It is aimed to investigate the cytotoxic effects of the various extracts from the leaf and seed of Centaurea derderiifolia on the growth human cervical adenocarcinoma (HeLa) cells by xCELLigence method and to isolate the cytotoxic constituents. The results showed that subfractions 2 and 3 exhibited remarkable inhibitory effect against HeLa (IC50 < 10 mu g/mL). The chloroform extract of leaf displayed the highest cytotoxic effect on HeLa cells (IC50 < 50 mu g/mL) and was therefore subjected to a bioassay-guided multistep separation procedure. The pure compounds were elucidated by spectroscopic and mass-spectrometric analyses, including 1 D-, 2 D-NMR. In addition to cytotoxic effects of the isolated constituents, their antioxidant activities were also studied. On the other hand, subfraction 4 exhibited the highest DPPH radical scavenging activity (IC50 = 0.76 +/- 0.03 mg/mL). beta-sitosterol-3-O-beta-d-glucopyranoside was isolated for the first time from this plant and three compounds from the bioactive subfractions were identified.