3-Nitroatenolol: First Synthesis, Chiral Resolution and Enantiomers' Absolute Configuration.

4-Nitro and 7-nitro propranolol have been recently synthesized and characterized by us. (±)-4-NO2-propranolol has been shown to act as a selective antagonist of 6-nitrodopamine (6-ND) receptors in the right atrium of rats. As part of our follow-up to this study, herein, we describe the first synthesis of (±)-3-nitroatenolol as a probe to evaluate the potential nitration of atenolol by endothelium. Chiral chromatography was used to produce pure enantiomers. By using Riguera's method, which is based on the sign distribution of ΔδH, the absolute configuration of the secondary alcohol was determined.

Measurement of 6-cyanodopamine, 6-nitrodopa, 6-nitrodopamine and 6-nitroadrenaline by LC-MS/MS in Krebs-Henseleit solution. Assessment of basal release from rabbit isolated right atrium and ventricles.

This study presents the validation of a sensitive method for the determination of 6-nitrodopa, 6-nitrodopamine, 6-nitroadrenaline and 6-cyanodopamine in Krebs-Henseleit solution by LC-MS/MS with ESI+ . HRMS was used to precisely characterize the structures of the fragment ions. The method was applied to investigate the catecholamine basal release from rabbit isolated atria and ventricles. The atria and ventricles were suspended separately in a 5 ml organ bath containing Krebs-Henseleit solution with ascorbic acid (3 mM), gassed (95%O2 /5%CO2 ) at 37°C for 30 min. Strata-X 33 µm SPE cartridges were employed for the extraction of the catecholamines and the internal standard 6-nitrodopamine-d4 . The catecholamines were separated employing a 150 × 3 mm Shim-pack GIST C18-AQ (3 mm particle size), placed in an oven at 40°C and perfused by 65% of mobile phase A (MeCN/H2 O; 90/10, v/v) + 0.4% CH3 COOH and 35% mobile phase B (deionized H2 O) + 0.2% CH2 O2 at 320 µl/min in isocratic mode. The method was linear at 0.1-20 ng/ml. The method was used to identify for the first-time basal release of the three nitrocatecholamines mentioned above and a member of a novel class of catecholamines, the cyanocatecholamines.

The Application of Microwaves, Ultrasounds, and Their Combination in the Synthesis of Nitrogen-Containing Bicyclic Heterocycles.

The use of alternative energy sources, such as microwaves (MW) or ultrasounds (US), and their mutual cross-combination have been widely described in the literature in the development of new synthetic methodologies in organic and medicinal chemistry. In this review, our attention is focused on representative examples, reported in the literature in the year range 2013-2023 of selected N-containing bicyclic heterocycles, with the aim to highlight the advantages of microwave- and ultrasound-assisted organic synthesis.

Enhanced efficacy of formoterol-montelukast salt in relieving asthma features and in preserving ß2-agonists rescue therapy.

Adrenergic ß2-agonists represent a mainstay in asthma management. Their chronic use has been associated with decreased bronchoprotection and rebound hyperresponsiveness. Here we investigate on the possible therapeutic advantage of a pharmacological association of ß2-agonists with montelukast, a highly selective leukotriene receptor antagonist, in modulating bronchial reactivity and controlling asthma features. The study has been conducted in vitro and in vivo and also takes advantage of the synthesis of a salt that gave us the possibility to simultaneously administer in vivo formoterol and montelukast (MFS). In vitro studies demonstrate that montelukast (1) preserves ß2-agonist response in isolated bronchi by preventing homologous ß2-adrenoceptor desensitization; (2) reduces desensitization by modulating ß2-receptor translocation in bronchial epithelial cells. In vivo studies demonstrate that sensitized mice receiving formoterol or montelukast display a significant reduction in airway hyperresponsiveness, but the ß2-agonist relaxing response is still impaired. Allergen challenge causes ß2 heterologous desensitization that is further increased by treatment in vivo with formoterol. Conversely MFS not only inhibits airway hyperresponsiveness but it rescues the ß2-agonist response. Histological analysis confirms the functional data, demonstrating an enhanced therapeutic efficiency of MSF in controlling also pulmonary metaplasia and lung inflammation. MFS is efficacious also when sensitized mice received the drug by local administration. In conclusion, the data obtained evidenced a therapeutic advantage in the association of ß2-agonists with montelukast in the control of asthma-like features and a better rescue bronchodilation response to ß2-agonists.

Design, Synthesis and Evaluation of Novel Molecular Hybrids between Antiglaucoma Drugs and H2S Donors.

Glaucoma is a group of eye diseases consisting of optic nerve damage with corresponding loss of field vision and blindness. Hydrogen sulfide (H2S) is a gaseous neurotransmitter implicated in various pathophysiological processes. It is involved in the pathological mechanism of glaucomatous neuropathy and exerts promising effects in the treatment of this disease. In this work, we designed and synthetized new molecular hybrids between antiglaucoma drugs and H2S donors to combine the pharmacological effect of both moieties, providing a heightened therapy. Brinzolamide, betaxolol and brimonidine were linked to different H2S donors. The H2S-releasing properties of the new compounds were evaluated in a phosphate buffer solution by the amperometric approach, and evaluated in human primary corneal epithelial cells (HCEs) by spectrofluorometric measurements. Experimental data showed that compounds 1c, 1d and 3d were the hybrids with the best properties, characterized by a significant and long-lasting production of the gasotransmitter both in the aqueous solution (in the presence of L-cysteine) and in the intracellular environment. Because, to date, the donation of H2S by antiglaucoma H2S donor hybrids using non-immortalized corneal cells has never been reported, these results pave the way to further investigation of the potential efficacy of the newly synthesized compounds.

Synthesis, Chiral Resolution and Enantiomers Absolute Configuration of 4-Nitropropranolol and 7-Nitropropranolol.

We recently identified 6-nitrodopamine and other nitro-catecholamines (6-nitrodopa, 6-nitroadrenaline), indicating that the endothelium has the ability to nitrate the classical catecholamines (dopamine, noradrenaline, and adrenaline). In order to investigate whether drugs could be subject to the same nitration process, we synthesized 4-nitro- and 7-nitropropranolol as probes to evaluate the possible nitration of the propranolol by the endothelium. The separation of the enantiomers in very high yields and excellent enantiopurity was achieved by chiral HPLC. Finally, we used Riguera's method to determine the absolute configuration of the enantiomers, through double derivatization with MPA and NMR studies.

Synthesis, Docking Studies and Pharmacological Evaluation of Serotoninergic Ligands Containing a 5-Norbornene-2-Carboxamide Nucleus.

A new series of 5-norbornene-2-carboxamide derivatives was prepared and their affinities to the 5-HT1A, 5-HT2A, and 5-HT2C receptors were evaluated and compared to a previously synthesized series of derivatives characterized by exo-N-hydroxy-5-norbornene-2,3-dicarboximidenucleus, in order to identify selective ligands for the above-mentioned subtype receptors. Arylpiperazines represents one of the most important classes of 5-HT1AR ligands, and recent research concerning new derivatives has been focused on the modification of one or more portions of such pharmacophore. The combination of structural elements (heterocyclic nucleus, propyl chain and 4-substituted piperazine), known to be critical to the affinity to 5-HT1A receptors, and the proper selection of substituents led to compounds with high specificity and affinity towards serotoninergic receptors. The most active compounds were selected for further in vivo assays to determine their functional activity. Finally, to rationalize the obtained results, molecular docking studies were performed. The results of the pharmacological studies showed that Norbo-4 and Norbo-18 were the most active and promising derivatives for the serotonin receptor considered in this study.

Prolonged NCX activation prevents SOD1 accumulation, reduces neuroinflammation, ameliorates motor behavior and prolongs survival in a ALS mouse model.

Imbalance in cellular ionic homeostasis is a hallmark of several neurodegenerative diseases including Amyotrophic Lateral Sclerosis (ALS). Sodium-calcium exchanger (NCX) is a membrane antiporter that, operating in a bidirectional way, couples the exchange of Ca2+ and Na + ions in neurons and glial cells, thus controlling the intracellular homeostasis of these ions. Among the three NCX genes, NCX1 and NCX2 are widely expressed within the CNS, while NCX3 is present only in skeletal muscles and at lower levels of expression in selected brain regions. ALS mice showed a reduction in the expression and activity of NCX1 and NCX2 consistent with disease progression, therefore we aimed to investigate their role in ALS pathophysiology. Notably, we demonstrated that the pharmacological activation of NCX1 and NCX2 by the prolonged treatment of SOD1G93A mice with the newly synthesized compound neurounina: (1) prevented the reduction in NCX activity observed in spinal cord; (2) preserved motor neurons survival in the ventral spinal horn of SOD1G93A mice; (3) prevented the spinal cord accumulation of misfolded SOD1; (4) reduced astroglia and microglia activation and spared the resident microglia cells in the spinal cord; (5) improved the lifespan and mitigated motor symptoms of ALS mice. The present study highlights the significant role of NCX1 and NCX2 in the pathophysiology of this neurodegenerative disorder and paves the way for the design of a new pharmacological approach for ALS.

Synthesis, docking studies, and pharmacological evaluation of 2-hydroxypropyl-4-arylpiperazine derivatives as serotoninergic ligands.

A new series of norbornene and exo-N-hydroxy-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboximide derivatives was prepared, and their affinities to the 5-HT1A , 5-HT2A , and 5-HT2C receptors were evaluated and compared with a previously synthesized series of derivatives characterized by the same nuclei, to identify selective ligands for the subtype receptors. Arylpiperazines represent one of the most important classes of 5-HT1A R ligands, and the research of new derivatives has been focused on the modification of one or more portions of this pharmacophore. The combination of structural elements (heterocyclic nucleus, hydroxyalkyl chain, and 4-substituted piperazine), known to be critical for the affinity to 5-HT1A receptors, and the proper selection of substituents resulted in compounds with high specificity and affinity toward serotoninergic receptors. The most active compounds were selected for further in vivo assays to determine their functional activity. Finally, to rationalize the obtained results, molecular docking studies were performed. The results of the pharmacological studies showed that 3e, 4j, and 4n were the most active and promising derivatives for the serotonin receptor considered in this study.

Antagonizing S1P3 Receptor with Cell-Penetrating Pepducins in Skeletal Muscle Fibrosis.

S1P is the final product of sphingolipid metabolism, which interacts with five widely expressed GPCRs (S1P1-5). Increasing numbers of studies have indicated the importance of S1P3 in various pathophysiological processes. Recently, we have identified a pepducin (compound KRX-725-II) acting as an S1P3 receptor antagonist. Here, aiming to optimize the activity and selectivity profile of the described compound, we have synthesized a series of derivatives in which Tyr, in position 4, has been substituted with several natural aromatic and unnatural aromatic and non-aromatic amino acids. All the compounds were evaluated for their ability to inhibit vascular relaxation induced by KRX-725 (as S1P3 selective pepducin agonist) and KRX-722 (an S1P1-selective pepducin agonist). Those selective towards S1P3 (compounds V and VII) were also evaluated for their ability to inhibit skeletal muscle fibrosis. Finally, molecular dynamics simulations were performed to derive information on the preferred conformations of selective and unselective antagonists.

Synthesis, docking studies, and pharmacological evaluation of 5HT2C ligands containing the N'-cyanoisonicotinamidine or N'-cyanopicolinamidine nucleus.

N'-Cyanoisonicotinamidine and N'-cyanopicolinamidine derivatives, linked to an arylpiperazine moiety, were prepared and their affinities to the 5-HT1A , 5-HT2A , and 5-HT2C receptors were evaluated. Several of the newly synthesized compounds, tested by binding studies, showed nanomolar affinity at the 5-HT1A and 5-HT2C receptors and moderate or no affinity for other relevant receptors (D1 , D2 , α1 , and α2 ). Compound 8e (Ki = 21.4 nM) was the most affine for the 5-HT2C receptor, showing, at the same time, a high selectivity with respect to the other receptors analyzed. Compounds 4a and 4c, instead, showed an interesting mixed 5-HT1A /5-HT2C activity with Ki values of 21.3/11.5 and 23.2/6.48 nM, respectively. The compounds with better affinity and selectivity binding profiles toward 5-HT2C (4a, 4c, 8b, and 8e) were selected for further in vivo assays to determine their functional activity. Finally, to rationalize the obtained results, molecular docking studies were performed. The results of the pharmacological studies showed that compounds 4a, 8b, and 8e exerted antidepressant-like effects and 4a and 8e revealed also significant anxiolytic properties. Among the developed derivatives, the most promising compound seems to be 4a, which displayed antipsychotic-, antidepressant- and anxiolytic-like properties. No side effects, like catalepsy, motor-impairment or ethanol-potentiating effects, were observed after the injection of the tested compounds.

Non-Natural Linker Configuration in 2,6-Dipeptidyl-Anthraquinones Enhances the Inhibition of TAR RNA Binding/Annealing Activities by HIV-1 NC and Tat Proteins.

The HIV-1 nucleocapsid (NC) protein represents an excellent molecular target for the development of anti-retrovirals by virtue of its well-characterized chaperone activities, which play pivotal roles in essential steps of the viral life cycle. Our ongoing search for candidates able to impair NC binding/annealing activities led to the identification of peptidyl-anthraquinones as a promising class of nucleic acid ligands. Seeking to elucidate the inhibition determinants and increase the potency of this class of compounds, we have now explored the effects of chirality in the linker connecting the planar nucleus to the basic side chains. We show here that the non-natural linker configuration imparted unexpected TAR RNA targeting properties to the 2,6-peptidyl-anthraquinones and significantly enhanced their potency. Even if the new compounds were able to interact directly with the NC protein, they manifested a consistently higher affinity for the TAR RNA substrate and their TAR-binding properties mirrored their ability to interfere with NC-TAR interactions. Based on these findings, we propose that the viral Tat protein, sharing the same RNA substrate but acting in distinct phases of the viral life cycle, constitutes an additional druggable target for this class of peptidyl-anthraquinones. The inhibition of Tat-TAR interaction for the test compounds correlated again with their TAR-binding properties, while simultaneously failing to demonstrate any direct Tat-binding capabilities. These considerations highlighted the importance of TAR RNA in the elucidation of their inhibition mechanism, rather than direct protein inhibition. We have therefore identified anti-TAR compounds with dual in vitro inhibitory activity on different viral proteins, demonstrating that it is possible to develop multitarget compounds capable of interfering with processes mediated by the interactions of this essential RNA domain of HIV-1 genome with NC and Tat proteins.

New 5-HT1A, 5HT2A and 5HT2C receptor ligands containing a picolinic nucleus: Synthesis, in vitro and in vivo pharmacological evaluation.

Picolinamide derivatives, linked to an arylpiperazine moiety, were prepared and their affinity to 5-HT1A, 5-HT2A and 5-HT2C receptors was evaluated. The combination of structural elements (heterocyclic nucleus, alkyl chain and 4-substituted piperazine), known to play critical roles in affinity for serotoninergic receptors, and the proper selection of substituents led to compounds with high specificity and affinity towards serotoninergic receptors. In binding studies, several molecules showed high affinity in nanomolar and subnanomolar range at 5-HT1A, 5-HT2A and 5-HT2C receptors and moderate or no affinity for other relevant receptors (D1, D2, α1 and α2). N-(2-(4-(pyrimidin-2-yl)piperazin-1-yl)ethyl)picolinamide (3o) with Ki=0.046nM, was the most affine and selective derivative for the 5-HT1A receptor compared to other serotoninergic dopaminergic and adrenergic receptors. N-(2-(4-(2-methoxyphenyl)piperazin-1-yl)ethyl)picolinamide (3b), instead, showed a subnanomolar affinity towards 5-HT2A with Ki=0.0224nM, whereas N-(2-(4-(bis(4-fluorophenyl)methyl)piperazin-1-yl)ethyl)picolinamide (3s) presented an attractive 5-HT2C affinity with Ki=0.8nM. Moreover, the compounds having better affinity and selectivity binding profiles towards 5-HT2A were selected and tested on rat ileum, to determine their effect on 5HT induced contractions. Those more selective towards 5-HT1A receptors were studied in vivo on several behavioral tests.

Development of 1,2,3-Triazole-Based Sphingosine Kinase Inhibitors and Their Evaluation as Antiproliferative Agents.

Two series of N-(aryl)-1-(hydroxyalkyl)pyrrolidine-2-carboxamides (2a-2g and 3a-3g) and 1,4-disubstituted 1,2,3-triazoles (5a-5h and 8a-8h) were synthesized. All the compounds, containing a lipophilic tail and a polar headgroup, were evaluated as sphingosine kinase (SphK) inhibitors by assessing their ability to interfere with the acetylcholine (Ach) induced relaxation of aortic rings pre-contracted with phenylephrine. Moreover, their antiproliferative activity was tested on several cell lines expressing both SphK1 and SphK2. Compounds 5h and 8f, identified as the most efficient antiproliferative agents, showed a different selectivity profile, with 8f being selective for SphK1.

Synthesis, biological evaluation, and docking studies of PAR2-AP-derived pseudopeptides as inhibitors of kallikrein 5 and 6.

A series of protease activated receptor 2 activating peptide (PAR2-AP) derivatives (1-15) were designed and synthesized. The obtained compounds were tested on a panel of human kallikreins (hKLK1, hKLK2, hKLK5, hKLK6, and hKLK7) and were found completely inactive toward hKLK1, hKLK2, and hKLK7. Aiming to investigate the mode of interaction between the most interesting compounds and the selected hKLKs, docking studies were performed. The described compounds distinguish the different human tissue kallikreins with compounds 1 and 5 as the best hKLK5 and hKLK6 inhibitors, respectively.

Synthesis and in vitro pharmacological evaluation of novel 2-hydroxypropyl-4-arylpiperazine derivatives as serotoninergic ligands.

This paper reports the synthesis of new norbornene and exo-N-hydroxy-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboximide derivatives and their binding to the 5-HT1A , 5-HT2A , and 5-HT2C receptors, in order to identify selective ligands for these 5-hydroxytryptamine (5-HT, serotonine) receptor subtypes. The combination of structural elements (heterocyclic nucleus, hydroxyalkyl chain, and 4-substituted piperazine) known to be critical for affinity to 5-HT1A receptors and the proper selection of substituents led to compounds with high specificity and affinity toward serotoninergic receptors. The most active compounds were selected and further evaluated for their binding affinities to D1 , D2 dopaminergic and α1 , α2 adrenergic receptors. 4-[3-[4-(2-Furoyl)piperazin-1-yl]propoxy-2-ol]-4-aza-tricyclo[5.2.1.02,6]dec-8-ene-3,5-dione 3e with Ki = 5.04 ± 0.227 nM was the most active and selective derivative for the 5-HT2C receptor with respect to other serotonin receptors, and the most selective derivative versus dopaminergic and adrenergic receptors.

Isothiocyanate-Corticosteroid Conjugates against asthma: Unity makes strength.

Asthma is a major noncommunicable disease, affecting both children and adults, and represents one of the major causes leading to high health care costs due to the need for chronic pharmacological treatments. The standard gold therapy of inflammation in asthmatic patients involves the use of glucocorticoids even if their chronic use is often related to serious adverse effects. Growing evidence suggests the biological relevance of hydrogen sulfide (H2S) in the pathogenesis of airway diseases. Hence, aiming to associate the beneficial effects of steroidal anti-inflammatory drugs (SAIDs) to H2S biological activity, we designed and synthesized novel multi-target molecules by chemically combining a group of glucocorticoids, usually employed in asthma treatment, with an isothiocyanate moiety, well-known for its H2S releasing properties. Firstly, the synthesized compounds have been screened for their H2S-releasing profile using an amperometric approach and for their in vitro effects on the degranulation process, using RBL-2H3 cell line. The physicochemical profile, in terms of solubility, chemical and enzymatic stability of the newly hybrid molecules, has been assessed at different physiological pH values and in esterase-rich medium (bovine serum albumin, BSA). The selected compound 5c, through both its corticosteroid and H2S releasing component, has been evaluated in vivo in experimental model of asthma. The compound 5c inhibited in vivo all asthma features with a significative effect on the restoration of pulmonary structure and reduction of lung inflammation.

GKT137831 and hydrogen peroxide increase the release of 6-nitrodopamine from the human umbilical artery, rat-isolated right atrium, and rat-isolated vas deferens.

Introduction: The human umbilical artery (HUA), rat-isolated right atrium, and rat-isolated vas deferens present a basal release of 6-nitrodopamine (6-ND). The basal release of 6-ND from these tissues was significantly decreased (but not abolished) when the tissues were pre-incubated with Nω-nitro-L-arginine methyl ester (L-NAME). Methods: In this study, the effect of the pharmacological modulation of the redox environment on the basal release of 6-ND was investigated. The basal release of 6-ND was measured using Liquid chromatography with tandem mass spectrometry (LC-MS/MS). Results and Discussion: Pre-incubation (30 min) of the tissues with GKT137831 (1 µM) caused a significant increase in the basal release of 6-ND from all tissues. In the HUA, pre-incubation with diphenyleneiodonium (DPI) (100 µM) also caused significant increases in the basal release of 6-ND. Preincubation of the HUA with hydrogen peroxide (H2O2) (100 µM) increased 6-ND basal release, whereas pre-incubation with catalase (1,000 U/mL) significantly decreased it. Pre-incubation of the HUA with superoxide dismutase (SOD) (250 U/mL; 30 min) also significantly increased the basal release of 6-ND. Preincubation of the HUA with either allopurinol (100 µM) or uric acid (1 mM) had no effect on the basal release of 6-ND. Pre-treatment of the HUA with L-NAME (100 µM) prevented the increase in the basal release of 6-ND induced by GKT137831, diphenyleneiodonium, and H2O2. The results obtained indicate a major role of endogenous H2O2 and peroxidases as modulators of 6- ND biosynthesis/release and a lack of peroxynitrite contribution.

Technological and Physical-Chemical Evaluation of Cotton Gauzes Impregnated with Semisolid Preparations for Wound Healing.

Chronic wounds are marked by an extended healing period during which damaged tissues fail to undergo orderly and timely repair. Examples of chronic wounds encompass venous ulcers, pressure ulcers, and diabetic foot ulcers. The process of wound healing is complex and dynamic, relying on the interplay and response among various cells and mediators. In this study, four marketed wound dressing products based on cotton gauzes impregnated with different semisolid products (namely Betadine® 10%, Connettivina® Bio Plus Fitostimoline® Plus, and Non-Ad® gauzes) have been characterized for their physicochemical properties and ex vivo behaviors. More in detail, the pH and rheological features of semisolid formulations impregnating the gauzes were analyzed along with their ability to adhere to the gauzes. The most promising ones were selected and compared in ex vivo experiments on fresh pig skin. The pH measurements showed an acidic environment for all the tested solutions, albeit with variations in mean values, ranging from 2.66 to 4.50. The outcomes of rheological studies demonstrated that all the semisolid preparations impregnating the gauzes exhibited a pseudoplastic behavior, with significant differences in the pseudoplasticity index across the preparations, which is likely to influence their ability to adhere to the gauze. A rheological study in oscillatory mode revealed rheological behavior typical of a viscous solution only for the cream impregnating non-paraffin gauzes. The other products exhibited rheological behavior typical of a weak gel, which is expected to be advantageous as regards the capability of the semisolid preparation to create and maintain the space within the wound and to provide protection to the injured tissue. Results of ex vivo experiments demonstrated that Fitostimoline® Plus was more effective than Connettivina® Bio Plus in promoting both skin hydration and energy.

Identification of a pepducin acting as S1P3 receptor antagonist.

Sphingosine-1-phosphate (S1P) is a bioactive lipid with key functions in the immune, inflammatory, and cardiovascular systems. S1P exerts its action through the interaction with a family of five known G protein-coupled receptors, named S1P(1-5). Among them, S1P(3) has been implicated in the pathological processes of a number of diseases, including sepsis and cancer. KRX-725 (compound 1) is a pepducin that mimics the effects of S1P by triggering specifically S1P(3). Here, aiming to identify novel S1P(3) antagonists, we carried out an alanine scanning analysis to address the contribution of the side chains of each amino acid residue to the peptide function. Then, deleted peptides from both the C- and N-terminus were prepared in order to determine the minimal sequence for activity and to identify the structural requirements for agonistic and, possibly, antagonistic behaviors. The pharmacological results of the Ala-scan derived compounds (2-10) suggested a high tolerance of the pepducin 1 to amino acid substitutions. Importantly, the deleted peptide 16 has the ability to inhibit, in a dose-dependent manner, both pepducin 1-induced vasorelaxation and fibroblast proliferation. Finally, a computational analysis was performed on the prepared compounds, showing that the supposed antagonists 16 and 17 appeared to be aligned with each other but not with the others. These results suggested a correlation between specific conformations and activities.