RESUMO
Peperomia hispidula (Sw.) A. Dietr. is used in Mexican traditional medicine for treating respiratory illnesses such as asthma. The latter disorder results from an excessive and inappropriate constriction of airway smooth muscle. The aim of the present study was to evaluate the relaxant activity of P. hispidula on isolated rat tracheal rings contracted with carbachol. The methyleugenol was identified as the main active constituent in the dichloromethane extract. To explore the possible mechanism of action, concentration-response curves were constructed in the presence and absence of propranolol (3 µM), indomethacin (10 µM), glibenclamide (1 µM), and L-NAME (300 µM), finding that neither reduced methyleugenol-induced smooth muscle relaxation. In conclusion, P. hispidula herein displayed relaxant activity on rat tracheal rings. The effect of methyleugenol, was probably not related to the activation of ß2-adrenoceptors, prostaglandins, K+ATP channels or nitric oxide.
Peperomia hispidula (Sw.) A. Dietr. es utilizada en la medicina tradicional mexicana para tratar enfermedades respiratorias como el asma. Este uÌltimo trastorno es el resultado de una contraccioÌn excesiva e inapropiada del muÌsculo liso de las viÌas respiratorias. El objetivo del presente estudio fue evaluar la actividad relajante de P. hispidula sobre anillos aislados de traÌquea de rata contraiÌdos con carbacol. El metileugenol fue identificado como el principal constituyente activo en el extracto de diclorometano. Para explorar el posible mecanismo de accioÌn, se construyeron curvas concentracioÌn-respuesta en presencia y ausencia de propranolol (3 µM), indometacina (10 µM), glibenclamida (1 µM), y L-NAME (300 µM), encontrando que ninguno redujo la relajacioÌn del muÌsculo liso inducida por metileugenol. En conclusioÌn, P. hispidula muestra actividad relajante en anillos de traÌquea de rata. El efecto de metileugenol, al parecer no estaÌ implicado con la activacioÌn de los receptores ß2-adreneÌrgicos, prostaglandinas, canales de K+ATP u oÌxido niÌtrico.
Assuntos
Animais , Masculino , Ratos , Traqueia/efeitos dos fármacos , Eugenol/análogos & derivados , Eugenol/farmacologia , Extratos Vegetais/farmacologia , Peperomia , Asma/metabolismo , Estenose Traqueal/induzido quimicamente , Eugenol/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas em Tandem , Cloreto de Metileno/química , Relaxamento Muscular/efeitos dos fármacosRESUMO
The present study was carried out to evaluate the gastroprotective effect of caryophyllene oxide, and investigate the gastroprotective mechanism. For this purpose, Wistar rats received vehicle, caryophyllene oxide (10-100 mg/kg) or carbenoxolone (1-100 mg/kg, used as the reference drug). Thirty minutes later absolute ethanol was given orally, and 2 h later the stomach was dissected and the damaged area measured. In other experiments, the rats received L-NAME (70 mg/kg, i. p.), indomethacin (10 mg/kg, s. c.), and N-ethylmaleimide (10 mg/kg, s. c.), before the administration of the caryophyllene oxide (100 mg/kg) or carbenoxolone (100 mg/kg). Two control groups were included in these evaluations. Again, thirty minutes later absolute ethanol was given orally, and 2 hours later the animals were sacrificed to measure the ulcer index. Treatment of rats with caryophyllene oxide and carbenoxolone elicited a dose-dependent gastroprotective effect. The gastroprotection observed with the administration of caryophyllene oxide was attenuated in rats pretreated with the inhibitors. This suggests that the gastroprotective mechanism of action of caryophyllene oxide involves NO, prostaglandins and sulfhydryl groups. In the case of carbenoxolone, the partial participation of NO, prostaglandins and sulfhydryls was observed.