Two new compounds, 2,5-dihydroxyisocostic acid and 2,3-dihydroxycostic acid together with three known sesquiterpene compounds, Isocostic acid, Carabrone and Tomentosin, have been isolated from the acetone extract of Inula viscosa (L.) Aiton. The structures of all new compounds were determined by
Phytochemical investigation of the aerial parts of Inula hupehensis Ling. led to the isolation and identification of 27 sesquiterpene lactones (1-27), including three new eudesmanolides (3-5), three new germacranolides (9-11), one new xanthanolide (16), two new carabrone derivatives (25-26), and 18