Effect of AL on endothelial cell proliferation in vitro . A, the structure of Aloin. B, treatment with AL significantly inhibited VEGF-induced HUVECs proliferation in dose-dependent manner as described in “Materials and methods.” C, effects of AL on HUVECs viability under normal culture condition. Cell viability was quantified by MTT assay. The bars represent triplicate analysis.**, P < 0.01; ***, P < 0.001 vs. control.