μM and displayed selectivity of 193 folds and 178 folds over Monoamine oxidase‐B (MAO‐B), respectively. In the series, RP1 showed good intracellular ROS inhibitory activity along with neuroprotective properties. These compounds were found nontoxic against SH‐SY5Y cells and explored antidepressant activities. In the in vivo Forced swimming test (FST) and Tail suspension test (TST) studies, RP1 exhibited potential antidepressant‐like behavior similar to standard drug fluoxetine while compound RP9 showed antidepressant‐like activity only in the TST studies. The molecular docking and dynamics studies further supported the results obtained in the in vitro and in vivo studies. Thus, the indole functionalized piperazinyl derivatives were found to be promising ligands and can be developed as new antidepressant molecules. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new series of oxadiazole clubbed benzhydrylpiperazines (AP1-12) was designed, synthesized and evaluated for MAO inhibitory potential. • In this series, compounds AP3 and AP12 displayed most potent, selective and reversible inhibition of MAO-A enzyme. • In FST and TST studies, AP3 and AP12 exhibited potential antidepressant-like behaviour similar to standard drug fluoxetine. • Both potent compounds displayed good binding affinity and stability at binding pocket of MAO-A in in silico studies. Arylpiperazine clubbed various heterocyclic molecules present potential pharmacophoric structural features for the development of psychoactive drugs. There are various CNS active molecules possessing arylpiperazine moiety in their pharmacophore approved by USFDA. In the current study, we have explored the benzhydrylpiperazine moiety clubbed with various substituted oxadiazole moieties (AP1-12) for their monoamine oxidase (MAO) inhibition and antidepressant potential. Compounds AP3 and AP12 exhibited highly potent and selective MAO-A inhibition with IC 50 values of 1.34 ± 0.93 µM and 1.13 ± 0.54 µM, respectively, and a selectivity index of 10- and 13-folds, respectively. Both the compounds displayed reversible binding character at the active site of MAO-A. In further in vivo evaluation, both the compounds AP3 and AP12 displayed potential antidepressant-like character in FST and TST studies via significantly reduced immobility time in comparison to non-treated animals. These compounds displayed no cytotoxicity in SH-SY5Y cell lines, which indicates that these compounds are safe for further evaluation. In silico studies reveal that synthesized compounds possess drug-likeness with minimal to no toxicity. In silico studies were conducted to understand the binding interactions and stability of compounds at the binding pocket of enzyme and observed that both the best compounds fit well at the active site of MAO-A lined by amino acid residues Tyr69, Asn181, Phe208, Ile335, Leu337, Phe352, and Tyr444 similar to standard MAO-A inhibitor clorgiline. The molecular dynamic studies demonstrated that AP3 and AP12 formed quite a stable complex at the active site of MAO-A and did not break under small abruption forces. The favourable binding interactions and appropriate ADMET properties present the benzhydrylpiperazine clubbed oxadiazole pharmacophoric features as a potential structural skeleton for further clinical evaluation and development of a new antidepressant drug molecule. [ABSTRACT FROM AUTHOR]

• Recent developments of nitrogen-containing heterocyclic compounds as antidepressant have been discussed. • The antidepressant profile of the potent derivatives along with structural insights is presented. • The SAR studies of recently developed compounds are discussed in details for providing key structural features. • The lead compounds for further development are identified and discussed in the perspective part of this review. According to the World Health Organization (WHO), depression is a common mental disorder and includes complex interaction between social and psychological behaviour affecting 264 million people worldwide. The review aims to highlight the role and importance of nitrogen-based heterocyclics in the development of antidepressant compounds. Many research groups have attempted to design drug candidates capable of binding within the receptors. The commonest drug design strategy includes the incorporation of different structural features widely recognized as an antidepressant in the synthesized derivatives to enhance their CNS antidepressant effects. In this review, we have shed light on nitrogenous heterocyclic moieties such as quinazoline, pyridine, pyrimidine, pyrrolidine, imidazole, pyrazole, piperidine, oxadiazole, benzimidazole, benzothiazole, piperazine, triazine, purine, benzoxazole, and isoxazole as core nucleus and/or in combination as an antidepressant compound. These molecules with different structural features were noted to exert their antidepressant effects by multiple mechanisms viz., selective serotonin reuptake inhibitors (SSRIs), monoamine oxidase (MAO) inhibitors, and Catechol- O -methyltransferase (COMT) inhibitors. The review focuses on the selection of these heterocyclic moieties for the further design and development of promising antidepressants by taking a clue from the earlier reported potent antidepressant compounds or from the marketed products. The results have been correlated with their structural activity relationship (SAR) to identify the substituents for the potency and selectivity within the receptors. This review might help the researchers working in the antidepressant field to develop more novel molecules that could fill the gap by improving potency and reducing toxicity. [Display omitted] [ABSTRACT FROM AUTHOR]