ent-Abietane-type lactones with anti-inflammatory activity from Euphorbia helioscopia.

Euphohelinodes D-I (1-6), six previously unreported ent-abietane lactones, along with two known analogues (7 and 8), were isolated from the anti-inflammatory fraction extracted from E. helioscopia by a bioactivity-guided isolation. Their structures were characterized using a combination of spectroscopic data interpretation, single-crystal X-ray diffraction and ECD analysis. The anti-inflammatory activity of these compounds was evaluated by measuring their inhibitory effects on NO production in LPS-stimulated RAW264.7 macrophages. The most active candidate, euphohelinode H (5), had better inhibitory activity against NO production with an IC50 value of 30.23 ± 2.33 μM. Further study revealed that 5 significantly suppressed the expressions of iNOS and COX-2 through the NF-κB signaling pathway.