Myrrh is the oleo-gum resin of mainly Commiphora molmol and as a powdered substance, one compound in the traditional medicinal product Myrrhinil-Intest®, which has been used for the treatment of unspecific, inflammatory intestinal disorders. The aim of the present study was to evaluate the
antispasmodic effect of
myrrh under healthy and inflamed conditions, and to evaluate a
calcium-antagonistic effect as a possible mode of action. Therefore, an ethanolic
myrrh extract was tested for its effects on muscle tone and
acetylcholine-induced contractions in untreated and inflamed rat ileum/jejunum preparations.
Inflammation was experimentally induced by
2,4,6-trinitrobenzene sulfonic acid (10 mM, 30 min). Additionally, the effect of the
calcium channel agonist Bay K8644 in the presence of varying
myrrh extract concentrations was examined.
Myrrh extract (0.99 mg/mL) suppressed the
acetylcholine-induced contraction down to 25.8 % in untreated and 15.2 % in inflamed preparations.
Myrrh extract (0.15; 0.25 and 0.35 mg/mL) induced a concentration-dependent rightward shift of the
Bay K8644 concentration-response curve in untreated and inflamed preparations with a significant EC50 shift. Schild analysis resulted in a pA2 value of 0.93 for untreated preparations. Increasing
myrrh extract concentrations induced a concentration-dependent decrease of the agonistic maximum effect in untreated and inflamed preparations down to 15.8 % and 25.8 %, respectively, for the highest concentration leading to a pD2 value of 0.58.
Myrrh extract reduced intestinal muscle tone and
acetylcholine-induced contraction of untreated and inflamed ileum/jejunum preparations based on dual
calcium antagonism characterized by a right shift of the agonistic dose-response curve and a depression of the maximum effect. The resulting reduction of intestinal motility and
spasmolytic effects provide a rationale for the symptom treatment of intestinal disorders such as
irritable bowel syndrome.