Cytotoxic Triterpenes From Salacia Crassifolia And Metabolite Profiling Of Celastraceae Species

The new pentacyclic triterpene 11 beta-hydroxypristimerin (1), along with the known metabolites pristimerin (2), 6-oxopristimerol (3) and vitideasin (4), were isolated from a Salacia crassifolia 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 2 was the most active, with a mean GI(50) of 0.17 mu M, while compound 1 had a mean GI(50) of 8.7 mu M. 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(50) of 0.3 mu g . mL(-1)). A targeted search for pristimerin and related derivatives using LC-MS/ MS revealed the presence of pristimerin (2) and 6-oxopristimerol (3) in all Celastraceae species examined and in all plant parts tested, while vitideasin (4) was only detected in the genus Salacia.