Denudatine-type diterpenoid alkaloids from an aqueous extract of the lateral root of <i>Aconitum carmichaelii</i>

Five new denudatine-type diterpenoid alkaloids (1–5), along with the known analogue aconicarmine (6), were isolated from an aqueous decoction of lateral roots Aconitum carmichaelii (fu-zi). Their structures determined by spectroscopic data analysis and electronic circular dichroism (ECD) calculations. Compound 5 is first alcohol iminium alkaloid, which could be partially transformed into aza acetal form in pyridine-d5. inhibited mice writhing acetic acid-induced assay.