title: Antimicrobial activity and chemometric modelling of South African propolis.
abstract: OBJECTIVE
  This study reports on the inhibitory and bactericidal properties of 39 South African (SA) propolis samples and three propolis samples from Brazil.
  
  
  RESULTS
  Ethanolic extracts of propolis (EEP) were prepared and their antimicrobial activities tested using the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. Some samples displayed substantial antimicrobial activity with MIC and MBC values as low as 6 μg ml(-1) against Staphylococcus aureus. The correlation between liquid chromatography-mass spectrometry (LC-MS) chemical data and the antimicrobial activity of propolis extracts was investigated using multivariate data analysis tools. Orthogonal projections to latent structures (OPLS) models were created for the two Gram-positive bacteria (Enterococcus faecalis and S. aureus) and Candida albicans. Using the S-plot function, it was possible to identify the bioactive constituents in propolis as chrysin, pinocembrin, galangin and pinobanksin-3-O-acetate.
  
  
  CONCLUSIONS
  The SA propolis samples tested displayed noteworthy antimicrobial activity, favourably comparable to that of the Brazilian comparator and 'gold standard'. The observed antimicrobial activity of SA propolis can possibly be attributed to its flavonoid content.
  
  
  CONCLUSIONS
  Based on the good antimicrobial activity observed for SA propolis, this natural resource shows promise and should be considered for development which may contribute to growing the bio-economy in the region.
authors.affiliation: Department of Pharmacy and Pharmacology, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: T
authors.initials: T
authors.lastname: Suleman
authors.affiliation: Department of Pharmacy and Pharmacology, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: S
authors.initials: S
authors.lastname: van Vuuren
authors.affiliation: Department of Pharmaceutical Sciences, Tshwane University of Technology, Pretoria, South Africa.
authors.forename: M
authors.initials: M
authors.lastname: Sandasi
authors.affiliation: Department of Pharmaceutical Sciences, Tshwane University of Technology, Pretoria, South Africa.|SAMRC Herbal Drugs Research Unit, Department of Pharmaceutical Sciences, Tshwane University of Technology, Pretoria, South Africa.
authors.forename: A M
authors.initials: AM
authors.lastname: Viljoen
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects / Q000254:growth & development; D001938:Brazil; D002176:Candida albicans / Q000187:drug effects / Q000254:growth & development; D008826:Microbial Sensitivity Tests; D010938:Plant Oils / Q000737:chemistry / Q000494:pharmacology*; D011429:Propolis / Q000737:chemistry*; D013019:South Africa
chemical_list: D000890:Anti-Infective Agents; D010938:Plant Oils; D011429:Propolis
keywords: South African propolis; antimicrobial; bactericidal; chemometrics; flavonoid