Thirty three C19-diterpenoid alkaloids, twenty-two prepared from known C19-diterpenoid alkaloids and eleven isolated from Aconitum and Delphinium spp. were evaluated for their cardiac activity in the isolated bullfrog heart assay.
METHODS AND RESULTS:
Among them, eleven compounds exhibited cardiac activity, with average rate of amplitude increase in the range of 16-118%. Compound 7, mesaconine (17), Hypaconine (25), and beiwutinine (26) exhibited strong cardiac activities relative to the reference drug.
CONCLUSIONS:
The structure-activity relationship data acquired indicated that an alpha-hydroxyl group at C-15, a hydroxyl group at C-8, an alpha-methoxyl or hydroxyl group at C-1, and a secondary amine or N-methyl group in ring A are important structure features necessary for the cardiac activities of the aconitine-type C19-diterpenoid alkaloids without any ester groups. In addition, an alpha-hydroxyl group at C-3 is also helpful for the cardiac activity of these alkaloids. |