Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter calcoaceticus/efeitos dos fármacos , Antibacterianos/farmacologia , Carbapenêmicos/farmacologia , Infecção Hospitalar/microbiologia , Acinetobacter baumannii/genética , Acinetobacter calcoaceticus/genética , Colômbia , Farmacorresistência Bacteriana , Farmacorresistência Bacteriana Múltipla , Genes Bacterianos/genética , Humanos , Plasmídeos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , beta-Lactamases/genética , beta-Lactamases/metabolismoRESUMO
In this study we evaluated the anti-adrenergic response elicited by ayanin, a flavonoid compound isolated from Croton schiedeanus Schlecht, in the pithed rat, and the inhibitory effect of NO synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME), and its acute toxicity profile in mice. In pithed rats ayanin (5 - 50 mg/kg i. v.) caused a dose-dependent decrease in the pressor and chronotropic responses induced by intravenous noradrenaline administration (0.25 microg/kg). This anti-adrenergic response was completely abolished by prior treatment with L-NAME (10 mg/kg i.v ) and the inhibitory effect of L-NAME was reversed after intravenous administration of L-arginine (100 mg/kg, i. v.). No lethal or major toxic effects were observed in mice receiving i. p. administration of ayanin up to a dose of 500 mg/kg. Our findings confirm that ayanin exerts protective cardiovascular effects against the increase in blood pressure and heart rate mainly through a mechanism that depends on the NO/cyclic guanosine monophosphate (cGMP) pathway without acute toxic effects. These results suggest that extracts of Croton schiedeanus, the native south American plant from which ayanin was isolated, might be beneficial in cardiovascular disease.
Assuntos
Pressão Sanguínea/efeitos dos fármacos , Croton , Flavonoides/farmacologia , Frequência Cardíaca/efeitos dos fármacos , NG-Nitroarginina Metil Éster/farmacologia , Norepinefrina/farmacologia , Animais , Arginina/farmacologia , GMP Cíclico/metabolismo , Estado de Descerebração , Relação Dose-Resposta a Droga , Flavonoides/química , Masculino , Camundongos , NG-Nitroarginina Metil Éster/antagonistas & inibidores , Óxido Nítrico/metabolismo , Ratos , Testes de Toxicidade AgudaRESUMO
Antihypertensive and vasorelaxant effects of treatment with the aqueous extract of Croton schiedeanus Schlecht (AECS) were investigated in anaesthetized spontaneously hypertensive rats (SHR). Intravenous bolus injections of AECS (5-100 mg/kg) elicited dose-dependent decreases in mean arterial pressure (MAP) and heart rate (HR). Additionally, AECS (10(-6)-3x10(-3)g/ml) completely relaxed the contractions induced by high K(+) concentrations in intact rat aortic rings in a concentration-dependent manner.
Assuntos
Anti-Hipertensivos/farmacologia , Euphorbiaceae/química , Extratos Vegetais/farmacologia , Vasodilatadores/farmacologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Masculino , Ratos , Ratos Endogâmicos SHR , Ratos WistarAssuntos
Bebidas , Citrus , Café , Tetraciclina/farmacocinética , Adulto , Disponibilidade Biológica , Cálcio/sangue , Feminino , Humanos , Masculino , Tetraciclina/urinaRESUMO
Investigation of the MeOH extract of Exostema caribaeum (Rubiaceae) led to the isolation of three new 4-phenylcoumarins. Their structures, 5-O-beta-D-galactosyl-7-methoxy-3',4'-dihydroxy-4-phenylcoumarin [1a] 7,4',5'-trihydroxy-4-phenyl-5,2'-oxidocoumarin [2a] and 7,4'-dimethoxy-5'-hydroxy-4-phenyl-5,2'-oxido-coumarin [3a] were elucidated by spectral methods and chemical transformations. It was also demonstrated that 4-phenylcoumarins undergo oxidative cyclization under basic conditions in the presence of air to give 4-phenyl-5,2'-oxido-coumarins.