Objective:To study the effects of 17-hydroxy-jolkinolide B（HJB） on proliferation and apoptosis of U251 cells.Method:After the cells were treated with HJB at various concentrations（0

6.25

12.5

25

50

100

200

400

800 μmol·L-1）for 24 h

or at half maximal inhibitory concentration of a substance（IC50） for various durations（12

24

48

72 h）

cell viability was measured by 3-（4

5-Dimethylthiazol-2-yl）-2

5-diphenyltetrazolium bromide（MTT）.Annexin V-FITC by cytometry was used to test the apoptosis rate.Absorption spectrometry was adopt to measure the relative activity of Caspase-3 and Caspase-9.Result:The HJB evidently inhibited the growth of U251 cells in a time and dose-dependent manner（P<0.05）

with IC50value for 24 h being 62.236 11 μmol · L-1

and it could induce apoptosis of U251 cells.After HJB treatment at 30

60 and 120 μmol · L-1for 24 h

the apoptosis rate of U251 cells was 3.10%

3.51% and 5.98%

respectively（P<0.05）

and the relative activity of Caspase-3 or Caspase-9 was advanced with dose-dependent manner.Conclusion:The HJB evidently inhibits the growth of U251 and induces the apoptosis of U251.The mechanism may be mediated by mitochondrion pathways.