title: Anti-methicillin-resistant Staphylococcus aureus assay of azalomycin F5a and its derivatives.
abstract: OBJECTIVE
  To discover anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) microbial natural products or their derivatives.
  
  
  METHODS
  Azalomycin F5a (1) was prepared through fermentation of Streptomyces hygroscopicus var. azalomyceticus, and its derivatives were synthesized through hydrocarbylation in hydrocarbyl alcoholic-AcOH (4 : 1) and subsequent demalonylation with 2 mol·L(-1) KOH in MeOH-H2O (7 : 3). Their activities against MRSA ATCC 33592 and three clinical MRSA isolates were evaluated by the agar diffusion and broth microdilution methods.
  
  
  RESULTS
  Four demalonylazalomycin F5a derivatives 2 to 5 were synthesized. The anti-MRSA activity assay indicated that compounds 1 to 5 showed remarkable activity against MRSA, and their minimum inhibitory concentrations (MICs) were respectively 3.0-4.0, 0.5-1.0, 0.67-1.0, 0.67-0.83, and 0.5-0.83 μg·mL(-1).
  
  
  CONCLUSIONS
  Azalomycin F5a and the demalonylazalomycin F5a derivatives 2-5 showed remarkable anti-MRSA activity, and the anti-MRSA activities of 2 to 5 were higher than that of 1, while the anti-MRSA activities of 2 to 5 showed no obvious differences. It was also shown that the malonyl monoester group of azalomycin F5a was less important for its anti-MRSA activity.
authors.affiliation: College of Bioscience and Engineering, Jiangxi Agricultural University, Nanchang 330045, China. Electronic address: sqlygj@126.com.
authors.forename: Gan-Jun
authors.initials: GJ
authors.lastname: Yuan
authors.affiliation: School of Life Science, Sun Yat-sen University, Guangzhou 510275, China.
authors.forename: Pei-Bo
authors.initials: PB
authors.lastname: Li
authors.affiliation: College of Bioscience and Engineering, Jiangxi Agricultural University, Nanchang 330045, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.affiliation: College of Bioscience and Engineering, Jiangxi Agricultural University, Nanchang 330045, China.
authors.forename: Hui-Zhong
authors.initials: HZ
authors.lastname: Pang
authors.affiliation: College of Bioscience and Engineering, Jiangxi Agricultural University, Nanchang 330045, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Pei
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D006801:Humans; D018942:Macrolides / Q000737:chemistry* / Q000494:pharmacology*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D013203:Staphylococcal Infections / Q000382:microbiology; D013329:Structure-Activity Relationship
chemical_list: D000900:Anti-Bacterial Agents; D018942:Macrolides; C559579:azalomycin F5a
keywords: Anti-MRSA; Azalomycin F(5a); Demalonyl Derivatives; Macrocyclic antibiotics