RESUMO
Different pharmacological effects of Achillea millefolium including its relaxant effect on smooth muscle have been shown previously. In the present study the stimulatory effect of the plant extract on ß-adrenoceptor of tracheal muscle was examined in order to investigate one possible mechanism for its observed relaxant effect. Effect of three concentrations of hydroethanol extract, 10 nM propranolol, and saline on ß-adrenoceptor was tested in two experimental groups including; nonincubated tracheal smooth muscles (group 1) and incubated tracheal smooth muscle with chlorpheniramine (group 2). Concentration response curves to isoprenaline were performed in precontracted tracheal smooth muscle in the presence of the extract, propranolol and saline. Values of EC50 and CR-1 were measured. Leftward shifts in isoprenaline curves were observed in the presence of medium and high concentrations of the extract compared with saline in both groups. The values of EC50 obtained in the presence of medium and high concentrations of the extract only in group 1 were nonsignificantly lower than that of saline. The values of CR-1 obtained in the presence of all concentrations of the extract in both groups were negative and significantly different with that of propranolol. The results indicated a small stimulatory effect of the extract on ß2-adrenoceptors.
RESUMO
Different pharmacological effects of Crocus sativus have been demonstrated on guinea pig tracheal chains in previous studies. In the present study, the prophylactic effect of the extract of C. sativus and its constituent, safranal on lung pathology and total and differential white blood cells (WBC) of sensitized guinea pigs was examined. Guinea pigs were sensitized with injection and inhalation of ovalbumin (OA). One group of sensitized guinea pigs were given drinking water alone (group S) and three groups were given drinking water containing three concentrations of safranal (S+SA1, S+SA2 and S+SA3 groups), three groups, drinking water containing three concentrations of extract (S+CS1, S+CS2 and S+CS3 groups) and one group drinking water containing one concentration of dexamethasone (S+D group) (n=6, for all groups). The lung pathology was evaluated in control, non treated and treated sensitized groups. Total and differential WBC counts of lung lavage were also examined. All pathological indices in group S showed significant increased compared to control group (p<0.05 for lung congestion and p<0.001 for other groups). Total WBC number (p<0.001), eosinophyl percentage (p<0.001) in lung lavage and serum histamine levels (p<0.01) were also increased in sensitized animals compared to those of controls. Treatment of S animals with dexamethasone, all concentrations of the extract and safranal significantly improved lung pathological changes, most types of WBC and serum histamine levels compared to group S (p<0.05-0.001). Treatment of S group with first concentration of safranal also decreased total WBC. Treatment with safranal was more effective in improvement of most pathological changes, total and differential WBC count as well as serum histamine level (p<0.05-0.001). These results showed a preventive effect of the extract of C. sativus and its constituent safranal on lung inflammation of sensitized guinea pigs. The results also showed that the effect of the plant is perhaps due to its constituent safranal.
