Combating against methicillin-resistant Staphylococcus aureus - Two fatty acids from Purslane (Portulaca oleracea L.) exhibit synergistic effects with erythromycin

Ben C.L. Chan, X. Q. Han, Sau Lai Lui, C. W. Wong, Tina B.Y. Wang, David W.S. Cheung, Sau Wan Cheng, Margaret Ip, Simon Q B HAN, Xiao Sheng Yang, Claude Jolivalt, Clara B.S. Lau, Ping Chung Leung, Kwok Pui Fung*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

34 Citations (Scopus)

Abstract

Objectives The aims of this study were to identify the active ingredients from Portulaca oleracea L. (PO) that could provide synergism with antibiotics against methicillin-resistant Staphylococcus aureus (MRSA) and their possible mechanisms of resistance inhibition. Methods High-speed counter-current chromatography (HSCCC) coupled with gas chromatography-mass spectrometry and a panel of laboratory MRSA strains were used for checkerboard and efflux inhibitory assays. Key findings Linoleic and oleic acids were identified from HSCCC fraction 18 of PO with synergistic antibacterial activity when combined with erythromycin against RN4220/pUL5054. Ethidium bromide efflux inhibitory studies revealed that linoleic and oleic acids may interfere the activity of MsrA pump. By comparing among a panel of linoleic and oleic acids analogues, unsaturated fatty acids in salt form with cis configuration and an increase in number of double bonds were found to further increase the antibacterial activity when used alone or in combination with antibiotics. Conclusion This study reported for the first time that two active ingredients, namely linoleic and oleic acids, were identified from PO with synergistic antibacterial activity when combined with erythromycin against MRSA RN4220/pUL5054 and possibly act by inhibiting the efflux pumps of the bacteria cells.

Original languageEnglish
Pages (from-to)107-116
Number of pages10
JournalJournal of Pharmacy and Pharmacology
Volume67
Issue number1
DOIs
Publication statusPublished - Jan 2015

Scopus Subject Areas

  • Pharmacology
  • Pharmaceutical Science

User-Defined Keywords

  • fatty acid
  • linoleic acid
  • methicillin-resistant Staphylococcus aureus
  • oleic acid
  • synergy

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