Effects of dried Citrus unshiu peels on gastrointestinal motility in rodents

Aqueous extracts of the dried mature (ANP-W) and immature Citrus unshiu peels (CUP-W) have been used as a traditional folk medicine for the treatment of gastrointestinal (GI) motility disorders in Korea. In the present study, neither ANP-W nor CUP-W exhibited significant toxicity even at an oral dose of 5 g/kg to mice. The effects of ANP-W and CUP-W on GI motor function were investigated by measuring the intestinal transit rate (ITR) of Evans blue in normal mice and rats with experimental GI motility dysfunctions (GMDs). In normal mice, the ITR was significantly increased by ANP-W (0.1-1 g/kg) in a dose dependent manner, whereas CUP-W elicited no significant change. GMD was induced by appropriate surgery or an intraperitoneal injection of acetic acid to the rats. The ITR in the GMD rats was significantly retarded compared to that in normal rats. However, the retardation was significantly inhibited by ANP-W (0.1-1 g/kg) in a dose dependent manner. The above results suggest that ANP-W has the potential for development as a prokinetic agent that may prevent or alleviate GMD in human patients.