Cytotoxic effect of decursin against human leukemic cells. (A) Chemical structure of decursin (MW. 328). (B) Human leukemia KBM-5, HL-60 and U937 cells and human peripheral blood lymphocyte (PBL) cells were incubated with various concentrations of decursin for 24 h. Cell viability was determined by the XTT assay. The data represent mean ± S.D. Statistically significant difference was calculated by Student's t-test. *, p < 0.05, **, p < 0.01 and **, p < 0.001 versus control. (C) Western blotting was performed using cell lysates from human leukemia KBM-5, HL-60 and U937 cells with anti-PKC antibody.