New triterpenoid saponins with strong α-glucosidase inhibitory activity from the roots of Gypsophila oldhamiana

Seven new triterpenoid saponins (1-7), have been isolated and elucidated from the roots of Gypsophila oldhamiana together with five known triterpenoid saponins (8-12). These saponins which could be classified into three series: 3-O-monoglucosides (1, 8, 9), 28-O-monoglucosides (24, 12) and 3, 28-O-bidesmosides (5-7, 10, 11), have been evaluated for their a-glucosidase inhibition activity. As a result, the preliminary structure-activity relationships were discussed based on the position of sugar linkage attached to the aglycone, and 28-O-monoglucosides 2-4 and 12 showed significant inhibitory activities on a-glucosidase. (C) 2008 Elsevier Ltd. All rights reserved.