Argininosecologanin, a secoiridoid-derived guanidine alkaloid from the roots of <i>Lonicera insularis</i>

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