title: Antimicrobial activity of natural products from the flora of Northern Ontario, Canada.
abstract: BACKGROUND
  The number of multidrug resistant (MDR) microorganisms is increasing and the antimicrobial resistance expressed by these pathogens is generating a rising global health crisis. In fact, there are only a few antimicrobial agents left that can be used against MDR bacteria and fungi.
  
  
  OBJECTIVE
  In this study, the antimicrobial activities of selected natural products from the flora of Northern Ontario against selected microorganisms are reported.
  
  
  METHODS
  Plants were collected from Sault Ste. Marie, Ontario, Canada, and ethanol extracts were prepared using EtOH:H2O (1:1, v/v). Fungal cultures used in this study were Candida albicans ATCC 10231 and Schizosaccharomyces octosporus. Bacterial cultures employed included Staphylococcus aureus ATCC 29213, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Mycobacterium phlei ATCC 11758, and Streptococcus lactis ATCC 19435. The microplate resazurin assay was used to screen for antimicrobial activity.
  
  
  RESULTS
  Extracts of four plant species Chimaphila umbellata L. (Pyrolaceae), Betula papyrifera Marshall (Betulaceae), Rhus typhina L. (Anacardiaceae), and Fraxinus pennsylvanica Marshall (Oleaceae), and six compounds (gallic acid, ethyl gallate, caffeic acid, sinapic acid, gentisic acid, and chlorogenic acid) demonstrated antibacterial or antifungal activities with MICs ranging from 62.5 to 1000 µg/mL, respectively, for a chemical fraction of an extract from Betula papyrifera against the bacterium S. aureus.
  
  
  CONCLUSIONS
  The present study has shown that certain plant extracts and select fractions and standard chemical compounds exhibit antimicrobial effects. Prince's Pine, Chimaphila umbellate, White Birch, Betula papyrifera, Staghorn Sumac, Rhus typhina, and Green Ash, Fraxinus pennsylvanica were the principal extracts exhibiting notable antibacterial and/or antifungal activities; while gallic acid, ethyl gallate, and caffeic acid demonstrated antibacterial activities and sinapic acid, gentisic acid, and chlorogenic acid demonstrated antifungal activities.
authors.affiliation: Department of Biology, Laurentian University , Sudbury, Ontario , Canada .
authors.forename: Janique
authors.initials: J
authors.lastname: Vandal
authors.forename: Mamdouh M
authors.initials: MM
authors.lastname: Abou-Zaid
authors.forename: Garry
authors.initials: G
authors.lastname: Ferroni
authors.forename: Leo G
authors.initials: LG
authors.lastname: Leduc
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000890:Anti-Infective Agents / Q000494:pharmacology*; D000935:Antifungal Agents / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D001688:Biological Products / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D005658:Fungi / Q000187:drug effects; D007202:Indicators and Reagents; D008826:Microbial Sensitivity Tests; D009864:Ontario; D010078:Oxazines; D010936:Plant Extracts / Q000494:pharmacology; D010944:Plants / Q000737:chemistry*; D014966:Xanthenes
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D000935:Antifungal Agents; D001688:Biological Products; D007202:Indicators and Reagents; D010078:Oxazines; D010936:Plant Extracts; D014966:Xanthenes; C005843:resazurin
keywords: Betula; C. albicans; E. coli; Fraxinus; P. aeruginosa; S. aureus; chimaphila; phenolics