Figure 1: Emodin and aloe-emodin inhibit breast cancer cell growth. MCF-7 cells were treated with various concentrations of emodin (a) or aloe-emodin (b) for 0 to 6 days. Cell numbers were calculated by trypan blue staining. (c–f) MCF-7 and MDA-MB-453 cells were treated with various concentrations of emodin or aloe-emodin for 4 days. Cell proliferation was determined by an MTT assay. The control cell proliferation rate was set at 1. MCF-7 cells were transiently transfected with empty vector or pCMV5-ERα and treated with 25 μM emodin (g) or aloe-emodin (h) for 4 days. The transfected efficiencies of ERα overexpression and cell numbers were detected by western blotting and trypan blue staining, respectively. The results were presented as the mean SEM. * and ** correspond to and , respectively, versus the control group or empty vector group.