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.