Abstract
Sweet cherry (Prunus avium L.) stems in the form of infusions and decoctions
are traditionally consumed for diuretic and anti-inflammatory purposes. This
study aimed to evaluate antimicrobial and antibiofilm activity of ethanolic and
methanolic extract made from sweet cherry stems. Extracts are obtained by the
Soxhlet extraction and maceration procedures. For the determination of the
minimum inhibitory concentration, the broth microdilution method is employed,
and the assessment of the microbiocidal activity of the extracts is conducted. The
antibiofilm activity was tested through the tissue culture plate method, which
also allowed the determination of the biofilm-forming categories of investigated
strains. The final step involved the calculation of the biofilm inhibition
percentage. Examined extracts with the balanced activity inhibited the growth of
all microorganisms, with Gram-negative bacteria being more sensitive in
comparison to Gram-positive. The values of the minimum inhibitory
concentration were 125 μg/ml, and 250 μg/ml, respectfully. Candida albicans
was the most susceptible and the minimum inhibitory concentration of both
extracts was 62.50 μg/ml. The microbiocidal activity of the extracts was not
recorded. Extracts exhibited different impacts on the biofilm-forming capacity of
the investigated microbes, and both inhibition and stimulation effects are noted.
The percentage of the biofilm inhibition was from 14.27% to 84.78%, with the
highest inhibition recorded for the multidrug-resistant Escherichia coli, treated
with the ethanolic extract. Sweet cherry stems are a valuable source of natural
bioactive compounds, but their usage in the treatment of microbial infections
should be correctly and carefully implemented.