A new sesquiterpene hydroperoxide from the aerial parts of Aster oharai.

Phytochemical works on the aerial parts of Aster oharai (Compositae) led to the isolation of a new sesquiterpene hydroperoxide, 7alpha-hydroperoxy-3,11-eudesmadiene (2) and seven known compounds, teucdiol B (1), alpha-spinasterol (3), oleanolic acid (4), alpha-spinasterol 3-O-beta-D-glucopyranoside (5), methyl 3,5-di-O-caffeoyl quinate (6), 3,5-di-O-caffeoylquinic acid (7), 3,4-di-O-caffeoylquinic acid (8). The chemical structures of 1-8 were established by chemical and spectroscopic methods. Compound 2 showed cytotoxicity against cultured human tumor cell lines in vitro, SK-OV-3 (ovarian), SK-MEL-2 (skin melanoma), and HCT15 (colon) with ED50 values ranging from 3.86-17.21 microg/mL.