title: Synergistic effect of artocarpin on antibacterial activity of some antibiotics against methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli.
abstract: BACKGROUND
  Antibacterial resistance has dramatically increased and resulted in serious health problems worldwide. One appealing strategy to overcome this resistance problem is the use of combinations of antibacterial compounds to increase their potency.
  
  
  OBJECTIVE
  The objective of this study is to determine the synergistic effects of artocarpin for ampicillin, norfloxacin, and tetracycline against methicillin-resistant Staphylococcus aureus (MRSA) as well as the Gram-negative bacteria Pseudomonas aeruginosa and Escherichia coli.
  
  
  METHODS
  A broth microdilution method (1.95-250 µg/mL) was used to determine the minimum inhibitory concentration (MIC) of artocarpin and the antibiotics. Any synergistic effects were evaluated at their own MIC using the checkerboard method and a time-kill assay at 37 °C for 24 h.
  
  
  CONCLUSIONS
  Artocarpin showed antibacterial activity against MRSA and E. coli with an MIC value of 62.5 µg/mL, and against P. aeruginosa with an MIC value of 250 µg/mL. The interaction of artocarpin with all tested antibiotics produced synergistic effects against MRSA with a fractional inhibitory concentration index (FICI) of 0.15-0.37. In addition, a combination of artocarpin and norfloxacin showed a synergistic effect against E. coli with an FICI value of 0.37, while the combinations of artocarpin and tetracycline as well as artocarpin and norfloxacin exhibited synergy interactions against P. aeruginosa with FICI values of 0.24 and 0.37, respectively. Time-kill assays indicated that artocarpin enhanced the antimicrobial activities of tetracycline, ampicillin, and norfloxacin against MRSA as well as Gram-negative bacteria.
authors.affiliation: a Department of Pharmacognosy and Pharmaceutical Botany , Faculty of Pharmaceutical Sciences, Prince of Songkla University , Songkhla , Thailand and.
authors.forename: Abdi Wira
authors.initials: AW
authors.lastname: Septama
authors.affiliation: a Department of Pharmacognosy and Pharmaceutical Botany , Faculty of Pharmaceutical Sciences, Prince of Songkla University , Songkhla , Thailand and.|b Excellent Research Laboratory, Phytomedicine and Pharmaceutical Biotechnology Excellence Center, Faculty of Pharmaceutical Sciences, Prince of Songkla University , Songkhla , Thailand.
authors.forename: Pharkphoom
authors.initials: P
authors.lastname: Panichayupakaranant
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000302:isolation & purification; D031622:Artocarpus; D004338:Drug Combinations; D004357:Drug Synergism; D004926:Escherichia coli / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D037241:Mannose-Binding Lectins / Q000008:administration & dosage* / Q000302:isolation & purification; D008712:Methicillin / Q000008:administration & dosage; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000502:physiology; D008826:Microbial Sensitivity Tests / Q000379:methods; D010936:Plant Extracts / Q000008:administration & dosage / Q000302:isolation & purification; D037121:Plant Lectins / Q000008:administration & dosage* / Q000302:isolation & purification; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000502:physiology
chemical_list: D000900:Anti-Bacterial Agents; D004338:Drug Combinations; D037241:Mannose-Binding Lectins; D010936:Plant Extracts; D037121:Plant Lectins; C090683:artocarpin lectin; D008712:Methicillin
keywords: Ampicillin; Artocapus heterophyllus; MRSA; norfloxacin; tetracycline