Vasodilatory effect of asafoetida essential oil on rat aorta rings: The role of nitric oxide, prostacyclin, and calcium channels.

BACKGROUND: Asafoetida is an oleo-gum resin mainly obtained from Ferula assa-foetida L. species in the apiaceae family. Previous studies have shown that it has antispasmodic effects on rat's and pig's ileums. PURPOSE: The main goals of this study were to assess the vasodilatory effect of asafoetida essential oil (AEO) on the contractile response of rat's aorta rings and to find the role of nitric oxide, cyclooxygenase, and calcium channels. Thoracic aorta rings were stretched under a steady-state tension of 1 g in an organ bath apparatus for 1 h and then precontracted by KCl (80 mM) in the presence and absence of AEO. L-NAME (blocker of nitric oxide synthase) and indomethacin (blocker of cyclooxygenase) were used to assess the role of nitric oxide (NO) and prostacyclin in the vasodilatory effect of AEO. Also, the effect of AEO on the influx of calcium through the cell membrane calcium channels was determined. RESULTS: Data showed that AEO had vasodilatory effects on aorta rings with both intact (IC50 = 1.6 µl/l) or denuded endothelium (IC50 = 19.2 µl/l) with a significantly higher potency in intact endothelium rings. The vasodilatory effects of AEO were reduced, but not completely inhibited, in the presence of L-NAME or indomethacin. Adding AEO to the free-calcium medium also significantly reduced the CaCl2-induced contractions. CONCLUSION: The results indicated that AEO has a potent vasodilatory effect that is endothelium-dependent and endothelium-independent. Also, it reduced the influx of calcium into the cell through plasma membrane calcium channels.