The Comparison of Honey Enriched with Laboratory Fermented Pollen vs. Natural Bee Bread in Terms of Nutritional and Antioxidant Properties, Protein In Vitro Bioaccessibility, and Its Genoprotective Effect in Yeast Cells.

The aim of the study was to compare the nutritional value and bioactivity of honey enriched with a 10% addition of natural bee bread and its substitutes obtained as a result of laboratory fermentation of bee pollen. Physicochemical parameters, antioxidant properties, as well as the bioaccessibility of proteins using an in vitro static digestion model were analyzed. The bioactivity of the obtained enriched honeys was tested using the yeast model. The research indicates the similarity of honeys with the addition of "artificial bee bread" to honey with natural ones. During in vitro digestion, good bioaccessibility of the protein from the tested products was demonstrated. The ability of the products to protect yeast cells against hydrogen superoxide-induced oxidative stress was demonstrated using a qualitative spot test, which was stronger in the case of enriched honey than in pure rapeseed control honey. Significant inhibition of the growth of both strains of yeast exposed to bee pollen-enriched honeys was also demonstrated. Furthermore, all tested samples showed significant genoprotective activity against the genotoxic effect of zeocin and the reduction of the number of DNA double-strand breaks by a minimum of 70% was observed.

The Study of Chemical Profile and Antioxidant Properties of Poplar-Type Polish Propolis Considering Local Flora Diversity in Relation to Antibacterial and Anticancer Activities in Human Breast Cancer Cells.

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.