title: The mechanism of antimicrobial activity of sophoraflavanone B against methicillin-resistant Staphylococcus aureus.
abstract: Sophoraflavanone B (SPF-B), a prenylated flavonoid, can be isolated from the roots of Desmodium caudatum. The aim of this study was to determine the mechanism of SPF-B's antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA). MRSA is a multidrug-resistant pathogen and the main cause of hospital- and community-acquired infections. The minimum inhibitory concentration (MIC) of SPF-B was assessed using the broth microdilution method. The mechanism of action of SPF-B on S. aureus was analyzed in combination assays incorporating detergents, ATPase inhibitors, and peptidoglycan (PGN) derived from S. aureus. Furthermore, morphological changes in the SPF-B-treated MRSA strains were investigated using transmission electron microscopy. The MIC of SPF-B for MRSA was in the range of 15.6-31.25 μg/mL. The mechanism of action of SPF-B on MRSA was investigated using combination assays with detergent and ATPase inhibitors. The optical density at 600 nm of MRSA suspensions treated with a combination of detergent and SPF-B reduced the MRSA by 63%-73%. In the SPF-B and PGN combination assay, direct binding of SPF-B with PGN from S. aureus was evident. These data may be validated for the development of new antibacterial drugs for low MRSA resistance.
authors.affiliation: 1 BK21 Plus Team, Professional Graduate School of Oriental Medicine, Wonkwang University , Iksan, Jeonbuk, Korea.
authors.forename: Su-Hyun
authors.initials: SH
authors.lastname: Mun
authors.forename: Dae-Ki
authors.initials: DK
authors.lastname: Joung
authors.forename: Sung-Bae
authors.initials: SB
authors.lastname: Kim
authors.forename: Sung-Joo
authors.initials: SJ
authors.lastname: Park
authors.forename: Yun-Soo
authors.initials: YS
authors.lastname: Seo
authors.forename: Ryong
authors.initials: R
authors.lastname: Gong
authors.forename: Jang-Gi
authors.initials: JG
authors.lastname: Choi
authors.forename: Dong-Won
authors.initials: DW
authors.lastname: Shin
authors.forename: Jung-Rae
authors.initials: JR
authors.lastname: Rho
authors.forename: Ok-Hwa
authors.initials: OH
authors.lastname: Kang
authors.forename: Dong-Yeul
authors.initials: DY
authors.lastname: Kwon
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D002473:Cell Wall / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D003902:Detergents / Q000494:pharmacology; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology; D044950:Flavanones / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D008826:Microbial Sensitivity Tests; D046529:Microscopy, Electron, Transmission; D010457:Peptidoglycan / Q000378:metabolism*
chemical_list: D000890:Anti-Infective Agents; D003902:Detergents; D044950:Flavanones; D010457:Peptidoglycan; C433506:sophoraflavonone B; D004024:Dicyclohexylcarbodiimide