Synthesis, characterization and antinociceptive properties of the lappaconitine salts

A series of diterpene alkaloid derivatives (1–6) are prepared by reaction of the lappaconitine (0) with the corresponding organic or inorganic acid. The lappaconitine was isolated from the root of Aconitum sinomontanum Nakai in Gansu Province in China. The structures of all newly synthesized compounds were established by analytical and spectral data. In particular, the configurations of compounds 0–3 were determined by X-ray single-crystal diffraction. The analgesic potential has been investigated. Among the compounds tested, all derivatives (1–6) produced antinociceptive effects in a mouse model of acute pain, without inducing undesirable side effects. Furthermore, lappaconitine sulphate exhibited a pronounced analgesic activity. Thus, the present findings have demonstrated that lappaconitine sulphate is a promising analgesic agent and could emerge as a promising analgesic agent for further research work.