Bioautographic identification of alder gray Alnus incana (L.) Moench. fruits and geranium meadow Geranium pratense L. rhizomes extracts active components exhibiting synergism of antimicrobial action with macrolides

Annotation. The increase in the number of isolated antibiotic-resistant strains of microorganisms stimulates the search for alternative sources of biologically active substances that have antibiotic-potentiating action and are able to block the mechanisms of bacterial resistance to antibiotics. The aim of the study was to carry out bioautographic identification of the active components of gray alder fruits, geranium meadow rhizomes extracts and preparation “Altan” (extractant 90% aqueous-ethanolic), which showed synergism of antimicrobial action with erythromycin against skin isolates of staphylococci with different MLS phenotypes. Paper chromatography, thin-layer chromatography and bioautography were performed. Statistical processing of results: UTHSCSA ImageTool 2.0, Microsoft Office Excel 2011 On bioautograms of gray alder fruits extract and Altan with subinhibitory concentrations of erythromycin inoculated with S. epidermidis culture (inductive MLS-resistance phenotype), near the start line, areas with clear edges of growth inhibition were detected indicating the presence of hydrolysable tannins. Bioautograms of geranium meadow rhizomes extract showed the presence of compounds with antibiotic-potentiating activity with pronounced hydrophobic properties, indicating the presence of essential oils. In the extracts of gray alder fruits and geranium meadow rhizomes, the active components with antibiotic-potentiating properties, namely hydrolysable tannins and essential oils, have been identified. The fruits of gray alder and geranium meadow rhizomes are recommended for their preclinical and in-depth pharmacological study.