Aconicatisulfonines A and B, Analgesic Zwitterionic C20-Diterpenoid Alkaloids with a Rearranged Atisane Skeleton from Aconitum carmichaelii.

Two sulfonated C20-diterpenoid alkaloid iminiums with a novel skeleton, named aconicatisulfonines A (1) and B (2), respectively, were isolated from a water extract of the Aconitum carmichaelii lateral roots. Structures of 1 and 2 were determined by spectroscopic data and quantum calculations as well as X-ray crystallographic analysis. Biosynthetic pathways via semipinacol rearrangements of atisane derivatives are proposed for 1 and 2. Compounds 1 and 2 exhibited remarkable analgesic activities against acetic acid-induced mice writhing.