title: 15,21-Cyclowithanolides from Jaborosa bergii.
abstract: Six new withanolides (1-6) were isolated from the aerial parts of Jaborosa bergii plants and characterized by spectroscopic methods (1D and 2D NMR, MS). Five of the new compounds presented a novel norbornane-type structure in ring D of the steroid nucleus (1-5), resulting from a carbon-carbon bond between C-15 and C-21. The sixth withanolide isolated was the 5alpha-chloro-6beta-hydroxy analogue (6) of 2,3-dehydrojaborosalactol M (7), previously isolated from this plant. Compound 1 showed selective phytotoxicity toward monocotiledoneous and dicotiledoneous species.
authors.affiliation: Departamento de Química Orgánica 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: Roberto R
authors.initials: RR
authors.lastname: Gil
authors.forename: Clarisa
authors.initials: C
authors.lastname: Vaccarini
authors.forename: Juan C
authors.initials: JC
authors.lastname: Oberti
authors.forename: Gerardo
authors.initials: G
authors.lastname: Burton
mesh_terms: D001118:Argentina; D004305:Dose-Response Relationship, Drug; D004875:Ergosterol / Q000031:analogs & derivatives / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010946:Plants, Medicinal / Q000737:chemistry*; D019657:Solanaceae / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D004875:Ergosterol