RESUMO
Tuberculosis treatment requires months-long combination chemotherapy with multiple drugs, with shorter treatments leading to relapses. A major impediment to shortening treatment is that Mycobacterium tuberculosis becomes tolerant to the administered drugs, starting early after infection and within days of infecting macrophages. Multiple lines of evidence suggest that macrophage-induced drug tolerance is mediated by mycobacterial drug efflux pumps. Here, using assays to directly measure drug efflux, we find that M. tuberculosis transports the first-line antitubercular drug rifampicin through a proton gradient-dependent mechanism. We show that verapamil, a known efflux pump inhibitor, which inhibits macrophage-induced rifampicin tolerance, also inhibits M.tuberculosis rifampicin efflux. As with macrophage-induced tolerance, the calcium channel-inhibiting property of verapamil is not required for its inhibition of rifampicin efflux. By testing verapamil analogs, we show that verapamil directly inhibits M. tuberculosis drug efflux pumps through its human P-glycoprotein (PGP)-like inhibitory activity. Screening commonly used drugs with incidental PGP inhibitory activity, we find many inhibit rifampicin efflux, including the proton pump inhibitors (PPIs) such as omeprazole. Like verapamil, the PPIs inhibit macrophage-induced rifampicin tolerance as well as intramacrophage growth, which has also been linked to mycobacterial efflux pump activity. Our assays provide a facile screening platform for M. tuberculosis efflux pump inhibitors that inhibit in vivo drug tolerance and growth.
Assuntos
Mycobacterium tuberculosis , Tuberculose , Humanos , Rifampina/farmacologia , Inibidores da Bomba de Prótons/farmacologia , Antituberculosos/farmacologia , Verapamil/farmacologia , Macrófagos , Tuberculose/tratamento farmacológico , Tolerância a Medicamentos , Proteínas de Bactérias , Testes de Sensibilidade MicrobianaRESUMO
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.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP , Inibidores da Anidrase Carbônica , Anidrases Carbônicas , Resistência a Múltiplos Medicamentos , Resistencia a Medicamentos Antineoplásicos , Piperazinas , Humanos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/antagonistas & inibidores , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Piperazinas/farmacologia , Piperazinas/química , Piperazinas/síntese química , Inibidores da Anidrase Carbônica/farmacologia , Inibidores da Anidrase Carbônica/química , Inibidores da Anidrase Carbônica/síntese química , Anidrases Carbônicas/metabolismo , Doxorrubicina/farmacologia , Doxorrubicina/química , Piperazina/química , Piperazina/farmacologia , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/síntese química , Células HT29 , Relação Estrutura-Atividade , Linhagem Celular Tumoral , Estrutura Molecular , Células A549RESUMO
The tandem mass spectrometry (MS/MS) approach employing an ion trap mass analyzer (IT) was evaluated in isomers recognition. The proposed approach consists of sole, simple, and rapid liquid chromatographic separation (HPLC) without requiring resolution between the analytes. Then, the MS/MS properties were optimized to solve the signal assignment using post-processing data elaboration (LEDA). The IT-MS/MS experiment uses the same site, helium as collision gas, and different time steps to modify the applied conditions on the studied ions. Nevertheless, helium cannot ensure the quick energization of the precursor ion due to its small cross-section. Then, different combinations between excitation amplitude (ExA) and excitation time (ExT) were tested to achieve the activation of the fragmentation channels and the formation of the MS/MS spectrum. Usually, the IT-MS/MS acquisition cycle is longer for other multistage instruments, decreasing the frequency of sample data collection and influencing the chromatographic profile. To solve these problems, two time segments were set up, and the elution conditions were optimized with a compromise between peaks distinction and run time reduction. The developed HPLC-MS/MS method was checked and applied to analyze a series of human plasma samples spiked with an equimolar mixture of pair of isomers.
Assuntos
Hélio , Espectrometria de Massas em Tandem , Humanos , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas em Tandem/métodos , Cromatografia Líquida/métodos , AlgoritmosRESUMO
Metformin is the most prescribed glucose-lowering drug worldwide; globally, over 100 million patients are prescribed this drug annually. Some different action mechanisms have been proposed for this drug, but, surprisingly, no metabolite of metformin has ever been described. It was considered interesting to investigate the possible reaction of metformin with glucose following the Maillard reaction pattern. The reaction was first performed in in vitro conditions, showing the formation of two adducts that originated by the condensation of the two molecular species with the losses of one or two water molecules. Their structures were investigated by liquid chromatography coupled with mass spectrometry (HPLC-MS), tandem mass spectrometry (MS/MS) and accurate mass measurements (HRMS). The species originated via the reaction of glucose and metformin and were called metformose and dehydrometformose, and some structural hypotheses were conducted. It is worth to emphasize that they were detected in urine samples from a diabetic patient treated with metformin and consequently they must be considered metabolites of the drug, which has never been identified before now. The glucose-related substructure of these compounds could reflect an improved transfer across cell membranes and, consequently, new hypotheses could be made about the biological targets of metformin.
Assuntos
Metformina , Humanos , Espectrometria de Massas em Tandem , Espectrometria de Massa com Cromatografia Líquida , Membrana Celular , GlucoseRESUMO
The piperazine moiety is often found in drugs or in bioactive molecules. This widespread presence is due to different possible roles depending on the position in the molecule and on the therapeutic class, but it also depends on the chemical reactivity of piperazine-based synthons, which facilitate its insertion into the molecule. In this paper, we take into consideration the piperazine-containing drugs approved by the Food and Drug Administration between January 2011 and June 2023, and the synthetic methodologies used to prepare the compounds in the discovery and process chemistry are reviewed.
Assuntos
Piperazina , Estados Unidos , United States Food and Drug AdministrationRESUMO
Positive allosteric modulators (PAMs), negative allosteric modulators (NAMs), silent agonists, allosteric activating PAMs and neutral or silent allosteric modulators are compounds capable of modulating the nicotinic receptor by interacting at allosteric modulatory sites distinct from the orthosteric sites. This survey is focused on the compounds that have been shown or have been designed to interact with nicotinic receptors as allosteric modulators of different subtypes, mainly α7 and α4ß2. Minimal chemical changes can cause a different pharmacological profile, which can then lead to the design of selective modulators. Experimental evidence supports the use of allosteric modulators as therapeutic tools for neurological and non-neurological conditions.
Assuntos
Receptores Nicotínicos , Receptores Nicotínicos/metabolismo , Receptor Nicotínico de Acetilcolina alfa7/química , Regulação Alostérica , Sítio AlostéricoRESUMO
BACKGROUND: MDR in bacteria is threatening to public health. Overexpression of efflux pumps is an important cause of MDR. The co-administration of antimicrobial drugs and efflux pump inhibitors (EPIs) is a promising approach to address the problem of MDR. OBJECTIVES: To identify new putative EPIs and to characterize their mechanisms of action. METHODS: The effects of four selected piperazine derivatives on resistance-nodulation-cell division (RND) pumps was evaluated in Escherichia coli strains overexpressing or not expressing RND pumps by assays aimed at evaluating antibiotic potentiation, membrane functionality, ethidium bromide accumulation and AcrB expression. The cytotoxicity of selected piperazines towards primary cultures of human dermal fibroblasts was also investigated. RESULTS: Four molecules enhanced levofloxacin activity against strains overexpressing RND efflux pumps (AcrAB-TolC and AcrEF-TolC), but not against RND pump-deficient strains. They had little effects on membrane potential. Molecule 4 decreased, whereas the other three increased, membrane permeability compared with untreated control cells. The four molecules showed differences in the specificity of interaction with RND efflux pumps, by inactivating the transport of one or more antibiotics, and in the levels of ethidium bromide accumulation and of acrB expression inhibition. CONCLUSIONS: Piperazine derivatives are good candidates as inhibitors of RND efflux pumps. They decreased the activity of RND pumps by mixed mechanisms of action. Small structural differences among the molecules can be critical in defining their behaviour.
Assuntos
Antibacterianos , Proteínas de Escherichia coli , Escherichia coli , Proteínas Associadas à Resistência a Múltiplos Medicamentos , Piperazinas , Antibacterianos/farmacologia , Divisão Celular , Farmacorresistência Bacteriana Múltipla , Escherichia coli/efeitos dos fármacos , Proteínas de Escherichia coli/metabolismo , Humanos , Testes de Sensibilidade Microbiana , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Piperazinas/farmacologiaRESUMO
This paper proposes a tandem mass spectrometry (MS/MS) approach in isomer recognition by playing in the "energetic dimension" of the experiment. The chromatographic set up (HPLC) was tuned to minimize the run time, without requiring high efficiency or resolution between the isomers. Then, the MS/MS properties were explored to solve the signal assignment by performing a series of energy resolved experiments in order to optimize the parameters, and by applying an interesting post-processing data elaboration tool (LEDA). The reliability of the new approach was evaluated, determining the accuracy and precision of the quantitative results through analysis of the isomer mixture solutions. Next, the proposed method was applied in a chemical stability study of human plasma samples through the simultaneous addition of a pair of isomers. In the studied case, only one of the isomers suffered of enzymatic hydrolysis; therefore, the influence of the stable isomer on the degradation rate of the other was verified. In order to monitor this process correctly, it must be possible to distinguish each isomer present in the sample, quantify it, and plot its degradation profile. The reported results demonstrated the effectiveness of the LEDA algorithm in separating the isomers, without chromatographic resolution, and monitoring their behavior in human plasma samples.
Assuntos
Algoritmos , Espectrometria de Massas em Tandem , Humanos , Cromatografia Líquida de Alta Pressão/métodos , Espectrometria de Massas em Tandem/métodos , Reprodutibilidade dos Testes , IsomerismoRESUMO
A series of histamine (HST)-related compounds were synthesized and tested for their activating properties on five physiologically relevant human Carbonic Anhydrase (hCA) isoforms (I, II, Va, VII and XIII). The imidazole ring of HST was replaced with different 5-membered heterocycles and the length of the aliphatic chain was varied. For the most interesting compounds some modifications on the terminal amino group were also performed. The most sensitive isoform to activation was hCA I (KA values in the low micromolar range), but surprisingly none of the new compounds displayed activity on hCA II. Some derivatives (1, 3a and 22) displayed an interesting selectivity for activating hCA I over hCA II, Va, VII and XIII.
Assuntos
Anidrase Carbônica I/metabolismo , Compostos Heterocíclicos de 4 ou mais Anéis/química , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Histamina/química , Histamina/farmacologia , Anidrase Carbônica I/efeitos dos fármacos , Anidrase Carbônica II/efeitos dos fármacos , Anidrase Carbônica II/metabolismo , Anidrase Carbônica V/efeitos dos fármacos , Anidrase Carbônica V/metabolismo , Anidrases Carbônicas/efeitos dos fármacos , Anidrases Carbônicas/metabolismo , Compostos Heterocíclicos de 4 ou mais Anéis/síntese química , Histamina/análogos & derivados , Histamina/síntese química , Humanos , Imidazóis/química , Isoformas de Proteínas/efeitos dos fármacos , Isoformas de Proteínas/metabolismoRESUMO
Human neutrophil elastase (HNE) is a serine protease that is expressed in polymorphonuclear neutrophils. It has been recognized as an important therapeutic target for treating inflammatory diseases, especially related to the respiratory system, but also for various types of cancer. Thus, compounds able to inhibit HNE are of great interest in medicinal chemistry. In the present paper, we report the synthesis and biological evaluation of a new series of HNE inhibitors with an innovative 1,5,6,7-tetrahydro-4H-indazol-4-one core that was developed as a molecular modification of our previously reported indazole-based HNE inhibitors. Since the 1,5,6,7-tetrahydro-4H-indazol-4-one scaffold can occur in two possible tautomeric forms, the acylation/alkylation reactions resulted in a mixture of the two isomers, often widely unbalanced in favor of one form. Using analytical techniques and NMR spectroscopy, we characterized and separated the isomer pairs and confirmed the compounds used in biological testing. Analysis of the compounds for HNE inhibitory activity showed that they were potent inhibitors, with Ki values in the low nanomolar range (6-35 nM). They also had reasonable stability in aqueous buffer, with half-lives over 1 h. Overall, our results indicate that the 1,5,6,7-tetrahydro-4H-indazol-4-one core is suitable for the synthesis of potent HNE inhibitors that could be useful in the development of new therapeutics for treating diseases involving excessive HNE activity.
Assuntos
Elastase de Leucócito/antagonistas & inibidores , Inibidores de Serina Proteinase/farmacologia , Relação Dose-Resposta a Droga , Humanos , Elastase de Leucócito/metabolismo , Estrutura Molecular , Inibidores de Serina Proteinase/síntese química , Inibidores de Serina Proteinase/química , Relação Estrutura-AtividadeRESUMO
Differently substituted ß-hydroxy- and ß-amino dialkyl and alkyl-aryl tellurides and selenides have been prepared through ring-opening reactions of epoxides and aziridines with selenium- or tellurium-centered nucleophiles. The antioxidant properties and the cytotoxicity of such compounds have been investigated on normal human dermal fibroblasts. Most of the studied compounds exhibited a low cytotoxicity and a number of them proved to be non-toxic, not showing any effect on cell viability even at the highest concentration used (100 µM). The obtained results showed a significant antioxidant potential of the selected organotellurium compounds, particularly evident under conditions of exogenously induced oxidative stress. The antioxidant activity of selenium-containing analogues of active tellurides has also been evaluated on cells, highlighting that the replacement of Se with Te brought about a significant increase in the peroxidase activity.
Assuntos
Antioxidantes/farmacologia , Calcogênios/farmacologia , Ditiotreitol/metabolismo , Antioxidantes/síntese química , Antioxidantes/química , Células Cultivadas , Calcogênios/síntese química , Calcogênios/química , Relação Dose-Resposta a Droga , Humanos , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
The Carbonic Anhydrase (CA, EC 4.2.1.1) activating properties of histamine have been known for a long time. This compound has been extensively modified but only in few instances the imidazole ring has been replaced with other heterocycles. It was envisaged that the imidazoline ring could be a bioisoster of the imidazole moiety. Indeed, we report that clonidine, a 2-aminoimidazoline derivative, was found able to activate several human CA isoforms (hCA I, IV, VA, VII, IX, XII and XIII), with potency in the micromolar range, while it was inactive on hCA II. A series of 2-aminoimidazoline, structurally related to clonidine, was then synthesised and tested on selected hCA isoforms. The compounds were inactive on hCA II while displayed activating properties on hCA I, VA, VII and XIII, with KA values in the micromolar range. Two compounds (10 and 11) showed some preference for the hCA VA or VII isoforms.
Assuntos
Inibidores da Anidrase Carbônica/farmacologia , Anidrases Carbônicas/metabolismo , Clonidina/farmacologia , Imidazóis/farmacologia , Inibidores da Anidrase Carbônica/síntese química , Inibidores da Anidrase Carbônica/química , Clonidina/química , Relação Dose-Resposta a Droga , Humanos , Imidazóis/síntese química , Imidazóis/química , Isoenzimas/antagonistas & inibidores , Isoenzimas/metabolismo , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
Aiming to deepen the structure-activity relationships of the two P-glycoprotein (P-gp) modulators elacridar and tariquidar, a new series of amide and ester derivatives carrying a 6,7-dimethoxy-2-phenethyl-1,2,3,4-tetrahydroisoquinoline scaffold linked to different methoxy-substituted aryl moieties were synthesised. The obtained compounds were evaluated for their P-gp interaction profile and selectivity towards the two other ABC transporters, multidrug-resistance-associated protein-1 and breast cancer resistance protein, showing to be very active and selective versus P-gp. Two amide derivatives, displaying the best P-gp activity, were tested in co-administration with the antineoplastic drug doxorubicin in different cancer cell lines, showing a significant sensitising activity towards doxorubicin. The investigation on the chemical stability of the derivatives towards spontaneous or enzymatic hydrolysis, showed that amides are stable in both models while some ester compounds were hydrolysed in human plasma. This study allowed us to identify two chemosensitizers that behave as non-transported substrates and are characterised by different selectivity profiles.
Assuntos
Amidas/farmacologia , Antineoplásicos/farmacologia , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Ésteres/farmacologia , Neoplasias/tratamento farmacológico , Tetra-Hidroisoquinolinas/farmacologia , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/antagonistas & inibidores , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Amidas/síntese química , Amidas/química , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Células Cultivadas , Cães , Relação Dose-Resposta a Droga , Doxorrubicina/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Ésteres/síntese química , Ésteres/química , Humanos , Estrutura Molecular , Neoplasias/metabolismo , Relação Estrutura-Atividade , Tetra-Hidroisoquinolinas/síntese química , Tetra-Hidroisoquinolinas/químicaRESUMO
Human neutrophil elastase (HNE) is a proteolytic enzyme belonging to the serine protease family and is involved in a variety of pathologies. Thus, compounds able to inhibit HNE represent promising therapeutics for the treatment of inflammatory diseases. Here, we report the further elaboration of our previously reported 3-methylisoxazolone derivatives, synthesizing a new series of 3-nor-derivatives bearing different substituents at the 4-phenyl ring. The most potent compounds 3a, 3g, and 3h, had IC50 values of 16, 11, and 18 nM, respectively. Molecular modeling studies and molecular dynamic (MD) simulations demonstrated no substantial differences between the 3-methylisoxazole derivatives previously tested and the corresponding 3-unsubstituted derivatives in the snapshot conformations sampled during the MD simulations, which is consistent with their similar levels of HNE inhibitory activity. Thus, we conclude that the isoxazolone scaffold is a good scaffold for developing HNE inhibitors, as it tolerates several modifications when adhering to basic scaffold requirements, and the resulting derivatives are quite potent HNE inhibitors.
Assuntos
Isoxazóis/farmacologia , Elastase de Leucócito/antagonistas & inibidores , Proteínas Secretadas Inibidoras de Proteinases/farmacologia , Humanos , Concentração Inibidora 50 , Isoxazóis/síntese química , Isoxazóis/química , Modelos Moleculares , Simulação de Dinâmica Molecular , Proteínas Secretadas Inibidoras de Proteinases/síntese química , Proteínas Secretadas Inibidoras de Proteinases/química , Relação Estrutura-AtividadeRESUMO
A new series of N,N-bis(alkanol)amine aryl diesters was synthesized and studied as dual P-glycoprotein (P-gp) and carbonic anhydrase XII inhibitors (CA XII). These hybrids should be able to synergistically overcome P-gp mediated multidrug resistance (MDR) in cancer cells. It was reported that the efflux activity of P-gp could be modulated by CA XII, as the pH reduction caused by CA XII inhibition produces a significant decrease in P-gp ATPase activity. The new compounds reported here feature both P-gp and CA XII binding moieties. These hybrids contain a N,N-bis(alkanol)amine diester scaffold found in P-glycoprotein ligands and a coumarin or benzene sulfonamide moiety to target CA XII. Many compounds displayed a dual activity against P-gp and CA XII being active in the Rhd 123 uptake test on K562/DOX cells and in the hCA XII inhibition test. On LoVo/DOX cells, that overexpress both P-gp and CA XII, some coumarin derivatives showed a high MDR reversal effect in Rhd 123 uptake and doxorubicin cytotoxicity enhancement tests. In particular, compounds 7 and 8 showed higher activity than verapamil and were more potent on LoVo/DOX than on K562/DOX cells overexpressing only P-gp. They can be considered as valuable candidates for selective P-gp/CA XII inhibition in MDR cancer cells.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/química , Inibidores da Anidrase Carbônica/química , Anidrases Carbônicas/química , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/antagonistas & inibidores , Antineoplásicos/farmacologia , Transporte Biológico , Inibidores da Anidrase Carbônica/farmacologia , Doxorrubicina/farmacologia , Resistência a Múltiplos Medicamentos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Estabilidade de Medicamentos , Humanos , Células K562 , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
Starting from the molecular simplification of (R) 4-(3,4-dibenzylpiperazine-1-carbonyl)benzenesulfonamide 9a, a compound endowed with selectivity for human Carbonic Anhydrase (hCA) IV, a series of piperazines and 4-aminopiperidines carrying a 4-sulfamoylbenzamide moiety as Zn-binding group have been designed and tested on human isoforms hCA I, II, IV and IX, using a stopped flow CO2 hydrase assay. The aim of the work was to derive structure-activity relationships useful for designing isoform selective compounds. These structural modifications changed the selectivity profile of the analogues from hCA IV to hCA I and II, and improved potency. Several of the new compounds showed subnanomolar activity on hCA II. X-ray crystallography of ligand-hCAII complexes was used to compare the binding modes of the new piperazines and the previously synthesized 2-benzyl-piperazine analogues, explaining the inhibition profiles.
Assuntos
Inibidores da Anidrase Carbônica/farmacologia , Piperazinas/farmacologia , Sulfonamidas/farmacologia , Inibidores da Anidrase Carbônica/síntese química , Inibidores da Anidrase Carbônica/metabolismo , Anidrases Carbônicas/química , Anidrases Carbônicas/metabolismo , Domínio Catalítico , Cristalografia por Raios X , Humanos , Isoenzimas/química , Isoenzimas/metabolismo , Estrutura Molecular , Piperazinas/síntese química , Piperazinas/metabolismo , Ligação Proteica , Relação Estrutura-Atividade , Sulfonamidas/síntese química , Sulfonamidas/metabolismoRESUMO
In this study, a new series of heterodimers was synthesized. These derivatives are N,N-bis(alkanol)amine aryl esters or N,N-bis(ethoxyethanol)amine aryl esters carrying a methoxylated aryl residue combined with a flavone or chromone moiety. The new compounds were studied to evaluate their P-gp modulating activity on a multidrug-resistant leukemia cell line. Some of the new compounds show a good MDR reversing activity; interestingly this new series of compounds does not comply with the structure-activity relationships (SAR) outlined by previously synthesized analogs carrying different aromatic moieties. In the case of the compounds described in this paper, activity is linked to different features, in particular the characteristics of the spacer, which seem to be critical for the interaction with the pump. This fact indicates that the presence of a flavone or chromone residue influences the SAR of these series of products, and that flexible molecules can find different productive binding modes with the P-gp recognition site. These results support the synthesis of new compounds that might be useful leads for the development of drugs to control P-gp-dependent MDR.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Aminas/farmacologia , Cromonas/farmacologia , Desenho de Fármacos , Ésteres/farmacologia , Flavonas/farmacologia , Aminas/síntese química , Aminas/química , Cromonas/química , Dimerização , Relação Dose-Resposta a Droga , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Ésteres/síntese química , Ésteres/química , Flavonas/química , Humanos , Células K562 , Modelos Moleculares , Estrutura Molecular , Relação Estrutura-Atividade , Células Tumorais CultivadasRESUMO
Human neutrophil elastase (HNE) is a potent serine protease belonging to the chymotrypsin family. It is an important target for the development of novel and selective inhibitors for the treatment of inflammatory diseases, especially pulmonary pathologies. Here, we report the synthesis and biological evaluation of a new series of HNE inhibitors with a pyrrolo[2,3-b]pyridine scaffold, which is an isomer of our previously reported indazoles, in order to assess how a shift of the nitrogen from position 2 to position 7 influences activity. The majority of new compounds were effective HNE inhibitors and had IC50 values in the micromolar/submicromolar range, with some compounds active in low nanomolar levels. For example, 2a and 2b inhibited HNE with IC50 values of 15 and 14â¯nM, respectively. Molecular modeling of compounds differing in the position of heteroatom(s) in the bicyclic moiety and in the oxadiazole ring demonstrated that the calculated geometries of enzyme-inhibitor complexes were in agreement with the observed biological activities. Docking experiments showed that orientation of the active pyrrolo[2,3-b]pyridines in the HNE catalytic triad Ser195-His57-Asp102 correlated with effectiveness of the inhibitor interaction with the enzyme. Thus, the pyrrolo[2,3-b]pyridine scaffold represents a novel scaffold for the development of potent HNE inhibitors.
Assuntos
Elastase de Leucócito/antagonistas & inibidores , Piridinas/farmacologia , Pirróis/farmacologia , Inibidores de Serina Proteinase/farmacologia , Estabilidade de Medicamentos , Humanos , Elastase de Leucócito/química , Simulação de Acoplamento Molecular , Estrutura Molecular , Piridinas/síntese química , Piridinas/química , Pirróis/síntese química , Pirróis/química , Inibidores de Serina Proteinase/síntese química , Inibidores de Serina Proteinase/químicaRESUMO
The piperazine ring of the potent nootropic drug DM235 has been decorated with H-bond donor and acceptor groups (CH2OH, CH2OMe, CH2OCOMe, COOEt); the aim was to insert new functional groups, suitable for further chemical manipulation. The influence of these modifications on nootropic activity was assessed by means of the mouse passive avoidance test; some of the newly synthesized molecules (alcohol 7b, acetate 8b and ester 10d) showed interesting in vivo potency. This makes it possible to use these functional groups for adding other residues, in order to increase molecular diversity, or for anchoring a biotin group, to obtain compounds useful to capture the biological target. Moreover, the new compounds will improve our knowledge of structure activity relationships of this family of drugs.
Assuntos
Cognição/efeitos dos fármacos , Nootrópicos/farmacologia , Piperazinas/farmacologia , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Masculino , Camundongos , Nootrópicos/química , Piperazinas/química , Espectroscopia de Prótons por Ressonância Magnética , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
RATIONALE: A series of drug plasma stability experiments were carried out to evaluate the bioavailability of three multidrug resistance inhibitors. The studied compounds are positional isomers; therefore, a chromatographic separation or taking advantage of specific collisionally activated decomposition pathways, obtained by tandem mass spectrometry (MS/MS) experiments, is necessary in order to resolve them. METHODS: A method was developed for quantitative determination of the analytes in plasma using liquid chromatography (LC) coupled with a triple quadrupole mass spectrometer operating in MS/MS mode. Different collisional approaches were employed based on the potentiality of a triple quadrupole system. Aside from the classical product ion spectroscopy, energy-resolved MS/MS experiments and a post-processing mathematical algorithm tool (LEDA) were used to distinguish among different kinds of inhibitors present in the sample batch. RESULTS: The developed LC/MS/MS method showed precision between 1.8-7.9%, accuracy ranging from 92.8 to 99.9% and limit of detection (LOD) values in the range 1.0-1.4 ng mL(-1) for all the analytes. The evaluation of matrix effects demonstrated that the sample preparation procedure did not affect the ionization efficiency or recovery (matrix effects and recovery larger than 88%). Finally, the LEDA tool was able to differentiate among the isomers, ensuring their proper monitoring. CONCLUSIONS: The proposed LC/MS/MS method was suitable for evaluating the stability of the analytes in plasma samples, although small concentration variations occurred. Furthermore, the investigation on the energetics of fragmentation pathways allowed the better product ions and optimal abundance ratios to be selected for LEDA application into a multi-component analysis. Copyright © 2015 John Wiley & Sons, Ltd.