Planta Med 2010; 76 - P618
DOI: 10.1055/s-0030-1264916

Iberis amara L. constituents reduce excitatory cholinergic and inhibitory purinergic neurotransmission

A Sibaev 1, B Yuece 1, O Kelber 2, S Okpanyi 2, M Storr 3
  • 1Department of Internal Medicine II, Ludwig Maximilians University Munich, Klinikum Großhadern, Marchioninistr. 15, 81377 Munich, Germany
  • 2Scientific Department, Steigerwald Arzneimittelwerk GmbH, Havelstr. 5, 64295 Darmstadt, Germany
  • 3Department of Medicine, Division of Gastroenterology, University of Calgary, 6D56, TRW Building, 3280 Hospital Drive N.W., AB T2N 4N1 Calgary, Canada

An extract of Iberis amara L. (extraction solvent ethanol 50%, 1:1.5–2.5) is, together with eight other herbal extracts, component of STW 5 (Iberogast®), a phytomedicine with clinically proven efficacy and safety in functional gastrointestinal diseases (1, 2). The objective of this study was to evaluate the pharmacological effects of Iberis amara and some if its characteristic constituents (glucoiberin, kaempferol, cucurbitacin E and I, and kaempferol-3,4′-diglucopyranoside-7-O-rhamnopyranoside) on cholinergic neurotransmission in the enteric nervous system of rat and mouse. Cholinergic contractions of isolated muscle strips of ileum were studied in an organ bath. Myenteric reflex responses elicited by EFS were studied in a perfused organ bath using a four inch long ileum segment. Intracellular recordings of EJP and IJP in smooth muscle cells of the circular muscle layer of the proximal colon were performed. Iberis amara and its components kaempferol and cucurbitacin E reduced cholinergic contractions in organ bath studies in a concentration dependent manner. Kaempferol and the cucurbitacins E and I reduced the amplitude and latency of ascending and descending myenteric reflex contractions in a concentration dependent manner. Kaempferol reduced cholinergic EJP and increased the purinergic fast part of the IJP. Thus, Iberis amara and its characteristic components interact with mechanisms of excitatory cholinergic and inhibitory purinergic neurotransmission in the enteric nervous system. Characterization of these distinct effects on gastrointestinal neurotransmission helps to understand how the combination phytomedicine STW 5 alleviates patient symptoms.

References: 1. Roesch W et al.: Phytotherapy for functional dyspepsia: A review of the clinical evidence for the herbal preparation STW 5. Phytomedicine 2006, 13, 114–121.

2. Schmulson, MJ: How safe and effective is the herbal drug STW 5 for patients with functional dyspepsia? Nature Clinical Practice Gastroenterology & Hepatology 2008, 5, 136–137.