Isolation of Guaian-6,12-olides from Artemisia princeps and Their Antioxidant Activity

Background: Korean mugwort, Artemisia princeps, a plant that has been widely used in diet and traditional medicine throughout East Asia.<br/>Methods and Results: Two novel guaian-6,12-olides (1 and 2) and two known compounds (3 and 4) were isolated from Korean mugwort, their chemical structures were established by extensive spectroscopic analysis and comparison with those of known compounds. The antioxidant capacity of the isolated compounds was evaluated by measuring intracellular reactive oxygen species (ROS) generation in HT-1080 cells and the extent of oxidative damage to genomic DNA purified from HT-1080 cells. Compounds 1 and 3 exhibited outstanding intracellular ROS scavenging activity at a concentration of 10 μM compared to the untreated blank. Particularly, 3 exhibited an exceptional ROS scavenging activity of approximately 67% at a concentration of 1 μM after 2 h. Additionally, all compounds significantly inhibited DNA oxidation induced by hydroxyl radicals at a concentration greater than 1 μM. Among them, 4 showed the most effective protection against DNA damage.<br/>Conclusions: Further studies are expected to provide more insight on development of guaian-6,12-olides as potential antioxidants and mechanism by which these types of guaianolides act as antioxidants.