Sesquiterpene lactones and scopoletins from Artemisia scoparia Waldst. & Kit. and their angiotensin I-converting enzyme inhibitory activities.

Ten compounds, including a new guaiane-type sesquiterpene lactone, were isolated from the aerial parts of Artemisia scoparia. The structure of the new compound was determined to be 5-hydroxyguaia-3(4),11(13),10(14)-trien-6α,12-olide, named scoparanolide. Six known sesquiterpene lactones [estafiatone, 3β,4α-dihydroxyguaia-11(13),10(14)-dien-6α,12-olide, estafiatin, preeupatundin, 3β-hydroxycostunolide, and ludovicin B] and three known coumarin derivatives (scopoletin, scoparone, and isofraxidin) were identified by nuclear magnetic resonance and electrospray ionization mass spectroscopy. Six known sesquiterpene lactones were found for the first time in this plant. The angiotensin I-converting enzyme inhibitory activities of coumarin derivatives and scopoletins were significantly higher compared to those of sesquiterpene lactones and quercetin.