A new isopimarane-type diterpene with anti-inflammatory activity from the Clinacanthus nutans.

A new isopimarane-type diterpene clinacanoid A (1) together with seven known terpenoids (2-8) were obtained from the Clinacanthus nutans. Their structures were elucidated based on extensive spectroscopic analysis (NMR, HR-ESI-MS), and the absolute configuration of 1 was established based on single crystal X-ray diffraction. The inhibitory activity of all the compounds on NO production in lipopolysaccharide-induced (LPS) mouse leukemic monocyte macrophage RAW264.7 cells was evaluated. Among them, compounds 1 and 3 showed potential anti-inflammatory activities, with IC50 values of 13.3 ± 0.3 and 12.4 ± 0.4 µM, respectively.