Inhibitory effects of diterpenoid alkaloids on the growth of A172 human malignant cells

The cytotoxicity against A172 human malignant glioma cells was examined for 14 alkaloids from the roots of Aconitum yesoense var. macroyesoense and of Aconitum japonicum and from the seeds of Delphinium elatum as well as for 25 semisynthetic derivatives. The major alkaloid constituents of A. yesoense var. macroyesoense, kobusine (2) and pseudokobusine (3), a minor alkaloid constituent of A. japonicum, aljesaconitine A (5), and six alkaloid derivatives, N-deethyldelcosine (10), N-deethyldelsoline (11), 12-benzoylluciculine (18), 12-anisoylluciculine (19), 6,11-dibenzoylpseudokobusine (28), and 6-veratioylpseudokobusine (29), had only very weak activity. Four acylated alkaloid derivatives, 12-acetylluciculine (23), 11-veratroylpseudokobusine (30), 11-(m-trifluoromethylbenzoyl)pseudokobusine (32), and 11-(m-trifluoromethylbenzoyl)kobusine (39), exhibited more potent activity, while pseudokobusine 11-cinnamoate (31), 11-anisoate (33), and 11-p-nitrobenzoate (34) were found to be the most potent cytotoxic agents.