The Effects of an Extract of Atractylodes Japonica Rhizome, SKI3246 on Gastrointestinal Motility in Guinea Pigs

BACKGROUND/AIMS There are limited therapeutic options available for irritable bowel syndrome with diarrhea (IBS-D). We tested the effects of Atractylodes japonica rhizome, a perennial plant native to North Asia, on both upper and lower gastrointestinal (GI) motility in guinea pigs. METHODS The extract of A. japonica rhizome was administered orally at different doses to test its effects on upper GI motility as determined from charcoal transit in native guinea pigs and in guinea pigs pretreated with thyrotropin-releasing hormone or mustard oil. Regarding its effect on lower GI motility, the removed guinea pig colon was suspended in a chamber containing Krebs-Henseleit solution and the transit time of artificial feces was measured with various dilutions of the extract. As for in vivo assay, weight and number of fecal pellets expelled were determined under the same drug preparation used in upper GI motility experiment. RESULTS The extract of A. japonica rhizome had no significant effect on upper GI motility in either normal or altered physiological states. However, the extract increased colonic transit time in the in vitro model. In the fecal expulsion study, the cumulative weight and number of pellets did not differ significantly between the control group and groups treated with the extracts. In the animals pretreated in vivo with thyrotropin-releasing hormone, however, the weight and number of fecal pellets were sig-nificantly decreased in animals treated with 300 mg/kg and 600 mg/kg doses of extract. CONCLUSIONS Our findings suggest that the extract of A. japonica rhizome can be a potential agent for IBS-D.