title: A study of chemical composition and antimicrobial activity of Bulgarian propolis.
abstract: Propolis is a natural product which exhibits pronounced antimicrobial and anti-inflammatory effects.
  
  
  OBJECTIVE
  To analyze the chemical composition and antimicrobial effect of Bulgarian propolis, p-cumaric acid and ferulic acid on certain Gram-positive and Gram-negative microorganisms.
  
  
  METHODS
  Ethanol extract of Bulgarian propolis (Propolin) and water extract of Bulgarian propolis (Propolstom), ferulic acid and p-cumaric acid were used. The chemical HPLC-analysis of propolis was performed with Varian Prostar system. Microbiological tests were done on isolates of Streptococcus beta-haemolyticus, Enterococcus faecalis, Candida albicans and Escherichia coli. Non-treated and ethanol-treated cultures of the corresponding strains were used as controls. Minimal bactericidal and bacteriostatic concentration of Propolin were determined by agar method.
  
  
  RESULTS
  The concentration of p-cumaric acid and ferulic acid in ethanol extract of propolis is about 1%. The minimal bactericidal concentration of Bulgarian propolis against Streptococcus beta-haemolyticus is 281 +/- 89.3 microg/ml, against Enterococcus faecalis--3490 +/- 633.1 microg/ml, against Candida albicans--1375 +/- 255.2 microg/ml, and against Escherichia coli--24306 +/- 1706.4 microg/ml. The minimal bactericidal concentration of p-cumaric acid and ferulic acid against Streptococcus beta-haemolyticus is 212 +/- 6.5 microg/ml and 208 +/- 7.7 microg/ml, against Enterococcus faecalis--3013 +/- 176.6 and 3032 +/- 203.4 microg/ml, against Candida albicans--157 +/- 15.5 microg/ml and 149 +/- 23.2 microg/ml, and against Escherichia coli--798 +/- 7.7 microg/ml and 801 +/- 22.8 microg/ml, respectively.
  
  
  CONCLUSIONS
  The phenolic compounds p-cumaric acid and ferulic acid are 10 times less extracted in water extraction than in ethanol extraction. The most susceptible strains to the Bulgarian propolis and phenolic compounds are Streptococcus beta-haemolyticus and Candida albicans and the least affected are Escherichia coli and Enterococcus faecalis.
authors.affiliation: Department of Microbiology and Immunology, ' Medical University, Plovdiv, Bulgaria.
authors.forename: Petya A
authors.initials: PA
authors.lastname: Gardjeva
authors.forename: Stela Z
authors.initials: SZ
authors.lastname: Dimitrova
authors.forename: Iliya D
authors.initials: ID
authors.lastname: Kostadinov
authors.forename: Marianna A
authors.initials: MA
authors.lastname: Murdjeva
authors.forename: Lyudmil P
authors.initials: LP
authors.lastname: Peyche
authors.forename: Lyudmil K
authors.initials: LK
authors.lastname: Lukanov
authors.forename: Irina V
authors.initials: IV
authors.lastname: Stanimirova
authors.forename: Alexandar S
authors.initials: AS
authors.lastname: Alexandrov
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D001565:Benzoates / Q000494:pharmacology; D002176:Candida albicans / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D003373:Coumaric Acids / Q000494:pharmacology; D013293:Enterococcus faecalis / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D011429:Propolis / Q000032:analysis* / Q000494:pharmacology*; D013291:Streptococcus / Q000187:drug effects
chemical_list: D000890:Anti-Infective Agents; D001565:Benzoates; D003373:Coumaric Acids; C055607:cumic acid; D011429:Propolis; C004999:ferulic acid