Antioxidative and antibacterial properties of honey from Serbia, Kosovo and Bosnia and Herzegovina

Abstract

Honey is a natural sweetener produced by honeybees using nectar. It has been used not only for food, but also for therapeutic purposes. Carbohydrates, primarily glucose and fructose (85-95%), dominate in honey composition. In addition to sugars, honey contains about 200 substances present in small amounts, including minerals, proteins, enzymes, amino acids, organic acids, vitamins, polyphenols and other phytochemicals. The type of honey is determined by the type of pollen, i.e. nectar, insect secretions, as well as climatic conditions and soil composition. The health benefits of honey, used for centuries for therapeutic purposes, derive from its antioxidant nature, antimicrobial and antiproliferative activity. The antioxidant capacity of honey primarily depends on the phenolic profile of honey, which is conditioned by botanical and geographical variations. The antibacterial activity of honey results from the high osmolarity and acidity of honey, as well as the presence of hydrogen peroxide and phenolic compounds. With the aim to assess the antioxidant capacity and antibacterial activity of different types of honey characteristic for the region, nineteen samples (acacia, linden, heather, sunflower, phacelia, basil, anise, sage, chestnut, hawthorn, buckwheat, lavender and meadow) were collected from different locations in the Republic of Serbia, Kosovo and Bosnia and Herzegovina and examined. Honey samples were also tested for physicochemical parameters (moisture, pH value, electrical conductivity, free acidity and HMF) to ensure that they meet the requirements for honey quality. Based on the obtained results of honey physicochemical profile, it was concluded that all tested samples were in accordance with the regulations of national and EU regulations. The antioxidant potential of honey samples was assessed by determining the total phenol content (TPC) and evaluating the antiradical activity on diphenylpicrylhydrazyl radicals (DPPH·). The highest phenol content was found in basil honey (101 ± 2.72 mg GAE/100 g), while the lowest was registered in rapeseed honey (11.5 ± 0.70 mg GAE /100 g). Samples of heather, anise, phacelia, sage, chestnut and lavender honey were also rich in TP (80–100 mg GAE/100 g). Scavenging activity on DPPH· varied among samples and was highest for lavender honey (IC50 = 88.2 ± 2.11 mg/mL) and lowest for rapeseed honey (IC50 = 646 ± 8.72 mg/mL). Antibacterial activity was estimated in vitro using agar diffusion tests and measuring minimal inhibitory concentration (MIC). Among investigated bacterial strains following resistant potencies were determined: E. coli > E. coli ATCC 8739 > E. faecalis > Proteus mirabilis > S. aureus > S. epidermidis. The linden honey from Fruška Gora (MIC values of 3.12% and 6.25% against S. aureus and S. epidermidis, respectively) and phacelia honey (MIC values of 6.25% and 3.12% against S. aureus and S. epidermidis, respectively) showed the strongest antibacterial activity.