Planta Med 2013; 79 - SL70
DOI: 10.1055/s-0033-1351895

Calcium antagonistic effects of ethanolic myrrh extract in inflamed intestinal smooth muscle preparations

C Vissiennon 1, K Goos 2, O Goos 2, K Nieber 1
  • 1University of Leipzig/Institute of Pharmacy
  • 2REPHA GmbH Biologische Arzneimittel

Myrrh is the oleo-gum resin of mainly Commiphora molmol ENGLER (Burseraceae) and as powdered substance one compound in the traditional medicinal product Myrrhinil-INTEST®, which has been used for the treatment of unspecific and inflammatory intestinal disorders. To date only limited data is available regarding its mechanism of action. Besides antimykotic and antiphlogistic properties calcium antagonistic and antidiarrhoic effects have been discussed [1]. The aim of the present study was to evaluate the calcium antagonistic effect of myrrh. Therefore, an ethanolic myrrh extract (MY) was tested for its effects on muscle tone and acetylcholine (ACh)-induced contractions in untreated and inflamed rat ileum/jejunum preparations. Inflammation was experimentally induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS, 10 mM, 30 min). Additionally, the effect of the calcium channel agonist Bay K8644 in presence of varying MY concentrations was examined to confirm the calcium antagonistic effect.

MY suppressed the ACh-induced contraction down to 25,75% (0,99 mg/ml MY). MY (0,15; 0,25 and 0,35 mg/ml) induced a concentration-dependent right-ward shift of the Bay K8644 concentration-response curve in untreated and inflamed preparations with a significant EC50 shift. Schild analyses resulted in a pA2 value of 0,93 for untreated preparations. Increasing MY concentrations induced a concentration-dependent decrease of the agonistic maximum effect in untreated and inflamed preparations down to 15,84% and 25,78% respectively for the highest concentration leading to a pD2 value of 0,58.

MY reduced intestinal muscle tone and ACh-induced contraction of untreated and inflamed ileum/jejunum preparations based on dual calcium antagonism characterised by a right-shift of the agonistic dose-response curve and a depression of maximum effect. The resulting reduction of intestinal motility and spasmolytic effects provide a rationale for the treatment of intestinal disorders.