Novel Piperazine Based Compounds Target Alzheimer's Disease Relevant Amyloid ß42 and Tau Derived Peptide AcPHF6, and the Lead Molecule Increases Viability in the Flies Expressing Human Tau Protein.

Alzheimer's disease (AD) is the leading form of dementia in the United States and the world. The pathophysiology of AD is complex and multifaceted. Accumulation of senile plaques and neurofibrillary tangles (NFTs) are hallmarks of AD. The aggregation of amyloid ß (senile plaques) and tau tangles (NFTs) results in the death of neurons in the cortex and hippocampus, which manifests itself in cognitive decline and memory loss. Current therapies rely on conventional approaches that have only treated the underlying symptoms without disease modification. Data from clinical studies point to a complex role of amyloid ß (Aß) in a way that enhances the tau phenotype throughout the disease process. To address the co-pathogenic role of Aß and tau, we undertook development of multitarget compounds aiming at both tau and Aß to slow or stop disease progression and provide neuroprotection. Here, we demonstrate a dose-dependent effect of the novel test compounds that inhibit aggregation of AcPHF6 (a shorter version of tau protein) and Aß1-42 peptides in thioflavin T fluorescent assays. The compounds were also shown to disaggregate preformed aggregates dose dependently. To further validate these findings, circular dichroism experiments were carried out to examine the nature of inhibition. Additionally, transmission electron microscopy experiments were carried out to gain insights into the morphologies of aggregates obtained from dose-dependent inhibition of AcPHF6 and Aß1-42 as well as dissociation of preformed aggregates from these peptides. Compounds D-687 and D-688 reversed Aß1-42 induced toxicity in SH-SH5Y cells, significantly demonstrating neuroprotective properties. Finally, in a study with Drosophila melanogaster expressing human tau protein isoform (2N4R) in all the neurons, compound D-688 significantly increased the survival of flies compared to vehicle treated controls. Future studies will further examine the neuroprotective properties of these lead compounds in various animal models.

Design and Synthesis of 1,4-Diformyl-Piperazine Ferrostatin-1 Derivatives as Novel Ferroptosis Inhibitors.

The present study focuses on the design and synthesis of novel 1,4-diformyl-piperazine-based ferrostatin-1 (Fer-1) derivatives, and their evaluation against ferroptosis activity. The synthesized compounds demonstrated significant anti-ferroptosis activity in human umbilical vascular endothelial cells (HUVECs), with Compound 24 showing the highest potency. Mechanistic studies revealed that Compound 24 effectively reduced intracellular reactive oxygen species (ROS) levels, mitigated mitochondrial damage, and enhanced glutathione peroxidase 4 (GPX4) expression. Additionally, Compound 24 exhibited improved solubility and plasma stability compared to control compounds, Fer-1 and JHL-12. These findings suggest that 1,4-diformyl-piperazine-based Fer-1 derivatives hold promise as therapeutic agents for ferroptosis-associated cardiovascular diseases.

Discovery of a novel piperazine derivative, cmp2: a selective TRPC6 activator suitable for treatment of synaptic deficiency in Alzheimer's disease hippocampal neurons.

Alzheimer disease (AD) is characterized by progressive loss of memory. Synaptic loss is now the best correlate of cognitive dysfunction in patients with Alzheimer's disease. Thus, restoration or limitation of synapse loss is a promising strategy for pharmacotherapy of AD. N-N substituted piperazines are widely used chemical compounds for drug interventions to treat different illnesses including CNS diseases such as drug abuse, mental and anxiety disorders. Piperazine derivatives are small molecules that are usually well tolerated and cross blood brain barrier (BBB). Thus, disubstituted piperazines are good tools for searching and developing novel disease-modifying drugs. Previously, we have determined the piperazine derivative, 51164, as an activator of TRPC6 in dendritic spines. We have demonstrated synaptoprotective properties of 51164 in AD mouse models. However, 51164 was not able to cross BBB. Within the current study, we identified a novel piperazine derivative, cmp2, that is structurally similar to 51164 but is able to cross BBB. Cmp2 binds central part of monomeric TRPC6 in similar way as hypeforin does. Cmp2 selectively activates TRPC6 but not structurally related TRPC3 and TRPC7. Novel piperazine derivative exhibits synaptoprotective properties in culture and slices and penetrates the BBB. In vivo study indicated cmp2 (10 mg/kg I.P.) reversed deficits in synaptic plasticity in the 5xFAD mice. Thus, we suggest that cmp2 is a novel lead compound for drug development. The mechanism of cmp2 action is based on selective TRPC6 stimulation and it is expected to treat synaptic deficiency in hippocampal neurons.

Pyrrolidine, Piperazine, and Diazinane Alkaloids from the Marine Bacterium Strain Vibrio ruber ZXR-93.

Four new alkaloids, vibripyrrolidine A (1), vibripiperazine A (2), and vibridiazinane A, B (3, 4), comprising one pyrrolidine, one piperazine, and two diazinane alkaloids, along with two known analogs (5, 6), were isolated from the marine bacterium Vibrio ruber ZXR-93 cultured in ISP2 medium. Their chemical structures were elucidated by analysis of their 1D and 2D NMR, mass spectra, and electronic circular dichroism (ECD) calculations. Compounds 1 and 3-6 showed vigorous antibacterial activity against Staphylococcus aureus, with MIC values ranging from 0.96 to 7.81 µg/mL. Moreover, compound 1 exhibited robust anti-inflammatory activity in vitro using the LPS-induced RAW264.7 macrophage model. All compounds also showed moderate antineoplastic activity against cervical cancer cells (HeLa) and gastric cancer cells (SGC-7901).

Salicylaldehyde-derived piperazine-functionalized hydrazone ligand-based Pt(II) complexes: inhibition of EZH2-dependent tumorigenesis in pancreatic ductal adenocarcinoma, synergism with PARP inhibitors and enhanced apoptosis.

Piperazine is an important functional unit of many clinically approved drugs, including chemotherapeutic agents. In the current study, methyl piperazine was incorporated and eight salicylaldehyde-derived piperazine-functionalized hydrazone ONN-donor ligands (L) and their Pt(II) complexes (L-PtCl) were prepared. The structures of all these ligands (L1-L8) and Pt(II) complexes (C1-C8) were determined using 1H and 13C NMR, UV-vis, FT-IR and HR-ESI MS analyses, whereas the structures of C1, C5, C6, C7 and C8 were determined in the solid state using single crystal X-ray diffraction analysis. Solution state stabilities of C3, C4, C5 and C6 were determined via time-dependent UV-vis spectroscopy. All these complexes (C1-C8) were studied for their anticancer effect in pancreatic ductal adenocarcinoma cells, including BxPC3, MIAPaCa-2 and PANC1 cells. C1-C8 displayed a potential cytotoxic effect in all these cancer cells, among which C5, C6 and C8 showed the strongest inhibitory effect in comparison with standard chemotherapeutic agents, including 5-fluorouracil (5-FU), cisplatin (CP), oxaliplatin and doxorubicin (DOX). C5, C6 and C8 suppressed the growth of pancreatic cancer cells in a dose-dependent manner. Moreover, C5, C6 and C8 inhibited clonogenic potential and invasion ability and induced apoptosis in PANC1 cells. Importantly, C5, C6 and C8 synergized the anticancer effect with PARP inhibitors, including olaparib, veliparib and niraparib, in pancreatic cancer cells, thus suggesting an important role of C5, C6 and C8 in induction of apoptosis in combination with PARP inhibitors. C5 combined with PARP inhibitors induced caspase3/7 activity and suppressed ATP production. Mechanistically, C5, C6 and C8 inhibited EZH2 protein expression to suppress EZH2-dependent tumorigenesis. Overall, these results highlighted the importance of these piperazine-functionalized Pt(II) complexes as potential anticancer agents to suppress pancreatic ductal adenocarcinoma tumorigenesis by targeting the EZH2-dependent pathway.

Synthesis, biological evaluation, and molecular docking studies of novel N-substituted piperazine-tethered thiophene-3-carboxamide selenides as potent antiproliferative agents with EGFR kinase inhibitory activity.

In the context of structural investigation and optimization of various potential EGFR inhibitors, a novel series of asymmetrical piperazine-tethered trisubstituted thiophene-3-carboxamide selenide derivatives were synthesized and evaluated for their antiproliferative potential against selected human cancer cell lines. These derivatives, built based on a previously identified hit molecule, were synthesized via multiple-step reactions, including optimization of the C-Se cross-coupling reaction. Two compounds, 17i and 18i, displayed significant cytotoxicity (IC50 value: 4.82 ± 0.80 µM and 1.43 ± 0.08 µM) against HCT116 and A549 cancer cell lines, respectively. Quantitative analysis of apoptotic stages using Annexin V-FITC/PI double staining validated their apoptotic potential. Further, compound 18i demonstrated a remarkable inhibition of EGFR kinase, with an IC50 concentration of 42.3 nM. The lead compound 18i, with remarkable in vitro cytotoxicity, apoptosis induction capability, and EGFR inhibition, emerges as a promising candidate for anticancer therapy.

Morpholine, Piperazine, and Piperidine Derivatives as Antidiabetic Agents.

Diabetes mellitus is a severe endocrine disease that affects more and more people every year. Modern medical chemistry sets itself the task of finding effective and safe drugs against diabetes. This review provides an overview of potential antidiabetic drugs based on three heterocyclic compounds, namely morpholine, piperazine, and piperidine. Studies have shown that compounds containing their moieties can be quite effective in vitro and in vivo for the treatment of diabetes and its consequences.

Novel Piperazine Derivatives of Vindoline as Anticancer Agents.

A series of novel vindoline-piperazine conjugates were synthesized by coupling 6 N-substituted piperazine pharmacophores at positions 10 and 17 of Vinca alkaloid monomer vindoline through different types of linkers. The in vitro antiproliferative activity of the 17 new conjugates was investigated on 60 human tumor cell lines (NCI60). Nine compounds presented significant antiproliferative effects. The most potent derivatives showed low micromolar growth inhibition (GI50) values against most of the cell lines. Among them, conjugates containing [4-(trifluoromethyl)benzyl]piperazine (23) and 1-bis(4-fluorophenyl)methyl piperazine (25) in position 17 of vindoline were outstanding. The first one was the most effective on the breast cancer MDA-MB-468 cell line (GI50 = 1.00 µM), while the second one was the most effective on the non-small cell lung cancer cell line HOP-92 (GI50 = 1.35 µM). The CellTiter-Glo Luminescent Cell Viability Assay was performed with conjugates 20, 23, and 25 on non-tumor Chinese hamster ovary (CHO) cells to determine the selectivity of the conjugates for cancer cells. These compounds exhibited promising selectivity with estimated half-maximal inhibitory concentration (IC50) values of 2.54 µM, 10.8 µM, and 6.64 µM, respectively. The obtained results may have an impact on the design of novel vindoline-based anticancer compounds.

The impact of piperazine and antipsychotic co-exposures and CB1 blockade on the effects elicited by AMB-FUBINACA, a synthetic cannabinoid, in mice.

BACKGROUND & PURPOSE: The constant emergence and broad toxicological effects of synthetic cannabinoids create a discernible public health threat. The synthetic cannabinoid AMB-FUBINACA (AMB-FUB) is a potent agonist at the CB1 receptor and has been associated with numerous fatalities. Synthetic cannabinoids are commonly abused alongside other drugs and medications, including a "party pill" drug, para-fluorophenylpiperazine (pFPP), and the antipsychotic risperidone. This research aimed to investigate the mechanisms underpinning AMB-FUB toxicity and the impact of clinically relevant co-exposures in vivo. EXPERIMENTAL APPROACH: Male and female C57Bl/6 mice received a single dose of AMB-FUB (3 or 6 mg kg-1), pFPP (10 or 20 mg kg-1) or vehicle intraperitoneally. Mice were co-exposed to AMB-FUB (3 mg kg-1) and pFPP (10 mg kg-1) or risperidone (0.5 mg kg-1) to investigate these drug combinations. To study receptor-dependency and potential rescue of AMB-FUB toxicity, rimonabant (3 mg kg-1) was administered both pre- and post-AMB-FUB. Adverse effects caused by drug administration, including hypothermia and convulsions, were recorded. KEY RESULTS: AMB-FUB induced CB1-dependent hypothermia and convulsions in mice. The combination of AMB-FUB and pFPP significantly potentiated hypothermia, as did risperidone pre-treatment. Interestingly, risperidone provided significant protection from AMB-FUB-induced convulsions in female mice. Pre- and post-treatment with rimonabant was able to significantly attenuate both hypothermia and convulsions in mice administered AMB-FUB. CONCLUSION & IMPLICATIONS: Factors such as dose, CB1 signalling, and substance co-exposure significantly contribute to the toxicity of AMB-FUBINACA. Mechanistic understanding of synthetic cannabinoid toxicity and fatality can help inform overdose treatment strategies and identify vulnerable populations of synthetic cannabinoid users.

Dual Inhibitors of P-gp and Carbonic Anhydrase XII (hCA XII) against Tumor Multidrug Resistance with Piperazine Scaffold.

A new series of piperazine derivatives were synthesized and studied with the aim of obtaining dual inhibitors of P-glycoprotein (P-gp) and carbonic anhydrase XII (hCA XII) to synergistically overcome the P-gp-mediated multidrug resistance (MDR) in cancer cells expressing the two proteins, P-gp and hCA XII. Indeed, these hybrid compounds contain both P-gp and hCA XII binding groups on the two nitrogen atoms of the heterocyclic ring. All compounds showed good inhibitory activity on each protein (P-gp and hCA XII) studied individually, and many of them showed a synergistic effect in the resistant HT29/DOX and A549/DOX cell lines which overexpress both the target proteins. In particular, compound 33 displayed the best activity by enhancing the cytotoxicity and intracellular accumulation of doxorubicin in HT29/DOX and A549/DOX cells, thus resulting as promising P-gp-mediated MDR reverser with a synergistic mechanism. Furthermore, compounds 13, 27 and 32 induced collateral sensitivity (CS) in MDR cells, as they were more cytotoxic in resistant cells than in the sensitive ones; their CS mechanisms were extensively investigated.

Structure-based discovery of novel piperidine-biphenyl-DAPY derivatives as non-nucleoside reverse transcriptase inhibitors featuring improved potency, safety, and selectivity: From piperazine-biphenyl-DAPYs to piperidine-biphenyl-DAPYs.

Starting from our previously reported nonnucleoside reverse transcriptase inhibitor (NNRTI, 3), continuous efforts were made to enhance its potency and safety through a structure-based drug design strategy. This led to the discovery of a series of novel piperidine-biphenyl-diarylpyrimidines (DAPYs). Compound 10p, the most active compound in this series, exhibited an EC50 value of 6 nM against wide-type HIV-1 strain, which was approximately 560-fold more potent than the initial compound 3 (EC50 = 3.36 µM). Furthermore, significant improvements were observed in cytotoxicity and selectivity (CC50 > 202.17 µM, SI > 33144) compared to compound 3 (CC50 = 14.84 µM, SI = 4). Additionally, compound 10p demonstrated increased inhibitory activity against clinically mutant virus strains (EC50 = 7-63 nM). Further toxicity evaluation revealed that compound 10p exhibited minimal CYP enzyme and hERG inhibition. Importantly, single-dose acute toxicity testing did not result in any fatalities or noticeable pathological damage in mice. Therefore, compound 10p can be regarded as a lead candidate for guiding further development of biphenyl-diarylpyrimidine NNRTIs with favorable druggability for HIV therapy.

Hepatoprotective effect of diammonium glycyrrhizinate and neuroprotective effect of piperazine ferulate on AmB-induced liver and kidney injury by suppressing apoptosis in vitro and in vivo.

Amphotericin B (AmB) induced liver and kidney injury is often responsible for hepatic and renal dysfunction. Therefore, the protection strategy on liver and renal functions in patients treated with AmB should be emphasized. In this paper, diammonium glycyrrhizinate (DG) and piperazine ferulate (PF) were taken as the research object to study its hepatoprotective and neuroprotective effect on AmB-induced liver and kidney damage in vitro and in vivo. The microplate method and ELISA kits were employed for the biochemical detection in the serum and urine of mice. Flow cytometric analysis and western blotting analysis were conducted to study the mechanism of DG and PF. Our results confirmed the prevention capacity of DG and PF on AmB-induced liver and kidney injury through the alleviation of pathological changes and enzyme reducing action. Furthermore, DG and PF suppressed ROS-mediated mitochondrial apoptosis in AmB-treated mice and cells through Caspase pathway and Caspase-independent AIF pathway. In summary, DG and PF could protect AmB-induced hepatotoxicity and nephrotoxicity by disrupting oxidative stress and apoptosis.

Novel benzene sulfonamide-piperazine hybrid compounds: design, synthesis, antioxidant, enzyme inhibition activities and docking, ADME profiling studies.

Benzene sulfonamides are an important biological substituent for several activities. In this study, hybridization of benzene sulfonamide with piperazine derivatives were investigated for their antioxidant capacity and enzyme inhibitory potencies. Six molecules were synthesized and characterized. DPPH, ABTS, FRAP, CUPRAC, chelating and phosphomolybdemum assays were applied to evaluate antioxidant capacities. Results show that compounds have high antioxidant capacity and compound 4 has the best antioxidant activity among them. Compound 4 has higher antioxidant activity than references for FRAP (IC50: 0.08 mM), CUPRAC (IC50: 0.21 mM) and phosphomolybdenum (IC50: 0.22 mM) assays. Besides this, compound 4 has moderate DPPH and ABTS antioxidant capacity. Furthermore, enzyme inhibition activities of these molecules were investigated against AChE, BChE, tyrosinase, α-amylase and α-glucosidase enzymes. It was revealed that all compounds have good enzyme inhibitory potential except for α-amylase enzyme. The best inhibitory activities were observed for AChE with compound 5 the same value (IC50: 1.003 mM), for BChE with compounds 2 and 5 the same value (IC50: 1.008 mM), for tyrosinase compound 4 (IC50: 1.19 mM), and for α-glucosidase with compound 3 (IC50: 1.000 mM). Docking studies have been conducted with these molecules, and the results correlate well with the inhibitory assays.

Design, Synthesis, and Antifungal Activity of Acrylamide Derivatives Containing Trifluoromethylpyridine and Piperazine.

In this study, a series of acrylamide derivatives containing trifluoromethylpyridine or piperazine fragments were rationally designed and synthesized. Subsequently, the in vitro antifungal activities of all of the synthesized compounds were evaluated. The findings revealed that compounds 6b, 6c, and 7e exhibited >80% antifungal activity against Phomopsis sp. (Ps) at the concentration of 50 µg/mL. Furthermore, the EC50 values for compounds 6b, 6c, and 7e against Ps were determined to be 4.49, 6.47, and 8.68 µg/mL, respectively, which were better than the positive control with azoxystrobin (24.83 µg/mL). At the concentration of 200 µg/mL, the protective activity of compound 6b against Ps reached 65%, which was comparable to that of azoxystrobin (60.9%). Comprehensive mechanistic studies, including morphological studies with fluorescence microscopy (FM), cytoplasmic leakage, and enzyme activity assays, indicated that compound 6b disrupts cell membrane integrity and induces the accumulation of defense enzyme activity, thereby inhibiting mycelial growth. Therefore, compound 6b serves as a valuable candidate for the development of novel fungicides for plant protection.

Design, synthesis of combretastatin A-4 piperazine derivatives as potential antitumor agents by inhibiting tubulin polymerization and inducing autophagy in HCT116 cells.

A series of combretastatin A-4 (CA-4) derivatives were designed and synthesized, which contain stilbene core structure with different linker, predominantly piperazine derivatives. These compounds were evaluated for their cytotoxic activities against four cancer cell lines, HCT116, A549, AGS, and SK-MES-1. Among them, compound 13 displayed the best effectiveness with IC50 values of 0.227 µM and 0.253 µM against HCT116 and A549 cells, respectively, showing low toxicity to normal cells. Mechanistic studies showed that 13 inhibited HCT116 proliferation via arresting cell cycle at the G2/M phase through disrupting the microtubule network and inducing autophagy in HCT116 cells by regulating the expression levels of autophagy-related proteins. In addition, 13 displayed antiproliferative activities against A549 cells through blocking the cell cycle and inducing A549 cells apoptosis. Because of the poor water solubility of 13, four carbohydrate conjugates were synthesized which exhibited better water solubility. Further investigations revealed that 13 showed positive effects in vivo anticancer study with HCT116 xenograft models. These data suggest that 13 could be served as a promising lead compound for further development of anti-colon carcinoma agent.

New piperazine and morpholine derivatives: Mass spectrometry characterization and evaluation of their antimicrobial activity.

Recently, pharmaceutical research has been focused on the design of new antibacterial drugs with higher selectivity towards several strains. Major issues concern the possibility to obtain compounds with fewer side effects, at the same time effectively overcoming the problem of antimicrobial resistance. Several solutions include the synthesis of new pharmacophores starting from piperazine or morpholine core units. Mass spectrometry-based techniques offer important support for the structural characterization of newly synthesized compounds to design safer and more effective drugs for various medical conditions. Here, two new piperazine derivatives and four new morpholine derivatives were synthesized and structurally characterized through a combined approach of Fourier transform-ion cyclotron resonance (FT-ICR) and Linear Trap Quadrupole (LTQ) mass spectrometry. The support of both high-resolution and low-resolution mass spectrometric data namely accurate mass measurements, isotopic distribution and MSn spectra, was crucial to confirm the success of the synthesis. These compounds were further evaluated for inhibitory activity against a total of twenty-nine Gram-positive and Gram-negative bacteria to determine the action spectrum and the antimicrobial effectiveness. Results demonstrated compounds' antimicrobial activity against many tested bacterial species, providing an inhibitory effect linked to different chemical structure and suggesting that the new-synthesized derivatives could be considered as promising antimicrobial agents.

Multitarget action of Benzothiazole-piperazine small hybrid molecule against Alzheimer's disease: In silico, In vitro, and In vivo investigation.

A novel small molecule based on benzothiazole-piperazine has been identified as an effective multi-target-directed ligand (MTDL) against Alzheimer's disease (AD). Employing a medicinal chemistry approach, combined with molecular docking, MD simulation, and binding free energy estimation, compound 1 emerged as a potent MTDL against AD. Notably, compound 1 demonstrated efficient binding to both AChE and Aß1-42, involving crucial molecular interactions within their active sites. It displayed a binding free energy (ΔGbind) -18.64± 0.16 and -16.10 ± 0.18 kcal/mol against AChE and Aß1-42, respectively. In-silico findings were substantiated through rigorous in vitro and in vivo studies. In vitro analysis confirmed compound 1 (IC50=0.42 µM) as an effective, mixed-type, and selective AChE inhibitor, binding at both the enzyme's catalytic and peripheral anionic sites. Furthermore, compound 1 demonstrated a remarkable ability to reduce the aggregation propensity of Aß, as evidenced by Confocal laser scanning microscopy and TEM studies. Remarkably, in vivo studies exhibited the promising therapeutic potential of compound 1. In a scopolamine-induced memory deficit mouse model of AD, compound 1 showed significantly improved spatial memory and cognition. These findings collectively underscore the potential of compound 1 as a promising therapeutic candidate for the treatment of AD.

Synthetic Protocols, Structural Activity Relationship, and Biological Activity of Piperazine and its Derivatives.

The versatile basic structure of piperazine allows for the development and production of newer bioactive molecules that can be used to treat a wide range of diseases. Piperazine derivatives are unique and can easily be modified for the desired pharmacological activity. The two opposing nitrogen atoms in a six-membered piperazine ring offer a large polar surface area, relative structural rigidity, and more acceptors and donors of hydrogen bonds. These properties frequently result in greater water solubility, oral bioavailability, and ADME characteristics, as well as improved target affinity and specificity. Various synthetic protocols have been reported for piperazine and its derivatives. In this review, we focused on recently published synthetic protocols for the synthesis of the piperazine and its derivatives. The structure-activity relationship concerning different biological activities of various piperazine-containing drugs was also highlighted to provide a good understanding to researchers for future research on piperazines.

Novel Piperazine Derivatives as Potent Antihistamine, Anti-Inflammatory, and Anticancer Agents, their Synthesis and Characterization.

INTRODUCTION: In this study, a series of novel piperazine derivatives were synthesised with high-to-good yields, and their structural analogies were confirmed using FTIR, 1H-NMR, and LC-MS techniques. METHODS: The synthesised compounds were evaluated for antioxidant and antimicrobial activities. Among the four synthesised piperazine derivatives, compound PD-2 exhibited relatively good antioxidant activity, with an IC50 value of 2.396 µg/mL, while the other three derivatives showed moderate to low antioxidant activity. Furthermore, compound PD-2 displayed antimicrobial activity against Pseudomonas aeruginosa, a gram-negative bacterium, and Candida albicans, a fungus. However, all four compounds showed strong resistance against grampositive bacteria, Staphylococcus aureus. RESULTS: Additionally, compound PD-1 exhibited significant antihistamine activity, eliciting an 18.22% reduction in histamine levels. Both PD-1 and PD-2 demonstrated noteworthy anti-inflammatory activity in a dosedependent manner (5-10 µM), leading to the inhibition of nitrite production up to 39.42% and 33.7% at higher concentrations (10 µM) and inhibition of tumour necrosis factor-alpha (TNF-α) generation up to 56.97% and 44.73% at 10 µM, respectively. Additionally, both novel molecules PD-1 and PD-2 effectively restrained the growth of HepG2 cells in a manner that is dependent on the dosage up to 55.44% and 90.45% at the highest concentrations (100 µg/mL), respectively. CONCLUSION: These findings substantiate the rationale for further investigation into the novel series of persuasive piperazine analogues as potential agents with anti-inflammatory, antihistamine and anticancer properties.

Design, synthesis, and biological evaluation of aralkyl piperazine and piperidine derivatives targeting SSRI/5-HT1A/5-HT7.

Serotonin reuptake inhibition combined with the action targeting 5-hydroxytryptamine receptor subtypes can serve as a potential target for the development of antidepressant drugs. Herein a series of new aralkyl piperazines and piperidines were designed and synthesized by the structural modifications of the previously discovered aralkyl piperidine compound 1, targeting SSRI/5-HT1A/5-HT7. The results exhibited that compound 5a showed strong binding to 5-HT1A and 5-HT7 (Ki of 0.46 nM, 2.7 nM, respectively) and a high level of serotonin reuptake inhibition (IC50 of 1.9 nM), all of which were significantly elevated compared to 1. In particular, compound 5a showed weaker inhibitory activity against hERG than 1, and demonstrated good stability in liver microsomes in vitro. The preliminary screening using FST indicated that orally administered 5a, at a high dose, could reduce immobility time in mice markedly, indicating potential antidepressant activity.