Anti spasmolytic effect of Glycyrrhiza glabra leaf on rat ileum contractions

Glycyrrhiza glabra is a type of plant that a lot of researches have been carried out on components and properties of its licorice but the effect of its leaf extract has not been evaluated. Therefore, this study was aimed to investigate the effect of Glycyrrhiza glabra leaf extract on rat ileum contractions. In this experimental study, the terminal portion of ileum from male Wistar rat was contracted under 1 gram tension by 60 mM KCl and/or 10μM carbachol and then the effect of aquatic extraction of Glycyrrhiza glabra on the contractions was assessed. The new portions of the ileum were separately incubated with propranolol (1μM), naloxone (1μM), inhibitor of nitric oxide synthetize (L-NAME) (100μM), glibenclamide (10mM) and tetraethyl ammonium (1μM) and the tissue spasm and antispasmodic effect of the extract were recorded. Data were analyzed using one and two way analysis of variance and post hoc LSD tests. Cumulative concentrations of the extract (0.0625-0.5mg/ml) reduced the ileum contractions induced by KCl and carbacole, dose-dependently (P<0.001). Incubation of the tissue with propranolol, naloxone, L-NAME, and tetraethyl ammonium did not reduce the antispasmodic effect of the extract, but it was reduced by glibenclamide (0.125mg/ml). In Tyrode-containing solution, without calcium and with high concentrations of potassium (60μM), the cumulative concentrations of CaCl2 (0.5-8mM) contracted the ileum and the extract (0.0156-0.0625mg/ml) reduced the induced contractions (P<0.001). Based on our results, the aqueous extract of Glycyrrhiza glabra inhibited the ileum contractions without involving β-adrenergic, opioid, and tetraethyl ammonium receptors. Calcium channels were involved in the main part of this inhibitory effect and probably activation of ATP-dependent potassium channels partially was involved in this process..