Four New Diterpenoid Alkaloids From <i>Delphinium iliense</i> Huth

Four new C₁₉-diterpenoid alkaloids, sinchianidines A-D (1-4), together with eight known diterpenoid alkaloids (5-12), were isolated from the whole plant of Delphinium iliense Huth (Ranunculaceae). Their structures were established by extensive spectroscopic analyses, while the absolute configurations of sinchianidine A (1) and sinchianidine C (3) were determined by experimental electronic circular dichroism spectra comparison. Biological activity evaluations revealed that sinchianidines C and D (3 and 4) demonstrated significant pain inhibition (78.16% and 72.54%, respectively) in acetic acid-induced writhing tests of mice at a dose of 5 mg/kg. Compounds 1-4 showed no significant inhibitory activity on the Human Ether-à-go-go-related gene and CaV3.1 (T-type calcium) channels. Additionally, all isolates showed no significant cytotoxicity against Hela, HCT8, and MCF7 human cancer cells in vitro.