Cytotoxic ent-abietane diterpenes from Gelonium aequoreum

Seventeen ent-abietane diterpenes, including gelomulides K-X (1-14), were isolated from the leaves of Gelonium aequoreum together with three known compounds. Their structures were elucidated by spectroscopic and chemical methods, including NMR, MS, UV, IR, CD, and Mosher's method. The in vitro cytotoxic activity of the isolated compounds was determined. Only compounds 1 and 3 showed moderate cytotoxicity against lung (A549), breast (MDA-MB-231 and MCF7), and liver (HepG2) cancer cell lines.