title: Stereochemical analysis of leubethanol, an anti-TB-active serrulatane, from Leucophyllum frutescens.
abstract: Bioactivity-guided fractionation of the methanolic root bark extract of Leucophyllum frutescens led to the identification of leubethanol (1), a new serrulatane-type diterpene with activity against both multi-drug-resistant and drug-sensitive strains of virulent Mycobacterium tuberculosis. Leubethanol (1) was identified by 1D/2D NMR data, as a serrulatane closely related to erogorgiane (2), and exhibited anti-TB activity with minimum inhibitory concentrations in the range 6.25-12.50 μg/mL. Stereochemical evidence for 1 was gleaned from 1D and 2D NOE experiments, from 1H NMR full spin analysis, and by comparison of the experimental vibrational circular dichroism (VCD) spectrum to density functional theory calculated VCD spectra of two diastereomers.
authors.affiliation: Department of Analytical Chemistry, Faculty of Medicine, Universidad Autónoma de Nuevo Leon, P.O. Box 2316, Sucursal Tecnológico, Monterrey, N.L., 64841 Mexico.
authors.forename: Gloria M
authors.initials: GM
authors.lastname: Molina-Salinas
authors.forename: Verónica M
authors.initials: VM
authors.lastname: Rivas-Galindo
authors.forename: Salvador
authors.initials: S
authors.lastname: Said-Fernández
authors.forename: David C
authors.initials: DC
authors.lastname: Lankin
authors.forename: Marcelo A
authors.initials: MA
authors.lastname: Muñoz
authors.forename: Pedro
authors.initials: P
authors.lastname: Joseph-Nathan
authors.forename: Guido F
authors.initials: GF
authors.lastname: Pauli
authors.forename: Noemí
authors.initials: N
authors.lastname: Waksman
mesh_terms: D000995:Antitubercular Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D002942:Circular Dichroism; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D008800:Mexico; D015394:Molecular Structure; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D019906:Nuclear Magnetic Resonance, Biomolecular; D024301:Plant Bark / Q000737:chemistry; D018517:Plant Roots / Q000737:chemistry; D028083:Scrophulariaceae / Q000737:chemistry*
chemical_list: D000995:Antitubercular Agents; D004224:Diterpenes; C562291:erogorgiane; C562290:leubethanol