Seven new tirucallane-type triterpenoids (1-7), kumuquassin A-G, along with 20 known analogues (8-27) were isolated from the stems of Picrasma quassioides. The structures and the absolute configurations of new compounds were elucidated by spectroscopic data, electronic circular dichroism (ECD) spectroscopic analyses and quantum ECD calculations. Notably, kumuquassin A (1) contains a rare Δ17, 20 double bond, kumuquassin B (2) is the first example of tirucallane triterpenoid possessing a 5/3 biheterocyclic ring system at the side chain. All the compounds were screened for the cytotoxicity against two human hepatoma cell lines, HepG2 and Hep3B, and several compounds exhibited promising activity. The most potential compound 3 was selected for cell cycle analysis, which showed that 3 could cause an accumulation of HepG2 cells at subG1 peak. Annexin V-FITC/PI staining further confirmed that compound 3 caused death of hepatoma cells through apoptosis induction.

中文翻译：

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拟南芥中的新提洛卡伦三萜类化合物对肝癌细胞具有潜在的抗增殖活性。

从拟南皮草的茎中分离出七种新的三甲基十二烷类三萜化合物（1-7），kumuquassin AG，以及20种已知的类似物（8-27）。通过光谱数据，电子圆二色性（ECD）光谱分析和量子ECD计算，阐明了新化合物的结构和绝对构型。值得注意的是，kumuquassin A（1）含有稀有的Δ17，20双键，kumuquassin B（2）是在侧面链上具有5/3双杂环系统的替鲁卡烷三萜类化合物的第一个例子。筛选了所有化合物对两种人肝癌细胞系HepG2和Hep3B的细胞毒性，并且几种化合物表现出有希望的活性。选择最有潜力的化合物3进行细胞周期分析，结果表明3可能导致subG1峰处的HepG2细胞积聚。