Objective:To investigate the anti-proliferative effects of saponins prepared from Plena Clematis (PC) cultured in Fujian Province,China on 4 human tumor cell lines and its possible anti-tumor mechanism.Methods:The growth inhibition assays of saponins on human esophageal squamous carcinoma cell line (EC9706),human hepatoma cell line (HepG-2),human oral cancer cell line (KB) and human gastric cancer cell line (BGC-823) were evaluated in vitro by thiazolyl blue (MTT) method.The inhibitory effects on EC9706 treated with different concentrations of saponins (15.62,31.25,62.50,125,250 and 500 i g/mL) were performed in vitro by MTT method.The morphology and nuclear staining with acridine orange/ethidium bromide of EC9706 cells treated with saponins were illustrated under an inverted phase fluorescence microscope.The apoptotic effects of saponins were further evaluated by annexin-V/propidium iodide dual staining experiment to examine the occurrence of phosphatidylserine externalization onto the cell surface by a flow cytometer.Results:MFr assay showed that the saponins could inhibit the proliferation of 4 tumor cell lines.Among them,the maximum inhibition rate of 73.1％ was detected in EC9706 cells at the saponins concentration of 250 i g/mL for 24 h.Further investigation indicated that the saponins induced EC9706 cells apoposis.The EC9706 cells presented apoptotic characteristics when treated with saponins,including that the morphologies of EC9706 cells were appeared round-shaped with higher refraction,and the cell nuclear stained orange with EB after 250 μ g/mL saponins exposure.The flow cytometry analysis results showed that the induction of cell cycle arrest in apoptotic system may participate in the anti-proliferative activity of saponins on EC9706 cells.Conclusion:The saponins from PC exhibited significant cytotoxicity against human EC9706,KB,BGC-823,and HepG-2 cells and might be beneficial to development of ethnic pharmaceutical plant for potential anti-tumor drugs.