Planta Med 2009; 75 - PD33
DOI: 10.1055/s-0029-1234512

Effects of STW 5 and its components on viability of Caco-2 cells

M Schwalbe 1, S Oehme 2, G Abraham 2, FR Ungemach 2, D Weiser 3, O Kelber 3, K Nieber 1
  • 1University of Leipzig, Institute of Pharmacy, D-04103 Leipzig, Germany
  • 2University of Leipzig, Faculty of Veterinary Medicine, Institute of Pharmacology, Pharmacy and Toxicology, D-04103 Leipzig, Germany
  • 3Steigerwald Arzneimittelwerk GmbH, D- 64295 Darmstadt, Germany

Herbal preparations like STW 5 (Iberogast®) are widely used in treatment of dyspepsia and motility-related disorders of the gastrointestinal tract. STW 5 is a fixed combination of nine individual plant extracts, containing 15% Iberis amara fresh plant extract (STW 6) and showing a very good efficacy and tolerability in a large number of clinical and preclinical studies. In order to characterize the mode of action STW 5, STW 6 as well as cucurbitacines E and I, belonging to the phytochemical constituents of STW 6, were tested on the Caco-2 model to determine cell viability using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay. The effects were tested time-dependently, 0.5, 1, 3 and 24 hours, after substance application. Short-term incubation of cells with STW 5 (0.5, 1h) increased cell viability highly in a concentration-dependent manner, but moderately within 3 hours. After long-term incubation (24h) the viability was maximum stimulated by 256µg/ml STW 5, whereas high concentrations reduced cell viability concentration-dependently. STW 6 as well as cucurbitacine I (0.01–100µM) did not influence the cell viability. Cucurbitacin E (0.1–100µM) had no effect after short-term incubation (0.5, 1h) but reduced the cell viability at high concentration (50–100µM) after long-term incubation (24h). The present data indicate: (1) STW 5 is able to increase cell viability of epithelial cells in vitro, suggesting this mechanism may contribute to the protective effect against morphological changes seen in an experimental model of intestinal inflammation; (2) STW 5 did not affect the integrity of epithelial cells at concentrations of 512µg/ml and below, not even at long-term incubation; (3) cucurbitacin E had no effect in relevant concentrations. Taken together, these results are in accordance to the well-characterized tolerability of STW 5 and in addition give information on the mechanisms of action involved in its mucosa-protective effects.