The results revealed that TD and LB showed specific cytotoxicity against MDA-MB-231 and MCF-7 cells. To elucidate mode of cell death via cytotoxic activities, breast cancer cell lines were treated. TD and LB induced MDA-MB-231 and MCF-7 cells to apoptosis, with the highest number of apoptotic cells at 24 and 72h, respectively. Furthermore, TD and LB inhibited cell cycle progression via up-regulation of p21. Both compounds stimulated apoptosis through down-regulation of bcl-2, up-regulation of bax and releasing of cytochrome C proteins.