Neuroprotective and antioxidant activity of compounds from the aerial parts of Dioscorea opposita

Bioactivity-guided fractionation of an ethanol extract of the aerial parts of Dioscorea opposita afforded a new compound, 6,7-dihydroxy-2-methoxy-1,4-phenanthrenedione (1), and four known compounds, chrysoeriol 4'-O-beta-D-glucopyranoside (2), chrysoeriol 7-O-beta-D-glucopyranoside (3), alternanthim (4), and daucosterol. The structure of 1 was established on the basis of the interpretation of its 1D and 2D NMR spectrascopic data. Compounds 1-4 exhibited both promising neuroprotective effects and discernible to moderate antioxidant activities in vitro.