THE CHARACTERIZATION AND STRUCTURE-ACTIVITY EVALUATION OF TOXIC NORDITERPENOID ALKALOIDS FROM 2 DELPHINIUM SPECIES

A new N-(methylsuccinimido)anthranoyllycoctonin norditerpenoid alkaloi d, geyerline, has been isolated and characterized from extracts of the poisonous larkspur Delphinium glaucum. A previously described nordite rpenoid alkaloid, grandiflorine, has also been isolated from Delphiniu m geyeri. Both alkaloids are closely related structurally to the poten t neurotoxin methyllycaconitine, established as the primary toxin in m any larkspurs poisonous to cattle. Mouse bioassay tests showed grandif lorine to possess toxicity comparable to methyllycaconitine, while its synthetically derived monoacetate, grandiflorine acetate, and geyerli ne are significantly less toxic.