DARU Journal of Pharmaceutical Sciences154Relaxant effect of Satureja hortensis on guinea pig tracheal chains and its possible mechanism(s(199204Boskabady MH.Aslani MR.Mansuri F.Amery S.20151006Background: In Iranian ancient medical books, the therapeutic effects of Satureja hortensis on respiratory diseases have been reported. In order to verify these reports, the relaxant effect of aqueous-ethanolic extract of Satureja hortensis on guinea pig trachea was examined. Methods: The relaxant effects of 6 cumulative concentrations of extract (0.15, 0.3, 0.45, 0.6, 0.75 and 0.9 g %) in comparison with saline and 4 cumulative concentrations of theophylline (0.15, 0.3, 0.45, and 0.6 mM) by their effects on precontracted tracheal chains of guinea pig by 10 µM methacholine (group 1) or 60 mM KCl in two different conditions including: non-incubated tissues (group 2) and incubated tissues with 1 µM propranolol, 1 µM chlorpheniramine and 1 µM atropine (group 3, for each group  n=6) were examined.  Results: In group 1, the extract and theophylline showed concentration dependent relaxant effects compared to that of saline (p<0.05 to p<0.001). In group 2, three last concentrations of theophylline and four higher concentrations of extract showed significant relaxant effects compared to that of saline (p<0.05 to p<0.001). The effects of four lower concentrations of extracts in groups 1 and 2 were significantly lower than those of theophylline (p<0.05 p<0.001). In group 3, the extract did not show any significant relaxant effect. There were significant correlations between the relaxant effects and concentrations of extract and theophylline in  groups 1 and 2 (p<0.001 for all cases). Conclusion: These results showed a potent relaxant effect of Satureja hortensis on guinea pigs trachea which was comparable to that of theophylline.https://daru.tums.ac.ir/index.php/daru/article/view/329https://daru.tums.ac.ir/index.php/daru/article/download/329/329