Fig. 1. Effect of ursolic acid (UA) on MCF-7 cell growth. (A) Chemical structure of UA. (B) Cell viability measured by MTT assays following incubation with 0, 0.01, 0.1, 1, 10, and 100 μM UA for 24, 48, and 72 h. Results are expressed as mean±SD. Statistical differences were analyzed using Student’s t-test (**P<0.01 vs. control). (C) Morphological changes. UA inhibited MCF-7 cell growth and resulted in rounded cell morphologies in a concentration-dependent manner. Cell morphology was visualized using inverted microscopy (×200). Scale bar, 50 mm. MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide.