The known alkaloid lepenine and the new diterpene alkaloid akirine have been isolated from the epigeal part of Aconitum kirinense Nakai. To establish the structure of akirine, its spectral characteristics have been studied and an x-ray structural analysis has been made. It is 1α,8β-dihydroxy-16β-methoxy-9β,14β-methylenedioxy-3β,4β-epoxy-N-ethylaconitane - the first diterpene alkaloid with a lycoctonine skeleton containing a 9,14-methylenedioxy group and a β-oriented substituent at C14. © 1993 Plenum Publishing Corporation.