Herbal treatment options are increasingly used in functional gastroenterological disorders (FGID) like irritable bowel syndrome (IBS), while an understanding of their mechanisms of action is often lacking. According to recent national and international therapeutic guidelines (e.g, 1,2,3), STW 5, a combination product of nine herbal extracts, is an evidence-based treatment option for IBS. This poses the question as to what the mechanisms of action are and the utility for its therapeutic efficacy.
To warrant completeness, a systematic search according to the PRISMA statement was conducted in order to retrieve all data on STW 5 or its trade name (Iberogast), using PubMed, Toxlit and BIOSIS. Identification of data on the mechanisms of action was then done manually. In addition hand searching was done and text books were screened to get a complete picture.
The search identified 468 publications. A considerable number of publications on spasmolytic as well as prokinetic activities could be identified, as well as on prosecretory effects. Furthermore data showing that the product can counteract inflammatory changes as well as an intestinal hypersenstitivity and hyperpermeability were also found. Even a beneficial effect on the microbiota was described. Accordingly, the product has a multitude of mechanisms of action.
In IBS, a number of therapeutic options with different mechanisms of action are used. A search for the mechanisms of action of a herbal treatment used in this indication (STW 5) revealed not just one, but a multitude of mechanisms of action. This confirms for this product, that its action in IBS can be classified as multi-target, and makes its therapeutic efficacy in this indication plausible.
References
[1] Layer et al. 2011. Z Gastroenterol 49:237-93.
[2] Ivashkin et al. 2017. Ross z gastroenterol gepatol koloproktol 27:76-93
[3] Stanghellini V et al. 2016. Gastroenterology 150:1380-1392;