Abstract: BACKGROUND ＆ AIM: Ginsenoside Rg3 is a kind of effective chemical trace component extracted from the red panix. Many studies demonstrated that ginsenoside Rg3 might block angiogenesis and inhibit tumor growth and metastasis. The mechanism of ginsenoside Rg3 in anti-tumor is now one of hot point of chinese traditional medicine researches. The purpose of this study is to explore the effect of Rg3 on induction apopotosis of human MCF-7 breast cancer cell line. MATERAIL ＆ METHODS: The cell proliferation inhibition was measured by 3-[4,5-dimethylthiazo-2-yl]-2,5 diphenyl tetrazolium bromide(MTT) assay. The morphological changes of cells were observed by fluorescence staining of Hoechst 33258. Cell cycle and apoptosis rate were analyzed by flow cytometry. DNA ladder was showed by agarose gel electrophoresis. RESULTS： There was obviously a concentration-dependent relationship between Rg3 and inhibition of the cell proliferation，r=0.953, (P<0.05). IC50 was 71.91 μg/ml Rg3 after treatment for 48 hours. The cells treated with 150 μg/ml Rg3 for 48 hours showed morphological characteristics of apoptotic cells with the condensed chromatin, the nuclear fragmentation, the apoptotic body and brighter green fluorescent. FCM assay indicated that Rg3 regulated cell cycle and induced cell apoptosis. The percentage of cells in S phase and G2-M phase was increased, whereas the percentage of cells in G0-G1 was decreased. The apoptosis rates were increased from(0.45±0.25) ％ to(34.86±4.65)％ in MCF-7 cells after treatment with Rg3 for 48 hours. The cells treated with 150 μg/ml Rg3 for 24 and 48 hours reveal an obvious DNA ladder. CONCLUSION： The results suggested that Ginsenoside Rg3 exerts an inhibiting effect on human MCF-7 breast cancer cell line by inducing apoptosis of the cells.

Key words: Ginsenoside Rg3, apoptosis, tumor, MCF-7 cell line