title: New antibacterial hydrophobic assay reveals Abies balsamea oleoresin activity against Staphylococcus aureus and MRSA.
abstract: BACKGROUND
  Oleoresin of Abies balsamea (L.) Mill. was used by Native Americans of the boreal forest of Canada and French Canadians to treat various infections, suggesting that oleoresin has antibacterial properties.
  
  
  OBJECTIVE
  In this study, the antibacterial activity of whole oleoresin from A. balsamea was investigated against E. coli, S. aureus and two methicillin-resistant S. aureus (MRSA) strains using a new sensitive assay developed to evaluate hydrophobic matrix and compounds.
  
  
  METHODS
  Antibacterial activity of oleoresin was first investigated using dilution and disk diffusion methods against E. coli and S. aureus, and compared to a new sensitive assay for hydrophobic matrix. Moreover, whole oleoresin was analyzed by GC-MS to characterize the composition and to identify the compounds responsible of the antibacterial activity.
  
  
  RESULTS
  The results showed that whole oleoresin was inactive against Gram-negative E. coli (MIC90>90µg/ml) but active against Gram-positive S. aureus and MRSA with MIC90ranging from 18.2 to 30µg/ml. The oleoresin is mainly composed of monoterpene (28%), sesquiterpenes (2%), and diterpenes (45%). Resin acids were found, in part, responsible for the antibacterial activity of whole oleoresin. Isopimaric acid and levopimaric acid are the most active with a MIC90of respectively 9.7µg/ml and 10µg/ml.
  
  
  CONCLUSIONS
  This study supports the use of oleoresin of A. balsamea by the Native Americans and French Canadians to treat bacterial infections due to S. aureus.
authors: Laboratoire d'Analyse et de Séparation des Essences Végétales, Université du Québec à Chicoutimi, 555 boulevard de l'Université, Chicoutimi, QC, Canada G7G 4B7.
authors: Héloïse
authors: H
authors: Coté
authors: Laboratoire d'Analyse et de Séparation des Essences Végétales, Université du Québec à Chicoutimi, 555 boulevard de l'Université, Chicoutimi, QC, Canada G7G 4B7.
authors: Marie-Anne
authors: MA
authors: Boucher
authors: Laboratoire d'Analyse et de Séparation des Essences Végétales, Université du Québec à Chicoutimi, 555 boulevard de l'Université, Chicoutimi, QC, Canada G7G 4B7.
authors: André
authors: A
authors: Pichette
authors: Laboratoire d'Analyse et de Séparation des Essences Végétales, Université du Québec à Chicoutimi, 555 boulevard de l'Université, Chicoutimi, QC, Canada G7G 4B7.
authors: Benoit
authors: B
authors: Roger
authors: Laboratoire d'Analyse et de Séparation des Essences Végétales, Université du Québec à Chicoutimi, 555 boulevard de l'Université, Chicoutimi, QC, Canada G7G 4B7. Electronic address: Jean.Legault@uqac.ca.
authors: Jean
authors: J
authors: Legault
mesh_terms: D028202:Abies / Q000737:chemistry*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D057927:Hydrophobic and Hydrophilic Interactions; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D010936:Plant Extracts / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts; C018620:oleoresins
keywords: Abies balsamea; Antibacterial activity; Balsam fir; Gum; Oleoresin; Resin; Resin acids