A new secoiridoid-derived guanidine alkaloid, argininosecologanin (1), along with 12 known iridoids and secoiridoids (2-13), was isolated from the roots of Lonicera insularis. The structures of the isolated compounds were established by the spectroscopic analysis and comparison of their spectral data with previously reported data. Compound 1 was assigned as the first secoiridoid-derived guanidine alkaloid isolated as a natural product. A plausible biogenetic pathway for 1 is suggested based on its structural similarity to (E)-aldosecologanin (4).
Keywords: Caprifoliaceae; Lonicera insularis; argininosecologanin; guanidine alkaloid; secoiridoid.