Structures of Diterpenoid Tropolones, Salviolone and Miltipolone, from the Root of Salvia miltiorrhiza Bunge

New types of a bisnorditerpenoid and a norditerpenoid possessing a benzotropolonoid and a tropolonoid moieties, salviolone (8) and miltipolone (15), respectively, have been isolated and their structures were determined by spectroscopic methods. The structure of salviolone was confirmed by a total synthesis. These compounds exhibit cytotoxic activities against cultured cells.