Find in Library

Seven rare <span style="font-variant: small-caps;">e</span>:<span style="font-variant: small-caps;">b</span>-friedo-hopane-type triterpenoids including four new (<b>1</b>&#8722;<b>4</b>) and three known (<b>5</b>&#8722;<b>7</b>) ones with <b>5</b> being first reported as a natural product, together with five other known triterpenoids (<b>8</b>&#8722;<b>12</b>), were isolated from the nonpolar fractions of the ethanolic extract of <i>Euphorbia peplus</i>. Structural assignments for these compounds were based on spectroscopic analyses and quantum chemical computation method. The structural variations for the C-21 isopropyl group, including dehydrogenation (<b>1</b> and <b>3</b>) and hydroxylation at C-22 (simiarendiol, <b>2</b>), were the first cases among <span style="font-variant: small-caps;">e</span>:<span style="font-variant: small-caps;">b</span>-friedo-hopane-type triterpenoids. Simiarendiol (<b>2</b>) bearing a 22-OH showed significant cytostatic activity against HeLa and A549 human tumor cell lines with IC₅₀ values of 3.93 &#177; 0.10 and 7.90 &#177; 0.31 &#956;M, respectively. The DAPI staining and flow cytometric analysis revealed that simiarendiol (<b>2</b>) effectively induced cell apoptosis and arrested cell cycle at the S/G2 phases in a dose-dependent manner in HeLa cells.