Phytochemical Constituents from the Rhizomes of Osmunda japonica Thunb and Their Anti-oxidant Activity

Eleven compounds (1–11) were isolated from the rhizomes of Osmunda japonica, and their structures were elucidated based on 1H, 13C-NMR and LC-IT-TOF MS data. Of these compounds, all compounds (1 – 11) have been previously reported, although five (6 – 9, 11) have not previously been isolated from this plant. The antioxidant activities of isolated compounds (1 – 11) were measured by DPPH and ABTS assays, and compound 10 showed the high antioxidant activity.