ANTIMICROBIAL ACTIVITY OF ETHANOL EXTRACTS OF $RIBES~NIGRUM$ AND $RIBES~RUBRUM$ LEAVES

Antimicrobial activity of Ribes nigrum L. and Ribes rubrum L. leaf extracts was determined by disk-diffusion method as well as specific growth rate and generation succeeding factor determination. Different Gram-positive (Bacillus subtilis WT-A, Staphylococcus aureus MDC 5233, Enterococcus hirae ATCC 9790) and Gram-negative (Escherichia coli ATCC 25922, Salmonella typhimurium MDC1754, ampicillin resistant E. coli dhpα-pUC18 and kanamycin resistant E. coli pARG25) bacteria and yeasts (Saccharomyces cerevisiae ATCC 9804 and S. cerevisiae ATCC 13007) were used as test-microorganisms. 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay was applied to measure the radical scavenging capacity of extracts obtained from Ribes spp. R. rubrum and R. nigrum extracts antiradical activity expressed with IC50 value of 91.2±1.69 µg‧mL–1 and 66.01±1.65 µg‧mL–1, respectively. The total flavonoid content in plant extracts was determined employing AlCl3 colorimetric assay, and the values were 34.71±0.63 and 49.99±0.86 μg QE‧mg–1 for R. rubrum and R. nigrum extracts, respectively. Total phenolic content of studied extracts was investigated by Folin–Ciocalteu assay. The contents for R. rubrum and R. nigrum extracts were 133.12±6.65 and 167.15±7.29 μg GAE‧mg–1, respectively. Thus, these plants can be considered as potential sources of biologically active substances.