Effects of wogonoside on cell cycle progression and related proteins. (A) Shown is a representative cell cycle analysis performed by flow cytometry of U937 and HL-60 cells treated with 50, 100, and 150 μM wogonoside for 48 hours. (B) The percentages of cells in the G₀/G₁ phases of the cell cycle after wogonoside treatment of 48 hours are shown. Data represent mean ± SEM from 3 independent experiments. Asterisks denote statistically significant (P < .05) differences compared with controls by one-way ANOVA. (C) Expression levels of CDK4, CDK2, cyclin D1, cyclin E, cyclin A, and p16 were analyzed by western blotting after treatment of 48 hours. β-actin was used as a loading control. Results are representative of 3 independent experiments.