Figure 1. Chemical structure of oridonin and cytotoxic effect of oridonin alone or in combination with imatinib on SUP-B15 cells. (A) chemical structure of oridonin.B, SUP-B15 cells were incubated with 0, 5, 7.5, 10, 12.5 μM oridonin for 1 d, 3 d and 5 d. At the end of incubation, MTT methods determined the cell survival rates. Cell viability is expressed as the percentage of cell survival compared with the control. (B) SUP-B15 cells were incubated with imatinib alone or in combination with 1 μM, 2 μM and 3 μM oridonin for 72 h. At the end of incubation, MTT methods were used to determine the cell survival rates and the IC₅₀ of imatinib. (C) The cell viability treated with imatinib alone or in combination with indicated concentration of oridonin for 72 h. D,The IC₅₀ of imatinib alone or in combination with indicated concentration of oridonin for 72 h. Data were from three independent experiments. *p < 0.05 was used to compare the effects of compounds.