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.

A Potent and Selective Janus Kinase Inhibitor with a Chiral 3D-Shaped Triquinazine Ring System from Chemical Space.

The generated databases (GDBs) enumerate billions of possible molecules following simple rules of chemical stability and synthetic feasibility. Exploring the GDBs shows that many chiral, 3D-shaped ring systems, often containing quaternary centers, have never been exploited for drug design. Shown herein is that such ring systems can be useful for medicinal chemistry by using the example of the enantioselective synthesis of triquinazine, a novel chiral piperazine analogue derived from angular triquinane. It is used to design a nanomolar and selective inhibitor of Janus Kinase 1 and is related to the marketed drug Tofacitinib, which is useful for treating autoimmune diseases.

N-Substituted piperazine derivatives as potential multitarget agents acting on histamine H3 receptor and cancer resistance proteins.

Taking into account that multidrug resistance (MDR) is the main cause for chemotherapeutic failure in cancer treatment, the ability of novel histamine H3 receptor ligands to reverse the cancer MDR was evaluated, using the ABCB1 efflux pump inhibition assay in mouse MDR T-lymphoma cells. The most active compounds displayed significant cytotoxic and antiproliferative effects as well as a very potent MDR efflux pump inhibitory action, 3-5-fold stronger than that of reference inhibitor verapamil. Although these compounds possess weak antagonistic properties against histamine H3 receptors, they are valuable pharmacological tools in the search for novel anticancer molecules. Furthermore, for the most active compounds, an insight into mechanisms of action using either, the luminescent Pgp-Glo™ Assay in vitro or docking studies to human Pgp, was performed.

Neuropharmacological assessment in mice and molecular docking of piperazine derivative LQFM212.

Piperazine derivatives are an attractive class of chemical compounds for the treatment of various mental illness. Herein, we demonstrated the synthesis of LQFM212, a piperazine derivative, behavioral evaluation in mice and computational studies. In neuropharmacological assessment, LQFM212 treatment at doses of 18, 54 or 162 µmol/kg increased the sleep duration in sodium pentobarbital-induced sleep test. LQFM212 at dose of 162 µmol/kg increased climbing time in the chimney test and decreased the number of squares crossed in the open field test, suggesting that LQFM212 in high doses reduces spontaneous movement. However, LQFM212 treatment at the doses of 18 or 54 µmol/kg increased the preference for the center of field which could be indicative of anxiolytic-like effects. In elevated plus maze and light-dark box tests, LQFM212 treatment altered all parameters observed that demonstrate anxiolytic-like activity. These effects were reversed by flumazenil, mecamylamine, WAY-100635 and PCPA, but not with ketanserin, showing that anxiolytic-like activity involve benzodiazepine site of GABAA receptor, nicotinic and serotonergic pathways. Molecular docking of LQFM212 showed that the ligand has more interactions with GABAA receptor than with 5-HT1A receptor. Despite the involvement of benzodiazepine site on anxiolytic-like effect of LQFM212, treatment with this compound did not alter cognitive function in the step-down avoidance test. In this sense, this piperazine derivative is a good prototype for treating anxiety disorders with putative mechanism of action.

Design, synthesis and evaluation of novel nonquaternary and 3 non-oxime reactivators for acetylcholinesterase inhibited by organophosphates.

A new series of novel nonquaternary conjugates and non-oxime reactivators for reactivation of both nerve agents and pesticides inhibited hAChE were described in this paper. Conjugates with piperazine linked to the substituted salicylaldoxime emerged as efficient reactivators for VX inhibited hAChE. The in vitro reactivation experiment showed that some of them were equal or more efficient reactivators for pesticides inhibited hAChE than obidoxime. It was also found that some non-oxime derivatives of Mannich phenols displayed obvious reactivation potency for VX, sarin and pesticides inhibited hAChE even in very low concentration. It has been proved that introduction of peripheral site ligands with widespread aromatic system and amide substitutions could increase binding affinity for inhibited hAChE in most cases, which contribute to the reactivation efficiency.

Benchtop NMR analysis of piperazine-based drugs hyperpolarised by SABRE.

Piperazine-based drugs, such as N-benzylpiperazine (BZP), became attractive in the 2000s due to possessing effects similar to amphetamines. Herein, BZP, in addition to its pyridyl analogues, 2-, 3-, and 4-pyridylmethylpiperidine (2-PMP, 3-PMP, and 4-PMP respectively) was subjected to the hyperpolarisation technique Signal Amplification By Reversible Exchange (SABRE) in order to demonstrate the use of this technique to detect these piperazine-based drugs. Although BZP was not hyperpolarised via SABRE, 2-PMP, 3-PMP, and 4-PMP were, with the ortho- and meta-pyridyl protons of 4-PMP showing the largest enhancement of 313-fold and 267-fold, respectively, in a 1.4-T detection field, following polarisation transfer at Earth's magnetic field. In addition to the freebase, 4-PMP.3HCl was also appraised by SABRE and was found not to polarise, however, the addition of increasing equivalents of triethylamine (TEA) produced the freebase, with a maximum enhancement observed upon the addition of 3 equivalents of TEA. Further addition of TEA led to a reduction in the observed enhancement. SABRE was also employed to polarise 4-PMP.3HCl (~20% w/w) in a simulated tablet to demonstrate the forensic application of the technique (138-fold enhancement for the ortho-pyridyl protons). The amount of 4-PMP.3HCl present in the simulated tablet was quantified via NMR using D2 O as a solvent and compared well to complimentary gas chromatography-mass spectrometry data. Exchanging D2 O for CD3 OD as the solvent utilised for analysis resulted in a significantly lower amount of 4-PMP.3HCl being determined, thus highlighting safeguarding issues linked to drug abuse in relation to determining the amount of active pharmaceutical ingredient present.

Biologically Active Echinulin-Related Indolediketopiperazines from the Marine Sediment-Derived Fungus Aspergillus niveoglaucus.

Seven known echinulin-related indolediketopiperazine alkaloids (1-7) were isolated from the Vietnamese sediment-derived fungus Aspergillus niveoglaucus. Using chiral HPLC, the enantiomers of cryptoechinuline B (1) were isolated as individual compounds for the first time. (+)-Cryptoechinuline B (1a) exhibited neuroprotective activity in 6-OHDA-, paraquat-, and rotenone-induced in vitro models of Parkinson's disease. (-)-Cryptoechinuline B (1b) and neoechinulin C (5) protected the neuronal cells against paraquat-induced damage in a Parkinson's disease model. Neoechinulin B (4) exhibited cytoprotective activity in a rotenone-induced model, and neoechinulin (7) showed activity in the 6-OHDA-induced model.

Piperidine and piperazine inhibitors of fatty acid amide hydrolase targeting excitotoxic pathology.

FAAH inhibitors offer safety advantages by augmenting the anandamide levels "on demand" to promote neuroprotective mechanisms without the adverse psychotropic effects usually seen with direct and chronic activation of the CB1 receptor. FAAH is an enzyme implicated in the hydrolysis of the endocannabinoid N-arachidonoylethanolamine (AEA), which is a partial agonist of the CB1 receptor. Herein, we report the discovery of a new series of highly potent and selective carbamate FAAH inhibitors and their evaluation for neuroprotection. The new inhibitors showed potent nanomolar inhibitory activity against human recombinant and purified rat FAAH, were selective (>1000-fold) against serine hydrolases MGL and ABHD6 and lacked any affinity for the cannabinoid receptors CB1 and CB2. Evaluation of FAAH inhibitors 9 and 31 using the in vitro competitive activity-based protein profiling (ABPP) assay confirmed that both inhibitors were highly selective for FAAH in the brain, since none of the other FP-reactive serine hydrolases in this tissue were inhibited by these agents. Our design strategy followed a traditional SAR approach and was supported by molecular modeling studies based on known FAAH cocrystal structures. To rationally design new molecules that are irreversibly bound to FAAH, we have constructed "precovalent" FAAH-ligand complexes to identify good binding geometries of the ligands within the binding pocket of FAAH and then calculated covalent docking poses to select compounds for synthesis. FAAH inhibitors 9 and 31 were evaluated for neuroprotection in rat hippocampal slice cultures. In the brain tissue, both inhibitors displayed protection against synaptic deterioration produced by kainic acid-induced excitotoxicity. Thus, the resultant compounds produced through rational design are providing early leads for developing therapeutics against seizure-related damage associated with a variety of disorders.

JS­K induces G2/M phase cell cycle arrest and apoptosis in A549 and H460 cells via the p53/p21WAF1/CIP1 and p27KIP1 pathways.

Lung cancer is one of the most common malignancies worldwide, with high mortality and morbidity rates. O2­â€‹(2,4­â€‹dinitrophenyl)­1­â€‹[(4­ethoxycarbonyl)piperazin­1­yl]diazen­1­ium­1,2­diolate (JS­K) is a potent anticancer agent that acts against a subset of human non­small cell lung cancer (NSCLC) cell lines; however, the underlying mechanisms of JS­K in NSCLC remain unclear. The present study aimed to evaluate the anticancer effect of JS­K and investigate its underlying mechanisms in A549 and H460 cells. In the present study, A549 and H460 cells were treated with JS­K, and then evaluated by cell viability assay, flow cytometry and western blot analysis. JS­K markedly induced cell cycle arrest at the G2/M phase in a concentration and time­dependent manner in both cell lines. This was associated with increased expression levels of p53, and the cell cycle inhibitors p21WAF1/CIP1 and p27KIP1, which, in turn, inhibited the expression of Cdc2, cyclin B1 and cyclin­dependent kinase 2. In addition, JS­K­induced inhibition of proliferation was revealed to be partially modulated by the upregulation of p53 and p21WAF1, the ratio of Bax/Bcl­2, and the activation of both the intrinsic and extrinsic apoptotic pathways in A549 and H460 cells. These results demonstrated that JS­K could trigger cell cycle arrest at the G2/M phase and apoptosis in A549 and H460 cells, which was likely mediated via the p53/p21WAF1/CIP1 and p27KIP1 pathways. Overall, the results indicated that JS­K may be used as an anticancer agent for the treatment of NSCLC.

Two New Piperazine-Triones from a Marine-Derived Streptomycetes sp. Strain SMS636.

Two new piperazine-triones lansai E and F (1, 2), together with four known secondary metabolites lansai D (3), 1-N-methyl-(E,Z)-albonoursin (4), imidazo[4,5-e]-1,2,4-triazine (5), and streptonigrin (6) were isolated from a deep-sea-derived Streptomycetes sp. strain SMS636. The structures of the isolated compounds were confirmed by comprehensive spectroscopic analysis, including HRESIMS, 1D and 2D NMR. Compound 4 exhibited moderate antibacterial activities against Staphylococcus aureus and methicillin resistant S. aureus (MRSA) with Minimum Inhibitory Concentration (MIC) values of 12.5 and 25 µg/mL, respectively. Compound 6 displayed significant antibacterial activities against S. aureus, MRSA and Bacillus Calmette-Guérin (BCG) with MIC values of 0.78, 0.78 and 1.25 µg/mL, respectively.

SYA 013 analogs as moderately selective sigma-2 (σ2) ligands: Structure-affinity relationship studies.

Several lines of evidence suggest that selective sigma-2 (σ2) ligands might be useful for the treatment of solid tumors. However, very few selective σ2 ligands have been identified. This study was aimed at identifying new selective σ2 receptor ligands using a previously identified agent, SYA 013 as a lead. Four groups, homopiperazine, piperazine, tropane and selected oxime analogs of the homopiperazines were identified, synthesized and subsequently screened at the σ1 and σ2 receptors. The results demonstrate that these scaffolds can be modified to obtain selective σ2 receptor ligands. 1-(5-Chloropyridin-2-yl)-4-(3-((4-fluorophenyl)thio)propyl)-1,4-diazepane, 7 and 3-(4-chlorophenyl)-8-(3-((2-fluorophenyl)thio)propyl)-8-azabicyclo[3.2.1]octan-3-ol, 21 were identified as the highest binding affinity ligands (σ2Ki = 2.2 nM) and (4-(4-(5-chloropyridin-2-yl)-1,4-diazepan-1-yl)-1-(4-fluorophenyl)-butan-1-one oxime, 22 as a high affinity and the most selective ligand for the σ2 receptor (σ1Ki/σ2Ki = 41.8).

New approach to address antibiotic resistance: Miss loading of functional membrane microdomains (FMM) of methicillin-resistant Staphylococcus aureus (MRSA).

The synthesized potent piperazine analog ChDiPiCa was characterised by various spectroscopic techniques and for the first time evaluated functional membrane microdomain (FMM) disassembly in methicillin-resistant Staphylococcus aureus (MRSA). The ChDiPiCa showed excellent in vitro biocidal activity against MRSA at 26 µg/mL compared to the antibiotic streptomycin and bacitracin 14 µg/mL and 13 µg/mL at 10 µg concentration respectively. The membrane damaging property was confirmed by the SEM analysis. Further, we addressed the new approach for the first time to overcome antibiotic resistance of MRSA through membrane microdomain miss loading to lipids. By which, the ChDiPiCa confirms the significant activity in miss loading of FMM of MRSA which is validated by the fatty acid profile and lipid analysis. The result shows that, altered saturated (Lauric acid and Myristic acid), mono unsaturated (Oleic acid), and poly unsaturated (Linoleic acid and Linolenic acid) fatty acids and hypothesises, altered the membrane functional lipids. For the better understanding of miss loading of FMM by the ChDiPiCa, the in-silico molecular docking studies was analyzed and confirmed the predicted role. This suggests the way to develop ChDiPiCa in medicinal chemistry as anti-MRSA candidates and also this report opens up new window to treat microbial pathogens and infections.

Novel Strategies To Activate the Dopamine D1 Receptor: Recent Advances in Orthosteric Agonism and Positive Allosteric Modulation.

The five dopamine receptor subtypes (D1-5) are activated by the endogenous catecholamine dopamine. Sustained research has sought to identify selective ligands for receptor subtypes. In particular, activation of the D1 receptor has attracted attention due to its promising role in neurological diseases. Initial attempts to identify agonists yielded catechol derivatives, mimicking dopamine, with suboptimal DMPK parameters and low selectivity over the D5 subtype. However, more recent efforts to identify ligands capable of activating the D1 receptor have made substantial progress with the identification of non-catechol agonists with suitable properties to progress to clinical studies. In addition, several research groups have identified positive allosteric modulators that offer new potential. Furthermore, structural studies have surprisingly uncovered two potential allosteric binding sites, the most characterized of which appears to be on intracellular loop 2 (ICL2). This review highlights the recent progress in the field, covering both orthosteric and allosteric modes of activation, discusses the elucidation of the allosteric binding sites, and summarizes the clinical development status of various compounds.

Design, synthesis, and systematic evaluation of 4-arylpiperazine- and 4-benzylpiperidine napthyl ethers as inhibitors of monoamine neurotransmitters reuptake.

Two series of 4-arylpiperazine- and 4-benzylpiperidine naphthyl ethers were designed based on structure-activity relationship (SAR) and docking model of reported monoamine neurotransmitters reuptake inhibitors. The compounds were synthesized in 3-simple steps and their biological activities were evaluated. Several compounds were proven to be potent inhibitors of serotonin and norepinephrine reuptake. Computer docking was performed to study the interaction of the most potent compound 35 with human serotonin transporter. The results of the analyses suggest that 4-arylpiperazine- and 4-benzylpiperidine naphthyl ethers might be promising antidepressants worthy of further studies.

Piperazine clubbed with 2-azetidinone derivatives suppresses proliferation, migration and induces apoptosis in human cervical cancer HeLa cells through oxidative stress mediated intrinsic mitochondrial pathway.

Piperazine scaffolds or 2-azetidinone pharmacophores have been reported to show anti-cancer activities and apoptosis induction in different types of cancer cells. However, the mechanistic studies involve in induction of apoptosis addressing these two moieties for human cervical cancer cells remain uncertain. The present study emphasizes on the anti-proliferating properties and mechanism involved in induction of apoptosis for these structurally related azoles derivatives in HeLa cancer cells. 1-Phenylpiperazine clubbed with 2-azetidione derivatives (5a-5h) were synthesized, characterized using various spectroscopic techniques and evaluated for their in-vitro anti-proliferative activities and induction of apoptosis. Further, we also evaluated oxidative stress generated by these synthetic derivatives (5a-5h). Cell viability studies revealed that among all, the compound N-(3-chloro-2-(3-nitrophenyl)-4-oxoazetidin-1-yl)-2-(4-phenylpiperazin-1-yl) acetamide 5e remarkably inhibited the growth of HeLa cells in a concentration dependent manner having IC50 value of 29.44 ± 1.46 µg/ml. Morphological changes, colonies suppression and inhibition of migration clearly showed the antineoplasicity in HeLa cells treated with 5e. Simultaneously, phosphatidylserine externalization, DNA fragmentation and cell-cycle arrest showed ongoing apoptosis in the HeLa cancer cells induced by compound 5e in concentration dependent manner. Additionally, generation of intracellular ROS along with the decrease in mitochondrial membrane potential supported that compound 5e caused oxidative stress resulting in apoptosis through mitochondria mediated pathway. Elevation in the level of cytochrome c and upregulation in expression of caspase-3 clearly indicated the involvement of the intrinsic pathway of programmed cell death. In brief; compound 5e could serve as a promising lead for the development of an effective antitumor agent.