Sesquiterpenoids from Artemisia argyi and their COXs inhibitory activities.

Four new sesquiterpene lactones, named artemargyinolides A–D (1–4), and seven known sesquiterpenoids (5–11) were isolated from Artemisia argyi. Their structures were elucidated based on the extensive analysis of spectroscopic data. The absolute configuration of 1 was assigned by X-ray crystallographic analysis. Compound 1 is an unprecedented sesquiterpene dimer-monoterpene lactone. The cyclooxygenases (COX-1 and COX-2) inhibitory activities of all isolated compounds were evaluated. Compounds 1, 2, 4, and 6–11 showed inhibitory activity against COX-2 with IC50 values ranging from 35.78 ± 0.39 to 256.07 ± 0.38 μM. However, compounds 7, 9, and 10 exhibited weak inhibitory activity against COX-1 with IC50 values of 465.70 ± 1.53, 281.43 ± 3.56, and 490.45 ± 6.07 μM, respectively. Other compounds are inactive against COX-1. Therefore, compounds 1, 2, 4, 6, 8, and 11 displayed selective COX-2 inhibitory activity.