Calcium blocking activity as a mechanism of the spasmolytic effect of the essential oil of Calamintha glandulosa Silic on the isolated rat ileum.

In this paper we present the results of studying the effects of the essential oil of Calamintha glandulosa Silic (EOCG) on the isolated rat ileum. C. glandulosa Silic has been used in folk medicine as an antispasmodic. EOCG (0.003-1 mg/ml) inhibited spontaneous contraction of the ileum (EC50 of 210.48 +/- 9.12 microg/ml). The calcium channel blocking activity was confirmed by inhibition of K(+) (80 mmol/l) induced contractions with EOCG (EC50 of 88.81 +/- 6.01 microg/ml). EOCG shifted cumulative calcium curves in depolarizing medium downward (EC50 of 18.18 +/- 1.87 mmol/l), similar to the effects of verapamil. Our results confirm that the EOCG shows spasmolytic action in rat ileum. The spasmolytic effect of the EOCG was due to blockade of calcium influx. One of the main components of the EOCG is monoterpenoide pulegone. Namely, pulegone (0.15-50 micromol/l) inhibited the spontaneous (EC50 of 9.02 +/- 0.08 microg/ml), and K(+) induced contractions of the ileum (EC50 of 4.05 +/- 0.14 microg/ml), and run rightward the dose response curve of calcium. Pulegone may have a main role in spasmolytic activities of the plant.