title: Ocimum basilicum: Antibacterial activity and association study with antibiotics against bacteria of clinical importance.
abstract: BACKGROUND
  Ocimum basilicum L. (Lamiaceae), popularly known as basil, is part of a group of medicinal plants widely used in cooking and known for its beneficial health properties, possessing significant antioxidant effects, antinociceptive, and others.
  
  
  OBJECTIVE
  The objective of this study is to determine the pharmacological effects produced on the bacterial strains Staphylococcus aureus and Pseudomonas aeruginosa when standard antibiotics and O. basilicum essential oil are combined.
  
  
  METHODS
  The extraction of O. basilicum (leaves) components was done by steam distillation. The Minimum inhibitory concentration (MIC) was calculated using microdilution technique, where the oil concentrations varied from 2 to 1024 μg/mL. The combinations of O. basilicum oil with ciprofloxacin or imipenem were analyzed by the checkerboard method where fractional inhibitory concentration (FIC) indices were calculated.
  
  
  RESULTS
  Ocimum basilicum essential oil, imipenem, and ciprofloxacin showed respective MIC antibacterial activities of 1024, 4, and 2 μg/mL, against S. aureus. In S. aureus, the oil with imipenem association showed synergistic effect (FIC = 0.0625), while the oil with ciprofloxacin showed antagonism (FIC value = 4.25). In P. aeruginosa, the imipenem/oil association showed additive effect for ATCC strains, and synergism for the clinical strain (FIC values = 0.75 and 0.0625). The association of O. basilicum essential oil with ciprofloxacin showed synergism for clinical strains (FIC value = 0.09).
  
  
  CONCLUSIONS
  Ocimum basilicum essential oil associated with existing standard antibiotics may increase their antibacterial activity, resulting in a synergistic activity against bacterial strains of clinical importance. The antibacterial activity of O. basilicum essential oil may be associated with linalool.
authors.affiliation: a Graduate Program in Synthetic and Natural Bioactive Products, Paraiba Federal University , João Pessoa , Paraiba , Brazil .
authors.forename: Viviane
authors.initials: V
authors.lastname: Araújo Silva
authors.affiliation: a Graduate Program in Synthetic and Natural Bioactive Products, Paraiba Federal University , João Pessoa , Paraiba , Brazil .
authors.forename: Janiere
authors.initials: J
authors.lastname: Pereira da Sousa
authors.affiliation: b Department of Molecular Biology , Paraiba Federal University , João Pessoa , Paraiba , Brazil .
authors.forename: Hilzeth
authors.initials: H
authors.lastname: de Luna Freire Pessôa
authors.affiliation: b Department of Molecular Biology , Paraiba Federal University , João Pessoa , Paraiba , Brazil .
authors.forename: Andrea
authors.initials: A
authors.lastname: Fernanda Ramos de Freitas
authors.affiliation: c Laboratory of Microbiology and Molecular Biology, Regional University of Cariri , Crato , CE , Brazil , and.
authors.forename: Henrique
authors.initials: H
authors.lastname: Douglas Melo Coutinho
authors.affiliation: d Department of Pharmaceutical Sciences , Paraiba Federal University , João Pessoa , PB , Brazil.
authors.forename: Larissa
authors.initials: L
authors.lastname: Beuttenmuller Nogueira Alves
authors.affiliation: d Department of Pharmaceutical Sciences , Paraiba Federal University , João Pessoa , PB , Brazil.
authors.forename: Edeltrudes
authors.initials: E
authors.lastname: Oliveira Lima
mesh_terms: D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D002939:Ciprofloxacin / Q000494:pharmacology; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D018649:Ocimum basilicum; D009822:Oils, Volatile / Q000302:isolation & purification / Q000494:pharmacology; D018515:Plant Leaves; D010938:Plant Oils / Q000302:isolation & purification / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000502:physiology; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000502:physiology
chemical_list: D000900:Anti-Bacterial Agents; D009822:Oils, Volatile; D010938:Plant Oils; D002939:Ciprofloxacin
keywords: Ciprofloxacin; Pseudomonas aeruginosa; imipenem, Staphylococcus aureus