Infectious diseases are an important problem worldwide for medicine and pharmacy. The search for natural antibacterial agents has gained significant interest recently, driven by the growing concerns over antibiotic resistance and the desire for natural alternatives. Blackberry leaf, known for their rich nutritional profile and high antioxidant content, have attracted attention for their potential antibacterial properties. Understanding the antibacterial potential of blackberries could provide insights into their use in natural medicine and food preservation.

The aim of work was to study a correlation between antimicrobial and antioxidant activities with biologically active compounds in blackberry leaf extracts.

Materials and methods. The spectrophotometric method was applied for quantification of the total amount of biologically active compounds. The antiradical activity of obtained blackberry leaf extracts was determined with the potentiometric method; antimicrobial activity was estimated by the “well” method.

Results. Results demonstrate that the highest amount of polyphenols, catechins, flavonoids were 3.72 %, 1.88 % and 1.48 % in 60 % EtOH extract, respectively. The organic acids were dominant in the aqueous extract (1.96 %). The most potent antioxidant property possessed 60 % EtOH extract of blackberry leaf (204.68 mmol-eqv./mdry res.). The blackberry leaf extracts showed antimicrobial effects against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Bacillus subtillis, Proteus vulgaris, and Candida albicans. Statistical analysis revealed a highly significant interdependence between the concentration of catechins, the magnitude of antioxidant activity, and the strength of the antimicrobial effect against the tested microorganisms (S. aureus, P. vulgaris, P. aeruginosa, and C. albicans).

Conclusions. These findings show the great potential of blackberry extracts in the development and creation of new medicines with antimicrobial, antioxidant effects that are not inferior to the action of synthetic analogues.