Effects of morroniside isolated from Cornus officinalis fruits on functional gastrointestinal disorders and gastric ulcer in mice

The dried fruits of Cornus officinalis (Cornaceae) are used in Kampo medicine (e.g. Hachimigan and Goshajinkigan) to treat senile osteoporosis, diabetes, gastric atony, frequent urination, and diarrhea/constipation associated with aging. The present study investigated the effects of a C. officinalis fruit extract and morroniside, an iridoid compound from isolated these fruits, on the reduction in gastric emptying small intestinal motility caused by 5-hydroxytryptamine (5-HT) and 1-(3-chlorophenyl) biguanide (5-HT₃ receptor agonist), and gastric ulcers induced by 150 or 75 mM HCl/90 % EtOH (HCl-EtOH) and/or 5-HT in mice. C. officinalis extract (500 mg/kg) and morroniside (20 and 50 mg/kg) suppressed the reduction in gastric emptying induced by 5-HT- and 5-HT₃ agonist. C. officinalis extract, morroniside and 5-HT₃ receptor antagonist (ramosetron) attenuated 5-HT-induced diarrhea. Furthermore, morroniside (20 and 50 mg/kg) prevented EtOH/HCl-induced gastric ulcers and those caused by 5-HT. Morroniside (20 and 50 mg/kg) attenuated elevations in the plasma levels of corticosterone, corticotropin-releasing factor (CRF), and adrenocorticotropic hormone (ACTH) in 75 mM HCl/90 % EtOH- and 5-HT-treated mice. The results obtained herein suggest the potential of morroniside as an effective treatment for irritable bowel syndrome, such as diarrhea and functional dyspepsia (reductions in gastric emptying and small intestinal motility), caused by 5-HT. The present study suggests a role for morroniside in the regulation of elevations in CRF, ACTH, and corticosterone levels through hypothalamic-pituitary-adrenal axis activity induced by stress loading, such as a 5-HT treatment and/or HCl/EtOH stimulation.