Antioxidant and Anti-nitric Oxide Components from Quercus glauca

From the ethanolic extract of Quercus glauca, two new lignans, (+)-5'-methoxyisolariciresinol-9'-O-alpha-L-rhamnopyranoside (1) and (7R,8S)-dihydrodehydrodiconiferyl alcohol 4-beta-D-xyloside (2), along with fourteen known compounds including four lignanoids (3-6), five triterpenoids (7-11), two flavonoids (12, 13), two aromatics (14, 15), and one steroid (16) were isolated. The structures of the new compounds were elucidated on the basis of spectroscopic analysis. Moreover, compounds 9 and 14 strongly inhibited nitric oxide (NO) production with IC50 values of 8.25 and 14.04 mu M, respectively, and compounds 1, 4-6, 14, and 15 showed moderate antioxidant activities.