Mechanisms of apigenin-7-glucoside as a hepatoprotective agent / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>Ixeris chinesis (Thunb.) Ankai has been used as a Chinese folk medicine, but only scanty information is available on the physiological and biochemical functions of the compounds extracted from I. chinesis. In the present study the effects of apigenin-7-glucoside (APIG) isolated from I. chinesis against liver injury caused by carbon tetrachloride (CCl4) were investigated.</p><p><b>METHODS</b>The contents of malondialdehyde (MDA), glutamic pyruvic transaminase (GPT), glutamic oxaloacetic transaminase (GOT), and reduced glutathione (GSH) were evaluated by spectrophotography. The content of 8-Hydroxydeoxyguanosine (8-OHdG) was measured with high-performance liquid chromatography (HPLC) equipped with electrochemical and UV detection methods. The antioxidant activity of APIG was evaluated using chemiluminescence single photon counting technology.</p><p><b>RESULTS</b>CCl4 significantly increased the enzyme activities of GPT and GOT in blood serum, as well as the level of MDA and 8-OHdG in liver tissue, and decreased the levels of GSH. Pretreatment with APIG was able not only to suppress the elevation of GPT, GOT, MDA and 8-OHdG, and inhibit the reduction of GSH in a dose-dependent manner in vivo, but also to reduce the damage of hepatocytes in vitro. On the other hand, we also found that APIG had strong antioxidant activity against reactive oxygen species (ROS) in vitro in a concentration-dependent manner.</p><p><b>CONCLUSION</b>The hepatoprotective activity of APIG is possibly due to its antioxidant properties, acting as scavengers of ROS. These results obtained in vivo and in vitro suggest that APIG has protective effects against hepatic oxidative injury induced by chemicals. Further studies on the pharmaceutical functions and immunological responses of APIG may help its clinical application.</p>

Redifferentiation of human gastric cancer cells induced by ascorbic acid and sodium selenite / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To explore the effects and mechanisms of ascorbic acid (AA) and sodium selenite (SS) on growth inhibition and redifferentiation in human gastric cancer cells.</p><p><b>METHODS</b>In the present study, trypan blue dye exclusion method was used to determine the cell growth curve and mitotic index, cell electrophoresis and colonogenic potential were used as the indexes of redifferentiation. In order to find out the mechanisms of redifferentiation, the activities of superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) were assayed, the content of malondialdehyde (MDA), reduced glutathione (GSH) and H2O2 were evaluated.</p><p><b>RESULTS</b>After treatment with AA 3 mol/L + SS 2 mu mol/L, the growth rate and mitotic index of human gastric cancer cells (MGc-803) decreased remarkably. The indexes related with cell malignancy were alleviated. For example, cell surface charge was obviously decreased, the electrophoresis rate was dropped from 2.21 to 1.15 mu m.s-1.V-1.cm-1. The indexes related with cell redifferentiation were promoted. For example, the colonogenic potential was decreased to 93.5%. These results indicated that redifferentiation of human gastric cancer cells was successfully induced by AA + SS. The activities of SOD and GPX were significantly higher, while the activity of CAT was slower in treated group than that in the control. The content of MDA was slightly decreased, GSH was sharply decreased, and H2O2 content was dramatically increased.</p><p><b>CONCLUSION</b>These results indicated that combination of ascorbic acid and sodium selenite may induce the redifferentiation of human gastric cancer cells and inhibit cell growth by virtue of enhancing the activities of antioxidative enzymes and inducing the formation of H2O2, and altering the cell redox status. Combination of ascorbic acid and sodium selenite may be a potent anticancer agent for human gastric cancer.</p>