Structure-Related Inhibitory Activity of Oleanolic Acid Glycosides on Gastric Emptying in Mice

Abstract

We examined the effects of various oleanolic acid oligoglycosides obtained from traditional herbs on gastric emptying in non-nutrient meal- or nutrient meal-loaded mice. Test samples were given orally to fasted mice 0.5h before loading of test meals. Oleanolic acid 3-O-monodesmosides [oleanolic acid 3-O-glucuronide (3, 12.5–50mg/kg), momordin Ic (4, 25 and 50mg/kg), momordin I (6, 12.5–50mg/kg), and 28-O-deglucosyl-chikusetsusaponins IV (8, 12.5–50mg/kg) and V (10, 50mg/kg)] were found to show inhibitory effects on gastric emptying in 1.5% CMC-Na test meal-loaded mice. 4, 6, and 8 also inhibited gastric emptying in mice given 40% glucose test meal, milk test meal, and 60% ethanol test meal. 3 inhibited gastric emptying in mice given milk test meal or 60% ethanol test meal, but lacked significant inhibition in 40% glucose test meal-loaded mice. 10 (50mg/kg) also slightly inhibited gastric emptying in milk test meal-loaded mice, but lacked the significant inhibition in mice given 40% glucose or 60% ethanol test meal. Whereas oleanolic acid 3,28-O-bisdesmosides [momordin IIc (5), chikusetsusaponins IV (7) and V (9)], oleanolic acid 28-O-monodesmoside [compound O (2)], and their common aglycon [oleanolic acid (1)] showed no such effects at dose of 50mg/kg. 28-O-Deglucosyl-chikusetsusaponin V (10) showed a little inhibition in these experiments. These results indicate that both the 3-O-monodesmoside structure and 28-carboxyl group were confirmed to be essential for such activity, and the 28-ester glucoside moiety and 2′-O-β-d-glucopyranoside moiety reduce the activity. ©