Effects of HHT and its five components on PDGF-induced VSMC proliferation. (A) Cytotoxicity of HHT and its five components in VSMCs. Cells were incubated with the indicated concentrations for 24 h. Cell viability was determined by using the CCK-8 assay. (B) Antiproliferative effects of HHT and its five components in PDGF-treated VSMCs. Quiescent VSMCs were stimulated with PDGF-BB (10 ng/mL) in the presence of the indicated concentrations of samples for 24 h and the proliferation was examined by using the CCK-8 assay. Geniposide (1), baicalin (2), coptisine (3), palmatine (4), and berberine (5). The data are mean values of three experiments ± SEM (n = 3). **P < 0.01 compared with the control group, #P < 0.05, ##P < 0.01 compared with the PDGF group.