New options for the treatment of functional gastrointestinal diseases with the phytomedicine STW 5
In functional dyspepsia, efficacy and mechanisms of action of STW 5 (Iberogast®) have been shown in a large number of studies [1, 2, 3]. We have shown a region specific inhibition of muscular tone in gastric fundus and corpus and an activation of gastric antrum by this herbal fixed combination in vitro  as well as in clinical studies . The aim of the actual studies was to identify further treatment options by assessing the effect of STW 5 in other regions of the gastro-intestinal tract.
In vitro studies in human colon preparations and in the human epithelial cell line T84 showed a pro-secretory effect of STW 5. This effect was mediated through epithelial activation of cAMP and Ca-dependent Cl-channels, as well as by activation of secretomotoneurons of the enteric nerval system. In part this pro-secretory effect was also prostaglandin dependent.
Studies of the muscular activity of human colon preparations in vitro showed a significant inhibition of basal tone and of phasic activity by STW 5. This effect was TTX insensitive and therefore myogen. The inhibitory effect was shown in longitudinal as well as in circular muscle.
In vitro registration of the lower esophageal sphincter of the guinea pig showed a significant tonicising effect of STW 5. Interestingly STW 5 did not influence the pyloric tone.
These effects of STW 5 (Iberogast®) open options for the treatment of a number of functional gastro-intestinal disturbances, as are intestinal hyposecretion, hyperactive respective spastic intestine, and atonic oesophageal sphincter. This is of special relevance in motility-related gastro-intestinal diseases, as are irritable bowel syndrome and gastroesophageal reflux.
References: 1. Von Arnim, U. (2007) Am J Gastroenterol 102:1268–1275; 2. Madisch, et al. (2004) Aliment Pharmacol Ther 19:271–79 3. Allescher, H.D., Wagner, H. (2007) Wien Med Wochenschr 157:301–307 4. Schemann, M. (2006) Phytomedicine 13 SV:90–99; 5. Pilichiewicz, A. (2007) Am J Gastroenterol 102:1–8