Effect of the Aqueous Extract of Crinum glaucum on Isolated Guinea Pig Trachea

The aqueous extract of Crinum glaucum was evaluated using guinea pig trachea and was observed to neither relax the spontaneous tone of the guinea pig trachea nor KCl-induced tone. It, however, produced a concentration-dependent relaxation of carbachol- and histamine- pre-contracted trachea. The relaxant effect of the extract on carbachol-induced tone was not inhibited by propranolol, but potentiated by glibenclamide, procaine, methylene blue and L-nitro arginine methyl ester (L-NAME) with a progressive decrease in the median effective concentration (EC50) values. The extract (5-40 mg/kg body weight/day) produced a rightward shift and a depression of the maximal effects (Emax) of the anaphylactic contractions of the trachea while the extract at 2mg/ml produced a complete inhibition of the contractions. The results of this study clearly showed that the aqueous extract of Crinum glaucum possesses spasmolytic and anti-spasmogenic properties on normal and sensitized trachea and this may account for its use in the treatment of cough, asthma, and convulsions in traditional medicine. Key words: Crinum glaucum , trachea, anaphylactic contractions, histamine, carbachol