Anti-diarrhoeal effects of seirogan in the rat small intestine and colon examined in vitro

Abstract

Background: Seirogan is a beechwood extract composed of guaiacol, creosol and other related phenolic compounds which is widely used as an anti-diarrhoeal agent in Asia. Abnormalities in water and electrolyte transport are often the cause of diarrhoea, but the mechanism of action of seirogan on small intestinal and colonic mucosal ion transport is unknown. Aim: To examine the effect of seirogan on electrogenic ion transport in vitro. Methods: Sheets of rat jejunum and colon were mounted in Ussing chambers, and transmural potential difference (PD) was used as an electrical marker of changes in mucosal ion transport. Hypersecretory conditions were induced by acetylcholine (ACh). Results: Serosal or mucosal application of seirogan (0.1-100 μg/mL) decreased basal jejunal transmural PD. Pre-treatment of the tissue with the neurotoxin, tetrodotoxin, did not inhibit the seirogan-induced changes in basal electrical activity. Seirogan had no effect on basal transmural PD in the ileum and colon. Under ACh-induced hypersecretory conditions in the small intestine and colon, addition of serosal or mucosal seirogan produced antisecretory effects determined indirectly by measurement of transmural PD. Conclusion: The ability of seirogan to decrease basal transmural PD in the jejunum, and inhibit the ACh-induced electrical responses, may contribute to its anti-diarrhoeal action.