2. Academic Validation
  3. Antistaphylococcal Prenylated Acylphoroglucinol and Xanthones from Kielmeyera variabilis

Antistaphylococcal Prenylated Acylphoroglucinol and Xanthones from Kielmeyera variabilis

  • J Nat Prod. 2016 Mar 25;79(3):470-6. doi: 10.1021/acs.jnatprod.5b00858.
Aline Coqueiro 1 2 3,  Young H Choi 1,  Robert Verpoorte 1,  Karthick B S S Gupta 4,  Maria De Mieri 5,  Matthias Hamburger 5,  Maria C M Young 6,  Paul Stapleton 2,  Simon Gibbons 2,  Vanderlan da S Bolzani 3
Affiliations

Affiliations

  • 1 Natural Products Laboratory, Institute of Biology, Leiden University , Sylviusweg 72, Leiden, 2333 BE, The Netherlands.
  • 2 Research Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy , 29-39 Brunswick Square, London, WC1N 1AX, United Kingdom.
  • 3 Department of Organic Chemistry, Institute of Chemistry, São Paulo State University , Prof. Francisco Degni 55, Araraquara, 14800-900, Brazil.
  • 4 NMR Facility, Leiden Institute of Chemistry, Leiden University , Einsteinweg 55, Leiden, 2333 CC, The Netherlands.
  • 5 Division of Pharmaceutical Biology, University of Basel , Klingelbergstrasse 50, Basel, CH-4056, Switzerland.
  • 6 Section of Plant Physiology and Biochemistry, Institute of Botany , São Paulo, 01061-970, Brazil.
PMID: 26900954 DOI: 10.1021/acs.jnatprod.5b00858
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.

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