Triterpenes from the Aerial Parts of <i>Cimicifuga yunnanensis</i> and Their Antiproliferative Effects on p53^N236S Mouse Embryonic Fibroblasts

Nine new triterpene derivatives, yunnanterpenes A–F (<b>1</b>–<b>6</b>), 15,16-seco-cimiterpenes A and B (<b>7</b>, <b>8</b>), and cimilactone C (<b>9</b>), and 15 known analogues (<b>10</b>–<b>24</b>) were isolated from the aerial parts of <i>Cimicifuga yunnanensis</i>. The new structures were established using a combination of MS, NMR, and single-crystal X-ray diffraction techniques. WT MEFs (wild-type mouse embryonic fibroblasts) and tumorigenic cell lines <i>p</i>53^{<i>–/–</i>}+H-RasV12 and <i>p</i>53^{<i>–/–</i>}+p53^N236S+H-RasV12 were used for evaluating active structures, targeting p53^N236S (corresponding to p53^N239S in humans) mutation. Compound <b>5</b> showed nonselective activities against these cell lines, with IC₅₀ values of 5.8, 8.6, and 6.0 μM, respectively. Compound <b>4</b> exhibited greater selectivity against the <i>p</i>53^{<i>–/–</i>}+p53^N236S+H-RasV12 cells (IC₅₀ 5.5 μM) than against the WT MEFs cells (IC₅₀ 14.3 μM)