Study On Inhibition Effect Of Flavonoid From Spirodela Polyrrhiza Schleid On Human Hepatoma Cells And Its Biological Mechanisms

Spirodela polyrrhiza Schleid's flavonoid (SPF) is a kind of active constitutent which is the main product extracted from Chinese traditional medicine Spirodela polyrrhiza Schleid. It plays an important role in antioxidant, antitumor and liver protection. Experiments indicate that flavonoid can inhibit the apoptosis of human liver cells and rat liver cells induced by TNF-α, protect rat liver cells from damage induced by diethylnitrosamine(DEN) and delay the forming of hepatoma. Meanwhile, it is reported that flavonoid can inhibit the proliferation of human hepatoma cells (HCC) and ovary cancer cells in vitro. These suggest that flavonoid potentially have antitumor effect on hepatoma and its mechanism is probably related to inducing apoptosis of hepatoma cell. However, there are few detailed reports about apoptosis and its mechanism of human's cancer cells induced by SPF.Based on the techniques of biochemistry and cell biology, SPF's effect on the proliferation, cancer related gene expression and enzymatic activity of human hepatoma cell line (SMMC-7721) were investigated in this thesis in order to elucidate the mechanism of HCC apoptosis induced by SPF.The main research methods, contents and conclusions are as follows:①With MTT assay, the growth inhibition of human hepatoma cells line SMMC-7721 and human normal liver cells HL-7702 treated by various concentration of SPF after different time was observed. Results showed that SPF could inhibit the growth of SMMC-7721 cells and HL-7702 cells and it presented dose- and time-dependent. However the effect of SPF on SMMC-7721 cells was significantly strong than that of HL-7702 cells.②With colorimetry,SPF could decrease the activities of lactate dehydrogenase, succinic dehydrogenase and alkaline phosphatase. Results showed that SPF couldn't induce the differentiation of SMMC-7721 cells.③Effect of cell cycle and apoptosis rate of SMMC-7721 cells was studied with flow cytometry (FCM), PI and AnnexinⅤfluorescent dyes. It showed that SPF could block the cell cycle at G2/M phase and S phase, prevent SMMC-7721 cells entering G0/G1 phase. It also showed that SPF could induce apoptosis of SMMC-7721 cells and the apoptosis rate was 59.32 percent after 48h treatment by 200μg/ml SPF.④Expression of cancer related protein bcl-2 and p53 was measured by FCM and...