EFFECT OF THE CRUDE EXTRACT OF EVODIAE-FRUCTUS ON THE INTESTINAL TRANSIT IN MICE

One of the uses of Evodiae Fructus (EF, the dried, unripe fruit of Evo dia rutaecarpa) in Chinese medicine is recommended in diarrhea, but it s underlying mechanism has not yet been studied. The present study exa mined the effect of an aqueous extract of EF on the intestinal transit in mice by the charcoal meal method. Intraperitoneal administration ( i.p.) of EF (1.9 - 30 g/kg) significantly inhibited the intestinal tra nsit in a dose- and time-dependent manner. This inhibitory effect of E F was not attenuated by the i.p. pretreatment with an alpha(2)-, alpha (1)-, or beta-adrenoceptor antagonist, i.e. yohimbine (10 mg/kg), praz osin (2 mg/kg), or propranolol (6 mg/kg), respectively. In the isolate d mouse duodenum, jejunum, and ileum preparations, EF (10 - 50 mg/ml) concentration-dependently abolished 10 mu M carbachol-induced contract ion with an IC50 of 9.9, 11.7, and 16.3 mg/ml, respectively. This inhi bitory effect was not competitive. Receptor binding assay showed that EF (1 - 50 mg/ml) significantly competed with [H-3]-N-methylscopolamin e for specific binding to muscarinic receptors on the duodenum, jejunu m, and ileum membrane preparations with a K-i value of 7.1, 8.4, and 1 4.4 mg/ml, respectively Therefore, the above results suggested that th e inhibitory effect of EF on intestinal transit was probably via an ac tion directly on the muscarinic receptors but not on the alpha(2), alp ha(1)-, and beta-adrenoceptors in the small intestine.