Antistaphylococcal Prenylated Acylphoroglucinol and Xanthones from Kielmeyera variabilis

Aline Coqueiro, Young H. Choi, Robert Verpoorte, Karthick B.S.S. Gupta, Maria De Mieri, Matthias Hamburger, Maria C.M. Young, Paul Stapleton, Simon Gibbons, Vanderlan Da S. Bolzani

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13 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)470-476
Number of pages7
JournalJournal of Natural Products
Volume79
Issue number3
Early online date22 Feb 2016
DOIs
Publication statusPublished - 25 Mar 2016

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