Phytochemical investigation and acetylcholinesterase inhibitory activity of bark of <i>Hymenodictyon orixense</i>

<p>The chemical investigation of the methanol extract of <i>Hymenodictyon orixense</i> bark, a Thai medicinal herb, provided five compounds. Their structures were identified on the basis of 1D NMR and MS data, as well as by comparison of the data with published values, as an iridoid glycoside: loganin (<b>1</b>), four coumarins: scopoletin (<b>2</b>), scopolin (<b>3</b>), hymexelsin (<b>4</b>) and scopoletin 7-<i>O</i>-<i>β</i>-D-xylopyranosyl-(1→6)-<i>β</i>-D-glucopyranoside (<b>5</b>). Compounds <b>1–5</b> showed acetylcholinesterase (AChE) inhibitory activity in the range of 13.92–34.18% at a concentration of 100 <i>μ</i>g/mL. In addition, compounds <b>1</b> and <b>5</b> are reported for the first time from this genus.</p