Genkwadane F—I, New Daphnane‐type Diterpenes from the Flower Buds of Daphne genkwa Sieb.et Zucc. Exhibit Anti‐tumor Activities via Inducing Apoptosis

of main observation and conclusion Genkwadane F-I (1-4), four new diterpenes, along with four known ones (5-8), were isolated from the flower buds ofD. genkwa. The structures including absolute configurations of1-4were determined based on the analysis of NMR and ECD calculations. All compounds were evaluated for their cytotoxicities against MCF-7 and Hep3B cell lines, among which compounds3and4showed significant activities. Compound4exhibited the most potent activity with IC(50)values of 1.33 mu M against MCF-7, and the IC(50)values of compound3against MCF-7 and Hep3B were 5.54 mu M and 8.73 mu M, respectively. Further studies by Hoechst 33258 staining and Annexin V/PI analysis demonstrated that compounds3and4could induce apoptosis to exhibit anti-tumor activities.