title: Phytotoxic withanolides from Jaborosa rotacea.
abstract: Twelve new withanolides were isolated from the aerial part of Jaborosa rotacea: five had a spiranoid delta-lactone (1-5); one contained a 26,12-delta-lactone and a C-12-C-23 bond (6); five corresponded to trechonolide-type withanolides with configuration at C-23 opposite of those previously isolated (7, 8, 10-12); two of these have an additional oxido-bridge between C-21 and C-24; finally a withanolide with a hemiketal ring formed between a 21-hydroxyl and a 12-ketone (13) and the closely related jaborosalactone R were also isolated. New compounds were fully characterized by a combination of spectroscopic methods (1D and 2D NMR and MS). The structures of the spiranoid withanolide and of the epimer of trechonolide A were confirmed by X-ray diffraction studies. Compounds 4, 5, 6, and 8 showed selective phytotoxicity toward monocotyledoneous and dicotyledoneous species.
authors.affiliation: Departamento de Química Organica and IMBIV, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, 5000 Córdoba, Argentina.
authors.forename: Viviana E
authors.initials: VE
authors.lastname: Nicotra
authors.forename: Natalia S
authors.initials: NS
authors.lastname: Ramacciotti
authors.forename: Roberto R
authors.initials: RR
authors.lastname: Gil
authors.forename: Juan C
authors.initials: JC
authors.lastname: Oberti
authors.forename: Gabriela E
authors.initials: GE
authors.lastname: Feresin
authors.forename: Cecilia A
authors.initials: CA
authors.lastname: Guerrero
authors.forename: Ricardo F
authors.initials: RF
authors.lastname: Baggio
authors.forename: M Teresa
authors.initials: MT
authors.lastname: Garland
authors.forename: Gerardo
authors.initials: G
authors.lastname: Burton
mesh_terms: D001118:Argentina; D018360:Crystallography, X-Ray; D004875:Ergosterol / Q000031:analogs & derivatives / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D018545:Lactuca / Q000187:drug effects / Q000254:growth & development; D008968:Molecular Conformation; D015394:Molecular Structure; D031783:Phalaris / Q000187:drug effects / Q000254:growth & development; D036226:Seedlings / Q000187:drug effects* / Q000254:growth & development*; D019657:Solanaceae / Q000737:chemistry*
chemical_list: D004875:Ergosterol