Antagonistic interactions between the flavonoids hesperetin and naringenin and β-lactam antibiotics against Staphylococcus aureus

• Published in: British journal of biomedical science Vol. 65; no. 3; pp. 145 - 147
• Main Authors: Denny, S., West, P.W.J., Mathew, T.C.
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 01.01.2008
• Subjects: Cefoxitin - pharmacology; Drug Interactions; Electron microscopy; Flavanones - pharmacology; Flavonoids - pharmacology; Hesperidin - pharmacology; Methicillin - pharmacology; Methicillin resistance; Methicillin-Resistant Staphylococcus aureus - drug effects; Methicillin-Resistant Staphylococcus aureus - ultrastructure; Microbial Sensitivity Tests; Microscopy, Electron, Scanning; Monobactams - pharmacology; Penicillins - pharmacology; Species Specificity; Staphylococcus aureus
• ISSN: 0967-4845; 2474-0896
• DOI: 10.1080/09674845.2008.11732819

Flavonoids are a group of polyphenolic plant compounds with a range of biological activities. This study shows that the flavonoids hesperetin and naringenin have antibacterial activity against methicillin-sensitive and methicillin-resistant Staphylococcus aureus isolates. Minimum inhibitory concentrations for hesperetin were 250 and 500 g/mL, respectively, and for naringenin were 125 and 250 g/mL, respectively. This effect was reversed by the -lactam antibiotics methicillin, penicillin and oxacillin, but not by cefoxitin. For bacteria growing in the presence of these antibiotics, the flavonoids had no effect on the levels of -lactamase enzymes and PBP-2' compared to controls. Electron microscopy showed abnormal morphology in bacteria treated with subinhibitory concentrations of flavonoids. These results are interesting because previous studies have reported synergistic interactions between flavonoids and -lactam antibiotics. It is suggested that an interaction removes both inhibitors from the bacterial growth milieu.