THE MECHANISM OF PURGATIVE ACTION OF GENIPOSIDE, AN IRIDOID GLUCOSIDE OF THE FRUIT OF GARDENIA, IN MICE

Abstract

Geniposide, an iridoid glucoside of the fruit of Gardenia spp., was found to cause diarrhea in mice through the oral administration, while, not through the parenteral injection. It was then found that this glucoside caused a propulsive action in the large intestine by examining the movement and the evacuation of a charcoal meal in the intestines. After an oral dosage of geniposide, the aglucone genipin was detected in all the gastrointestinal segments especially in the cecum and the colon. Direct injection of genipin into the cecum through a cecal tubing remarkably reduced the time required for the onset of diarrhea compared with the case of the injection of geniposide. 2',3'–Dimethyl ether of geniposide did not show the purgative action presumably because of the resistance to the enzymatic hydrolysis in the intestines. Accordingly, it has been concluded that genipin, a hydrolysate of geniposide, is effective and act as a propulsive agent in the large intestine. However, the direct action of genipin to the isolated mouse intestine has not yet been observed.