Relaxant effects of Peperomia hispidula (Sw.) A. Dietr. on isolated rat tracheal rings / Efecto relajante de Peperomia hispidula (Sw.) A. Dietr. sobre anillos aislados de tráquea de rata

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 último trastorno es el resultado de una contracción excesiva e inapropiada del músculo liso de las vías respiratorias. El objetivo del presente estudio fue evaluar la actividad relajante de P. hispidula sobre anillos aislados de tráquea de rata contraídos con carbacol. El metileugenol fue identificado como el principal constituyente activo en el extracto de diclorometano. Para explorar el posible mecanismo de acción, se construyeron curvas concentración-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 relajación del músculo liso inducida por metileugenol. En conclusión, P. hispidula muestra actividad relajante en anillos de tráquea de rata. El efecto de metileugenol, al parecer no está implicado con la activación de los receptores ß2-adrenérgicos, prostaglandinas, canales de K+ATP u óxido nítrico.

Nitrogen fertilizer influences yield and essential oil of ocimum americanum cultivated in Egypt

The present study was carried out during two successive seasons at the Experimental Farm of Cultivation and Production of Medicinal and Aromatic Plants Department, National Research Center, Giza, Egypt.The aim of this study was to investigate the effect of differc-t nitrogen levels on the yield and essential oil production of Ocimum cimericanum.Herbage yield was significantly increased with nitrogen fertilization especially at high levels [40, 60 and 80 kg N/fed]. Both fresh and dry yield of herb [ton/fed] in both seasons were significantly influenced. Similarly, the same effect was obtained on leaves fresh and dry yield per feddan [4200 m[2]]. The highest herb and leaves yields were obtained as a result of 60 kg N/fed. The highest oil percentage was associated with the highest nitrogen dose [80 kg N/fed] in most cuts of both seasons. All nitrogen doses significantly increased oil content [mi/plant] comparing to unfertilized plants. In all cuts of both seasons, 60 kg N/fed produced the highest oil content. The maximum total oil yield [ml/plants or 1/fed] were obtained with 80 and 60 kg N/fed in the lst and 2nd seasons, respectively. All identified compounds were observed in the essential oil of all treatments. The major compound was found to be eugenol followed by methyl chavicol. Generally, the higher the nitrdgen was applied, the higher the methyl chavicol was produced; the opposite was true with eugenol.As a conclusion we may recommend the fertilization of Ocirnum arnericanurn L. plants with 60 kg N/fed as ammonium sulfate to maximize herb, leaves and oil production either per plant or per feddan