title: Combination Therapy of Sophoraflavanone B against MRSA: In Vitro Synergy Testing.
abstract: Sophoraflavanone B (SPF-B), a known prenylated flavonoid, was isolated from the roots of Desmodium caudatum. The aim of this study was to determine the antimicrobial synergism of SPF-B combined with antibiotics against methicillin-resistant Staphylococcus aureus (MRSA). MRSA, a multidrug-resistant pathogen, causes both hospital- and community-acquired infections worldwide. The antimicrobial activity of SPF-B was assessed by the broth microdilution method, checkerboard dilution test, and time-kill curve assay. The MIC of SPF-B for 7 strains of S. aureus ranges from 15.6 to 31.25  μ g/mL determined. In the checkerboard method, the combinations of SPF-B with antibiotics had a synergistic effect; SPF-B markedly reduced the MICs of the β -lactam antibiotics: ampicillin (AMP) and oxacillin (OXI); aminoglycosides gentamicin (GET); quinolones ciprofloxacin (CIP) and norfloxacin (NOR) against MRSA. The time-kill curves assay showed that a combined SPF-B and selected antibiotics treatment reduced the bacterial counts below the lowest detectable limit after 24 h. These data suggest that the antibacterial activity of SPF-B against MRSA can be effectively increased through its combination with three groups of antibiotics ( β -lactams, aminoglycosides, and quinolones). Our research can be a valuable and significant source for the development of a new antibacterial drug with low MRSA resistance.
authors: BK21 Plus Team, Professional Graduate School of Oriental Medicine, Wonkwang University, 344-2 Sinyong-dong, Iksan, Chonbuk 570-749, Republic of Korea.
authors: Su-Hyun
authors: SH
authors: Mun
authors: Ok-Hwa
authors: OH
authors: Kang
authors: Dae-Ki
authors: DK
authors: Joung
authors: Sung-Bae
authors: SB
authors: Kim
authors: Yun-Soo
authors: YS
authors: Seo
authors: Jang-Gi
authors: JG
authors: Choi
authors: Young-Seob
authors: YS
authors: Lee
authors: Seon-Woo
authors: SW
authors: Cha
authors: Young-Sup
authors: YS
authors: Ahn
authors: Sin-Hee
authors: SH
authors: Han
authors: Dong-Yeul
authors: DY
authors: Kwon