Synergists from Portulaca oleracea with macrolides against methicillin-resistant Staphylococcus aureus and related mechanism
KP Fung, QB Han, M Ip, XS Yang, CBS Lau, BCL Chan
School of Biomedical Sciences, The Chinese University of Hong Kong
1. Two unsaturated fatty acids—linoleum acid and oleic acid—were identified from Portulaca oleracea that acted synergistically with erythromycin in vitro against methicillin-resistant Staphylococcus aureus RN4220-pUL5054, possibly by inhibiting the methionine sulfoxide reductase A multidrug efflux pump of the bacteria.
2. By comparing a panel of linoleic acid and oleic acid analogues, unsaturated fatty acids in salt form with cis configuration and an increase in number of double bonds were found to increase the antibacterial activity against RN4220-pUL5054 when used alone or in combination with erythromycin.
3. The salt forms of linoleic acid and oleic acid with erythromycin could significantly reduce the bacterial count in the lungs of mice infected with RN4220-pUL5054.