Seco-dammarane triterpenoids from the leaves of Cyclocarya paliurus.

The leaves of Cyclocarya paliurus with sweet taste are often used as herbal tea in People's Republic of China. In this study eight previously undescribed seco-dammarane type triterpenoids, cyclocariols A-H along with seven known compounds were isolated and characterized from its leaves. A possible biogenetic pathway for seco-dammarane type triterpenoids formation has been discussed. Cyclocariols A-H were evaluated for their cytotoxicities against human liver (SMMC-7721) and breast cancer (BT-549) cell lines. Cyclocariols A, B, E, and H were also tested against human colon tumor (HCT-116) cell lines, where all four exhibited good activities with IC50 values of 6.53, 4.94, 8.24, and 6.48 μM, respectively.