Euphorhelipanes A and B, Triglyceride-Lowering EuphorbiaDiterpenoids with a Bicyclo[4.3.0]nonane Core from Euphorbia helioscopia

Euphorhelipanes A (1) and B (2), two Euphorbiaditerpenoids with a new 4-(5,5-dimethylheptan-2-yl)-2,7-dimethylbicyclo[4.3.0]nonane skeleton, were isolated from a 95% ethanol extract of the whole plants of Euphorbia helioscopia. Their structures were elucidated by spectroscopic data analysis, quantum chemical calculations, and single-crystal X-ray diffraction data. Compounds 1and 2represent the first examples of Euphorbiaditerpenoids with a 5/6 fused carbon ring system, and their plausible biosynthetic pathways originating from jatrophanes are proposed. Compounds 1and 2showed a triglyceride-lowering effect in oleic-acid-stimulated HuH7 cells at concentrations of 1–50 μM.