AB4 inhibits SMMC7721 cell proliferation. A. The chemical structures of AB4. B. SMMC7721 cells were treated with ascending concentrations of AB4 (5, 10, 20, 40, 80, 160, 320 μM) for different time periods (24, 48 and 72 h) and cell viability was determined by CCK-8. C and D. Representative images of cell colonies after AB4 treatment. Cells were treated with AB4 (20, 40, 80 μM) for about 14 days, and cell colonies were stained crystal violet and analyzed. **P < 0.01 versus the control group.