New iridal-type triterpenoid derivatives with cytotoxic activities from Belamcanda chinensis

Eight new iridal-type triterpenoid derivatives, including two noriridals with ether bridge (1-2); two iridals lactone (3-4), four monocyclic iridals (5-8), together with five known iridals (9-14) were identified from the rhizome of Belamcanda chinensis. Their structures were elucidated on the basis of comprehensive spectroscopic methods and electronic circular dichroism (ECD) calculations. Bioassay results showed that belamcanoxide B (1) exhibited moderated cytotoxic activities against HCT-116 and MCF-7 cell lines with IC50 values of 5.58 and 3.35 μM.