Stilbenoids from Rheum undulatum Protect Hepatocytes Against Oxidative Stress Through AMPK Activation.

Oxidative stress promotes several diseases, including liver disease. We have isolated several stilbenoids from Rheum undulatum to investigate their hepatoprotective activities and mechanism. Stilbenoids from R. undulatum protects hepatocytes against arachidonic acid + iron (AA + Fe) induced oxidative stress. Pterostilbene (compound 5) shows stronger activity than the others. Trimethoxystilbenoid (compound 6) shows best activity on protection of HepG2 cells from AA + Fe-induced oxidative stress, and trans-stilbenoid (compound 7) shows weak activity. These stilbenoids suppress ROS generation in AA + Fe-treated HepG2 cells and also suppress AA + Fe-induced MMP disruption. Their protective effects on AA + Fe-induced MMP disruption were abrogated by treatment of AMP-activated protein kinase (AMPK) inhibitor, compound C or transfection of dominant negative form of AMPK. Taken together, stilbenoids from R. undulatum protect hepatocytes against AA + Fe-induced oxidative stress through AMPK activation. And the methoxy groups in the aryl groups are important for their cytoprotective activity.