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.