Determination of the effect of propolis on various gastroenteric pathogens and potential probiotic lactiplantibaccilus plantarum and weissella cibaria strains

In this thesis study, raw Caucasian bee propolis was obtained from a local producer in Ardahan province, one of the isolated regions of the Caucasian bee (Ardahan-Artvin). Crude propolis was used at the propolis: solvent ratios of 1:3% and 1:2% in 80% ethanol and ekstract (P10, P30 and P60) were obtained by ultra-sonication at different times (30 minutes and 60 minutes). Total phenolic content and fatty acid methyl ester composition of the solutions were determined. Propolis extracts obtained after removal of ethanol from the solutions were diluted with 100% DMSO, 50:50% ethanol:water and 20:80% ethanol:water and its antibacterial properties on Lactiplantibacillus plantarum and Weissella cibaria strains known to have probiotic properties and pathogenic microorganisms Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 259223) causing gastrointestinal disorders were determined by disk diffusion method and its effect on growth was determined by colony counting method. The highest total phenolic content (83.384 mgGAE/g) was determined in the sample (P10) which was subjected to ultra-sonication for 30 minutes at a ratio of 1:3. The lowest result was determined in the P60 sample (42.794 mgGAE/g), which had 1:2 ratio of crude propolis content and was subjected to ultra-sonication for 60 minutes. In the fatty acid methyl ester compositions of the solutions, in addition to being rich in various fatty acid esters, the presence of cinnamic acid (2-Propenoic acid, 3-phenyl-) esters, which are naturally found in plant sources and are reported to have antibacterial activity, is noteworthy. The zone formation determined due to the inhibition effect was observed in pathogen bacteria with a density of approximately 106 and 105 log cfu/mL. The growth of pathogen microorganisms and lactic acid bacteria were determined by adding 3% and 5% of P10 sample to the liquid medium, which showed the best inhibition effect as well as the highest phenolic content. In the growth, Gram-negative E. coli, one of the pathogen microorganisms, maintained its viability longer than S. aureus, a Gram-positive. While E. coli showed 54.94% viability at the end of 24 hours at 3% contribution, this percentage ix was 20.90% at 5% contribution. At the end of 24 hours, these values for S. aureus were 43.59% and 20.90%, respectively. At the end of 48 hours, S. aureus completely lost its viability in 5% propolis supplementation. In lactic acid bacteria, although there was no zone formation in the disk diffusion method, Lpb. plantarum strain exhibited 43.59% and W. cibaria exhibited 50.24% viability percentage at the end of 48 hours at 5% supplementation. At the end of the study, it was concluded that the solvents and propolis concentration used in propolis extraction were effective, and the propolis ratio and the duration of the application were effective on antimicrobial activity.