Four New Diterpenoid Alkaloids from Delphinium iliense Huth

Abstract: 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 (ECD) spectra comparison. Biological activity evaluations revealed that sinchianidines C and D (3‐4) 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 hERG (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.