A bioactive new protostane-type triterpenoid from <i>Alisma plantago</i>-<i>aquatica</i> subsp. <i>orientale</i> (Sam.) Sam.

<p>A new protostane-type triterpenoid, 5<i>β</i>,29-dihydroxy alisol A (<b>1</b>) was isolated from <i>Alisma plantago</i>-<i>aquatica</i> subsp<i>. orientale</i> (Sam.) Sam. as well as 12-deoxyphorbol-13<i>α</i>-pentadecanoate (<b>2</b>). We first report the presence of compound <b>2</b> in the genus <i>Alisma</i>. Their structures were established on the basis of 1D and 2D NMR, and HRESIMS spectroscopic analyses. All the isolated compounds were assayed for their inhibitory effects against human carboxylesterase 2 (HCE-2). Compounds <b>1</b> and <b>2</b> displayed inhibitory activities against HCE-2 with IC<sub>50</sub> values of 29.2 and 4.6 μM, respectively. The interaction mechanisms of HCE-2 with compounds <b>1</b> and <b>2</b> were investigated by molecular docking, respectively.</p>