New arylpiperazine derivatives with antidepressant-like activity containing isonicotinic and picolinic nuclei: evidence for serotonergic system involvement

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.

A Profound Insight into the Structure-activity Relationship of Ubiquitous Scaffold Piperazine: An Explicative Review

Despite extensive research in the field of drug discovery and development, still there is a need to develop novel molecular entities. Literature reveals a substantial heterocyclic nucleus named, piperazine, which shows an immense therapeutic voyage. For several decades, molecules having the piperazine nucleus have entered the market as a drug exhibiting biological potential. It was known to possess antipsychotic, antihistamine, antianginal, antidepressant, anticancer, antiviral, cardioprotective, and anti-inflammatory activity with a specific basis for structural activity relationship. Thus, it is regarded as a key structural feature in most of the already available therapeutic drugs in the market. Reports also suggest that the extensive utilization of these currently available drugs having a piperazine nucleus shows increasing tolerance significantly day by day. In addition to this, various other factors like solubility, low bioavailability, cost-effectiveness, and imbalance between pharmacokinetics and pharmacodynamics profile limit their utilization. Focusing on that issues, various structural modification studies were performed on the piperazine moiety to develop new derivatives/analogs to overcome the problems associated with available marketed drugs. Thus, this review article aims to gain insight into the number of structural modifications at the N-1 and N-4 positions of the piperazine scaffold. This SAR approach may prove to be the best way to overcome the above-discussed drawbacks and lead to the design of drug molecules with better efficacy and affinity. Hence, there is an urgent need to focus on the structural features of this scaffold which paves further work for deeper exploration and may help medicinal chemists as well as pharmaceutical industries.

New aryl-/heteroarylpiperazine derivatives of 1,7-dimethyl-8,9-diphenyl-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5,10-trione: Synthesis and preliminary studies of biological activities

Compounds containing dicarboximide skeleton such as succinimides, maleimides, glutarimides, and phthalimides possess broad biological properties including anti-fungal, antibacterial, antidepressant, or analgesic activities. The piperazine ring is found in a wide range of molecules that have demonstrated a variety of biological functions such as anticancer action and 5-HT receptors agonist/antagonist activity. In the present study, we combined both structures to develop new antitumor agents, a series of piperazine derivatives of 1,7-dimethyl-8,9-diphenyl-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5,10-trione and evaluated their biological activity. The structures of all tested compounds were confirmed by 1H and 13C NMR and by ESI MS spectral analysis. Their cytotoxicity was assessed in vitro against eight human cancer cell lines, namely prostate (PC3), colon (HCT116, SW480, SW620), leukemia (K562), liver (HepG2), lung (A549) and breast (MDA-Mb-231) in contrast to normal HMEC-1 cell line, by using MTT and Trypan blue method. The tested compounds showed significant activity toward cancer cells. The most pronounced cytotoxic effect was observed in K562 and HCT116 with IC50 values below 10 μM for all studied compounds. Importantly, the most promising derivatives for each cancer cell line (IC50 < 10 μM) exerted a weaker cytotoxic effect toward normal HMEC-1 cells than cancer cells. The evaluation of proapoptotic and inhibitory effects on IL-6 release showed that K562 and HCT116 cells were more sensitive to studied compounds than other cancer cell lines. Furthermore, for all piperazine derivatives, the functional activities at the 5-HT1A, D2 receptors as well as their binding affinities at the 5-HT2A, H1 and M receptors, were determined. The current investigation was able to successfully design compounds with both serotoninergic and anticancer properties. It serves as a good starting point for a multimodal approach for the management of cancer and cancer-related symptoms.

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.

Metabolite profiling of IMID-2, a novel anticancer molecule of piperazine derivative: In silico prediction, in vitro and in vivo metabolite characterization using UPLC-QTOF-MS/MS

IMID-2, a newly identified piperazine-based anticancer molecule, has been shown to be cytotoxic against various cancer cell lines. The primary aim of this research was to identify and characterize possible metabolites of the molecule formed during biotransformation. A metabolite identification study was first executed using an in silico tool to predict the possible metabolism sites of IMID-2. Thereafter, metabolites generated in vitro (rat liver microsomes, rat S9 fractions and human liver microsomes) and in vivo (rat plasma, urine and feces) were identified and characterized employing UPLC-QTOF-MS/MS. A total of eight metabolites, among which were six in phase I and two in phase II reactions, were recognized. The plausible structure of the metabolites and probable metabolic pathway have been established based on the mass fragmentation pattern, mass ppm error, ring double bond calculation and nitrogen rule. The majority of phase I metabolites were generated by N-oxidation, hydroxylation, oxidative deamination followed by reduction, oxidative dechlorination, N-dearylation, and N-dealkylation. Glucuronidation played a significant role in the formation of phase II metabolites of the molecule.

Novel piperazine-2,5-dione analogs bearing 1H-indole: Synthesis and biological effects

In this work, a series of novel piperazine-2,5-dione derivatives bearing indole analogs (2a-2q) was designed and synthesized. The synthesized compounds were characterized by IR, ¹H NMR, ¹³C NMR spectroscopy, and ESI-MS. They were then evaluated for their anti-depressant, anti-inflammatory, and analgesic activities in vivo. The experimental results revealed that all the compounds showed clear anti-depressant, anti-inflammatory, and analgesic effects at a dose of 10 mg/kg. Among them, compounds 2e and 2q exhibited the best anti-depressant effects (the percent decreases in the duration of immobility were 70.2% and 71.2%, respectively), which were similar to that of fluoxetine (67.9%) in the forced swim test. Additionally, compounds 2e and 2q also displayed good anti-inflammatory and analgesic activities. Literature reports have highlighted the anti-inflammatory and analgesic effects of anti-depressant drugs, suggesting that they may have a similar mechanism of action. Therefore, further studies to investigate the possible mechanisms of action of compounds 2e and 2q are warranted.

Antidepressant-like effect of a selenopropargylic benzamide in mice: involvement of the serotonergic system

RATIONALE

Major depressive disorder is a psychiatric disorder that requires considerable attention, since it dramatically impairs the quality of life of the sufferers. The available treatments do not have the efficacy needed, often presenting several side effects. Organoselenium compounds and benzamides have presented some pharmacological properties, among them an antidepressant-like effect.

OBJECTIVES AND METHODS

This study evaluated the antidepressant-like effect of N-(3-(phenylselanyl)prop-2-yn-1-yl)benzamide (SePB), an organoselenium compound containing a benzamide moiety, on the forced swimming test (FST) and the tail suspension test (TST) in mice, as well as the involvement of the serotonergic system in its effect.

RESULTS

SePB, tested after different times (15-120 min) and doses (1-50 mg/kg, intragastrically (i.g.)), reduced immobility of male mice during FST and TST, without changing locomotor activity in the open-field test (OFT), demonstrating its antidepressant-like effect. SePB (10 mg/kg) also produced an antidepressant-like effect in female mice in the TST. The preadministration of the serotonin (5-HT) depletor p-chlorophenylalanine (pCPA; 100 mg/kg, intraperitoneal route (i.p.) once daily for 4 days) prevented the anti-immobility effect of SePB, indicating that the serotonergic system is involved in the SePB antidepressant-like effect. The preadministration of the selective serotonergic receptor antagonists WAY100635 (0.1 mg/kg, subcutaneous route (s.c.), a selective 5-HT_1A receptor antagonist), ketanserin (1 mg/kg, i.p., a 5-HT_2A/2C receptor antagonist), and ondansetron (1 mg/kg, i.p., a selective 5-HT₃ receptor antagonist) also prevented the anti-immobility effect of SePB, demonstrating that these receptors are involved in the antidepressant-like effect of SePB.

CONCLUSION

The search for new antidepressants drugs is a noteworthy goal. This study has described a new compound with an antidepressant-like effect, whose mechanism of action is related to modulation of the serotonergic system.

Insight into antimicrobial activity of substituted phenylcarbamoyloxypiperazinylpropanols

3-[4-(Substituted)phenyl-/4-(diphenylmethyl)phenylpiperazin-1-yl]-2-hydroxypropyl-1-[(substituted)phenyl]carbamates and their salts with hydrochloric acid were synthesized, characterized, and tested in vitro against Staphylococcus aureus ATCC 29213 and Enterococcus faecalis ATCC 29212 as reference and quality control strains, against three methicillin-resistant isolates of S. aureus, and three isolates of vancomycin-resistant E. faecalis. All the compounds were evaluated against Mycobacterium tuberculosis H₃₇R_a/ATCC 25177, M. kansasii DSM 44162, and M. smegmatis ATCC 700084. All of the tested compounds demonstrated very good activity against all the tested strains/isolates comparable with or better than that of clinically used drugs (ampicillin, ciprofloxacin, vancomycin, isoniazid). 1-[{(3-Trifluoromethyl)phenyl}carbamoyloxy-2-hydroxypropyl]-4-(3,4-dichlorophenyl)piperazin-1-ium chloride demonstrated the highest potency against all the tested strains/isolates (MICs ranged from 3.78 to 30.2 µM), and 1-[{(3-trifluoromethyl)phenyl}carbamoyloxy-2-hydroxypropyl]-4-(diphenylmethyl)piperazin-1-ium chloride was the most effective against all the screened mycobacterial strains (MICs ranged from 3.64 to 14.5 µM). All the investigated derivatives had strong antibiofilm activity against S. aureus ATCC 29123 and a synergistic or additive effect with gentamicin against isolates of E. faecalis with both intrinsic and acquired resistance to gentamicin. The screening of the cytotoxicity of the compounds was performed using human monocytic leukemia THP-1 cells. The IC₅₀ values of the most effective compounds ranged from ca. 2.8 to 7.3 µM; thus, it can be stated that the antimicrobial effect is closely connected with their cytotoxicity. These observations disqualify these compounds from further development as antimicrobial agents, but they can be considered potential multi-target drugs with a preferred anticancer effect with good water solubility and additional anti-infectious activity.