Two oxoisoaporphine alkaloids, 2,3-dihydrodauriporphine and tyraminoporphine, together with the known alkaloid dauriporphine, were isolated from Menispermum dauricum roots cultured in a medium containing ketoconazole, a cytochrome P-450 inhibitor. Structures of the alkaloids were established by spectroscopic, crystallographic and chemical methods. (C) 1999 Elsevier Science Ltd. All rights reserved.