Two New C₁₈ -Diterpenoid Alkaloids from Aconitum leucostomum Worosch

Two new lappaconitine-type C₁₈ -diterpenoid alkaloids, named as leucostosines C (1) and D (2), together with six known compounds (3-8), were isolated from the roots of Aconitum leucostomum Worosch. Their structures were elucidated by various spectroscopic analyses, including IR, HR-ESI-MS, NMR spectra and X-ray experiments. Leucostosine C is the first diterpenoid alkaloid bearing the 7-amino group. The isolated compounds were tested for the acetylcholinesterase (AChE) inhibitory effect and neuroprotective activity, none of them showed significant activities.