Cytotoxic Triterpenes from and Metabolite Profiling of Celastraceae Species.

The new pentacyclic triterpene 11-hydroxypristimerin (), along with the known metabolites pristimerin (), 6-oxopristimerol () and vitideasin (), were isolated from a root wood extract, following a bioassay-guided fractionation approach. Both the extract and the purified triterpenes displayed pronounced cytotoxic activity against human cancer cell lines. The NCI-60 cell line screen revealed that compound was the most active, with a mean GI of 0.17 μM, while compound had a mean GI of 8.7 μM. A COMPARE analysis of the screening results showed that pristimerin is likely to be the main compound responsible for the cytotoxic activity of the extract (mean GI of 0.3 μg·mL). A targeted search for pristimerin and related derivatives using LC-MS/MS revealed the presence of pristimerin () and 6-oxopristimerol () in all Celastraceae species examined and in all plant parts tested, while vitideasin () was only detected in the genus .