Studies On Alkaloids From Aconitum Kirinense Nakai

This dissertation aimed at the in-depth phytochemical research of Aconitum kirinense Nakai in which 61 compounds were obtained.In this paper,the crude alkaloids were gained by several methods including solvent extraction,acid extraction,alkali precipitation and extraction.Then the residue was purified by various column chromatography methods including silica gel,reverse phase silica gel and alkaline Al₂O₃column chromatography.The structures of all diterpene alkaloids acquired were confirmed by extensive spectroscopic methods,including HR-ESI-MS,IR,1D and 2D-NMR.Twenty new compounds were determined as Kirisines A-T,including two lappaconitine-type C₁₈-diterpenoid alkaloids,four ranaconitine-type C₁₈-diterpenoid alkaloids,one aconitine-type C₁₉-diterpenoid alkaloids,three lycoctonine-type C₁₉-diterpenoid alkaloids,seven denudetine-type C₂₀-diterpenoid alkaloids and three napelline-type C₂₀-diterpenoid alkaloids.Kirisines A and B represented the second and third examples of diterpenoid alkaloids from nature whose methylenedioxy groups were located at C-9 and C-14,and the latter also had a rare chloro-substituent.In addition,the ¹³C NMR data of aconicarmichinium C and kiridine have been added and resived by 2D-NMR data.Besides,compounds 21,25-27,30-31,33,35-36,38-51,55 and 58-61 were isolated from A.kirinense Nakai for the first time.In order to search for compounds with promising anti-Alzheimer’s disease activity,the isolated alkaloids were tested for their neuroprotective activity and acetylcholinesterase inhibitory activity.Unfortunately,only compounds 8,21,24 and 37 exhibited mild activity against acetylcholinesterase.This study may play an important role in developing and popularizing the distinctive medicinal plants from the Aconitum genus in Northeast China and provide scientific evidences for the chemmotaxonomy of the Aconitum plants.