RESUMO
Benzenesulfonylureas and benzenesulfonylthioureas, as well as benzenecarbonylureas and benzenecarbonylthioureas, were prepared and evaluated as myorelaxants on 30mMKCl-precontracted rat aortic rings. The most active compounds were further examined as stimulators of elastin synthesis by vascular smooth muscle cells and as inhibitors of insulin release from pancreaticß-cells. The drugs were also characterized for their effects on glycaemia in rats. Benzenesulfonylureas and benzenesulfonylthioureas did not display any myorelaxant activity on precontracted rat aortic rings. Such an effect could be attributed to their ionization at physiological pH. By contrast, almost all benzenecarbonylureas and benzenecarbonylthioureas displayed a myorelaxant activity, in particular the benzenecarbonylureas with an oxybenzyl group linked to the ortho position of the phenyl ring. The vasodilatory activity of the most active compounds was reduced when measured in the presence of 80mMKCl or in the presence of 30mM KCl and 10µM glibenclamide. Such results suggested the involvement, at least in part, of KATP channels. Preservation of a vasodilatory activity in rat aortic rings without endothelium indicated that the site of action of such molecules was located on the vascular smooth muscle cells and not on the endothelial cells. Some of the most active compounds also stimulated elastin synthesis by vascular smooth muscle cells. Lastly, most of the active vasorelaxant drugs, except 15k and 15t at high concentrations, did not exhibit marked inhibitory effects on the insulin releasing process and on glycaemia, suggesting a relative tissue selectivity of some of these compounds for the vascular smooth muscle.
Assuntos
Derivados de Benzeno/farmacologia , Diazóxido/farmacologia , Elastina/metabolismo , Insulina/metabolismo , Canais de Potássio/agonistas , Tioureia/farmacologia , Vasodilatadores/farmacologia , Animais , Derivados de Benzeno/química , Células Cultivadas , Diazóxido/química , Desenho de Fármacos , Antagonistas da Insulina/química , Antagonistas da Insulina/farmacologia , Ratos Wistar , Tioureia/análogos & derivados , Vasodilatadores/químicaRESUMO
AIMS: The present study aimed at characterizing the impact of the presence or absence of fluorine atoms on the phenyl and benzopyran rings of 4-phenyl(thio)ureido-substituted 2,2- dimethylchromans on their ability to inhibit insulin release from pancreatic ß-cells or to relax vascular smooth muscle cells. METHODS: Most compounds were found to inhibit insulin secretion and to provoke a marked myorelaxant activity. RESULTS: The lack of a fluorine or chlorine atom at the 6-position of the 2,2-dimethylchroman core structure reduced the inhibitory activity on the pancreatic endocrine tissue. One of the most active compounds on both tissues, compound 11h (BPDZ 678), was selected for further pharmacological investigations. CONCLUSION: The biological data suggested that 11h mainly expressed the profile of a KATP channel opener on pancreatic ß-cells, although a calcium entry blockade effect was also observed. On vascular smooth muscle cells, 11h behaved as a calcium entry blocker.
Assuntos
Cálcio , Insulina , Animais , Aorta/fisiologia , Flúor/farmacologia , Insulina/metabolismo , Músculo Liso/metabolismo , Canais de Potássio/farmacologia , Ratos , Ratos Wistar , Relação Estrutura-AtividadeRESUMO
The synthesis of different series of 4- and 6-substituted R/S-3,4-dihydro-2,2-dimethyl-2H-1-benzopyrans is described. All of these new benzopyran derivatives were bearing, at the 4-position, a phenylthiourea moiety substituted on the phenyl ring by a meta or a para-electron-withdrawing group such as Cl or CN. The study aimed at exploring the influence of the nature of the substituent at the 6-position in order to develop new benzopyran-type K(ATP) channel activators exhibiting an improved selectivity towards the insulin secreting cells. The original compounds were examined in vitro on rat pancreatic islets (inhibition of insulin release) as well as on rat aorta rings (vasorelaxant effect) and their activity was compared to that of the reference K(ATP) channel activators (±)-cromakalim, (±)-pinacidil, diazoxide and to previously synthesized cromakalim analogues. Structure-activity relationships indicated that the inhibitory effect on the insulin secreting cells was related to the lipophilicity of the molecules and to the size of the substituent located at the 6-position. A marked inhibitory activity on the insulin secretory process was obtained with molecules bearing a bulky tert-butyloxycarbonylamino group at the 6-position (20-23). The latter compounds were found to have the same efficacy on the pancreatic endocrine tissue than some previously described molecules. Lastly, radioisotopic experiments further identified R/S-N-4-chlorophenyl-N'-(6-tert-butyloxycarbonylamino-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-4-yl)thiourea (23) as a K(ATP) channel opener.
Assuntos
Benzopiranos/química , Insulina/metabolismo , Animais , Aorta/citologia , Benzopiranos/síntese química , Benzopiranos/farmacologia , Cromakalim/síntese química , Cromakalim/química , Cromakalim/farmacologia , Diazóxido/química , Diazóxido/farmacologia , Secreção de Insulina , Células Secretoras de Insulina/efeitos dos fármacos , Canais KATP/agonistas , Canais KATP/metabolismo , Pinacidil/química , Pinacidil/farmacologia , Ratos , Relação Estrutura-Atividade , Vasodilatadores/síntese química , Vasodilatadores/química , Vasodilatadores/farmacologiaRESUMO
The present work aimed at exploring a series of diversely 4-arylthiourea-substituted R/S-3,4-dihydro-2,2-dimethyl-6-halo-2H-1-benzopyrans structurally related to (+/-)-cromakalim. These new compounds were examined in vitro as putative potassium channel openers (PCOs) on rat pancreatic islets (inhibition of insulin release) as well as on rat aorta rings (relaxation of aorta ring) and their activity was compared to that of the reference K(ATP) channel activators (+/-)-cromakalim, (+/-)-pinacidil, diazoxide and of previously reported cromakalim analogues. Structure-activity relationships indicated that the most pronounced inhibitory activity on the insulin secretory process was obtained with molecules bearing a strong meta- or para-electron-withdrawing group (CN or NO(2)) on the phenyl ring of the arylthiourea moiety at the 4-position of the benzopyran nucleus (compounds 12-23). Among those, R/S-6-chloro-4-(4-cyanophenylaminothiocarbonylamino)-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran (16) was found to be the most potent benzopyran-type inhibitor of insulin release ever described. Most of these original benzopyran derivatives show increased selectivity for pancreatic versus vascular tissue. Radioisotopic investigations indicated that these new compounds activated pancreatic K(ATP) channels.
Assuntos
Trifosfato de Adenosina/metabolismo , Benzopiranos/farmacologia , Canais de Potássio/agonistas , Animais , Benzopiranos/síntese química , Benzopiranos/química , Cromakalim/química , Cromakalim/farmacologia , Diazóxido/química , Diazóxido/farmacologia , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/metabolismo , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/metabolismo , Pinacidil/química , Pinacidil/farmacologia , Canais de Potássio/metabolismo , Ratos , Ratos Wistar , Estereoisomerismo , Relação Estrutura-Atividade , Vasodilatadores/síntese química , Vasodilatadores/química , Vasodilatadores/farmacologiaRESUMO
The present study describes the synthesis and biological evaluation of 4-phenylureido/thioureido-substituted 2,2-dimethyl-3,4-dihydro-2H-1,4-benzoxazines as isosteres of corresponding 2,2-dimethylchromans reported to be pancreatic ß-cell KATP channel openers. The benzoxazines were found to be less active as inhibitors of the glucose-induced insulin release than their corresponding chromans, while the myorelaxant activity of some 4-arylureido-substituted benzoxazines was more pronounced than that exhibited by their chroman counterparts. The myorelaxant activity of the most potent benzoxazine 8e was further characterized on rat aortic rings precontracted by 30 mM KCl in the presence of glibenclamide (10 µM) or precontracted by 80 mM extracellular KCl. Our findings indicate that, on vascular smooth muscle cells, the benzoxazine 8e mainly behaved as a calcium entry blocker.
RESUMO
Ring-opened analogues of dihydrobenzopyran potassium channel openers (PCOs) were prepared and evaluated as putative PCOs on rat aorta rings (myorelaxant effect) and rat pancreatic beta-cells (inhibition of insulin secretion). These derivatives are characterized by the presence of a sulfonylurea, a urea or an amide function. Some compounds bearing an arylurea moiety provoked vasorelaxant effects and a marked inhibition of insulin release. Derivatives bearing a sulfonylurea or an amide function were, however, poorly active on both tissues. Structure-activity relationships and apparent tissue selectivity are discussed.
Assuntos
Aorta/efeitos dos fármacos , Aorta/metabolismo , Benzopiranos/síntese química , Cromakalim/análogos & derivados , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Canais de Potássio/metabolismo , Animais , Benzopiranos/química , Benzopiranos/farmacologia , Cromanos/síntese química , Cromanos/química , Cromanos/farmacologia , Cromakalim/farmacologia , Técnicas In Vitro , Insulina/metabolismo , Antagonistas da Insulina/síntese química , Antagonistas da Insulina/farmacologia , Secreção de Insulina , Relaxamento Muscular/efeitos dos fármacos , Ratos , Ratos WistarRESUMO
The present work was aimed at exploring a series of R/S-3,4-dihydro-2,2-dimethyl-6-halo-4-(phenylaminothiocarbonylamino)-2H-1-benzopyrans structurally related to (+/-)-cromakalim and differently substituted at the 4- and 6-positions. The biological effects of these putative activators of ATP-sensitive potassium channels (K(ATP)) were characterized in vitro on the pancreatic endocrine tissue (inhibition of insulin release) and on the vascular smooth muscle tissue (relaxation of aorta rings). The biological activity of these new dimethylchroman derivatives was further compared to that of (+/-)-cromakalim, (+/-)-pinacidil, diazoxide and BPDZ 73. Structure-activity relationships indicated that an improved potency for the pancreatic tissue was obtained by introducing a meta- or a para-electron-withdrawing group such as a chlorine atom on the C-4 phenyl ring, independently of the nature of the halogen atom at the 6-position of the benzopyran nucleus. Most original dimethylchroman thioureas were more potent than their 'urea' homologues and even more potent than diazoxide at inhibiting insulin release. Moreover, and unlike (+/-)-cromakalim or (+/-)-pinacidil, such compounds appeared to be highly selective towards the pancreatic tissue. Radioisotopic and fluorimetric investigations indicated that the new drugs activated pancreatic K(ATP) channels. Lastly, conformational studies suggested that the urea/thiourea dimethylchromans can be regarded as hybrid compounds between cromakalim and pinacidil.
Assuntos
Transportadores de Cassetes de Ligação de ATP/efeitos dos fármacos , Benzopiranos/química , Benzopiranos/farmacologia , Cromakalim/química , Cromakalim/farmacologia , Células Secretoras de Insulina/efeitos dos fármacos , Canais de Potássio/efeitos dos fármacos , Animais , Aorta/citologia , Aorta/efeitos dos fármacos , Diazóxido/análogos & derivados , Diazóxido/química , Diazóxido/farmacologia , Avaliação Pré-Clínica de Medicamentos , Células Secretoras de Insulina/citologia , Estrutura Molecular , Pinacidil/química , Pinacidil/farmacologia , Teoria Quântica , Ratos , Ratos Wistar , Estereoisomerismo , Relação Estrutura-Atividade , Temperatura , Fatores de TempoRESUMO
4,6-Disubstituted 2,2-dimethylchromans are reported as pharmacologically active compounds that mainly target the ATP-sensitive potassium channels. The present study is an attempt to characterize the impact of the nature of substituents introduced at the 4- and 6-positions of 2,2-dimethylchromans on their capacities to inhibit insulin release from pancreatic ß-cells or to relax vascular smooth muscle cells, both biological responses that are supposed to reflect interaction with specific ion channels. From the core structure 4-amino-2,2-dimethylchroman, a progressive increase in the steric hindrance of the chemical functionalities introduced at the 4-position (amino, formamido, acetamido, arylureido/thioureido) and at the 6-position (amino, formamido, acetamido, alkoxycarbonylamino) led to a progressive magnification of the inhibitory effect on the insulin release process and, to a lesser extent, of the vasorelaxant activity. Moreover, the dextrorotatory enantiomer of 2,2-dimethylchroman compound 29 was more potent than its levorotatory counterpart for inhibiting the insulin secretory process. Additional pharmacological investigations suggested, however, that the myorelaxant activity of 11 and 15 resulted from a direct Ca2+ entry blockade.
Assuntos
Cromanos/química , Insulina/metabolismo , Fármacos Neuromusculares/química , Animais , Aorta/efeitos dos fármacos , Aorta/fisiologia , Células Cultivadas , Cromanos/farmacologia , Secreção de Insulina , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/metabolismo , Músculo Liso Vascular/citologia , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/metabolismo , Fármacos Neuromusculares/farmacologia , Ratos , Ratos Wistar , Relação Estrutura-AtividadeRESUMO
In the search of a novel series of benzopyrans structurally related to (+/-)-cromakalim and acting as pancreatic beta-cell potassium channel openers, several R/S-3,4-dihydro-2,2-dimethyl-6-halo-4-(phenylaminocarbonylamino)-2H-1-benzopyrans with or without a substituent on the phenyl ring in the 4-position were synthesized. Their activity on rat-insulin-secreting cells and rat aorta rings was compared to that of the K(ATP) channel activators (+/-)-cromakalim, diazoxide, (+/-)-pinacidil, and compound 4. Structure-activity relationships indicated that the most pronounced inhibitory activity on the pancreatic tissue was obtained by introducing a meta- or para-electron-withdrawing group (a chlorine atom) on the C-4 phenyl ring (drugs 37-42). Such molecules, unlike the parent compound (+/-)-cromakalim, also exhibited a high selectivity for the pancreatic tissue versus the vascular tissue. Radioisotopic and electrophysiological investigations performed with R/S-6-chloro-4-(3-chlorophenylaminocarbonylamino)-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran (38) confirmed that the drug activated pancreatic KATP channels.
Assuntos
Trifosfato de Adenosina/fisiologia , Benzopiranos/síntese química , Cromakalim/química , Células Secretoras de Insulina/efeitos dos fármacos , Compostos de Fenilureia/síntese química , Canais de Potássio/efeitos dos fármacos , Animais , Aorta Torácica/efeitos dos fármacos , Aorta Torácica/fisiologia , Benzopiranos/química , Benzopiranos/farmacologia , Técnicas In Vitro , Insulina/metabolismo , Secreção de Insulina , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/fisiologia , Ativação do Canal Iônico/efeitos dos fármacos , Contração Muscular , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/fisiologia , Técnicas de Patch-Clamp , Compostos de Fenilureia/química , Compostos de Fenilureia/farmacologia , Ratos , Ratos Wistar , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
The synthesis of 2,2-dimethylchromans bearing a 3/4-chloro/cyano-substituted phenylureido or phenylthioureido moiety at the 4-position and an alkoxycarbonylamino ('carbamate') group at the 6-position is described. These new analogs of the potassium channel opener (±)-cromakalim were further tested on rat pancreatic islets as putative inhibitors of insulin release and on rat aorta rings as putative vasorelaxants. All compounds inhibited insulin secretion and induced a myorelaxant activity. Compound 14o [R/S-N-3-cyanophenyl-N'-(6-tert-butoxycarbonylamino-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-4-yl)urea; BPDZ 711] emerged as the most potent inhibitor of the glucose-sensitive insulin releasing process (IC50 = 0.24 µM) and displayed selectivity towards the pancreatic endocrine tissue. Radioisotopic, fluorimetric and pharmacological investigations were performed on rat pancreatic islet and rat vascular smooth muscle cells in order to decipher its mechanism of action. Our findings suggest that the mechanism of action of 14o is rather unspecific. The compound behaves as a KATP channel opener, a Ca(2+) entry blocker, and promotes an intracellular calcium translocation.
Assuntos
Carbamatos/química , Cromakalim/análogos & derivados , Cromakalim/farmacologia , Glucose/farmacologia , Insulina/metabolismo , Vasodilatadores/química , Vasodilatadores/farmacologia , Animais , Aorta/efeitos dos fármacos , Aorta/fisiologia , Fura-2/metabolismo , Secreção de Insulina , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/metabolismo , Ratos , Ratos WistarRESUMO
The present study described the synthesis of original R/S-6-alkylsulfonylamino-3,4-dihydro-2,2-dimethyl-2H-1-benzopyrans bearing a 3- or 4-substituted phenylthiourea or phenylurea moiety at the 4-position. Their biological effects were evaluated both on insulin-secreting and smooth muscle cells and were compared to those of reference KATP channel activators such as (±)-cromakalim, diazoxide and previously synthesized cromakalim analogues. The study aimed at exploring the influence of the introduction of an alkylsulfonylamino substituent at the 6-position of 2,2-dimethylchromans in order to improve biological activity, tissue selectivity but also hydrophilicity of dihydrobenzopyran derivatives. Several compounds were found to be equipotent or even more potent than (±)-cromakalim and diazoxide at inhibiting the insulin releasing process. Most of the newly synthesized and more hydrophilic dihydrobenzopyrans also exhibited a marked vasorelaxant activity although they were less potent than (±)-cromakalim. Additional pharmacological and radioisotopic investigations suggested that R/S-N-3-chlorophenyl-N'-(3,4-dihydro-6-methylsulfonylamino-2,2-dimethyl-2H-1-benzopyran-4-yl)thiourea (21) did not act as a potassium channel opener but rather as a Ca(2+) entry blocker.
Assuntos
Cálcio/metabolismo , Cromanos/química , Cromakalim/química , Cromakalim/farmacologia , Ativação do Canal Iônico/efeitos dos fármacos , Canais de Potássio/metabolismo , Compostos de Enxofre/química , Animais , Aorta/citologia , Aorta/efeitos dos fármacos , Aorta/fisiologia , Transporte Biológico/efeitos dos fármacos , Relação Dose-Resposta a Droga , Insulina/metabolismo , Secreção de Insulina , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Contração Muscular/efeitos dos fármacos , Cloreto de Potássio/farmacologia , Ratos , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
The synthesis of diversely substituted 3-alkyl/aralkyl/arylamino-1,4,2-benzodithiazine 1,1-dioxides and 3-alkylaminopyrido[4,3-e]-1,4,2-dithiazine 1,1-dioxides is described. Their biological activities on pancreatic ß-cells and on smooth muscle cells were compared to those of the reference ATP-sensitive potassium channel (KATP channel) openers diazoxide and 7-chloro-3-isopropylamino-4H-1,2,4-benzothiadiazine 1,1-dioxide. The aim was to assess the impact on biological activities of the replacement of the 1,2,4-thiadiazine ring by an isosteric 1,4,2-dithiazine ring. Most of the dithiazine analogues were found to be inactive on the pancreatic tissue, although some compounds bearing a 1-phenylethylamino side chain at the 3-position exerted a marked myorelaxant activity. Such an effect did not appear to be related to the opening of KATP channels but rather reflected a mechanism of action similar to that of calcium channel blockers. Tightly related 3-(1-phenylethyl)sulfanyl-4H-1,2,4-benzothiadiazine 1,1-dioxides were also found to exert a pronounced myorelaxant activity, resulting from both a KATP channel activation and a calcium channel blocker mechanism. The present work highlights the critical importance of an intracyclic NH group at the 4-position, as well as an exocyclic NH group linked to the 3-position of the benzo- and pyridothiadiazine dioxides, for activity on KATP channels.
Assuntos
Células Secretoras de Insulina/efeitos dos fármacos , Canais KATP/efeitos dos fármacos , Relaxamento Muscular/efeitos dos fármacos , Tiadiazinas/síntese química , Animais , Benzotiadiazinas/síntese química , Benzotiadiazinas/farmacologia , Diazóxido/análogos & derivados , Diazóxido/farmacologia , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/fisiologia , Parassimpatolíticos/farmacologia , Relação Estrutura-Atividade , Tiadiazinas/farmacologiaRESUMO
The enantiomeric purity determination of a synthetic intermediate of new 3,4-dihydro-2,2-dimethyl-2H-1-benzopyrans, i.e. 4-amino-2,2-dimethyl-6-ethoxycarbonylamino-3,4-dihydro-2H-1-benzopyran, was successfully carried out using an anionic cyclodextrin (CD) derivative combined with a chiral ionic liquid (IL). In order to obtain high resolution and efficiency values, the addition of a chiral IL, i.e. ethylcholine bis(trifluoromethylsulfonyl)imide (EtChol NTf(2)), to the background electrolyte containing heptakis(2,3-di-O-methyl-6-O-sulfo)-ß-CD (HDMS-ß-CD) was found to be essential. A simultaneous increase in separation selectivity and enantioresolution seems to indicate a synergistic effect of HDMS-ß-CD and EtChol NTf(2). The best enantioseparation of the key intermediate was achieved using a methanolic solution of 0.75M formic acid, 10mM ammonium formate, 1.5mM HDMS-ß-CD and 5mM EtChol NTf(2). Levamisole was selected as internal standard. The optimized conditions allowed the determination of 0.1% of each enantiomer in the presence of its stereoisomer using the method of standard additions. The NACE method was then fully validated with respect to selectivity, response function, trueness, precision, accuracy, linearity and limits of detection and quantification.
Assuntos
Benzopiranos/química , Ciclodextrinas/química , Eletroforese Capilar/métodos , Benzopiranos/síntese química , Eletroforese Capilar/instrumentação , Líquidos Iônicos/química , EstereoisomerismoRESUMO
The synthesis of 5-chloro-, 6-chloro-, and 8-chloro-substituted 3-alkylamino/cycloalkylamino-4H-1,2,4-benzothiadiazine 1,1-dioxides is described. Their inhibitory effect on the insulin releasing process and their vasorelaxant activity was compared to that of previously reported 7-chloro-3-alkylamino/cycloalkylamino-4H-1,2,4-benzothiadiazine 1,1-dioxides. "5-Chloro" compounds were found to be essentially inactive on both the insulin-secreting and the smooth muscle cells. By contrast, "8-chloro" and "6-chloro" compounds were found to be active on insulin-secreting cells, with the "6-chloro" derivatives emerging as the most potent drugs. Moreover, the "6-chloro" analogues exhibited less myorelaxant activity than their "7-chloro" counterparts. 8-Chloro-3-isopropylamino-4H-1,2,4-benzothiadiazine 1,1-dioxide (25b) and 6-chloro-3-cyclobutylamino-4H-1,2,4-benzothiadiazine 1,1-dioxide (19e) were further identified as K(ATP) channel openers by radioisotopic measurements conducted on insulin-secreting cells. Likewise, current recordings on HEK293 cells expressing human SUR1/Kir6.2 channels confirmed the highly potent activity of 19e (EC(50) = 80 nM) on such types of K(ATP) channels. The present work indicates that 6-chloro-3-alkylamino/cycloalkylamino-4H-1,2,4-benzothiadiazine 1,1-dioxides appear to be more attractive than their previously described 7-chloro-substituted analogues as original drugs activating the SUR1/Kir6.2 K(ATP) channels.