Search

Based on our earlier studies of structure activity relationships on 4-substituted piperazine derivatives, in this work we synthesized a novel set of long-chain arylpiperazines with the purpose of elucidating if some structural modifications in the terminal fragment could affect the binding affinity for the 5-HT 7 and 5-HT 1A receptors. In this new series, the quinazolinone system of the previous derivatives was replaced by a 6-phenylpyrimidine or a 2-methylquinazoline, which were used as versatile building blocks for the preparation of new compounds. A 4-arylpiperazine moiety through a five methylene chain was anchored at the nitrogen or oxygen atom of the heterocyclic scaffolds. The substituents borne by the piperazine nucleus were phenyl, phenylmethyl, 3- or 4-chlorophenyl, and 2-ethoxyphenyl. Binding tests, performed on human cloned 5-HT 7 and 5-HT 1A receptors, showed that, among the newly synthesized derivatives, 4-[5-[4-(2-ethoxyphenyl)-1-piperazinyl]pentoxy]-6-phenyl-pyrimidine (13) and 3-[5-[4-(2-ethoxyphenyl)-1-piperazinyl]pentyl]-2-methyl-4(3H)-quinazolinone (20) displayed the best affinity values, K i =23.5 and 8.42nM for 5-HT 7 and 6.96 and 2.99nM for 5-HT 1A receptors, respectively. Moreover, the functional properties for both compounds were further evaluated using the cAMP assay. Finally, a molecular modeling study has been performed for 5-HT 7 and 5-HT 1A receptor homology models to investigate the binding mode of N- and O-alkylated pyrimidinones/pyrimidines 4-13, 2-methylquinazolinones/quinazolines 17-22, and previously reported 2- and 3-substituted quinazolinones 23-30., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Oxidative stress is a hallmark of retinal degenerations such as age-related macular degeneration and diabetic retinopathy. Enhancement of heme oxygenase-1 (HO-1) activity in the retina would exert beneficial effects by protecting cells from oxidative stress, therefore promoting cell survival. Because a crosstalk exists between nitric oxide (NO) and HO-1 in promotion of cell survival under oxidative stress, we designed novel NO-releasing molecules also capable to induce HO-1. Starting from curcumin and caffeic acid phenethyl ester (CAPE), two known HO-1 inducers, the molecules were chemically modified by acylation with 4-bromo-butanoyl chloride and 2-chloro-propanoyl chloride, respectively, and then treated in the dark with AgNO 3 to obtain the nitrate derivatives VP10/12 and VP10/39. Human retinal pigment epithelial cells (ARPE-19) subjected to H 2 O 2 -mediated oxidative stress were treated with the described NO-releasing compounds. VP10/39 showed significant ( p < 0.05) antioxidant and protecting activity against oxidative damage, in comparison to VP10/12, which in turn showed at 100  μ M concentration a slight but significant cell toxicity. Only VP10/39 significantly ( p < 0.05) induced HO-1 in ARPE-19, most likely through covalent bond formation at Cys151 of the Keap1-BTB domain, as revealed from molecular docking analysis. In conclusion, the present data indicate VP10/39 as a promising candidate to protect ARPE-19 cells against oxidative stress.

Background: Heme Oxygenase-1 (HO-1) is a metabolic enzyme strongly involved in processes including cytoprotection, modulation of inflammatory response, anti-oxidative functions, regulation of cellular proliferation, angiogenesis, cardiovascular homeostasis, and immuno-modulation. HO-1 induction and/or activation is able to counterbalance, at least in part, oxidative stress and inflammation. For this reason, HO-1 can be regarded as an attractive target to ameliorate different stress-related pathologies. Caffeic acid phenethyl ester, a natural polyphenolic compound, behaves as HO-1 inducer and possesses a plethora of beneficial effects under oxidative stress conditions., Objectives: A small focused series of caffeic acid phenethyl ester (Cape) analogues was designed and synthesized with the aim of obtaining more potent HO-1 inducers., Method: The capacity of these new compounds to modify the levels of HO-1 was evaluated in human mesenchymal stem cells (hMSCs) derived from bone marrow., Results and Conclusion: Some of tested compounds were found to be good HO-1 inducers and 3-(3,4- dihydroxyphenyl)-(2E)-2-propenoic acid 2-(3,4-dimethoxyphenyl) ethyl ester (VP961) was the most potent. VP961 tested to measure HO-1 protein expression and HO activity in in vitro system resulted more potent than the parent compound Cape both as inducer and as direct activator of the enzyme. VP961, selected as lead compound for further characterization, showed antioxidant properties in a model of H2O2-mediated ROS production and cytoprotective effects in a model of H2O2 cells viability impairment. To the best of our knowledge, VP961 is the first known compound able to activate directly HO-1 enzyme and to induce at the same time its protein expression., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

(±)-MRJF22 [(±)-2], a novel prodrug of haloperidol metabolite II (sigma-1 receptor antagonist/sigma-2 receptor agonist ligand) obtained by conjugation to valproic acid (histone deacetylase inhibitor) via an ester bond, exhibits antiangiogenic activity, being able to reduce human retinal endothelial cell (HREC) viability in a comparable manner to bevacizumab. Moreover, (±)-2 was able to significantly reduce viable cells count, endothelial cell migration, and tube formation in vascular endothelial growth factor A (VEGF-A) stimulated HREC cultures.

In this work we report the discovery of new homo and hetero bis-piperazinyl-1-propanone derivatives as selective ligands for 5-HT7 over 5-HT1A receptor. These newly synthesized compounds possess a 4-arylpiperazine linked through an acyl spacer to another substituted piperazine system and were tested for their binding properties on human cloned 5-HT1A and 5-HT7 serotonin receptors. Among these, phenyl, 4- and 2-chlorophenyl, 2-methoxyphenyl, 2-pyridyl, and 2-pyrimidyl derivatives 15, 24, 25, and 27-29 displayed nanomolar affinity values for the 5-HT7 receptor (Ki 23.5-52.0nM) and no affinity for the 5-HT1A receptor., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

In light of the involvement of serotonergic 5-HT1A receptors in the mediation of the memory of aversive events, the potent and selective 5-HT1A receptor antagonists, MC18 fumarate and VP08/34 fumarate, were tested in the passive avoidance task (PA), a rodent model of instrumental conditioning. Either alone or in combination with the prototypical agonist 8-OH-DPAT, MC18 fumarate at doses (0.1, 0.3 and 1mg/kg given 15min prior to training) exerted a dose-dependent facilitation of PA memory retention. When administered 15min prior to 8-OH-DPAT (0.3 and 1mg/kg), MC18 fumarate at a dose of 0.3mg/kg, enhanced significantly the impairment of PA retention caused by 8-OH-DPAT (1mg/kg). However, VP08/34 fumarate given at the same doses exerted no statistically effect on PA retention memory. Furthermore, VP08/34 fumarate given 15min prior to 8-OH-DPAT (0.3 and 1mg/kg) only slightly enhanced the PA impairment induced by 8-OH-DPAT. In conclusion, the profile of MC18 fumarate is intriguing since it behaves in a manner which differs from both full receptor antagonists such as NAD-299 or partial receptor agonists. The results also illustrate the importance of subtle receptor interaction and probably ligand efficacy in determining the actions of two almost identical 5-HT1A receptor ligands in cognitive function such as instrumental learning., (Copyright © 2015 Elsevier B.V. and ECNP. All rights reserved.)

In this study, we report the design and synthesis of novel hybrids of caffeic acid phenetyl ester (CAPE) and non-steroidal anti-inflammatory drugs (NSAIDs). We assessed their effects on an experimental ocular inflammation in New Zealand rabbits. The formulations of CAPE-aspirin and CAPE-indomethacin hybrids were topical instilled in the rabbit׳s eye. Afterwards, the anti-inflammatory activity was evaluated by grading the clinical signs and by assessing the inflammatory cell count, protein, PGE2 and TNFα levels in the aqueous humor. Furthermore, ocular tolerability of hybrids formulations was evaluated in a separate set of animals by using a modified Draize test. The ocular inflammation in the control group was significantly higher than in both the hybrid-treated groups, as indicated by clinical grading and biomarkers assessment. However, only the CAPE-aspirin hybrid reduced, in a significant dose-dependent manner, the ocular inflammation elicited by paracentesis. CAPE-indomethacin hybrid was able to significantly attenuate the clinical grading and the PGE2 aqueous levels only at the highest dose (0.1%). CAPE-aspirin significantly reduced PGE2 and TNFα levels in the aqueous humor as well as proteins and PMNs. Finally, all formulations showed no ocular irritation compared with vehicle-treated group. In conclusion, CAPE-aspirin shows full anti-inflammatory efficacy in experimental model of ocular inflammation demonstrating an optimal pharmacological and safety profile. Taken together these data indicate that CAPE-aspirin hybrid represents a valid and safe new chemical entity potentially useful for the treatment of ocular inflammation., (Copyright © 2015 Elsevier B.V. All rights reserved.)

New long-chain 4-substituted piperazines linked to a thienopyrimidine or a quinazoline system were synthesized and tested for their binding properties on human cloned 5-HT1A and 5-HT7 serotonin receptors. Some structural modifications, concerning tree main portions, that is, terminal fragment, chain length, and aryl substituents, were examined. The 2- and 3-substituted thienopyrimidinone and quinazolinone systems were selected as terminal fragment and a chain length of four or five methylene units was set. Explored aryl substituents were phenyl, phenylmethyl, 3- or 4-chlorophenyl, and 2-ethoxyphenyl. Title compounds showed affinity for 5-HT1A and 5-HT7 receptors. In particular, 2-ethoxyphenyl derivatives 40 and 45 displayed Ki values in the nanomolar range on both receptors, acting as dual ligands., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Heme oxygenase (HO) is a cytoprotective enzyme that can be overexpressed in some pathological conditions, including certain cancers. In this work, novel imidazole derivatives were designed and synthesized as inhibitors of heme oxygenase-1 (HO-1) and heme oxygenase-2 (HO-2). In these compounds the imidazole ring, crucial for the activity, is connected to a hydrophobic group, represented by aryloxy, benzothiazole, or benzoxazole moieties, by means of alkyl or thioalkyl chains of different length. Many of the tested compounds were potent and/or selective against one of the two isoforms of HO. Furthermore, most of the pentyl derivatives showed to be better inhibitors of HO-2 with respect to HO-1, revealing a critical role of the alkyl chain in discriminating between the two isoenzymes. Compounds which showed the better profile of HO inhibition were selected and tested to evaluate their cytotoxic properties in prostate and breast cancer cell lines (DU-145, PC3, LnCap, MDA-MB-231, and MCF-7). In these assays, aryloxyalkyl derivatives resulted more cytotoxic than benzothiazolethioalkyl ones; in particular compound 31 was active against all the cell lines tested, confirming the anti-proliferative properties of HO inhibitors and their potential use in the treatment of specific cancers., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

A novel series of arylpiperazinylalkyl 2-benzoxazolones and 2-benzothiazolones 18-38 was designed, synthesized and tested to evaluate their affinity for the 5-HT7 and 5-HT1A receptors. Compounds with a 2-benzothiazolone nucleus generally had affinity values higher than the corresponding 2-benzoxazolone compounds. In particular, derivatives possessing a six or seven carbon chain linker between 2-benzothiazolone and arylpiperazine had Ki values in the subnanomolar range for the 5-HT1A receptor and in the low nanomolar range for the 5-HT7 receptor, indicating that they may be interesting dual ligands. Molecular modeling studies revealed different docking poses for the investigated compounds in homology models of 5-HT1A and 5-HT7 receptors, which explained their experimentally determined affinities and general low selectivity. Additionally, structural interaction fingerprints analysis identified the important amino acid residues for the specific interactions of long-chain arylpiperazines within the binding pockets of both serotonin receptors., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

A new series of high affinity ligands and antagonists for the α1D-adrenergic receptor (AR) has been discovered. New molecules present a [1]benzothieno[3,2-d]pyrimidin-2,4(1H,3H)-dione or a [1]benzothieno[3,2-d]pyrimidin-4(3H)-one scaffold and bear a 2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl moiety in the 3-position and various amide substituents in the 8-position. In binding assays at the three human cloned α1A-, α1B-, and α1D-AR subtypes, they showed high affinity values, particularly for the α1D-AR subtype. Compound 22 (RX18), N(1)-methyl-N(5)-[3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-2,4-dioxo-1,2,3,4-tetrahydro[1]benzothieno[3,2-d]pyrimidin-8-yl]-N(1)-(phenylmethyl)pentanediamide, was the most interesting in the series displaying very high affinity (pKi = 10.25) and potent antagonism (pKb = 9.15) when tested in a functional assay at the α1D-AR., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Eggplant fruit is a very rich source of polyphenol compounds endowed with antioxidant properties. The aim of this study was to extract polyphenols from eggplant entire fruit, pulp, or skin, both fresh and dry, and compare results between conventional extraction and microwave-assisted extraction (MAE). The effects of time exposure (15, 30, 60, and 90 min) and solvent (water 100% or ethanol/water 50%) were also evaluated. The highest amount of polyphenols was found in the extract obtained from dry peeled skin treated with 50% aqueous ethanol, irradiated with microwave; this extract contained also high quantity of flavonoids and showed good antioxidant activity expressed by its capacity to scavenge superoxide anion and to inhibit lipid peroxidation.

A novel series of aryloxyalkyl derivatives of imidazole and 1,2,4-triazole, 17-31, was designed and synthesized as inhibitors of heme oxygenase-1 (HO-1) and heme oxygenase-2 (HO-2). Some of these compounds were found to be good inhibitors of HO-1, in particular those carrying an imidazole moiety as azolyl group and a 3-bromo or 4-iodophenyl as aryl moiety. The most potent compounds 6 and 30 were selected and studied for their antitumor properties in a model of LAMA-84 R cell line overexpressing HO-1 and resistant to imatinib mesylate (IM), a tyrosine-kinase inhibitor used in the treatment of multiple types of cancer, most notably Philadelphia Chromosome positive (Ph(+)) Chronic Myelogenous Leukemia (CML). Results show that both 6 and 30 sensitized LAMA-84 R cell line to antitumor properties of IM., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

A novel class of indole derivatives characterized by a (αE)-α-(1H-indol-3-ylmethylene)benzeneacetic acid or amide scaffold was synthesized. These derivatives, assayed for cell-growth inhibition activity against a panel of six different tumor cell lines, showed strong antiproliferative activity and selectivity mainly towards DU145 cell line. In particular, compounds 2d-m and 5 stand out for their cell growth inhibitory activity and, among them, compound 2d emerged for its selectivity towards DU145 with respect to other tested tumor cell lines. DU145 treated with 1μM of 2d for 72h showed p21(Cip1) induction and suppression of Akt signaling together with induction of Rb. From a computational point of view, two different approaches were used in order to study topology and electronic properties of the novel compounds and to shed light on their drug-likeness properties. Firstly, topological and electronic features of the compounds endowed with the most relevant biological activity were deepened; in parallel, some ADME properties like solubility and permeability were predicted., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Imidazole-based compounds previously synthesized in our laboratory were selected and reconsidered as inhibitors of heme oxygenase-1 obtained from the microsomal fractions of rat spleens. Most of tested compounds were good inhibitors with IC(50) values in the low micromolar range. Compounds were also assayed on membrane-free full-length recombinant human heme oxygenase-1; all tested compounds were unable to interact with human heme oxygenase-1 at 100 μm concentrations with the exception of compounds 11 and 13 that inhibited the enzyme of 54% and 20%, respectively. The binding of the most active compound 11 with heme or heme-conjugated human heme oxygenase-1 was also examined by spectral analyses. When heme was not conjugated to human heme oxygenase-1, compound 11 caused changes in the heme spectrum only at concentration 50-fold (100 μm) higher than that required to inhibit rat heme oxygenase-1; when heme was conjugated to human heme oxygenase-1, compound 11 was able to form a heme-compound 11 complex also at low micromolar concentrations. To obtain information on the binding mode of the tested compounds with enzyme, docking studies and pharmacophore analysis were performed. Template docking results were in agreement with experimental inhibition data and with a structure-based pharmacophoric model. These data may be exploitable to design new OH-1 inhibitors., (© 2012 John Wiley & Sons A/S.)

We previously described a series of imidazole-based inhibitors substituted at N-1 with an arylethanone chain as interesting inhibitors of neuronal nitric oxide synthase (nNOS), endowed with good selectivity vs endothelial nitric oxide synthase (eNOS). As a follow up of these studies, several analogs characterized by the presence of substituted imidazoles or other mono or bicyclic nitrogen-containing heterocycles instead of simple imidazole were synthesized, and their biological evaluation as in vitro inhibitors of both nNOS and eNOS is described herein. Most of these compounds showed improved nNOS and eNOS inhibitory activity with respect to reference inhibitors. Selected compounds were also tested to analyze their antioxidant properties. Some of them displayed good capacity to scavenge free radicals and ability to reduce lipid peroxidation., (Copyright © 2012 Elsevier Masson SAS. All rights reserved.)

Three different series of 1H-pyrrolopyrimidine-2,4-dione derivatives were designed and synthesized as ligands for the α(1)-adrenergic receptors (α(1)-ARs). A microwave-assisted protocol was developed in order to improve purity and yields of some final products. The majority of the synthesized compounds, tested in binding assays, displayed α(1)-AR affinities in the nanomolar range. Highest affinity values were found in derivatives 10b and 10c (K(i)=1.4 nM for both) whereas compound 10e was endowed with the best profile in term of α(1)-AR affinity (K(i)=2.71 nM) coupled with high selectivity towards 5-HT(1A) receptors (K(i) >10,000). Molecular docking studies were performed on human α(1)-ARs and human 5-HT(1A) receptors in order to rationalize the observed experimental affinity and selectivity; these computational studies helped to clarify molecular requirements for the design of high-selective α(1)-adrenergic ligands., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

A simple high-performance liquid chromatography method using a diode array detector (DAD) is developed for the simultaneous analysis of five major catechins: (+)-catechin (C), (-)-epicatechin (EC), (-)-gallocatechin (GCT), (-)-epigallocatechin (EGC), (-)-epigallocatechin gallate (EGCG), and the phenolic plant metabolites gallic acid (GA) and rutin (RT) in lyophilized extracts of Cistus species. The optimal analytical conditions are investigated to obtain the best resolution and the highest UV sensitivity for the quantitative detection of catechins. The optimized conditions (acetonitrile-phosphate buffer 50 mM, pH 2.5, gradient elution system on a C18 reversed-phase column with a flow rate of 1 mL/min and UV absorbance at 210 nm) allowed a specific and repeatable separation of the studied analytes to be achieved. All compounds are successfully separated within 32 min. Calibration curves are linear in the 2-50 microg/mL range for GCT, C, and EGCG and in the 5-50 microg/mL range for GA, EGC, EC, and RT. The limit of detection values ranged from 0.24 to 0.74 microg/mL. The limit of quantitation limit values ranged from 0.77 to 1.94 microg/mL. The validated method is applied to the determination of the specific phytochemical markers GA, GCT, C, and RT in Cistus incanus and Cistus monspeliensis lyophilised extracts. The recovery values ranged between 78.7% and 98.2%. The described HPLC method appears suitable for the differentiation and determination of the most common catechins together with the glycoside rutin and the phenolic compound gallic acid and can be considered an effective and alternative procedure for the analyses of this important class of natural compounds.

The 5-HT(7) receptors (5-HT(7)Rs) are the most recent classified members of the serotonin family. Characterized in 1993, they belong to the G protein-coupled receptor family. Since their discovery, they have been the subject of intense research due to their widespread distribution in the brain, suggestive of multiple central roles. The focus of this review is to discuss the literature concerning recent advances on 5-HT(7)Rs and their ligands.

With the aim to develop new ligands able to discriminate among the three subtypes of alpha1-adrenergic receptors (alpha1A-AR, alpha1B-AR, and alpha1D-AR), a series of new 1,2,3,9-tetrahydro-4H-carbazol-4-ones bearing a 3-[[[2-(4-hydroxyphenyl)ethyl]amino]methyl] or a 3-[[4-(2-substitutedphenyl)piperazin-1-yl]methyl] side chain were synthesized. The general structure of the new compounds is reminiscent of HEAT and RN5, two potent alpha1-AR antagonists which show high affinities for all three alpha1-AR subtypes. Some derivatives in which one ring of the tetrahydrocarbazolone system was opened were also prepared. Compounds were tested in radioligand binding assays on human cloned alpha1A-AR, alpha1B-AR, and alpha1D-AR subtypes stably expressed in HEK293 cells. They showed moderate to good affinities, although their selectivity among the receptor subtypes hardly reached one order of magnitude.

Endothelin-1 (ET-1), a peptide of 21 amino acid residues, is the most potent vasoconstrictor substance known and now it is understood to be one of a family of three mammalian vasoactive peptides that also includes ET-2 and ET-3. The endothelins (ETs) affect multiple organ systems and seem to be involved in the pathogenesis of many diseases such as hypertension, pulmonary hypertension, atherosclerosis, apoptosis inhibition and angiogenesis. The ETs exert their effects via activation of two distinct G-protein coupled receptor subtypes termed ET(A) and ET(B). To date a number of ET receptor ligands with good affinity and selectivity is known, nevertheless these compounds belong only to few chemical classes. The aim of this work was the identification of a "hit compound" with novel chemical structure, endowed with reasonable ET affinity and selectivity. Accordingly, a new class of (E)-alpha-[(1H-indol-3-yl)methylene]benzeneacetic acid derivatives (1-23) was synthesized for evaluation of their binding profiles.

Endothelins (ETs) are the most ubiquitous, highly potent and unusually long-lasting peptidic constrictors of human vessels known. Elevated levels of the plasma concentration of ETs were observed in several diseases such as hypertension, acute myocardial infarction, congestive heart failure, renal failure, pulmonary hypertension, and atherosclerosis. ETs exert their activities via specific seven-transmembrane, G protein-coupled receptors. To date two receptor subtypes, endothelin A (ET(A)) and endothelin B (ET(B)), have been identified and cloned. A literature survey revealed that a number of compounds that bind ET receptors with affinity and selectivity are known, nevertheless these compounds belong only to few chemical classes. The aim of this work is the identification of an "hit compound" with novel chemical structure endowed with reasonable ET affinity and selectivity. Accordingly, new variously substituted 2-carboxamido-3-carboxythiophene derivatives (29-52) were synthesized. These compounds were tested for their ability to inhibit ETs binding in radioligand binding assay using CHO cells stably expressing human ET(A) and ET(B) receptors.

Novel compounds characterized by a pyrrolo[3,2-d]pyrimidine-2,4-dione (PPm) system connected through an alkyl chain to a phenylpiperazine (PPz) residue were designed as structural analogues of the alpha(1)-adrenoceptor (alpha(1)-AR) ligand RN5 (1). In this new series of derivatives an arylpyrrolo moiety has replaced the indole nucleus of RN5. Several structural modifications were performed on the PPm and PPz moieties and the connecting alkyl chain. These compounds were synthesized and tested in radioligand binding experiments where many of them showed interesting binding profiles. Some compounds, including 31, 34, and 36, displayed substantial alpha(1)-AR selectivity with respect to serotoninergic 5-HT(1A) and dopaminergic D(1) and D(2) receptors. Two different molecular modeling approaches (pharmacophoric mapping and quantitative structure-affinity relationship analysis) have been applied to rationalize, at a quantitative level, the relationships between affinity toward alpha(1)-ARs and the structure of the studied compounds. Several QSAR models have been reported and described, accounting for the influence of various molecular portions on such affinity data.