the differences in the relaxant effects of different fractions of rosa damascena on guinea pig tracheal smooth muscle

objective(s) in the present study, the differences in the relaxant effects of aqueous, ethyl acetate and n-butanol fractions of rosa damascena on tracheal smooth muscle of guinea pigs were examined. materials and methods the relaxant effects of three cumulative concentrations of each fraction (0.1, 0.2 and 0.4 g%) in comparison with saline and three cumulative concentrations of theophylline (0.1, 0.2, and 0.4 mm) were examined on precontracted tracheal chains of guinea pig by 60 mm kcl (group 1, n= 5) and 10 pm methacholine (group 2, n= 8). results in group 1, all concentrations of theophylline, ethyl acetate fraction and two final concentrations of n-butanol fraction showed significant relaxant effects in comparison with saline (p< 0.05 to p< 0.001). in group 2, all concentrations of theophylline, ethyl acetate and aqueous fractions showed concentration dependent relaxant effects compared to that of saline (p< 0.01 to p< 0.001). in addition, the effect of ethyl acetate fraction in group 1 was significantly higher than those of theophylline (p< 0.05 to p< 0.001). however, the effects of other fractions were significantly lower than theophylline in both groups (p< 0.01 to p< 0.001). there were significant correlations between the relaxant effects and concentrations for theophylline and all fractions (except aqueous fractions in group 1) in both groups. conclusion the results showed a potent relaxant effect for ethyl acetate fraction of r. damascena on tracheal smooth muscle comparable to that of theophylline but a relatively weak relaxant effect for aqueous and n-butanol fractions at concentrations used.