Objective: To study the effect and mechanism of beta-elemene in vivo and in vitro. Method: The in vitro effects of beta-elemene(12.5-200 μmol·L-1) on human lung cancer SPC-A-1 cell line

A549 cells and human diploid fibroblasts MRC-5 cell proliferation were observed by MTT method;the morphological changes of apoptotic cells were detected by Hoechst 33258;the cells stained by Annexin V and propidium iodide (PI)were observed by flow cytometry for apoptosis

cell morphological changes were observed by electron microscope. Its in vivo anti-tumor effect on transplanted human SPC-A-1 tumor cells in nude mice was detected by conventional methods. Result: Fifty percent inhibition concentration(IC50) of the above-mentioned 2 kinds of lung cancer cells by beta-elemene was 126.0

134.1 μmol·L-1

but the effect on human diploid fibroblasts MRC-5 cells was promoting growth. The inhibition effects of beta-elemene on human lung cancer cell line SPC-A-1 depended on the duration and concentrations. IC50 at the 24

48

72 h was 549.7

126.0

21.2 μmol·L-1

respectively. Apoptotic body in apoptotic cells could be observed by Hoechst 33258 dying. Flow cytometry showed that beta-elemene could induce SPC-A-1 cell apoptosis distinctly at different levels.The growth inhibition rates of beta-elemene (45

135 mg·kg-1) on transplanted human lung cancer cell line SPC-A-1 cells in vivo were 34.01%

49.57%. Conclusion: Beta-elemene has an antitumor effect between 12.5-200 μmol·L-1.The mechanism of anti-tumor effect is possibly achieved by inducing apoptosis of tumor cells.