Objective： This work aimed to study the inhibitory effect and the related mechanism of metformin （MET） on the proliferation of human hepatoma HepG2 cells. Methods： Human hepatoma HepG2 cells were treated with MET ...Objective： This work aimed to study the inhibitory effect and the related mechanism of metformin （MET） on the proliferation of human hepatoma HepG2 cells. Methods： Human hepatoma HepG2 cells were treated with MET （0, 2, 10, and 50 mM）. The inhibitory effect of MET on the proliferation of HepG2 cells was determined by MTT method. The apoptosis of HepG2 cells was detected by flow cytornetry. The expression of cyclin D1 in HepG2 cells was examined by Western blot. ROS-DHE fluorescence probe was used to stain the reactive oxygen species （ROS） generated by HepG2 cells after treat- ment. Results： MET could inhibit the proliferation of HepG2 cells in a dose and time dependent manner. MET promoted the apoptosis of HepG2 cells. In addition, MET suppressed the expression of cell cycle protein cyclin D1 and induced the produc- tion of ROS in HepG2 cells. Conclusion： MET can inhibit the proliferation of human hepatoma HepG2 cells and induce cell apoptosis. Meanwhile, MET has the ability to decrease the expression of cyclin D1 and induce ROS generation, which may be involved in the mechanism of inhibiting hepatoma cells proliferation.展开更多
The use of a microwave-assisted extraction （MAE） method for the extraction ofphlorotannins from Saccharinajaponica Aresch （S.japonica） has been evaluated with particular emphasis on the influential parameters, inc...The use of a microwave-assisted extraction （MAE） method for the extraction ofphlorotannins from Saccharinajaponica Aresch （S.japonica） has been evaluated with particular emphasis on the influential parameters, including the ethanol concentration, solid/liquid ratio, extraction time, extraction temperature, and microwave power. The MAE procedure was optimized using single-factor design and orthogonal array design （OAD）. The content of total phlorotannins in S. japonica was determined using a Folin-Ciocalteu （FC） assay. A maximum total phlorotannin content of 0.644 mg of phloroglucinol equivalent per gram of dry weight plant （mg PGE/g DW） was obtained using the optimized model, which included an ethanol concentration of 55%, solid/liquid ratio of 1：8, extraction time of 25 min, irradiation power of 400 W, and temperature of 60~C. Under similar conditions, the application of a conventional extraction method led to a lower phlorotarmin yield of 0.585 mg PGE/g WD. These results demonstrated that the MAE approach provided better results for the extraction ofphlorotarmins from S.japonica and was a promising technique for the extraction of phenolic compounds from S. japonica and other materials. In addition, screening tests for the inhibitory activity showed that the phlorotannin-containing extracts significantly inhibited the growth of human hepatocellular carcinoma cells （HepG2） by inducing their apoptosis. The morphological changes that occurred during cell apoptosis were characterized using Hoechst33258 staining.展开更多
文摘Objective： This work aimed to study the inhibitory effect and the related mechanism of metformin （MET） on the proliferation of human hepatoma HepG2 cells. Methods： Human hepatoma HepG2 cells were treated with MET （0, 2, 10, and 50 mM）. The inhibitory effect of MET on the proliferation of HepG2 cells was determined by MTT method. The apoptosis of HepG2 cells was detected by flow cytornetry. The expression of cyclin D1 in HepG2 cells was examined by Western blot. ROS-DHE fluorescence probe was used to stain the reactive oxygen species （ROS） generated by HepG2 cells after treat- ment. Results： MET could inhibit the proliferation of HepG2 cells in a dose and time dependent manner. MET promoted the apoptosis of HepG2 cells. In addition, MET suppressed the expression of cell cycle protein cyclin D1 and induced the produc- tion of ROS in HepG2 cells. Conclusion： MET can inhibit the proliferation of human hepatoma HepG2 cells and induce cell apoptosis. Meanwhile, MET has the ability to decrease the expression of cyclin D1 and induce ROS generation, which may be involved in the mechanism of inhibiting hepatoma cells proliferation.
基金Supported by the National Natural Science Foundation of China(No.51203028)Rural Science and Technology Correspondent and Technology Service System Construction Projects,Guangdong Province(No.2010A020507001-91)Science and Technology Project of Panyu District,Guangzhou City(No.2010-12-08)
文摘The use of a microwave-assisted extraction （MAE） method for the extraction ofphlorotannins from Saccharinajaponica Aresch （S.japonica） has been evaluated with particular emphasis on the influential parameters, including the ethanol concentration, solid/liquid ratio, extraction time, extraction temperature, and microwave power. The MAE procedure was optimized using single-factor design and orthogonal array design （OAD）. The content of total phlorotannins in S. japonica was determined using a Folin-Ciocalteu （FC） assay. A maximum total phlorotannin content of 0.644 mg of phloroglucinol equivalent per gram of dry weight plant （mg PGE/g DW） was obtained using the optimized model, which included an ethanol concentration of 55%, solid/liquid ratio of 1：8, extraction time of 25 min, irradiation power of 400 W, and temperature of 60~C. Under similar conditions, the application of a conventional extraction method led to a lower phlorotarmin yield of 0.585 mg PGE/g WD. These results demonstrated that the MAE approach provided better results for the extraction ofphlorotarmins from S.japonica and was a promising technique for the extraction of phenolic compounds from S. japonica and other materials. In addition, screening tests for the inhibitory activity showed that the phlorotannin-containing extracts significantly inhibited the growth of human hepatocellular carcinoma cells （HepG2） by inducing their apoptosis. The morphological changes that occurred during cell apoptosis were characterized using Hoechst33258 staining.
基金supported by the National Natural Science Foundation of China(No.30771690)the Specific Fund for Public Interest Research of Traditional Chinese Medicine,Ministry of Finance(No.200707008)National Technology Pedestal Program(No.2007BA130B04)
