Spasmolytic Effects of Aqueous Extract of Sterculia setigera Delile on Isolated Rat Trachea

The spasmolytic properties of aqueous extract of Sterculia setigera was tested on Rat isolated trachea. Inhibition of the contraction was observed in presence of the aqueous extract (EC50 = 0.91mg/mL ± 0.02) after a pre contraction of the trachea by acetylcholine (10-5M). In the presence of propranolol (10-6M), the spasmolytic activity of the extract was inhibited. The EC50 value was 0.46mg/mL ± 0,11. The aqueous extract of Sterculia setigera also inhibited contraction induced by KCl (4.10-2 M) with EC50 value = 1.9mg/mL ± 0.48).  These results clearly show a relaxing effect of aqueous extract of Sterculia setigera on the trachea isolated from rat. This effect involves at least in part β-adrenergic receptor inhibition