Figure 5. MP [4-(3′,3′-dimethylallyloxy)-5-methyl-6-methoxyphthalide] caused cell cycle arrest in G1 phase. HeLa cells were treated with DMSO (0.05%) or 10, 20 and 40 μg/mL MP for 24 h, stained with propidium iodide, and their DNA content analyzed using flow cytometry. Each value represents the average of three independent experiments.