Fig. 5. Ursolic acid (UA) exerts cytotoxicity in MCF-7 cells and MCF-7 cell-derived breast cancer stem (BCS)-like cells. Comparison of cell viability in MCF-7 cells (A) and MCF-7 cell-derived BCS-like cells (B) by MTT assays following incubation with UA (0, 5, 10, 20, and 40 μM) for 24, 48, and 72 h. UA inhibited MCF-7 cell and MCF-7 cell-derived BCS-like cell growth in dose- and time-dependent manners compared with control cells. Results are expressed as mean±SD. Statistical differences were analyzed using Student’s t-test (*P<0.05, **P<0.01, and ***P<0.001 vs. control). MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide.