Chemical constituents from Daphne tangutica and their cytotoxicity against nasopharyngeal carcinoma cells

Abstract Two new sesquiterpenoids ( 1 − 2 ), together with 30 known compounds including one sesquiterpenoid ( 3 ), six diterpenoids ( 4 − 9 ), fourteen lignans ( 10 − 23 ), and nine other kinds of compounds ( 24 − 32 ), were isolated from the stems of Daphne tangutica Maxim. Their structures were determined through extensive spectroscopic analyses, and the absolute configuration of daphnoid A ( 1 ) and B ( 2 ) were determined by the experimental and calculated electron circular dichroism (ECD) spectra. All the isolates were evaluated against two human nasopharyngeal carcinoma cells (HONE-1 and SUNE-1). Compound 25 (daphnenone) showed potent cytotoxicity toward HONE-1 and SUNE-1with IC 50 values of 2.23 and 1.43 μM, respectively. Further studies indicated that compound 25 exhibited cytotoxic effects by inducing tumor cell apoptosis and arresting the cell cycle at G2/M phases in HONE-1 cells.