Chemical constituents from the aerial parts of Melandrium firmum.

Two new anthraquinones, melrubiellin C (1) and melrubiellin D (2), were isolated from the aerial parts of Melandrium firmum Rohrbach, together with eight known compounds (3-10). The structures of these compounds were elucidated using 1D and 2D NMR (COSY, HMQC, HMBC and NOESY) experiments. All isolated compounds were tested for their cytotoxicity against NCI-H460, Hep G2, MKN-28 and A-549 cells. Of these 10 compounds, 1 and 2 exhibited moderate cytotoxicity with IC50 values ranging from 9.54 to 32.41 μM.