Pepluane and Paraliane Diterpenoids from Euphorbia peplus with Potential Anti-inflammatory Activity

Twelve new diterpenoids based on two rare skeletal types, namely, paralianones A–D (1–4) and pepluanols A–H (5–12), along with five known compounds, were isolated from an acetone extract of Euphorbia peplus. Their structures were proposed based on 1D and 2D NMR spectroscopic data analysis. These diterpenoids were evaluated for potential anti-inflammatory activity in a lipopolysaccharide-stimulated mouse macrophage cellular model. Compounds 3, 4, 11, 13, and 16 displayed moderate inhibitory effects on NO inhibition, with IC50 values ranging from 29.9 to 38.3 μM.