title: Saliniketals A and B, bicyclic polyketides from the marine actinomycete Salinispora arenicola.
abstract: An extensive study of the secondary metabolites produced by several strains of the marine actinomycete Salinispora arenicola has led to the isolation of two unusual bicyclic polyketides, saliniketals A and B (1, 2). The structures, which contain a new 1,4-dimethyl-2,8-dioxabicyclo[3.2.1]octan-3-yl ring, were assigned mainly by 2D NMR spectroscopic methods. Unexpectedly, chemical derivatization of saliniketal A with Mosher's acid chloride resulted in a functional group interconversion of an unsaturated primary amide to the corresponding nitrile in a quantitative yield under unusually mild conditions. Saliniketals A and B were found to inhibit ornithine decarboxylase induction, an important target for the chemoprevention of cancer, with IC50 values of 1.95 +/- 0.37 and 7.83 +/- 1.2 microg/mL, respectively.
authors.affiliation: Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California - San Diego, La Jolla, California 92093-0204, USA.
authors.forename: Philip G
authors.initials: PG
authors.lastname: Williams
authors.forename: Ratnakar N
authors.initials: RN
authors.lastname: Asolkar
authors.forename: Tamara
authors.initials: T
authors.lastname: Kondratyuk
authors.forename: John M
authors.initials: JM
authors.lastname: Pezzuto
authors.forename: Paul R
authors.initials: PR
authors.lastname: Jensen
authors.forename: William
authors.initials: W
authors.lastname: Fenical
mesh_terms: D000190:Actinomyces / Q000737:chemistry*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D006141:Guam; D020128:Inhibitory Concentration 50; D008386:Marine Biology; D015394:Molecular Structure; D009955:Ornithine Decarboxylase / Q000378:metabolism*; D065108:Ornithine Decarboxylase Inhibitors
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D065108:Ornithine Decarboxylase Inhibitors; C517709:saliniketal A; C517708:saliniketal B; D009955:Ornithine Decarboxylase