Two new diterpenoid alkaloids from Delphinium trichophorum

Two previously undescribed diterpenoid alkaloids, trichophinines D (1) and E (2), were isolated from the ethanol extract of Delphinium trichophorum Franch. Compound 1 was characterized as a hetisine-type C20-diterpenoid alkaloid, whereas compound 2 was determined as a ranaconitine-type C18-diterpenoid alkaloid. Their structures were determined by IR, HR-ESI-MS, 1D/2D NMR, and other spectroscopic analyses. Compounds 1 and 2 were evaluated for their antiproliferative activity against HepG2 cells, but neither showed detectable inhibitory activity.