Evaluation of the antitussive effects of the aqueous extract of the trunk bark of Albizia ferruginea (Mimosaceae) in the wistar rats with model of airway inflammation by liquid ammonia

The aim of this study was to evaluate the antitussive effects of the aqueous extract of the stem bark of Albizia ferruginea (Mimosaceae) in airway inflammation model induced by ammonia liquor in Wistar rat. Animals, weighting between 180-195 g, were used. They were divided in 5 groups of 5 rats each as follow: Normal control and Negative control groups receiving distilled water; Positive control group receiving promethazine (10 mg/kg); and two test groups receiving the aqueous extract of Albizia ferruginea at the doses of 100 and 200 mg/kg respectively. Except the Normal control group, all groups were exposed to the ammonia liquor (25%) for 2 min in the cage that was hermetically sealed. Airway inflammation was marked by coughing. Animal behavior and the number of coughs was recorded for 5 minutes by experimented observers. To characterize the aqueous extract of Albizia ferruginea, a phytochemical analysis was done. As results, animal submitted to ammonia liquor exposition only. A 1.6 L cage containing a grid was used as a platform to move the animal for exposure to liquid ammonia. Liquid ammonia supplied by MoleculesGas, Douala (Cameroon), was used to induce coughing. A 5-mL syringe was used to withdraw three milliliters of liquid ammonia (25%), which was then poured into the 15-mL bowl to collect the ammonia. The rat was removed from the cage and placed in the observation cage. Animals whose cough frequency was between 15 and 30 were retained for the rest of the experiment. The aqueous extract of A. ferruginea was administered orally at the doses of 100 and 200 mg/kg. Promethazine, a cough suppressant, was used as a reference. Animals exposed to the liquid ammonia in observation cages showed reddening of the nose, some with snot discharge and reddened eyes. The cough was differentiated from sneezing by changing in posture (stretching of the front legs and forward stretching of the neck). The characteristic opening of the mouth was associated with the emission of a specific sound (undetermined origin). It was showed that A. ferruginea extract (100 or 200 mg/kg) significantly (p