ANTIBACTERIAL ACTIVITY OF BEE HONEY AND ITS PEPTIDE FRACTIONS

Recently, the problem of bacteriological resistance has become more and more urgent. The antibiotics used in medical practice are constantly becoming obsolete due to the acquisition of resistance by pathogenic microorganisms, therefore there is an ever-increasing need to search for new antimicrobial drugs of various nature. A promising line of research in this area is the study of the antibacterial activity of protein molecules. Over the past two decades, a lot of data has accumulated showing the wide distribution of antimicrobial peptides among almost all living organisms. This article studied the antibacterial activity of peptide fractions weighing less than 5 kDa obtained from honey of two varieties — buckwheat and mixed origin, as well as the similar activity of various solutions of the same honey samples. The following methods were sequentially applied for isolation and purification of peptide fractions: ultrafiltration — to obtain a solution containing molecules with a mass of less than 5 kDa; ion exchange chromatography on DEAE-cellulose for purification of the peptide fraction from low molecular weight impurities (carbohydrates, pigments, phenols, etc.) and gel filtration on Sephadex G-25 to desalt the obtained peptide fraction from the buffer solution. Determination of antibacterial activity was carried out using the disk diffusion method with antibiotic-resistant strains of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Salmonella enteritis obtained from patients with various bacterial infections in chronic and acute forms. In the studied samples, the concentration of peptides, carbohydrates in ketosis and hydrogen peroxide was measured. The results obtained indicate that among the studied solutions of honey, buckwheat has the highest antibacterial activity, which is associated with an increased content of hydrogen peroxide. The study of the antagonistic activity of peptide fractions against test cultures showed that low molecular weight peptides obtained from the studied honey samples do not have an antibacterial effect against the used strains of microorganisms. Apparently, this is due to the absence of low molecular weight antimicrobial peptides in the obtained fractions. Probably, antimicrobial peptides weighing less than 5 kDa are completely absent in bee honey.