Synergistic effect of kaempferol glycosides purified from Laurus nobilis and fluoroquinolones on methicillin-resistant Staphylococcus aureus

Mei Hua Liu, Nao Otsuka, Kumiko Noyori, Sumiko Shiota, Wakano Ogawa, Teruo Kuroda, Tsutomu Hatano, Tomofusa Tsuchiya

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29 Citations (Scopus)


In a previous study, we reported that two kaempferol glycosides isolated from Laurus nobilis L., kaempferol-3-O-α -L-(2″,4″-di-E-p- coumaroyl)-rhamnoside (C2) and kaempferol-3-O-α -L-(2″-E-p- coumaroyl-4″-Z-p-coumaroyl)-rhamnoside (C3), showed strong antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci. Thereafter we found that these compounds greatly reduced the minimum inhibitory concentrations (MICs) of some fluoroquinolones in MRSA. In other words, C2 and C3 greatly potentiated anti-MRSA activity of fluoroquinolones. The effect of C2 and C3 with fluoroquinolones was found to be synergistic. The potentiation activity was observed with hydrophilic fluoroquinolones, such as norfloxacin and ciprofloxacin, but not with hydrophobic quinolones. We also found that norfloxacin reduced MICs of C2 and C3. The effect was synergistic. Possible mechanism of the synergistic effect was discussed.

Original languageEnglish
Pages (from-to)489-492
Number of pages4
JournalBiological and Pharmaceutical Bulletin
Issue number3
Publication statusPublished - Mar 1 2009



  • Kaempferol glycoside
  • Methicillin-resistant Staphylococcus aureus
  • Norfloxacin
  • Synergistic effect
  • Topoisomerase IV

ASJC Scopus subject areas

  • Pharmacology
  • Pharmaceutical Science

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