Antiproliferative and cytotoxic secondary metabolites from fruits of <i>Leplaea mayombensis</i>

<p>Two new <i>seco</i>-lanostane-type triterpenes, named mayomlactones A (<b>1</b>) and B (<b>2</b>) were isolated from the fruits of <i>Leplaea mayombensis</i> together with 10 known compounds (<b>3</b>–<b>12</b>). Structures of the new compounds were elucidated by extensive spectroscopic studies. Except compounds <b>11</b> and <b>12</b>, all the other chemical compounds are newly reported from <i>Leplaea</i> genus. From the results of this investigation, compounds <b>1</b>–<b>10</b> were examined for antiproliferative activity against HeLa cells as well as cytotoxicity against 3T3 cell line. Compounds <b>3</b> and <b>4</b> showed moderate antiproliferative activity with IC₅₀ values of 10.4 ± 0.1 and 18.6 ± 0.2 μM, respectively. On the other hand, compounds <b>1</b>, <b>4</b> and <b>9</b> showed weak cytotoxicity with IC₅₀ values 44.1 ± 0.5, 55.8 ± 0.7 and 55.1 ± 0.5 μM. Overall, none of the tested compounds showed good selectivity (SI ranging from 0.51 to 3.06) but high toxicity against the 3T3 cell line.</p