title: Synergistic effect of kaempferol glycosides purified from Laurus nobilis and fluoroquinolones on methicillin-resistant Staphylococcus aureus.
abstract: In a previous study, we reported that two kaempferol glycosides isolated from Laurus nobilis L., kaempferol-3-O-alpha-L-(2'',4''-di-E-p-coumaroyl)-rhamnoside (C2) and kaempferol-3-O-alpha-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.
authors.affiliation: Department of Molecular Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Japan.
authors.forename: Mei-Hua
authors.initials: MH
authors.lastname: Liu
authors.forename: Nao
authors.initials: N
authors.lastname: Otsuka
authors.forename: Kumiko
authors.initials: K
authors.lastname: Noyori
authors.forename: Sumiko
authors.initials: S
authors.lastname: Shiota
authors.forename: Wakano
authors.initials: W
authors.lastname: Ogawa
authors.forename: Teruo
authors.initials: T
authors.lastname: Kuroda
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Hatano
authors.forename: Tomofusa
authors.initials: T
authors.lastname: Tsuchiya
mesh_terms: D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D003373:Coumaric Acids / Q000302:isolation & purification / Q000494:pharmacology*; D004357:Drug Synergism; D024841:Fluoroquinolones / Q000302:isolation & purification / Q000494:pharmacology*; D006027:Glycosides / Q000302:isolation & purification / Q000502:physiology*; D044949:Kaempferols / Q000302:isolation & purification / Q000494:pharmacology*; D027442:Laurus / Q000737:chemistry*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D008826:Microbial Sensitivity Tests
chemical_list: D000900:Anti-Bacterial Agents; D003373:Coumaric Acids; D024841:Fluoroquinolones; D006027:Glycosides; D044949:Kaempferols; C093866:kaempferol 3-(2,4-di-(4-coumaroyl)rhamnoside); C540136:kaempferol-3-O-alpha-L-(2''-E-p-coumaroyl-4''-Z-p-coumaroyl)-rhamnoside