Anti-Pathogenic Effect of Propolis Extracts from Different Romanian Regions on Staphylococcus Sp. Clinical Strains

Propolis, a natural product elaborated by bees, determines a wide variety of therapeutic actions because of its bioactive compounds. Our researches were focused on evaluating the anti-pathogenic effect of eight ethanolic propolis extracts (EEP) from different Romanian regions on 11 Staphylococcus sp. clinical strains. The content of flavons, flavonols and polyphenols was investigated by spectrophotometric methods. The following parameters were investigated for the biological evaluation: i) the microbial biofilms development on inert the substratum assessed by the microtiter method; ii) the microbial adherence to the eukaryotic cells (adapted Cravioto's method); iii) the expression of soluble enzymatic factors involved in the microbial virulence (cultuvation on specific substrates). The results showed that all studied EEP exhibited an antibiofilm activity. A correlation between the increased polyphenol content (EEP Arad 17.62% and EEP Cluj 21.54%) and the lowest value of minimum biofilm eradication concentration (0.2343 mg / ml) was noticed. EEP Arad, EEP Bihor and EEP Dolj exhibited a strong inhibitory effect on Staphylococcus strains adherence to the cellular substratum and induced changes in the adherence pattern. EEP inhibited the secretion of soluble enzymatic factors of tested Staphylococcus strains. These results demonstrate that the tested EEP could be used for the design of new anti-pathogenic agents for preventing microbial colonization and dissemination of infections.