Therapeutic effect of Portulaca oleraceae on respiratory diseases is indicated in Iranian ancient Medical books. In the present study, the relaxant effects of boiled and aqueous extracts of Portulaca oleraceae on tracheal chains of guinea pigs were examined.
The relaxant effects of 5 cumulative concentrations of boiled and aqueous extracts (0.25, 0.5, 0.75, 1.0, and 1.25 W/V) in comparison with saline as negative control and 4 cumulative concentrations of theophylline (0.25, 0.5, 0.75, and 1.0 mM) were examined by their relaxant effects on precontracted tracheal chains of guinea pig by 60 mM KCl (group 1) and 10 µM methacholine in two different conditions including: non-incubated tissues (group 2) and incubated tissues with 1 µM propranolol and 1 µM chlorpheniramine (group 3), (for group 1 and 2, n=6 and for group 3, n=4).
In group 1 only the last two concentrations of theophylline (p<0.001) and boiled (p<0.05) extract showed significant relaxant effect compared to that of saline. However, in groups 2 and 3 both boiled and aqueous extracts and theophylline showed concentration dependent relaxant effect compared to that of saline (p<0.05 to p<0.001). There were no significant differences between relaxant effects of boiled and aqueous extracts with those of theophylline in group 2. The effects of extracts between groups 2 and 3 and those of theophylline between groups 1 and 2 were not statistically significant. These results showed a potent relaxant effect of Portulaca oleraceae on tracheal chains of guinea pigs that was comparable to that of teophylline at concentrations used.