Antinociceptive C 19 -Diterpenoid Alkaloids from Aconitum episcopale

chemical investigation of the 80% ethanol extract of the roots of Aconitum episcopale led to the isolation of two undescribed C 19 -diterpenoid alkaloids, designated as episcopines A and B. The structures of the new compounds were elucidated by spectroscopic analysis (NMR, IR, UV, and MS). The isolated alkaloids were tested in vivo for antinociceptive potential. Episcopine A showed a 2-fold more potent antinociceptive effect (ID 50 = 66.1 μmol/kg) than the positive control drugs aspirin and acetaminophen.