Prokinetic activity of an aqueous extract from dried immature fruit of Poncirus trifoliata (L.) Raf.

Aqueous extracts from dried immature fruit of Poncirus trifoliata Raf. (Rutaceae) (PF-W) are used as a traditional Korean folk medicine for the treatment of digestive dysfunction. In the present study, PF-W exhibited no significant toxicity even at a dose of 5 g/kg when orally administered to mice. The effect of PF-W on gastrointestinal (GI) motor function was investigated by examining its effect on the serum concentration of orally administered ranitidine, a putative indicator of GI motility, in human subjects. The area under the serum concentration-time curve and the peak serum concentration of ranitidine following an oral administration (300 mg/individual) were decreased by one half as the result of a predose (10 g/individual) of PF-W, except for the time to reach peak serum concentration and the serum half-life at the terminal phase of ranitidine. In rat studies, PF-W had no effect on the apparent permeability of ranitidine across the jejunum or the gastric emptying rate (GER) of phenol red. However, the transit time for charcoal in the intestine was significantly increased by the PF-W pretreatment. The above results are consistent with the hypothesis that PF-W has a unique prokinetic activity, which accelerates the transit of intestinal contents, but has no effect on the GER.