Antitumor effect of FA-HP-β-CyD. (a,b) Antitumor activity of FA-HP-β-CyD (0, 0.05, 0.1, 0.25, 0.5, and 1.0 mM) in K562 and BV173 cells. Cells were incubated with FA-HP-β-CyD for 72 h at 37 °C. (c) Antitumor activity of FA-HP-β-CyD and HP-β-CyD in A549 cells. Cells were incubated with 0, 2.5, 5, 7.5, and 10 mM of FA-HP-β-CyD or HP-β-CyD for 72 h at 37 °C. (d,e) Treatment with FA-HP-β-CyD in the presence or absence of FA. K562 and BV173 cells were incubated for 2 h at 37 °C with medium only (control), medium containing FA-HP-β-CyD (5 mM) and HP-β-CyD (5 mM) in the absence and presence of FA (2 mM). Each value represents the mean ± SEM of three experiments. * p < 0.05. The cell number ratio is the number of cells calculated with the number of cells in the control as 1.