Ebracpenes A and B, Unusual Ring C-seco and Ring D‑aromatic Nor-Triterpenoids, from Euphorbia ebracteolata and Lipase Inhibitory Evaluation

Two unusual ring C-seco and ring D-aromatic nor-triterpenoids, ebracpenes A (1) and B (2), were obtained from Euphorbia ebracteolata roots and elucidated by widely spectroscopic data analyses, such as 1D, 2D NMR, HRESIMS, and X-ray crystallography analysis. Compound 2 showed a significant inhibitory activity on lipase (IC50 = 0.89 μM as well as the Ki determined to be 0.69 μM). Enzyme kinetics analysis and molecular docking experiments revealed that compound 2 was a competitive inhibitor, binding to the active site of lipase.