ABCB1 and leukemia: The recorded IC50 values ranged from 11.43 μg/mL (against the P-glycoprotein (gp)-overexpressing CEM/ADR5000 leukemia cells) to 26.75 μg/mL (against HCT116 (p53+/+) colon adenocarcinoma cells) for the crude extract HRB.