Norditerpenoid and diterpenoid alkaloids from the roots of Aconitum nasutum Fisch ex Reichb.

Investigation of the alkaloidal constituents of the roots of Aconitum nasutum led to the isolation and identification of a new diterpenoid alkaloid designated as trabzonine (1). Three known norditerpenoid alkaloids, lappaconitine (2), lycoctonine (3) and gigactonine (4), and two known diterpenoid alkaloids pseudokobusine (5) and septatisine (6) were also isolated. The structures of 1 and 5 were established by detailed analyses of H-1 and C-13 NMR data. The structure and absolute stereochemistry of pseudokobusine (5) was determined by an X-Ray crystal structure determination