Potent anti-tumor promoter activity has been found in the nonpolar extracts of the root of "Ashita-Ba", Angelica keiskei Koidz. (Umbelliferae), which is eaten as a vegetable in Japan. From this active fraction, two angular furanocoumarins, archangelicin (1) and 8(S),9(R)-9-angeloyloxy-8,9-dihydrooroselol (2), three linear furanocoumarins, psoralen (3), bergapten (4) and xanthotoxin (5), and three chalcones, 4-hydroxyderricin (6), xanthoangelol (7) and a novel chalcone named ashitaba-chalcone (8), were isolated. Among these compounds, two angular type furanocoumarins, 1 and 2, and three chalcones, 6-8, suppressed 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated 32Pi-incorporation into phospholipids of cultured cells, whereas coumarins 3-5 were less effective. In addition, chalcones 6 and 7 were proved to have anti-tumor-promoting activity in mouse skin carcinogenesis induced by 7,12-dimethylbenz[a]anthracene (DMBA) plus TPA. Since chalcones 6 and 7 showed calmodulin-interacting property, both chalcones may reveal anti-tumor-promoting activity via the modulation of calmodulin involved systems. These chalcones may be useful to develop the effective method for cancer prevention.