C19-diterpenoid alkaloids from the rhizomes of Aconitum pendulum

Six new C19-aconitine-type diterpenoid alkaloids, pendulumines A-F (1–6), together with six known ones (7–12), were isolated from the rhizomes of Aconitum pendulum. Their structures were elucidated using extensive spectroscopic data analysis, including 1D and 2D NMR, MS, and single-crystal X-ray diffraction analysis. The isolates were also tested for their analgesic activity based on the thermal avoidance response of the roundworm Pirstionchus pacificus, and 9 showed significant biological activity with an EC50 value of 0.08 ± 0.02 mg.mL−1.