Anti-inflammatory diterpenoids from the roots of Euphorbia ebracteolata.

Thirteen diterpenoids (1-13), including two new norditerpene lactones (1-2) and eight new rosane diterpenoids (3-10), were isolated from the roots of Euphorbia ebracteolata. The structures were determined by 1D and 2D NMR, HRESIMS, and electronic circular dichroism (ECD). The ECD-based empirical rule for α,β-unsaturated-γ-lactones was applied to determine the absolute configurations of 1 and 2. Compounds 7, 10, and 13 exhibited significant inhibition of nitric oxide production in RAW 264.7 lipopolysaccharide-induced macrophages, with IC50 values of 2.44, 2.76, and 1.02 μM, respectively.