RESUMO
A series of new of furan derivatised [1,4] benzothiazepine analogues were synthesized starting from 1-(furan-2-yl)ethanone. 1-(Furan-2-yl)ethanone was converted into chalcones by its reaction with various aromatic aldehydes, then were reacted with 2-aminobenzenethiol in acidic conditions to obtain the title compounds in good yields. The synthesized new compounds were characterized by 1H NMR, 13C NMR, Mass spectral studies and elemental analyses. All the new compounds were evaluated for their in vitro VRV-PL-8a and H+/K+ ATPase inhibitor properties. Preliminary studies revealed that, some molecules amongst the designed series showed promising VRV-PL-8a and H+/K+ ATPase inhibitor properties. Further, rigid body docking studies were performed to understand possible docking sites of the molecules on the target proteins and the mode of binding. This finding presents a promising series of lead molecules that can serve as prototypes for the treatment of inflammatory related disorder that can mitigate the ulcer inducing side effect shown by other NSAIDs.
Assuntos
Desenho de Fármacos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Fosfolipases A2 do Grupo II/antagonistas & inibidores , ATPase Trocadora de Hidrogênio-Potássio/química , Tiazepinas/síntese química , Tiazepinas/farmacologia , Anti-Inflamatórios não Esteroides/síntese química , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/metabolismo , Anti-Inflamatórios não Esteroides/farmacologia , Sítios de Ligação , Chalconas/química , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Furanos/química , Fosfolipases A2 do Grupo II/metabolismo , ATPase Trocadora de Hidrogênio-Potássio/metabolismo , Concentração Inibidora 50 , Espectroscopia de Ressonância Magnética , Conformação Molecular , Simulação de Acoplamento Molecular , Estrutura Terciária de Proteína , Inibidores da Bomba de Prótons/síntese química , Inibidores da Bomba de Prótons/química , Inibidores da Bomba de Prótons/metabolismo , Inibidores da Bomba de Prótons/farmacologia , Tiazepinas/química , Tiazepinas/metabolismoRESUMO
INTRODUCTION: K201, a 1,4-benzodiazepine derivative, acts on multiple cardiac ion channels and the ryanodine receptor. We tested whether administration of M-II, the main metabolite of K201, would terminate induced atrial flutter (AFL) or atrial fibrillation (AF) in the canine sterile pericarditis model. METHODS: In 6 dogs, electrophysiologic studies were performed at baseline and after drug administration, measuring atrial effective refractory period (AERP), and conduction time from 3 sites during pacing at cycle lengths (400, 300, and 200 milliseconds) on postoperative days 1-4. In 12 induced episodes of sustained AF/AFL (2/10, respectively), M-II was administered intravenously to test efficacy. Five of the AFL episodes were studied in the open chest state during simultaneous multisite atrial mapping. RESULTS: M-II terminated 2/2 AF and 8/10 AFL episodes, prolonged AERP (P < 0.05), significantly increased atrial pacing capture thresholds but did not significantly change atrial conduction time. AFL CL prolongation was largely explained by prolonged conduction in an area of slow conduction in the reentrant circuit. AFL terminated with block in the area of slow conduction. CONCLUSIONS: M-II was very effective in terminating AFL/AF in the canine sterile pericarditis model. AFL terminated due to block in the area of slow conduction of the reentrant circuit.
Assuntos
Antiarrítmicos/farmacologia , Fibrilação Atrial/tratamento farmacológico , Flutter Atrial/tratamento farmacológico , Sistema de Condução Cardíaco/efeitos dos fármacos , Pericardite/complicações , Tiazepinas/farmacologia , Tiazolidinedionas/farmacologia , Animais , Antiarrítmicos/metabolismo , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/etiologia , Fibrilação Atrial/fisiopatologia , Flutter Atrial/diagnóstico , Flutter Atrial/etiologia , Flutter Atrial/fisiopatologia , Biotransformação , Estimulação Cardíaca Artificial , Modelos Animais de Doenças , Cães , Eletrocardiografia , Técnicas Eletrofisiológicas Cardíacas , Sistema de Condução Cardíaco/fisiopatologia , Tiazepinas/metabolismo , Tiazolidinedionas/metabolismo , Fatores de TempoRESUMO
A synthesis of the benzothiazepine phosphonic acid 3, employing both enzymatic and transition metal catalysis, is described. The quaternary chiral center of 3 was obtained by resolution of ethyl (2-ethyl)norleucinate (4) with porcine liver esterase (PLE) immobilized on Sepabeads. The resulting (R)-amino acid (5) was converted in two steps to aminosulfate 7, which was used for construction of the benzothiazepine ring. Benzophenone 15, prepared in four steps from trimethylhydroquinone 11, enabled sequential incorporation of phosphorus (Arbuzov chemistry) and sulfur (Pd(0)-catalyzed thiol coupling) leading to mercaptan intermediate 18. S-Alkylation of 18 with aminosulfate 7 followed by cyclodehydration afforded dihydrobenzothiazepine 20. Iridium-catalyzed asymmetric hydrogenation of 20 with the complex of [Ir(COD)2BArF] (26) and Taniaphos ligand P afforded the (3R,5R)-tetrahydrobenzothiazepine 30 following flash chromatography. Oxidation of 30 to sulfone 31 and phosphonate hydrolysis completed the synthesis of 3 in 12 steps and 13% overall yield.
Assuntos
Esterases/metabolismo , Irídio/química , Transportadores de Ânions Orgânicos Dependentes de Sódio/antagonistas & inibidores , Simportadores/antagonistas & inibidores , Tiazepinas/farmacologia , Animais , Catálise , Cristalografia por Raios X , Esterases/química , Humanos , Fígado/enzimologia , Modelos Moleculares , Estrutura Molecular , Relação Estrutura-Atividade , Suínos , Tiazepinas/química , Tiazepinas/metabolismoRESUMO
Mitochondrial Ca(2+) efflux is linked to numerous cellular activities and pathophysiological processes. Although it is established that an Na(+)-dependent mechanism mediates mitochondrial Ca(2+) efflux, the molecular identity of this transporter has remained elusive. Here we show that the Na(+)/Ca(2+) exchanger NCLX is enriched in mitochondria, where it is localized to the cristae. Employing Ca(2+) and Na(+) fluorescent imaging, we demonstrate that mitochondrial Na(+)-dependent Ca(2+) efflux is enhanced upon overexpression of NCLX, is reduced by silencing of NCLX expression by siRNA, and is fully rescued by the concomitant expression of heterologous NCLX. NCLX-mediated mitochondrial Ca(2+) transport was inhibited, moreover, by CGP-37157 and exhibited Li(+) dependence, both hallmarks of mitochondrial Na(+)-dependent Ca(2+) efflux. Finally, NCLX-mediated mitochondrial Ca(2+) exchange is blocked in cells expressing a catalytically inactive NCLX mutant. Taken together, our results converge to the conclusion that NCLX is the long-sought mitochondrial Na(+)/Ca(2+) exchanger.
Assuntos
Cálcio/metabolismo , Mitocôndrias/metabolismo , Trocador de Sódio e Cálcio/metabolismo , Sódio/metabolismo , Animais , Encéfalo/citologia , Encéfalo/metabolismo , Clonazepam/análogos & derivados , Clonazepam/metabolismo , Homeostase , Humanos , Camundongos , Mitocôndrias/ultraestrutura , Membranas Mitocondriais/metabolismo , Membranas Mitocondriais/ultraestrutura , Miocárdio/citologia , Miocárdio/metabolismo , Ratos , Trocador de Sódio e Cálcio/antagonistas & inibidores , Trocador de Sódio e Cálcio/genética , Tiazepinas/metabolismoRESUMO
New drugs with enhanced electron donor properties that target the ryanodine receptor from skeletal muscle sarcoplasmic reticulum (RyR1) are shown to be potent inhibitors of single-channel activity. In this article, we synthesize derivatives of the channel activator 4-chloro-3-methyl phenol (4-CmC) and the 1,4-benzothiazepine channel inhibitor 4-[-3{1-(4-benzyl) piperidinyl}propionyl]-7-methoxy-2,3,4,5-tetrahydro-1,4-benzothiazepine (K201, JTV519) with enhanced electron donor properties. Instead of activating channel activity (~100 µM), the 4-methoxy analog of 4-CmC [4-methoxy-3-methyl phenol (4-MmC)] inhibits channel activity at submicromolar concentrations (IC(50) = 0.34 ± 0.08 µM). Increasing the electron donor characteristics of K201 by synthesizing its dioxole congener results in an approximately 16 times more potent RyR1 inhibitor (IC(50) = 0.24 ± 0.05 µM) compared with K201 (IC(50) = 3.98 ± 0.79 µM). Inhibition is not caused by an increased closed time of the channel but seems to be caused by an open state block of RyR1. These alterations to chemical structure do not influence the ability of these drugs to affect Ca(2+)-dependent ATPase activity of sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase type 1. Moreover, the FKBP12 protein, which stabilizes RyR1 in a closed configuration, is shown to be a strong electron donor. It seems as if FKBP12, K201, its dioxole derivative, and 4-MmC inhibit RyR1 channel activity by virtue of their electron donor characteristics. These results embody strong evidence that designing new drugs to target RyR1 with enhanced electron donor characteristics results in more potent channel inhibitors. This is a novel approach to the design of new, more potent drugs with the aim of functionally modifying RyR1 single-channel activity.
Assuntos
Bloqueadores dos Canais de Cálcio/síntese química , Bloqueadores dos Canais de Cálcio/metabolismo , Descoberta de Drogas , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Tiazepinas/química , Tiazepinas/metabolismo , Animais , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio/síntese química , Canais de Cálcio/metabolismo , Sinalização do Cálcio/efeitos dos fármacos , Sinalização do Cálcio/fisiologia , Descoberta de Drogas/métodos , Transporte de Elétrons/fisiologia , Músculo Esquelético/citologia , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiologia , Estabilidade Proteica/efeitos dos fármacos , Coelhos , Canal de Liberação de Cálcio do Receptor de Rianodina/síntese químicaRESUMO
Neprilysin (NEP) and angiotensin-converting enzyme (ACE) are two key zinc-dependent metallopeptidases in the natriuretic peptide and kinin systems and renin-angiotensin-aldosterone system, respectively. They play an important role in blood pressure regulation and reducing the risk of heart failure. Vasopeptidase inhibitors omapatrilat and sampatrilat possess dual activity against these enzymes by blocking the ACE-dependent conversion of angiotensin I to the potent vasoconstrictor angiotensin II while simultaneously halting the NEP-dependent degradation of vasodilator atrial natriuretic peptide. Here, we report crystal structures of omapatrilat, sampatrilat, and sampatrilat-ASP (a sampatrilat analogue) in complex with NEP at 1.75, 2.65, and 2.6 Å, respectively. A detailed analysis of these structures and the corresponding structures of ACE with these inhibitors has provided the molecular basis of dual inhibitor recognition involving the catalytic site in both enzymes. This new information will be very useful in the design of safer and more selective vasopeptidase inhibitors of NEP and ACE for effective treatment in hypertension and heart failure.
Assuntos
Inibidores da Enzima Conversora de Angiotensina/metabolismo , Desenho de Fármacos , Mesilatos/metabolismo , Neprilisina/metabolismo , Peptidil Dipeptidase A/metabolismo , Piridinas/metabolismo , Tiazepinas/metabolismo , Tirosina/análogos & derivados , Inibidores da Enzima Conversora de Angiotensina/química , Anti-Hipertensivos/química , Anti-Hipertensivos/metabolismo , Cristalografia por Raios X/métodos , Mesilatos/química , Neprilisina/química , Peptidil Dipeptidase A/química , Ligação Proteica/fisiologia , Estrutura Secundária de Proteína , Piridinas/química , Tiazepinas/química , Tirosina/química , Tirosina/metabolismoRESUMO
BACKGROUND: We previously demonstrated that defective interdomain interaction between N-terminal (0 to 600) and central regions (2000 to 2500) of ryanodine receptor 2 (RyR2) induces Ca2+ leak in failing hearts and that K201 (JTV519) inhibits the Ca2+ leak by correcting the defective interdomain interaction. In the present report, we identified the K201-binding domain and characterized the role of this novel domain in the regulation of the RyR2 channel. METHODS AND RESULTS: An assay using a quartz-crystal microbalance technique (a very sensitive mass-measuring technique) revealed that K201 specifically bound to recombinant RyR2 fragments 1741 to 2270 and 1981 to 2520 but not to other RyR2 fragments from the 1 to 2750 region (1 to 610, 494 to 1000, 741 to 1260, 985 to 1503, 1245 to 1768, 2234 to 2750). By further analysis of the fragment(1741-2270), K201 was found to specifically bind to its subfragment(2114-2149). With the use of the peptide matching this subfragment (DP(2114-2149)) as a carrier, the RyR2 was fluorescently labeled with methylcoumarin acetate (MCA) in a site-directed manner. After tryptic digestion, the major MCA-labeled fragment of RyR2 (155 kDa) was detected by an antibody raised against the central region (Ab(2132)). Moreover, of several recombinant RyR2 fragments, only fragment(2234-2750) was specifically MCA labeled; this suggests that the K201-binding domain(2114-2149) binds with domain(2234-2750). Addition of DP(2114-2149) to the MCA-labeled sarcoplasmic reticulum interfered with the interaction between domain(2114-2149) and domain(2234-2750), causing domain unzipping, as evidenced by an increased accessibility of the bound MCA to a large-size fluorescence quencher. In failing cardiomyocytes, the frequency of spontaneous Ca2+ spark was markedly increased compared with normal cardiomyocytes, whereas incorporation of DP(2114-2149) markedly decreased the frequency of spontaneous Ca2+ spark. CONCLUSIONS: We first identified the K201-binding site as domain(2114-2149) of RyR2. Interruption of the interdomain interaction between the domain(2114-2149) and central domain(2234-2750) seems to mediate stabilization of RyR2 in failing hearts, which may lead to a novel therapeutic strategy against heart failure and perhaps lethal arrhythmia.
Assuntos
Cálcio/metabolismo , Miócitos Cardíacos/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Sequência de Aminoácidos , Animais , Anexina A5/química , Anexina A5/metabolismo , Sítios de Ligação , Modelos Animais de Doenças , Cães , Insuficiência Cardíaca/metabolismo , Modelos Lineares , Dados de Sequência Molecular , Canal de Liberação de Cálcio do Receptor de Rianodina/química , Retículo Sarcoplasmático , Homologia de Sequência de Aminoácidos , Tiazepinas/metabolismoRESUMO
New insights into the biochemistry of cardiac arrhythmia and skeletal muscle fatigue have yielded new drug candidates to counteract these phenomena. Major biological targets have become ryanodine receptor (RyR)-based Ca(2+)-release channels, which tend to 'leak' under various circumstances including strenuous exercise and, thus, cause aberrant calcium sparks that entail impaired muscle function. Therapeutics, which are referred to as rycals, are currently being developed to treat cardiac arrhythmia via enhancement of calstabin-ryanodine affinities that causes a stabilization of the RyR. These therapeutics possess potential for misuse in sports, and an early implementation of target analytes such as the benzothiazepine derivatives S-107 and JTV-519 or putative metabolites into doping control screening procedures is recommended. Reference compounds, deuterated analogues, and a putative metabolic product were synthesized, and electron ionization mass spectra of these products were studied and dissociation pathways elucidated by means of tandem mass spectrometry (MS/MS) and accurate mass measurements. The characterized analytes were incorporated into existing sports drug testing assays based on liquid-liquid extraction and subsequent gas chromatography/mass spectrometry (GC/MS) analysis, and specificity, lower limit of detection (4-6 ng/mL), intraday and interday precision (1.5-17.2%), as well as recovery (63-66%) were determined. The established procedure proved suitable for routine doping control analysis to detect a potential misuse of the drug candidate S-107 in elite sport.
Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Espectrometria de Massas por Ionização por Electrospray/métodos , Detecção do Abuso de Substâncias/métodos , Tiazepinas/síntese química , Tiazepinas/urina , Feminino , Humanos , Masculino , Estrutura Molecular , Sensibilidade e Especificidade , Tiazepinas/metabolismoRESUMO
Temocapril is a prodrug whose hydrolysis by carboxylesterase 1 (CES1) yields the active ACE inhibitor temocaprilat. This molecular-dynamics (MD) study uses a resolved structure of the human CES1 (hCES1) to investigate some mechanistic details of temocapril hydrolysis. The ionization constants of temocapril (pK1 and pK3) and temocaprilat (pK1, pK2, and pK3) were determined experimentally and computationally using commercial algorithms. The constants so obtained were in good agreement and revealed that temocapril exists mainly in three ionic forms (a cation, a zwitterion, and an anion), whereas temocaprilat exists in four major ionic forms (a cation, a zwitterion, an anion, and a dianion). All these ionic forms were used as ligands in 5-ns MS simulations. While the cationic and zwitterionic forms of temocapril were involved in an ion-pair bond with Glu255 suggestive of an inhibitor behavior, the anionic form remained in a productive interaction with the catalytic center. As for temocaprilat, its cation appeared trapped by Glu255, while its zwitterion and anion made a slow departure from the catalytic site and a partial egress from the protein. Only its dianion was effectively removed from the catalytic site and attracted to the protein surface by Lys residues. A detailed mechanism of product egress emerges from the simulations.
Assuntos
Inibidores da Enzima Conversora de Angiotensina/química , Inibidores da Enzima Conversora de Angiotensina/metabolismo , Carboxilesterase/metabolismo , Tiazepinas/química , Tiazepinas/metabolismo , Algoritmos , Biotransformação , Simulação por Computador , Eletroquímica , Ligantes , Modelos Biológicos , Modelos Moleculares , Potenciometria , Software , Difração de Raios XRESUMO
K201 (JTV519), a benzothiazepine derivative, has been shown to possess anti-arrhythmic and cardioprotective properties, but the mechanism of its action is both complex and controversial. It is believed to stabilize the closed state of the RyR2 (cardiac ryanodine receptor) by increasing its affinity for the FKBP12.6 (12.6 kDa FK506 binding protein) [Wehrens, Lehnart, Reiken, Deng, Vest, Cervantes, Coromilas, Landry and Marks (2004) Science 304, 292-296]. In the present study, we investigated the effect of K201 on spontaneous Ca2+ release induced by Ca2+ overload in rat ventricular myocytes and in HEK-293 cells (human embryonic kidney cells) expressing RyR2 and the role of FKBP12.6 in the action of K201. We found that K201 abolished spontaneous Ca2+ release in cardiac myocytes in a concentration-dependent manner. Treating ventricular myocytes with FK506 to dissociate FKBP12.6 from RyR2 did not affect the suppression of spontaneous Ca2+ release by K201. Similarly, K201 was able to suppress spontaneous Ca2+ release in FK506-treated HEK-293 cells co-expressing RyR2 and FKBP12.6. Furthermore, K201 suppressed spontaneous Ca2+ release in HEK-293 cells expressing RyR2 alone and in cells co-expressing RyR2 and FKBP12.6 with the same potency. In addition, K201 inhibited [3H]ryanodine binding to RyR2-wt (wild-type) and an RyR2 mutant linked to ventricular tachycardia and sudden death, N4104K, in the absence of FKBP12.6. These observations demonstrate that FKBP12.6 is not involved in the inhibitory action of K201 on spontaneous Ca2+ release. Our results also suggest that suppression of spontaneous Ca2+ release and the activity of RyR2 contributes, at least in part, to the anti-arrhythmic properties of K201.
Assuntos
Antiarrítmicos/metabolismo , Cálcio/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Rianodina/metabolismo , Proteína 1A de Ligação a Tacrolimo/metabolismo , Tiazepinas/metabolismo , Animais , Células Cultivadas , Humanos , Imunossupressores/metabolismo , Miócitos Cardíacos/citologia , Miócitos Cardíacos/metabolismo , Ratos , Rianodina/química , Canal de Liberação de Cálcio do Receptor de Rianodina/genética , Tacrolimo/metabolismoRESUMO
Omapatrilat was designed as a vasopeptidase inhibitor with dual activity against the zinc metallopeptidases angiotensin-1 converting enzyme (ACE) and neprilysin (NEP). ACE has two homologous catalytic domains (nACE and cACE), which exhibit different substrate specificities. Here, we report high-resolution crystal structures of omapatrilat in complex with nACE and cACE and show omapatrilat has subnanomolar affinity for both domains. The structures show nearly identical binding interactions for omapatrilat in each domain, explaining the lack of domain selectivity. The cACE complex structure revealed an omapatrilat dimer occupying the cavity beyond the S2 subsite, and this dimer had low micromolar inhibition of nACE and cACE. These results highlight residues beyond the S2 subsite that could be exploited for domain selective inhibition. In addition, it suggests the possibility of either domain specific allosteric inhibitors that bind exclusively to the nonprime cavity or the potential for targeting specific substrates rather than completely inhibiting the enzyme.
Assuntos
Desenho de Fármacos , Peptidil Dipeptidase A/química , Peptidil Dipeptidase A/metabolismo , Piridinas/metabolismo , Tiazepinas/metabolismo , Sequência de Aminoácidos , Domínio Catalítico , Humanos , Ligantes , Modelos MolecularesRESUMO
Tianeptine is an atypical antidepressant with a unique mechanism of action and recently it has been also reported that its major metabolite, compound MC5, possesses pharmacological activity similar to that of the parent drug. The current study aims to investigate the pharmacokinetics (PK) of both tianeptine and MC5 after intravenous or intraperitoneal administration of the parent drug as well as the metabolic ratio of MC5 in rats. To achieve these goals an LC-MS/MS method using the small sample volume for the quantitation of tianeptine and its active metabolite MC5 in rat plasma and liver perfusate has been developed and validated. Following an intravenous administration of tianeptine pharmacokinetic parameters were calculated by non-compartmental analysis. The average tianeptine volume of distribution at steady state was 2.03 L/kg and the systemic clearance equaled 1.84 L/h/kg. The mean elimination half-lives of tianeptine and MC5 metabolite were 1.16 and 7.53 h, respectively. The hepatic clearance of tianeptine determined in the isolated rat liver perfusion studies was similar to the perfusate flow rate despite the low metabolic ratio of MC5. Mass spectrometric analysis of rat bile indicated that tianeptine and MC5 metabolite are eliminated with bile as glucuronide and glutamine conjugates. Bioavailability of tianeptine after its intraperitoneal administration was 69%. The PK model with a metabolite compartment developed in this study for both tianeptine and MC5 metabolite after two routes of administration may facilitate tianeptine dosage selection for the prospective pharmacological experiments.
Assuntos
Espectrometria de Massas em Tandem/métodos , Tiazepinas/administração & dosagem , Tiazepinas/metabolismo , Tiazepinas/farmacocinética , Animais , Antidepressivos Tricíclicos/administração & dosagem , Antidepressivos Tricíclicos/análise , Antidepressivos Tricíclicos/farmacocinética , Cromatografia Líquida/métodos , Vias de Administração de Medicamentos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Ratos , Ratos Wistar , Tiazepinas/análiseRESUMO
Depression is a debilitating chronic illness that affects around 350 million people worldwide. Current treatments, such as selective serotonin reuptake inhibitors, are not ideal because only a fraction of patients achieve remission. Tianeptine is an effective antidepressant with a previously unknown mechanism of action. We recently reported that tianeptine is a full agonist at the mu opioid receptor (MOR). Here we demonstrate that the acute and chronic antidepressant-like behavioral effects of tianeptine in mice require MOR. Interestingly, while tianeptine also produces many opiate-like behavioral effects such as analgesia and reward, it does not lead to tolerance or withdrawal. Furthermore, the primary metabolite of tianeptine (MC5), which has a longer half-life, mimics the behavioral effects of tianeptine in a MOR-dependent fashion. These results point to the possibility that MOR and its downstream signaling cascades may be novel targets for antidepressant drug development.
Assuntos
Antidepressivos Tricíclicos/farmacologia , Receptores Opioides mu/metabolismo , Tiazepinas/farmacologia , Analgésicos Opioides/farmacologia , Animais , Antidepressivos Tricíclicos/metabolismo , Antidepressivos Tricíclicos/farmacocinética , Transtorno Depressivo/tratamento farmacológico , Transtorno Depressivo/metabolismo , Relação Dose-Resposta a Droga , Tolerância a Medicamentos , Células HEK293 , Humanos , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Estrutura Molecular , Morfina/farmacologia , Receptores Opioides mu/agonistas , Receptores Opioides mu/genética , Tiazepinas/metabolismo , Tiazepinas/farmacocinéticaRESUMO
As a mechanism of defense against pathogens and other types of stress, watercress plants produce a variety of elicited chemical defenses generally known as phytoalexins. Herein the chemical structure, synthesis, biosynthesis and antifungal activity of cyclonasturlexin, the most intriguing indolyl phytoalexin isolated to date, are reported.
Assuntos
Indóis/farmacologia , Nasturtium/metabolismo , Tiazepinas/farmacologia , Alternaria/efeitos dos fármacos , Ciclização , Fungicidas Industriais/síntese química , Fungicidas Industriais/metabolismo , Fungicidas Industriais/farmacologia , Indóis/síntese química , Indóis/metabolismo , Tiazepinas/síntese química , Tiazepinas/metabolismo , Tiocarbamatos/metabolismoRESUMO
The crystal structure of recombinant human annexin V complexed with K-201, an inhibitor of the calcium ion channel activity of annexin V, was solved at 3.0 A by molecular replacement including the apo and high-calcium forms. K-201 was bound at the hinge region cavity formed by the N-terminal strand and domains II, III and IV, at the side opposite the calcium and membrane-binding surface, in an L-shaped conformation. Based on the complex and other annexin structures, K-201 is proposed to restrain the hinge movement of annexin V in an allosteric manner, resulting in the inhibition of calcium movement across the annexin V molecule.
Assuntos
Anexina A5/química , Bloqueadores dos Canais de Cálcio/química , Canais de Cálcio/efeitos dos fármacos , Tiazepinas/química , Anexina A5/genética , Anexina A5/metabolismo , Cristalografia por Raios X , Humanos , Ligantes , Modelos Moleculares , Ligação Proteica , Proteínas Recombinantes/química , Espectrometria de Fluorescência , Tiazepinas/metabolismoRESUMO
The paper begins with a discussion of the goals of metabolic predictions in early drug research, and some difficulties toward this objective, mainly the various substrate and product selectivities characteristic of drug metabolism. The major in silico approaches to predict drug metabolism are then classified and summarized. A discrimination is, thus, made between 'local' and 'global' systems. In its second part, an evaluation of METEOR, a rule-based expert system used to predict the metabolism of drugs and other xenobiotics, is reported. The published metabolic data of ten substrates were used in this evaluation, the overall results being discussed in terms of correct vs. disputable (i.e., false-positive and false-negative) predictions. The predictions for four representative substrates are presented in detail (Figs. 1-4), illustrating the interest of such an evaluation in identifying where and how predictive rules can be improved.
Assuntos
Sistemas Inteligentes , Galantamina/metabolismo , Indinavir/metabolismo , Piridinas/metabolismo , Tiazepinas/metabolismo , Tramadol/metabolismo , Analgésicos Opioides/metabolismo , Fármacos Cardiovasculares/metabolismo , Simulação por Computador , Inibidores da Protease de HIV/metabolismo , Humanos , Estrutura Molecular , Parassimpatomiméticos/metabolismo , SoftwareRESUMO
BACKGROUND: Omapatrilat, a vasopeptidase inhibitor, preserves natriuretic peptides and inhibits the renin angiotensin aldosterone system by simultaneously inhibiting neutral endopeptidase and angiotensin-converting enzyme. METHODS: Oral omapatrilat, 10 mg/d, was administered for 8 to 9 days to three groups of eight subjects with varying degrees of renal function (CLCR values, normal > or = 80; mild to moderate impairment < 80 to > or = 30; severe impairment < 30 mL/min/1.73 mL2) and to six subjects undergoing maintenance hemodialysis. Omapatrilat and its metabolites (phenylmercaptopropionic acid, S-methylomapatrilat, S-methylphenylmercaptopropionic acid, and cyclic S-oxide-omapatrilat) were quantified in plasma by a validated liquid chromatography/mass spectrometry method. The model, Cmax or AUC(0-T) = intercept + slope x CLCR, was tested for a possible linear correlation between Cmax (peak plasma concentrations) or AUC(0-T) (area under plasma concentration versus time curve) and CLCR. RESULTS: For omapatrilat and its inactive metabolites, phenylmercaptopropionic acid, S-methylomapatrilat, and S-methylphenylmercaptopropionic acid, the median times to peak plasma concentrations (tmax) were 1.5 to 2, 2 to 3, 2.5 to 3.5, and 7 to 10 hours, respectively, and were independent of renal function. After Cmax attainment, plasma concentrations declined rapidly to about 10% of Cmax values. Cyclic S-oxide-omapatrilat, a potentially active metabolite, was undetectable at all sampling time points. Hemodialysis did not decrease circulating levels of omapatrilat. There was minimal accumulation of omapatrilat and phenylmercaptopropionic acid and moderate accumulation of the S-methylated metabolites. For omapatrilat and S-methylphenylmercaptopropionic acid, neither Cmax nor AUC(0-T) was CLCR dependent. However, AUC(0-T) for phenylmercaptopropionic acid and both the Cmax and AUC(0-T) for S-methylomapatrilat were CLCR dependent. CONCLUSIONS: The pharmacokinetics of omapatrilat, the only clinically relevant active compound studied, was independent of CLCR. For patients with reduced renal function, adjusting initial omapatrilat dose is not suggested. Hemodialysis did not significantly contribute to the clearance of omapatrilat. The long-term pharmacodynamic response to omapatrilat will dictate dose-adjustment needs.
Assuntos
Inibidores da Enzima Conversora de Angiotensina/farmacocinética , Nefropatias/metabolismo , Piridinas/farmacocinética , Tiazepinas/farmacocinética , Administração Oral , Adulto , Idoso , Inibidores da Enzima Conversora de Angiotensina/administração & dosagem , Inibidores da Enzima Conversora de Angiotensina/metabolismo , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Área Sob a Curva , Cromatografia Líquida de Alta Pressão , Feminino , Humanos , Nefropatias/terapia , Masculino , Taxa de Depuração Metabólica , Pessoa de Meia-Idade , Piridinas/administração & dosagem , Piridinas/metabolismo , Piridinas/farmacologia , Diálise Renal , Tiazepinas/administração & dosagem , Tiazepinas/metabolismo , Tiazepinas/farmacologiaRESUMO
A series of 42 6-arylpyrrolo[2,1-d][1,5]benzothiazepines, which we have recently described as selective ligands of the mitochondrial benzodiazepine receptor (MBR) (Fiorini I.; et al. J. Med. Chem. 1994, 37, 1427-1438), have been investigated using the comparative molecular field analysis (CoMFA) approach. The resulting 3D-QSAR model rationalizes the steric and electronic factors which modulate affinity to the MBR with a cross-validation standard error of 0.648 pIC50 unit. A set of seven novel pyrrolobenzothiazepine congeners has successively been synthesized and tested. The CoMFA model forecasts the binding affinity values of these new compounds with a prediction standard error of 0.536.
Assuntos
Mitocôndrias/metabolismo , Modelos Moleculares , Pirróis/metabolismo , Receptores de GABA-A/metabolismo , Tiazepinas/metabolismo , Animais , Isoquinolinas/metabolismo , Ligantes , Masculino , Conformação Molecular , Ratos , Ratos Sprague-Dawley , Análise de Regressão , Relação Estrutura-AtividadeRESUMO
The 7-(acyloxy)-6-arylpyrrolo[2,1-d][1,5]benzothiazepine derivatives have been recently proposed as a new class of ligands specific for the mitochondrial benzodiazepine receptor (Fiorini et al. J. Med. Chem. 1994, 37, 1427-1438) (Greco et al. J. Med. Chem. 1994, 37, 4100-4108). In this paper we report the X-ray crystallographic structures of three potent (1-3) and two inactive (4 and 5) previously described benzothiazepines, as well as binding affinity constants for two newly assayed analogs in which the acyloxy side chain was replaced by a methoxy group (6) or removed (7). Structure-affinity relationships and molecular mechanics calculations performed using crystal structures as references have led to a revised 3D pharmacophore model accounting for all the data available up until now. Interestingly, the hypothetical receptor-bound conformations of 1-3 display a considerable degree of similarity with their crystal geometries. Additional calculations have confirmed that the poor affinities of benzothiazepines bearing an aroyloxy group (4 and 5) should be ascribed to the steric and/or electronic features of the side chain aryl moieties rather than to unfavorable conformational properties.
Assuntos
Mitocôndrias/metabolismo , Modelos Moleculares , Pirróis/química , Pirróis/metabolismo , Receptores de GABA-A/metabolismo , Tiazepinas/química , Tiazepinas/metabolismo , Difração de Raios X , Animais , Encéfalo/ultraestrutura , Simulação por Computador , Cristalização , Masculino , Conformação Molecular , Ratos , Relação Estrutura-AtividadeRESUMO
A novel class of ligands specific for MBR receptors has been identified: 6-arylpyrrolo[2,1-d][1,5]benzothiazepine derivatives. The majority of newly synthesized esters 37-64 as well as some intermediate ketones showed micro- or nanomolar affinity for [3H]PK 11195 binding inhibition. A SAR study on 42 compounds and a molecular modeling approach led to a preliminary structural selectivity profile: the 6,7-double bond, the carbamoyloxy, alcanoyloxy, and mesyloxy side chains at the 7-position, and the prospective chloro substitution at the 4-position seemed to be the most important structural features improving affinity. Therefore, 7-[(dimethylcarbamoyl)oxy]- and 7-acetoxy-4-chloro-6-phenylpyrrolo[2,1-d][1,5]benzothiazepine (43 and 57) were synthesized. With 7-[(dimethylcarbamoyl)oxy]-6-(p-methoxyphenyl)pyrrolo[2,1- d][1,5]benzothiazepine (65), these were the most promising compounds with IC50s of respectively 9, 8, and 9 nM, under conditions where PK 11195 had an IC50 of 2 nM.