A new antioxidant flavone glycoside from Scutellaria baicalensis Georgi

A new flavone glycoside, wogonin 7-O-β-D-ethylglucuronide (1), together with a new natural flavone glycoside baicalein 7-O-β-D-ethylglucuronide (2) and four known analogues, wogonoside (3), wogonin (4), oroxylin A 7-O-β-D-methylglucuronide (5) and oroxylin A (6), was isolated from the roots of Scutellaria baicalensis Georgi. The structure elucidation of the new compound was primarily based on HR-ESI-MS, 1D and 2D NMR analyses. Compounds 1 and 3 inhibited FeSO4-Cys-induced liver homogenate lipid peroxidation with IC50 at 18.2 μM and 24.9 μM, respectively, and exhibited strong cytoprotective effects against H2O2-induced oxidative damage in human umbilical vein endothelial cells at low concentrations of 10.0 μM and 3.0 μM.