1. Antistaphylococcal Prenylated Acylphoroglucinol and Xanthones from Kielmeyera variabilis.
- Author
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Coqueiro A, Choi YH, Verpoorte R, Gupta KB, De Mieri M, Hamburger M, Young MC, Stapleton P, Gibbons S, and Bolzani Vda S
- Subjects
- Brazil, Methicillin-Resistant Staphylococcus aureus drug effects, Microbial Sensitivity Tests, Molecular Structure, Nuclear Magnetic Resonance, Biomolecular, Plant Components, Aerial chemistry, Stereoisomerism, Anti-Bacterial Agents chemistry, Anti-Bacterial Agents isolation & purification, Anti-Bacterial Agents pharmacology, Clusiaceae chemistry, Phloroglucinol analogs & derivatives, Phloroglucinol chemistry, Phloroglucinol isolation & purification, Phloroglucinol pharmacology, Staphylococcus aureus drug effects, Xanthones chemistry, Xanthones isolation & purification, Xanthones pharmacology
- 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.
- Published
- 2016
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