Figure 4. Effect of P-glycoprotein (P-gp) inhibitor on BBR uptake in HepG2, HeLa and SY5Y cells.

Cells were treated with 0.5 µg/ml BBR and 0.3 µmol Zosuquidar, the inhibitor of P-gp activity, for 12 h. The intracellular concentrations of BBR were determined by HPLC assay. Data are presented as mean ± S.D from three independent experiments (n = 3). * v.s. the control, P<0.05. ** v.s. the control, P<0.005, t-test.