title: Screening of some plants from Northern Argentina for their antimicrobial activity.
abstract: OBJECTIVE
  Screening of antimicrobial activity in 25 plant species from Northern Argentina.
  
  
  RESULTS
  Inhibition of microbial growth was measured by a microplate assay with an oxidation-reduction indicator (Alamar Blue). Test organisms were: Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus and Enterococcus faecium. Weak inhibitory activities (MIC=0.5 mg dry matter ml(-1)) were found in methanolic extracts of Rivina humilis, Crateva tapia, Funastrum claucum and Schinopsis balansae. Stronger bacteriostatic power was detected in Vassobia breviflora (MIC=0.25 mg ml(-1) against Staphylococcus aureus, and 0.5 mg ml(-1) against Enterococcus faecium). This activity was purified five-fold by extraction with dichloromethane, and it was found equally effective against susceptible or antibiotic-resistant strains of Staph. aureus. In addition, the purified extract was synergistic with gentamicin, and it was bactericidal at 24 h, with a concentration of 0.25 mg ml(-1).
  
  
  CONCLUSIONS
  There is a significant antimicrobial activity in Vassobia breviflora.
  
  
  CONCLUSIONS
  Further studies will be required to disclose the potential importance of these findings.
authors.affiliation: Instituto de Patobiología, Centro Nacional de Investigaciones Agropecuarias, INTA-Castelar, Buenos Aires, Argentina.
authors.forename: A
authors.initials: A
authors.lastname: Salvat
authors.forename: L
authors.initials: L
authors.lastname: Antonnacci
authors.forename: R H
authors.initials: RH
authors.lastname: Fortunato
authors.forename: E Y
authors.initials: EY
authors.lastname: Suarez
authors.forename: H M
authors.initials: HM
authors.lastname: Godoy
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis / Q000494:pharmacology*; D001118:Argentina; D004926:Escherichia coli / Q000187:drug effects; D007709:Klebsiella / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000494:pharmacology*; D010946:Plants, Medicinal; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D012475:Salmonella / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts