Cytotoxic prenylated flavones from the stem and root bark of Daphne giraldii

Three new prenylated flavones (1–3), along with three known analogues (4–6), were isolated from the stem and root bark of Daphne giraldii. Their structures were determined by comprehensive NMR and HRESIMS spectroscopic data analyses. The absolute configurations of compounds 2 and 3 were assigned by optical rotation comparison, CD and [Rh2(OCOCF3)4]-induced CD spectral methods. The in vitro cytotoxicity experiments carried out involving five cancer cell lines (U251, A549, HepG2, MCF-7 and Bcap37) showed that 2 markedly inhibited the proliferation of all tested cells with IC50 values ranging from 4.26 to 20.82 μM. The preliminary structure–activity relationships of these flavones are discussed. In addition, compound 2 was found to effectively induce apoptosis in HepG2 cells according to a flow cytometry analysis.

Figure optionsDownload as PowerPoint slide