Germacranolide sesquiterpenes from Carpesium cernuum and their anti-leukemia activity

In this study, three new germacranolide sesquiterpenes (1–3), together with six related known analogues (4–9) were isolated from the whole plant of Carpesium cernuum. Their structures were established by a combination of extensive NMR spectroscopic analysis, HR-ESIMS data, and ECD calculations. The anti-leukemia activities of all compounds towards three cell lines (HEL, KG-1a, and K562) were evaluated in vitro. Compounds 1–3 exhibited moderate cytotoxicity with IC50 values ranging from 1.59 to 5.47 μmol·L−1. Mechanistic studies indicated that 2 induced apoptosis by decreasing anti-apoptotic protein Bcl-2 and activating the caspase family in K562 cells. These results suggest that compound 2 is a potential anti-leukemia agent.