本研究从黄花三宝木(Trigonostemon fragilis)中分离得到了4个具有不同二聚模式的新型降二萜类异源二聚体，分别为trigofragiloids A–C (化合物1~3)和(+)-、(−)-trigofragiloid D (化合物4)，以及三个新型菲酮类降二萜单体，trigofragiloids E–G (化合物5~7)。化合物1和2具有全新的异源二聚碳骨架，其由一个四降二萜和一个九降二萜骨架聚合形成；通过量子化学计算，它们被确定为第二类阻转异构体。化合物3则是具有全新二聚模式的苯丙素-降二萜加合物。化合物(+)-、(−)-4是首例以1,4-二氧六环聚合的“S”形降二萜二聚体。受化合物4结构解析的启发，两种共存的二聚体类似物，即actephilol A和epiactephilol A，被修正为一对几何异构体，并进一步被鉴定为两对对映异构体，分别为(+)-、(−)-8和(+)-、(−)-9。采用多种表征方法对它们的结构进行了确证。值得注意的是，化合物7对三磷酸腺苷-柠檬酸裂解酶(ACLY)具有显著的抑制作用，其半抑制浓度(IC₅₀)值为(0.46 ± 0.11) μmol∙L⁻¹，与阳性对照BMS-303141的活性相当。

Four new norditerpenoid heterodimers with different dimerization patterns—namely, trigofragiloids A-C (denoted as compounds 1-3) and (+)- and (−)-trigofragiloid D (compound 4)—and three new phenanthrenone norditerpenoids—namely, trigofragiloids E-G (compounds 5-7)—were isolated from Trigonostemon fragilis. Compounds 1 and 2 feature a novel heterodimeric carbon skeleton formed by the conjugation of a tetra-norditerpenoid and an ennea-norditerpenoid; they have been identified as class 2 atropisomers by means of quantum chemical calculations. Compound 3 is an unprecedented phenylpropanoid-norditerpenoid adduct with a new dimerization pattern. Compounds (+)- and (−)-4 are the first example of S-shaped 1,4-dioxane-fused norditerpenoid dimers. Inspired by the structure elucidation of compound 4, two co-occurring analogues, actephilol A and epiactephilol A, were structurally revised as a pair of geometrical isomers and were identified as two pairs of enantiomers, (+)- and (−)-8 and (+)- and (−)-9, respectively. Their structures were characterized using a combined method. Notably, compound 7 exhibits remarkable adenosine triphosphate-citrate lyase (ACLY) inhibition with a half-maximal inhibition concentration (IC₅₀) value of (0.46 ± 0.11) μmol∙L⁻¹, as active as the positive control BMS-303141, and a molecular docking study offers deep insight into the interaction between compound 7 and ACLY.