Spasmolytic effect of Anethum graveolens (dill) fruit extract on rat ileum

Introduction: Dill (Anethum graveolens), a herb from from Umbelliferae, is used traditionally to treat convulsion and increasing milk production. Its antimicrobial, antihyperlipidaemic, anti-hypercholesteroaemic effects and gastric acid secretion reducing effect have been reported. The spasmolytic effect of dill fruit on rat uterus has also been shown recently. The aim of present study was to investigate the effects of dill fruit hydroalcoholic (DFHE) extract on rat ileum contractions induced by KCl (60mM), acetylcholine (1μM) and BaCl2 (4mM). Methods: Dill fruit was extracted by 70 % alcohol for 72 h and macerated method was used. Male Wistar rats were killed by a blow to head and pieces of end portion of ileum (2 cm) were dissected out and washed with cooled oxygenated Tyrode’s solution. Ileum was mounted in an isolated organ bath containing Tyrode solution (37 ºC) bubbled by air. An isotonic transducer was used to record contractile responses under 0.5g initial tension. Results: The cumulative concentrations of DFHE (0.5, 1, 2, and 4 mg/ml) relaxed the KCl- , acetylcholineand BaCl2-induced contractions dose-dependently (n=8, p<0.0001). This spasmolytic effect of extract (at all concentrations) on BaCl2-induced contraction was more potent than on the acetylcholine-induced contraction. In addition, the antispasmodic effect of DFHE was reversible after washing the organ bath. The inhibitory effect of extract (1mg/ml) on contraction induced by KCl was unaffected neither by phentolamine (1 μM, for 30 min), propranolol (1 μM, for 30 min) nor naloxone (1 μM, for 30 min). L-NAME (100 μM, for 20 min) was also ineffective in this respect. In Ca2+-free, rich K+ (120 mM) Tyrode solution, cumulative adding of calcium (0.225. 0.45, 0.9, 1.8 and 3.6 mM), increased contractions dose dependently (p<0.0001). DFHE (1 mg/ml) shifted this dose-response curve to the right (p<0.0001). Conclusion: These results suggest that the relaxatory effect of DFHE on ileum contractions is due to the blockade of voltage dependent calcium channels. In addition, the α- and β-adrenoceptors, opioid receptors and NO production are not involved in this inhibitory effect of DFHE.