Herbal medicine in bowel diseases: Mechanisms of action of STW 5 in colonic inflammation
Phytomedicine is a successful therapeutic approach in functional dyspepsia and irritable bowel syndrome, diseases often triggered by inflammatory processes. Earlier pharmacological studies showed that STW 5 (Iberogast®), a phytomedicine with clinically proven efficacy in these functional gastrointestinal diseases and excellent therapeutic safety and tolerability [1, 2], has a marked anti-inflammatory effect [3, 4, 5, 6]. To explore further the anti-inflammatory activity of the drug, it was tested in an in vivo experimental model for inflammatory bowel disease. Male rats were injected intra-colonically with 10mg/kg trinitro benzene sulfonic acid (TNBS) in 50% ethanol under light ether anaesthesia. This induced the development of lesions, which were then examined macroscopically 4 days later. STW 5 was given orally in different dose levels (0.5–5ml/kg) for 1 week before TNBS and for the 4 days to follow. Macroscopically, the drug markedly reduced the area of lesions and colonic and spleen mass indices. Biochemically, it prevented changes in myeloperoxidase activity and reduced glutathione levels in the colon. The drug also protected against changes in the level of various relevant mediators, including ICAM-1, TNFα, IL-1β, IL-10, LTB4, and PGE2 in both blood and colonic tissue. The effect was comparable to that of sulfasalazine, 300mg/kg, which was used as reference drug in the same manner as STW 5. The beneficial effect of STW 5 was dose dependent. A positive correlation was observed between the therapeutic efficacy of STW 5 and the effect on the measured mediators. The protective value of STW 5 was further confirmed by histopathological examination of the colon. The findings allow the conclusion on a therapeutic potential of STW 5 (Iberogast®) in inflammatory conditions of the lower gastrointestinal tract, relevant also for its established therapeutic effect in functional gastrointestinal diseases.
References: 1. Schmulson MJ (2008) Nature Clin Pract Gastroenterol Hepatol 5:136–137; 2. Rösch W et al. (2006) Phytomedicine 13 SV 114–121; 3. Okpanyi SN (1993) Planta Med 59:A665; 4. Schempp H (2006) Phytomedicine 13 SV: 36–44; 5. Michael S (2007) Gastroenterol 132 S2:577; 6. Abdel-Aziz H (2008) Z Phytotherapie 29: S4