Triterpenoid alkaloids from Buxus rugulosa and their cytotoxic activities

Phytochemical study of the twigs and leaves of Buxus rugulosa resulted in the isolation of eight triterpenoid alkaloids, including four new triterpenoid alkaloids, namely buxruguloids A-D (1-4), together with four known analogues 5-8. The structures of 1-4 were identified by the analysis of NMR and MS spectroscopic data. All the new compounds were assessed in vitro for their cytotoxic activities against five human tumor cell lines (HCT-116, HT-29, A549, MCF-7 and SW480). It turned out that compound 2 exhibited remarkable cytotoxic activities against these five cell lines with IC50 value ranged from 2.5-12.3 mu M, respectively.