Studies on the anti-asthmatic and antitussive properties of aqueous leaf extract of Bryophyllum pinnatum in rodent species

Objective: To evaluate the antiasthmatic and antitussive properties of the aqueous leaf extract of Bryophyllum pinnatum (B. pinnatum) (BP) Lam. Methods: Ovalbumin-sensitized guinea pigs which were treated with BP for 21 consecutive days were exposed to 0.2% histamine aerosol in a glass chamber. Mucus viscosity, white blood cell and lymphocyte counts and tracheal wall morphometry were measured. Bouts of cough were counted pre and post acute exposure of extract treated (x7 d) guinea pigs to 7.5% citric acid aerosol in a chamber. Phenol red expectoration was estimated in mice after 7 d of daily administration of BP. Results: Doses of 200 and 400 mg/kg/day (x21 d) BP significantly increased the time for guinea pigs to experience preconvulsive dyspnoea. BP and salbutamol (0.5 mg/kg/day X 21 d) reduced mucus viscosity in the sensitized group to values comparable with controls. White blood cell, lymphocyte counts and tracheal morphometry were not significantly altered. Both doses of BP also significantly reduced the bouts of cough but only 400 mg/kg/day significantly inhibited the amount of phenol red secreted. Conclusions: BP has demonstrated antiasthmatic and antitussive properties in these rodent models. These properties may underscore its use in Nigerian ethnomedicine.