title: Sesquiterpene lactones from Centaurea tweediei.
abstract: Aerial parts of Centaurea tweediei from Argentina afforded as the main constituent the sesquiterpene lactone onopordopicrin and minor amounts of a new heliangolide, a new guaianolide, a new eudesmanolide, a new eudesmane acid and the lignans arctigenin and matairesinol.
authors.affiliation: Instituto de Química Orgánica, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 491, 4000 S. M. de, Tucumán, Argentina
authors.forename: A M.
authors.initials: AM
authors.lastname: Fortuna
authors.forename: E C.
authors.initials: EC
authors.lastname: de Riscala
authors.forename: C A.N.
authors.initials: CA
authors.lastname: Catalan
authors.forename: T E.
authors.initials: TE
authors.lastname: Gedris
authors.forename: W
authors.initials: W
authors.lastname: Herz