Reversing effects of silybin on TAA-induced hepatic CYP3A dysfunction through PXR regulation / 中国天然药物

AIM@#Silybin (SB), a major constituent of the milk thistle, has been used to treat several liver disorders. However, liver diseases were always accompanied by CYP450 dysfunction. This study was designed to explore the relationship between the hepatoprotective effect and CYP3A regulation of SB during thioacetamide (TAA)-induced rat liver injury.@*METHODS@#Serum biochemical analysis and histopathological study were taken to evaluate the hepatoprotectinve effect of SB. α-SMA were detected by immunohistochemical analysis and cytokine release in rat liver was determined by ELISA assay. CYP3A and PXR expression were determined by RT-PCR and Western blot analysis, and CYP3A activity was based on the midazolam 4-hydroxylation reaction. Also, siRNA transfection was induced in HepG2 cells to evaluate the effect of PXR on cytotoxicity and CYP3A4 dysregulation caused by TAA.@*RESULTS@#SB showed powerful hepatoprotective effects, and anti-inflammatory and anti-fibrosis effects, and reversed the loss of CYP3A and PXR in TAA-injured rat liver, and decreased PXR translocation into the cell nucleus. PXR silencing weakened the effect of SB on cytoprotection and CYP3A regulation.@*CONCLUSIONS@#PXR was a very important factor of CYP3A regulation and might be the target of SB in TAA-induced liver disease. Also, because of the potential interactions of SB and co-administered medicines, it might be necessary to adjust the dosage in the clinical medication of liver disease.

Antitumor effects of two extracts from Oxytropis falcata on hepatocellular carcinoma in vitro and in vivo / 中国天然药物

AIMS@#To investigate the antitumor effects of extracts from Oxytropis falcata on human hepatocellular carcinoma SMMC-7721 cells in vitro and in transplanted murine H22 tumors in vivo.@*METHODS@#Cell proliferation, cell cycle distribution and apoptosis in SMMC-7721 cells were determined and tumor growth inhibition in H22 tumors was investigated. Cell cycle distribution was analyzed by flow cytometry with propidium iodide (PI) and Annexin V-FITC/ PI double staining.@*RESULTS@#MTT assay revealed that essential oil and flavonoids of O. falcata (named EOOF and FOF) inhibited proliferation of SMMC-7721 cells in a dose-dependent manner. The IC50 value of EOOF and FOF were 0.115 and 0.097 mg·mL(-1), respectively. Cell cycle was arrested at G(1) phase, and induction of apoptosis occurred in SMMC-7721 cells when subjected to FOF. Growth inhibition in H22 solid tumors transplanted mice was significantly pronounced after being treated with FOF, and the inhibition ratio were 56.1% and 70.8% at the concentration of 30 and 60 mg·kg(-1).@*CONCLUSION@#The results suggest that FOF promotes apoptosis in SMMC-7721 cells and inhibits H22 tumor growth, resulting in a potential antitumor effect on hepatic cancer.