Figure 3: Cytotoxic effects of compounds K1-K5 on MCF7 cells following exposure with the different concentrations (μM) of the compounds. Cell survival was determined using the MTT method. Data are presented as mean ± SD *P < 0.05 and ‘P < 0.001 indicate significant differences compared to the negative control group; and °P < 0.05 versus the lowest concentration of each compound. n = 3 × 3. Paclitaxel at 1 μM used as the positive control.