Effect of Crocus sativus (Saffron) on Muscarinic Receptors of Guinea Pig Tracheal Chains

The effects of aqueous-ethanolic extracts of Crocus sativus (Iridaceae) on muscarinic receptors were examined on tracheal chains of guinea pigs. The effects of three concentrations of aqueous-ethanolic extract, safranal, atropine and saline on muscarinic receptors were tested (n=8). The EC50 (effective concentration of methacoline causing 50% of maximum response) obtained in the presence of atropine, all concentrations of the extract and safranal were significantly greater than those of saline (p<0.05 to p<0.001). Maximum responses to methacholine obtained in the presence of different concentrations of saffron extract were significantly lower than that in saline (p<0.01 to p<0.005). There were parallel rightward shift in concentration response curves obtained in the presence of only low concentration of saffron and safranal. These results may indicate an inhibitory effect of Crocus sativus and especially for safranal on muscarinic receptors. _____________________________________________________________________________________________________________