Spring heath (Erica carnea) is an evergreen plant, with many biological activities, including antibacterial activity. In this thesis we checked the antibacterial and antiadhesion effect of ethanolic extracts of spring heath and some chemically pure active ingredients of these ethanolic extracts on selected target microorganisms. We used two gram positive target bacteria, Staphylococcus aureus and Listeria innocua, and two gram negative bacteria, Escherichia coli and Pseudomonas fragi. We determined the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of ethanolic extracts and some of their chemically pure active ingredients. The results showed the best antibacterial effect of ethanolic extracts against S. aureus (MIC 1 mg/ml) and the best antibacterial effect of quercetin, the chemically pure active substance, with the lowest values for gram positive bacteria (MIC 0,25 mg/ml; MBC 1 mg/ml). The results for gram negative P. fragi are interesting, due to relatively low MIC values (1-2 mg/ml), which are comparable or, in case of chemically pure active compounds, even lower than the values obtained for gram positive bacteria. Presumably, this is influenced by specific enzymatic activity of P. fragi. We also determined a statistically significant reduction (52,5 %) in the adhesion of P. fragi to polystyrene, after the addition of ethanol extract. We have confirmed the antibacterial effect of spring heath extract on selected target microorganisms and found that the obtained MIC values and antiadhesion activity for P. fragi are an interesting topic for additional studies.
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