Antispasmodic Effect of Teucrium polium Leaf Extract on Rat Ileum

Teucrium polium (locally called as chez or kalporeh in Khuzestan Province, Iran) is used traditionally as a remedy for treatment of headache, convulsion and dysmenorrhea and moreover, its hypoglycemic, hypolipidemic and antibacterial effects have been reported in recent researches. In addition, it is also used traditionally to treat gastrointestinal disorders. The aim of the present study was to investigate the effects of Teucrium polium aqueous leaf extract on rat ileum contractions evoked by receptor and non-receptor stimulants and also to study the mechanism(s) involved. Freshly dried leaves of Teucrium polium were extracted with boiling water. Pieces of ileum from adult male Wistar rat were mounted in an organ bath containing Tyrode solution and an isotonic transducer recorded contractile responses under 1g initial tension. Data indicate that cumulative concentrations of the extract (0.25, 0.5, 1, 2, 4 and 8 mg/ml) reduced the ileum contractions induced by KCl (60 mM) and acetylcholine (1 μM) in a dose-dependent manner (P<0.0001). The spasmolytic effect of the extract on KCl-induced contraction was more potent than on the ACh-induced contractions. The spasmolytic effect of extract was totally reversible. The spasmolytic effect of the extract was not affected by L-NAME (100 μM, 20min) in KCl-induced contractions. Spasmolytic effect of extract was not reduced by ileum incubation (30 min) with propranolol, phentolamine and naloxone (all at 1μM) in KCl-induced contractions. The cumulative concentrations of calcium evoked contractions in a dose dependent manner in Ca2+-free Tyrode solution with high potassium. These contractions were attenuated by the extract, significantly. The results suggested that the voltage dependent calcium channels might be involved in spasmolytic effects of Teucrium polium aqueous leaf extract. In this inhibitory effect, however, neither NO, opioid receptors, nor adrenoceptors (α and β) were involved.