New Alkaloids from Aconitum stapfianum

Abstract

Aconitum stapfianum Hand.-Mazz. belongs to the genus Aconitum of the Ranunculaceae, and is distributed mainly at an altitude of 2800–3400 m in the northwest of Yunnan Province in China [ 1 ]. Up to now, only four diterpenoid alkaloids have been isolated from A. stapfianum [ 2 ]. As part of our continuous work on the discovery of bioactive ingredients from the Aconitum plants [ 3 , 4 ], an phytochemical investigation on the roots of A. stapfianum was carried out to afford nineteen alkaloids (Fig. 1 ), including a new C 19 -diterpenoid alkaloid stapfianine A ( 1 ), a new benzamide derivative stapfianine B ( 2 ), and a known amide 4-oxo-pentanoic acid dimethylamide ( 3 ) found in nature for the first time. Their structures were established on the basis of extensive spectroscopic analyses. In this paper, the isolation and structure determination of these alkaloids are described.