title: Antifeedant activity of neo-clerodane diterpenes from Baccharis flabellata Hook & Arn var. flabellata toward Tribolium castaneum Herbst: structure-activity relationships.
abstract: In order to establish structure-activity relationships, nine neo-clerodane diterpenes isolated from the acetone extract of aerial parts of Baccharis flabellata Hook & Arn var. fabellata were assayed for antifeedant activity against Tribolium castaneum (Coleoptera: Tenebrionidae). Compounds exhibiting maximal antifeedant activities showed an alpha,beta-unsaturated carbonyl group on the decalin portion and a furan ring at the side chain. Stereoelectronic studies indicate that the distance between the furan heteroatom and the more electrophilic carbon of the decaline moiety, as well as the electrostatic charge on that atom, were important features for antifeedant activity. Compounds possesing an alpha,beta,gamma,delta-unsaturated carbonyl group or an acetoxyl group at C-2, were inactive. Theoretical calculations were performed in order to find some structure-activity relationships.
authors.affiliation: Intequi-Conicet, Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700 San Luis, Argentina.
authors.forename: Virgina E
authors.initials: VE
authors.lastname: Juan Hikawczuk
authors.forename: María A
authors.initials: MA
authors.lastname: López Verrilli
authors.forename: Eduardo J
authors.initials: EJ
authors.lastname: Borkowski
authors.forename: Marta E
authors.initials: ME
authors.lastname: Sosa
authors.forename: Oscar S
authors.initials: OS
authors.lastname: Giordano
authors.forename: José R
authors.initials: JR
authors.lastname: Saad
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Tonn
mesh_terms: D000818:Animals; D031175:Baccharis / Q000737:chemistry*; D045785:Diterpenes, Clerodane / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D005247:Feeding Behavior / Q000187:drug effects; D008968:Molecular Conformation; D019906:Nuclear Magnetic Resonance, Biomolecular; D009904:Optical Rotation; D021241:Spectrometry, Mass, Electrospray Ionization; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013329:Structure-Activity Relationship; D014231:Tribolium / Q000187:drug effects* / Q000502:physiology
chemical_list: D045785:Diterpenes, Clerodane