Radish extract stimulates motility of the intestine via the muscarinic receptors

The effects of radish (Brassica oleraceae, Cruciferae) on gastrointestinal motility were examined using rat intestinal segments with myenteric plexus in-vitro and measuring the intestinal transit of charcoal in-vivo. Radish e xtract (10 mu g mL(-1) to 2 mg mL(-1)) caused a dose-dependent increase in contractions of the duodenum, jejunum and ileum, and 1 mg mL(-1) was the ma ximum effective dose, The largest contraction by the extract was found in i leal segments. The extract-induced (0.5 mg mL(-1)) ileal contraction was re markably inhibited by pretreatment of segments with atropine (10(-7) M) for 10 min, but not by hexamethonium (0.5 mM), Moreover, antagonists of the mu scarinic receptor reduced the radish-induced ileal contraction by a differe nt ratio. The rank order of inhibitory effects was 4-diphenylacetoxy-N-meth yl-(2-chloroethyl)-piperidine methiodide (90.5% of control)> tropicamide (6 7.4%) > pirenzepine (42.8%)> methoctramine (16.7%). Oral administration of radish extract (300-500 mg kg(-1) body weight) to mice remarkably improved the intestinal transit of charcoal, and this was significantly attenuated b y co-administration of atropine (50 mg kg(-1)). Taken together, these resul ts suggest that radish extract stimulates gastrointestinal motility through activation of muscarinic pathways.