THE ANTITUMOR ACTIVITY OF ELEMENE IS ASSOCIATED WITH APOPTOSIS

Elemene, isolated from the Chinese medicinal herbRhizoma Zedoariae was shown to exhibit antitumoractivity in vitro and in vivo to human and murine tumorcells. This novel antineoplastic agent has beendemonstrated to have substantial clinical activity againstvarious tumors. In this paper, the mechanisms ofantitumor activity of elemene are reported. The in vitroeffect of elemene on the growth of leukemia cells wasevaluated by MTT assay. The IC50 values of elemene forpromyelocytic leukemia HL-60 cells and erythroleukemiaK562 cells were found to be 27.5 μg/ml and 81μg/ml,respectively, while IC50 for peripheral blood leukocytes(PBL) was 254.3 μg/ml. The inhibitory effect of elemeneon proliferation of HL-60 cells was associated with cellcycle arrest from S to G2M phase transition and withinduction of apoptosis. The apoptosis of tumor cells wasconfirmed by DNA ladder formation on gelelectrophoresis and characteristic ultrastructuralalternations. These results indicate that induction ofapoptosis contributes to the mechanisms of antitumoractivity of elemene.