Ingenane diterpenoids with anti-inflammatory activity from Euphorbia antiquorum

The Euphorbia plants are famous for their diterpenoid constituents with diverse structures and broad biological activities. Herein, the discovery of 15 ingenane diterpenoids including 10 previously unreported ones ( 1 − 10 ) from Euphorbia antiquorum was presented. Structures of the undescribed compounds were established via detailed spectroscopic analyses. Meanwhile, a preliminary anti-inflammatory screening revealed that compound 6 showed significant inhibitory activity against the production of nitric oxide, as well as downregulated the expression of COX-2 and IL-6, in lipopolysaccharide-stimulated RAW264.7 macrophages. Further mechanistical exploration revealed that compound 6 could exert its anti-inflammatory effect by inhibiting NF-κB and activating Nrf2 signaling pathways.