Alkaloids from Corydalis decumbens modulate neuronal excitability.

Eight new alkaloids, including five isoquinoline alkaloids, a benzoazepine alkaloid, two isoindole alkaloids, and three synthetic alkaloids firstly obtained from the natural sources, together with three known ones were isolated from the bulbs of Corydalis decumbens. The structures were determined by analysis of their spectroscopic data and single-crystal X-ray diffraction. This is the first report of isoindole alkaloid and benzoazepine alkaloid from the genus Corydalis. Full NMR data for 9-11 are reported here for the first time. Moreover, the ability to modulate neuronal Ca mobilization of the isolated alkaloids was tested in primary cultured neocortical neurons. Compound 7 inhibited spontaneous Ca oscillations in primary neocortical neuron cultures at low micromolar concentrations.