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

Abstract

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.