Honey variety is commonly defined by beekeepers based on nectar flow availability and the only laboratory method to provide verification is the melissopalynological analysis. Therefore, a quick and simple method for accurate assessment of honey variety is still being researched. The aim of the study was to evaluate the antioxidant activity of honey as an indicator of variety through the use of multivariate statistical analysis. Materials for the study consisted of 90 samples of varietal Polish honeys (rape-12, tilia-10, goldenrod-11, dandelion-5, buckwheat-6, multifloral-17, nectar-honeydew-8 and coniferous honeydew-16 and leafy honeydew-5) obtained directly from apiaries. Honeys were investigated in aspect of antioxidant capacity by photochemiluminescence (PCL) methods using standard ACW and ACL kits. As the reference FRAP and DPPH methods were used. The total phenolics content (TPC) was determined through the Folin-Ciocalteu method. The strongest antioxidant activity was found for buckwheat, while the weakest was found for rape honeys regardless of the used method. Results of the used methods were positively correlated (r = 0.42 to 0.94). Analysis conducted by PCL method confirmed that the minor fraction of honey antioxidants exhibits hydrophobic properties. Clear separation of honey varieties using PCA and Clustering method indicate that antioxidant activity can be a useful parameter for determining the botanical origin of honey.

The influence of geographical origin on honey composition studied by Polish and Slovak honeys | Monika Tomczyk, Maria Tarapatskyy, Małgorzata Dżugan | Agricultural Journals

Two various species of mulberry (Morus sp.) were selected to enrich rape honey with dried leaves or lyophilized fruits (4% w/v). Finally, fruits and leaves of the ‘Ukraińska’ clone were introduced into the honey during creaming in concentrations from 1 to 4% w/v. The total phenolic content, antioxidant activity, anthocyanins content, and polyphenolic profile were tested in plant extracts and enriched honeys. Moreover, α-glucosidase, β-galactosidase, and diastase activities were investigated in honeys. For mulberry extracts, chlorogenic acid isomers and rutin were considered main antioxidant compounds. The antioxidant activity of honey enriched with mulberry leaves increased even more than 50 times, due to introducing numerous phenolic acids and flavonoid glycosides. A significant decrease in the diastase activity in honey depending on the content of added mulberry leaves (almost 50% decrease in the case of 4% addition) was found, suggesting the inhibitory effect of honey with mulberry leaves against carbohydrate hydrolyzing enzymes.

Nine samples of ethanolic extracts of poplar-type propolis (EEP) originated from South-Eastern Poland were analyzed in terms of the diversity of the flora around the apiary. The mineral composition, antioxidant properties, polyphenolic profile (HPTLC), and main polyphenolic constituents (HPLC-DAD) were determined. Only minor differences in chemical composition and antioxidant capacity between tested EEPs were found regardless of their botanical origin. However, the biological activity of the EEPs was more diversified. The tested EEPs showed stronger antibacterial activity against Gram-negative bacteria (Escherichia coli) compared to Gram-positive bacteria (Staphylococcus aureus and Staphylococcus epidermidis). Staphylococci biofilm inhibition occurred as a result of exposure to the action of four out of nine EEPs (P1–P4). Due to the various compositions of individual EEPs, a different MCF-7 cellular response was observed according to inhibition of cells migration and proliferation. Almost every sample inhibited the migration of breast cancer cells at a low concentration (0.04 µg/mL) of propolis. Even at the lowest concentration (0.02 µg/mL), each EEP inhibited the proliferation of MCF-7 cells, however, the level of inhibition varied between samples.