Cytotoxic Activities of Total Saponins from Plena Clematis on Human Tumor Cell Lines In Vitro

ObjectiveTo 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.MethodsThe 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 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 flflow cytometer.ResultsMTT 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 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 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.ConclusionThe 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.