Chemical constituents, cytotoxic and antioxidant activities of extract from the rhizomes of Thunb.

Thirty-three compounds (-) were isolated from the rhizomes of . Their structures were elucidated on the basis of spectral analysis and identified as -kaurene terpenoids (1-3), anthraquinones (4-8), flavonoids (9-12), steroids (13-15), and other compounds (-). Compound -, - were isolated from the genus osmunda for the first time. Compound were isolated from the plant for the first time. Cytotoxicities of all compounds against Hela, HepG2 and A549 cell lines were measured by MTT assay, and their antioxidant activities were determined by DPPH and ABTS radical scavenging assays. Compound exhibited potent cytotoxicity against Hela, HepG2 cell lines with IC values of 9.31 and 9.66 μM, respectively. Compound showed good antioxidant activity. The Trolox-equivalent antioxidant capacity (TEAC) value was 0.95 mM in ABTS assay, and the IC value was 18.63 μM in DPPH assay.