Cytotoxic 3,4-<i>seco</i>-Cycloartane Triterpenes from <i>Gardenia sootepensis</i>

Five new 3,4-seco-cycloartanes, sootepins A−E (1−5), along with four known triterpenes (6−9), were isolated from the apical buds of Gardenia sootepensis. Their structures were elucidated on the basis of spectroscopic methods (1D and 2D NMR, HRESIMS, and X-ray crystallography), and the compounds were tested for in vitro cytotoxic activity against human breast (BT474), lung (CHAGO), liver (Hep-G2), gastric (KATO-3), and colon (SW-620) cancer cell lines. Generally, the compounds possessing an exomethylene γ-lactone ring showed broad cytotoxicity for all cell lines tested.