Inhibitory effects of zingerone, a pungent component of Zingiber officinale Roscoe, on colonic motility in rats

Ginger (rhizome of Zingiber officinale Roscoe) is an herbal medicine for the treatment of gastrointestinal disorders including constipation and diarrhea. Zingerone is a likely active constituent responsible for the antidiarrheal activity of ginger. The current study was designed to characterize pharmacological actions of zingerone on colonic motility. To evaluate pharmacological effects of zingerone on colonic motility, we used isolated colonic segments from rats, in which mechanical responses were recorded in the longitudinal direction. In addition, we evaluated the effects on colonic motility in vivo by measuring intraluminal pressure changes and expelled fluid volume from the colon in anesthetized rats. Zingerone was applied to the lumen of the colon to allow the drug to access from the mucosal side. Zingerone inhibited spontaneous contractile movements in the isolated colonic segments in a dose-dependent manner. The inhibitory effects of zingerone on colonic movements were not affected by pretreatment with capsazepine, a typical antagonist of transient receptor potential vanilloid 1. In addition, tetrodotoxin, a blocker of voltage-dependent sodium channels on neurons, did not affect the suppression of colonic movements by zingerone, suggesting that zingerone acts on the smooth muscles directly. Zingerone also attenuated colonic motility in vivo without affecting blood pressure and heart rate. The effects were reversible and reproducible. Our findings suggest that zingerone can inhibit colonic motility via direct action on smooth muscles. Zingerone might exert beneficial therapeutic effects on hypermotility-induced diarrhea by abrogating excessive gastrointestinal motility.