Effects of magnolol on the cell cycle phases distribution in A431 cells. (A) Cell cycle histograms. Cells were treated with magnolol (0, 75, 100 and 125 μM) for 12 h. At the end of the treatment, cells were harvested and digested with RNase. Cellular DNA was stained with propidium iodide and analyzed by flow cytometer as described in the Materials and Methods. (B) Data from the cell cycle distribution histograms were summarized into a bar graph and presented as the mean ± SE of three observations. *p < 0.05 indicates statistical significance in magnolol treated groups as compared to the control.