A lignan with hepatoprotective activity; increases the expression of the PXR target genes Cyp3a11, Ugt1a1, Oatp2, and Mrp3 in mouse liver and CYP3A4, UGT1A1, and OATP2 in HEK293T cells; protects against lithocholic acid-induced hepatic necrosis and intrahepatic cholestasis in wild-type, but not Pxr-null, mice; decreases mortality in a mouse model of cholestasis at 100 mg/kg twice per day