In vitro anti-biofilm activity of Quercus brantii subsp. persica on human pathogenic bacteria

Background and objectives: Quercus brantii subsp. persica is used in folk medicine to treat infections in Iran. There is not available report on the anti-biofilm activity of Quercus brantii subsp.  persica. The aim of the present study was to investigate the effects of Quercus brantii subsp. persica against bacterial biofilms. Methods: Eighty biofilm producing strains of Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa were collected. Quercus brantii subsp. persica fruits aqueous extraction (QBAE) was prepared though maceration method. Chemical analysis to distinguish the main components of the QBAE was carried out using thin-layer chromatography. The antibacterial effects of QBAE on bacterial isolates were determined by the Kirby-Bauer and broth microdilution methods. The antibiofilm effects of QBAE on bacterial isolates were determined using a microtiter assay. Results: The Quercus brantii subsp. persica exhibited bacterial growth inhibition and bactericidal activity on the majority of the strains at concentrations between 0.2 and 1.2 mg/mL. The average of biofilm formation inhibition by Quercus brantii subsp. persica at a minimum inhibitory concentration MIC50 in Pseudomonas aeruginosa, Escherichia coli, Staphylococcus epidermidis and Staphylococcus aureus strains were 35%, 45%, 57% and 61%, respectively. coumarins, phenols, terpenes and steroids were found in the QBAE by TLC. Conclusion: The results showed that Quercus brantii subsp. persica aqueous extraction was effective against the tested microorganisms and showed anti-biofilm activity which can be a basis for future studies to investigate for new anti-biofilm drugs.