Effects of oleanolic acid glycosides on gastrointestinal transit and ileus in mice

The effects of various oleanolic acid glycosides obtained from medicinal herbs on gastrointestinal transit (GIT) and ileus were investigated in fasted mice. Ileus was induced by the peritoneal-irritation or by the laparotomy with manipulation. One hour after the oral administration, three oleanolic acid 3-O-monodesmosides (oleanolic acid 3-O-glucuronide (3, 50 mg/kg), momordin Ic (4, 25 and 50 mg/kg), and momordin I (6, 25 mg/kg)) significantly accelerated GIT, but two oleanolic acid 3-O-monodesmosides (28-deglucosyl-chikusetsusaponins IV (8) and V (10)), oleanolic acid 3,28-O-bisdesmosides (momordin IIc (5), chikusetsusaponins IV (7) and V (9)), and their common aglycon (oleanolic acid (1)) (50 mg/kg) showed no significant effect. On the other hand, oleanolic acid 28-O-monodesmoside (compound O (2, 50 mg/kg)) significantly inhibited GIT. 4 (5-25 mg/kg) and 6 (12.5 and 25 mg/kg) also significantly prevented the inhibition of GIT induced by the peritoneal injection of acetic acid. 2 and 9 (50 mg/kg) significantly potentiated the inhibition of GIT, whereas 1, 3, 5, 7, 8, and 10 (50 mg/kg) showed no significant effect. 3, 4, 6, and 10 (50 mg/kg) significantly prevented the inhibition of GIT induced by laparotomy with manipulation, while 1, 2, 5, 7, 8, and 9 (50 mg/kg) showed no significant effect. These results indicate that the 3-O-glycoside moiety seems to be essential to show the GIT accelerating activity, and the 28-O-glucoside moiety reduce the activity. The accelerations of GIT by 3, 4, and 6 were completely abolished by the pretreatment with streptozotocin (100 mg/kg, i.v.), but not by the pretreatment with capsaicin (75 mg/kg in total, s.c.). These results suggest that sympathetic nervous system, but not capsaicin-sensitive sensory nerves, be involved in the enhancements of GIT by 3, 4, and 6. It is worthy to study their therapeutical effect in the prevention of the inhibition of GIT, including ileus, in clinic.