Detection of Some Active Compounds in Aqueous and Ethanolic Extracts of Iraqi Propolis and Examine Their Antibacterial Effects

The crude Iraqi propolis has been collected from an area surrounding by eucalyptus trees at the west of Baghdad city. The aqueous and ethanolic total soluble solids of crude Iraqi propolis were found to be 13.9 and 34.5% respectively. The quantitatively detection of propolis extract refer to the presence of phenolic compounds (such as flavonoids) as the mainly active components. Spectrophotometric analysis was used to determine flavonoids in the local propolis extracts. Flavones and flavonols were determined using aluminum chloride and expressed as quercetin equivalent and were found 2.1 and 6.71% in aqueous and ethanolic extracts respectively. The flavanones were determined using 2, 4-dinitrophenyl hydrazine and expressed as naringenin and found to represent 4.27 and 13.65% of aqueous and ethanolic extracts. Total phenolic, free phenolic and tannin compounds were determined in crude propolis using Lowenthal-Proctor method and were found 9.98, 8.32 and 1.66% by using aqueous extraction and 24.80, 22.72 and 2.08% by ethanol extraction respectively. The inhibitory action of aqueous and ethanolic extract with concentrations 120, 240…to 1200 and 2000, 2500…to 4000 ppm were examined against gram-positive bacteria (Staphylococcus aureus, Bacillus cereus and Bacillus stearothermophilus) and gram-negative bacteria (Escherichia coli, Salmonella enteritidis and Pseudomonas fluorescens). The ethanolic extract of local propolis showed highly inhibitory percentages (up to 83.80% against gram-negative and 87.80% against gram-positive) as compared with aqueous extract (70.58% against gram-negative and 59.59% against gram-positive).