title: Antistaphylococcal Prenylated Acylphoroglucinol and Xanthones from Kielmeyera variabilis.
abstract: Bioactivity-guided fractionation of the EtOH extract of the branches of Kielmeyera variabilis led to the isolation of a new acylphoroglucinol (1), which was active against all the MRSA strains tested herein, with pronounced activity against strain EMRSA-16. Compound 1 displayed an MIC of 0.5 mg/L as compared with an MIC of 128 mg/L for the control antibiotic norfloxacin. The structure of the new compound was elucidated by 1D and 2D NMR spectroscopic analysis and mass spectrometry, and experimental and calculated ECD were used to determine the absolute configurations. The compounds β-sitosterol (2), stigmasterol (3), ergost-5-en-3-ol (4), and osajaxanthone (5) also occurred in the n-hexane fraction. The EtOAc fraction contained nine known xanthones: 3,6-dihydroxy-1,4,8-trimethoxyxanthone (6), 3,5-dihydroxy-4-methoxyxanthone (7), 3,4-dihydroxy-6,8-dimethoxyxanthone (8), 3,4-dihydroxy-2-methoxyxanthone (9), 5-hydroxy-1,3-dimethoxyxanthone (10), 4-hydroxy-2,3-dimethoxyxanthone (11), kielcorin (12), 3-hydroxy-2-methoxyxanthone (13), and 2-hydroxy-1-methoxyxanthone (14), which showed moderate to low activity against the tested MRSA strains.
authors.affiliation: Natural Products Laboratory, Institute of Biology, Leiden University , Sylviusweg 72, Leiden, 2333 BE, The Netherlands.|Research Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy , 29-39 Brunswick Square, London, WC1N 1AX, United Kingdom.|Department of Organic Chemistry, Institute of Chemistry, São Paulo State University , Prof. Francisco Degni 55, Araraquara, 14800-900, Brazil.
authors.forename: Aline
authors.initials: A
authors.lastname: Coqueiro
authors.affiliation: Natural Products Laboratory, Institute of Biology, Leiden University , Sylviusweg 72, Leiden, 2333 BE, The Netherlands.
authors.forename: Young H
authors.initials: YH
authors.lastname: Choi
authors.affiliation: Natural Products Laboratory, Institute of Biology, Leiden University , Sylviusweg 72, Leiden, 2333 BE, The Netherlands.
authors.forename: Robert
authors.initials: R
authors.lastname: Verpoorte
authors.affiliation: NMR Facility, Leiden Institute of Chemistry, Leiden University , Einsteinweg 55, Leiden, 2333 CC, The Netherlands.
authors.forename: Karthick B S S
authors.initials: KB
authors.lastname: Gupta
authors.affiliation: Division of Pharmaceutical Biology, University of Basel , Klingelbergstrasse 50, Basel, CH-4056, Switzerland.
authors.forename: Maria
authors.initials: M
authors.lastname: De Mieri
authors.affiliation: Division of Pharmaceutical Biology, University of Basel , Klingelbergstrasse 50, Basel, CH-4056, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Hamburger
authors.affiliation: Section of Plant Physiology and Biochemistry, Institute of Botany , São Paulo, 01061-970, Brazil.
authors.forename: Maria C M
authors.initials: MC
authors.lastname: Young
authors.affiliation: Research Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy , 29-39 Brunswick Square, London, WC1N 1AX, United Kingdom.
authors.forename: Paul
authors.initials: P
authors.lastname: Stapleton
authors.affiliation: Research Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy , 29-39 Brunswick Square, London, WC1N 1AX, United Kingdom.
authors.forename: Simon
authors.initials: S
authors.lastname: Gibbons
authors.affiliation: Department of Organic Chemistry, Institute of Chemistry, São Paulo State University , Prof. Francisco Degni 55, Araraquara, 14800-900, Brazil.
authors.forename: Vanderlan da S
authors.initials: Vda S
authors.lastname: Bolzani
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D001938:Brazil; D028084:Clusiaceae / Q000737:chemistry*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010696:Phloroglucinol / Q000031:analogs & derivatives / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D035261:Plant Components, Aerial / Q000737:chemistry; D013211:Staphylococcus aureus / Q000187:drug effects*; D013237:Stereoisomerism; D044004:Xanthones / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D044004:Xanthones; C000609817:kielmeyeracin; D010696:Phloroglucinol