title: Cytotoxic withaphysalins from the leaves of Acnistus arborescens.
abstract: Three withaphysalins, rel-(17S,20R,22R)-5 beta,6 beta:18,20-diepoxy-4 beta-hydroxy-1,18-dioxowitha-2,24-dienolide(withaphysalin M) (1), rel-(17S,20R,22R)-5 beta,6 beta:18,20-diepoxy-4 beta-hydroxy-18-ethoxy-1-oxowitha-2,24-dienolide (withaphysalin F ethyl ether, withaphysalin O) (2), and rel-(17S,20R,22R)-5 beta,6 beta:18,20-diepoxy-4 beta-hydroxy-1,18-dioxowitha-24-enolide (withaphysalin N) (3), were isolated from the leaves of Acnistus arborescens. The structures were deduced from 1D ((1)H NMR, (13)C NMR, DEPT-(13)C NMR) and 2D (COSY, HMQC, HMBC) NMR analysis and the relative stereochemical assignments based on 1D NOESY correlations and analysis of coupling constants. Compounds 1 and 2 displayed potent cytotoxic activity against a panel of human cancer cell lines.
authors.affiliation: Curso de Pós-Graduação em Química Orgânica, Departamento de Química Orgânica e Inorgânica, Centro de Ciências, Universidade Federal do Ceará, 12.200, Fortaleza, CE, 60021-970, Brazil.
authors.forename: Maria Leopoldina
authors.initials: ML
authors.lastname: Veras
authors.forename: Maria Zeneide B
authors.initials: MZ
authors.lastname: Bezerra
authors.forename: Telma Leda G
authors.initials: TL
authors.lastname: Lemos
authors.forename: Daniel Esdras de A
authors.initials: DE
authors.lastname: Uchoa
authors.forename: Raimundo
authors.initials: R
authors.lastname: Braz-Filho
authors.forename: Hee-Byung
authors.initials: HB
authors.lastname: Chai
authors.forename: Geoffrey A
authors.initials: GA
authors.lastname: Cordell
authors.forename: Otília Deusdênia L
authors.initials: OD
authors.lastname: Pessoa
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D001938:Brazil; D004354:Drug Screening Assays, Antitumor; D004875:Ergosterol / Q000031:analogs & derivatives / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D006801:Humans; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D018515:Plant Leaves / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D012632:Secosteroids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D019657:Solanaceae / Q000737:chemistry*; D013237:Stereoisomerism; D014407:Tumor Cells, Cultured
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D012632:Secosteroids; C486267:withaphysalin M; C486265:withaphysalin N; C486266:withaphysalin O; D004875:Ergosterol