Page 75 - Petelin, Ana, ur. 2024. Zdravje delovno aktivnih in starejših odraslih / Health of Working-Age and Older Adults. Zbornik povzetkov z recenzijo ▪︎ Book of Abstracts. Koper: Založba Univerze na Primorskem/University of Primorska Press

Antimicrobial potential in chestnut honey

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Urša Lapanja , Domen Jaklič , Nataša Lilek , Adriana Pereyra Gonzales , Katja Kranjc ,
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Rok Kopinč 2
1 University of Primorska Faculty of Health Sciences, Izola, Slovenia
2 Medex d.o.o, Ljubljana, Slovenija
Introduction: Due to the increasing resistance to antimicrobial agents, more and more
attention is directed to the use of substances of natural origin. Honey is a sweet and
viscous substance made of carbohydrates, water and more than 200 bioactive sub-
stances. The composition of honey can be influenced by several factors, such as: plant
source, type of bee, seasonal and environmental factors, processing and storage con-
ditions. Due to the combination of bioactive substances, honey is known for its anti-
oxidant, immunomodulatory, anti-inflammatory, anticancer and antimicrobial effects.
The main antimicrobial factors are high osmolarity, the presence of hydrogen perox-
ide, low pH, the content of organic acids and flavonoids. The purpose of our study was
to determine the antimicrobial activity of different samples of chestnut honey and to
verify the correlation of antimicrobial activity with other characteristics of honey, such
as the concentration of hydrogen peroxide and bioflavonoids.
Methods: We analyzed 30 samples of chestnut honey of Slovenian, Italian and Bos-
nian origin. Antimicrobial activity was determined using the microdilution method and
the dye p-iodo-nitro-tetrazolium chloride (INT) against the bacterium Escherichia coli
ATCC 8739. The minimum inhibitory concentration (MIC) was determined visually, at
the first concentration of honey, where no discoloration of the medium was detected
as a result of bacterial growth. The content of total bioflavonoids was also determined
for all samples according to the Folin-Cioccalteu method. The concentration of hydro-
gen peroxide was measured by the reaction between H2O2 and o-dianisidine. The
oxidation product is determined spectrophotometrically at a wavelength of 450 nm.
Results: All chestnut honey samples were working antimicrobialy against E. coli ATCC

8739, with MIC values ranging from 37.5 mg/mL to 150 mg/mL of honey. The low-
est measured concentration of hydrogen peroxide was 27.5 µg/g, and the highest was
146.5 µg/g of honey. The concentration of total flavonoids was between 58.6 mg/100
g and 208.5 mg/100 g of honey. We did not prove a correlation between the concen-
tration of hydrogen peroxide or the total number of flavonoids and the antimicrobi-
al activity of honey. prehrana in zdravje delovno aktivnih in starejših odraslih | nutrition and health of working-age and older adults
Discussion and conclusions: Despite the proven antimicrobial activity of all honey sam-
ples, we could not attribute the latter to different concentrations of hydrogen per-
oxide or differences in the total amount of flavonoids. The main conclusion of the
research is that the antimicrobial activity of honey is probably the result of the inter-
action of various parameters.
Keywords: bacterial resistance, antimicrobial, chestnut honey

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