Novel C-17 spirost protostane-type triterpenoids from with anti-inflammatory activity in Caco-2 cells.

Twenty-one protostane-type triterpenoids with diverse structures, including nine new compounds (-), were isolated from the of Linn. Structurally, alisolides A‒F (-), composed of an oxole group coupled to a five-membered ring, represent unusual C-17 spirost protostane-type triterpenoids. Alisolide H () is a novel triterpenoid with an unreported endoperoxide bridge. Alisolide I () represents the first example of 23,24-acetal triterpenoid. Their structures were elucidated based on spectroscopic analysis, wherein the absolute configurations of ‒, were further confirmed by the Mo(OAc)-induced ECD method. Furthermore, all isolates were evaluated for their inhibitory effects on LPS-induced NO production in Caco-2 cells, and all the compounds showed remarkable inhibitory activities, with IC values in the range of 0.76-38.20 μmol/L.