Isolation of active substances and bioactivity of Aconitum sinomontanum Nakai.

In order to obtain the active compounds against third armyworm (Mythimna separata) contained in Aconitum sinomontanum Nakai by solvent partition, successive fractionation on silica gel and bioassay by the conventional leaf disc method, three diterpenoidal alkaloids were isolated for the first time from the roots of A. sinomontanum Nakai. Their structures were established as demethylenedelcorine, 18-O-methylgigactonine and lepenine based on their spectral data and X-ray diffraction analysis. Demethylenedelcorine and 18-O-methylgigactonine exhibited better pesticidal activities against M. separata, while lepenine had the induce-feeding activity against M. separata. The three diterpenoidal alkaloids exhibited bactericidal and fungicidal activities against certain kinds of the tested bacteria and fungi.