Aconicarmisulfonine A, a Sulfonated C20-Diterpenoid Alkaloid from the Lateral Roots of Aconitum carmichaelii

-diterpenoid alkaloid with an unprecedented carbon skeleton and significant analgesic activity (46.7% inhibition at 0.1 mg/kg, i.p.), named aconicarmisulfonine A (1), was isolated from an aqueous extract of the lateral roots of Aconitum carmichaelii. Its structure was determined by comprehensive analysis of spectroscopic data, especially by 2D NMR spectroscopic data combined with ECD calculation and single-crystal X-ray diffraction. The plausible biosynthetic pathways of compound 1 are also discussed.