Isolation and identification of terpenoids from chicory roots and their inhibitory activities against yeast α-glucosidase

Chicory (Cichorium intybus L. var. sativum L., Asteraceae) is a multipurpose plant cultivated as vegetable and coffee substitute in Europe and North America, also as folk medicine in China. The extracts from chicory roots showed significant effect on inhibition against alpha-glucosidase. By a bioassay-guided approach, the chemical fraction with high alpha-glucosidase inhibition was found and its chemical profile was tentatively described by UPLC-Q-TOF/MS to include 28 compounds. Further chemical isolation yielded six compounds, their chemical structures were elucidated as 11 beta-13-dihydrolactucin (1), lactucin (2), 8-deoxylactucin (3), jacquinelin (4), 11 beta,13-dihydrolactucopicrin (5) and lactucopicrin (6), and among them, the compound 4 showed the strongest inhibitory activity against yeast alpha-glucosidase with IC50 value of 4.180 mu M. The present results suggest that chicory roots can eventually exhibit anti-diabetic effect and the sesquiterpenes may be responsible for the activity.