Three new 3,4-seco-cycloartane triterpenoids (1-3), including an unusual C-1 oxygenated 3,4-seco-cycloartane triterpenoid lactone (3), along with six known triterpenoids, were isolated from 95% ethanol extract of the flower of Gardenia jasminoides. Their structures were determined by spectroscopic methods, especially 2D NMR and HRESIMS techniques. Compounds 3, 4 (dikamaliartane D), and 7 (ursolic acid) showed promising cytotoxic activity against HepG2 human hepatocellular carcinoma cell line with IC50 values of 9.3, 27.7, and 39.3 mu M, respectively.