Biological and Pharmaceutical Bulletin
Online ISSN : 1347-5215
Print ISSN : 0918-6158
ISSN-L : 0918-6158
Synergistic Effect of Kaempferol Glycosides Purified from Laurus nobilis and Fluoroquinolones on Methicillin-Resistant Staphylococcus aureus
Mei-Hua LiuNao OtsukaKumiko NoyoriSumiko ShiotaWakano OgawaTeruo KurodaTsutomu HatanoTomofusa Tsuchiya
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2009 Volume 32 Issue 3 Pages 489-492


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.

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© 2009 The Pharmaceutical Society of Japan
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