Diterpenoids from the stems of Tripterygium hypoglaucum (Celastraceae) and cytotoxic evaluation

Four new diterpenoids, 2α,16α-hydroxy- ent -kauran-19,20-olide ( 1 ), isopimara-8(14),15-diene-11β,19-diol ( 2 ), isopimara-8(14),15-diene-12α,19-diol ( 3 ), and 3-oxo-14,15-dihydroxyabieta-8,11,13-trien-19-ol ( 4 ), along with seven known compounds ( 5 – 11 ) were isolated from Tripterygium hypoglaucum . Their structures were established on the basis of extensive spectroscopic analysis. Triptolide ( 5 ) and 2-epitripdiolide ( 6 ) showed significant cytotoxicity against A549, DU145, KB, KBvin and MDA-MB-231 cell lines with IC 50 values of 0.0012–0.1306 μM in vitro .