Karwinaphthopyranones from the Fruits of Karwinskia parvifoliaand Their Cytotoxic Activities

The new 2-acetyl-8-methoxynaphthol (1) and five new “dimeric” napthopyranones, karwinaphthopyranones A1 and A2 (2and 3) and karwinaphthopyranones B1–B3 (4–6), possessing a methoxy group at C-5′, were isolated together with four other known compounds from the dried fruits of Karwinskia parvifolia. The structures of compounds 2–6were determined by spectroscopic data interpretation. Cell culture assays showed that some of these compounds possess antiproliferative activities in representative human cancer cell lines, with half-maximal growth inhibitory concentrations in the micromolar range.