Fuente: PubMed "propolis" Food Res Int. 2026 Apr 30;230:118544. doi: 10.1016/j.foodres.2026.118544. Epub 2026 Feb 2.ABSTRACTAs the importance of polyphenolics to human health becomes more documented, the interest in natural sources of these bioactive compounds is receiving increasing attention. Bee products, especially propolis, contain an array of bioactive polyphenolics, and ethanol is recognized as the most effective solvent to obtain an extract of propolis highly concentrated in phenolic acids and flavonoids. Nevertheless, the actual release and stability of these compounds from the extract of propolis under physiological conditions has been scarcely reported. Not to mention the lack of studies about the propolis and geopropolis produced by stingless bees that have been more overlooked. In the current study, we report for the first time data about the bioaccessibility of phenolics and flavonoids compounds in ethanolic extracts of geopropolis and propolis produced by stingless bees and compared them with propolis from Apis mellifera bees collected in southern Brazil. To this aim, in vitro static gastrointestinal digestion (GI) was conducted on the geopropolis/propolis extracts and fractions from the oral, gastric, and intestinal phases were analyzed by spectrophotometric methods to determine total phenolic and total flavonoid contents and the antioxidant capacity of samples (FRAP and CUPRAC assays). Statistically significant differences in the total phenolic and flavonoid contents as well as the antioxidant capacity throughout the oral to the intestinal phases were observed for virtually all the samples, indicating that the release and stability of the polyphenolic compounds depend on the specific chemical composition of the extracts (with synergistic or antagonistic effects) but also on pH, enzyme and saline conditions in each fluid. For most extracts bioaccessibility of polyphenolics and, therefore, the antioxidant capacity, increased after the gastric phase and was higher in the intestinal fluids which indicates an increase in solubility and stability of the phenolic compounds in this medium. Additionally, low to medium bioaccessible fractions were measured for most propolis and geopropolis regardless of the type of bee or geographical origin, although data suggests a slight trend to greater bioaccessibility of the phenolic compounds in propolis from Apis mellifera bees. Another observation is that samples with the highest initial contents did not exhibit the greatest bioaccessibility, which may suggest that factors such as the type of phenolic and its stability are more important to their release in GI fluids than total quantity. Only the results for antioxidant capacity variation by CUPRAC presented a strong positive correlation (r = 0.855) between activity before and after simulated digestion. Finally, when considering all samples, the average bioaccessible fraction was around 30%, indicating low bioaccessibility of the phenolic compounds in propolis or geopropolis ethanolic extracts produced either by Meliponids or by Apis mellifera bees. Our results sustain the use of geopropolis/propolis from Meliponids as a source of potentially bioavailable bioactive compounds. Nevertheless, further studies aimed at improving overall bioaccessibility and bioavailability should be prioritized in future research.PMID:41794533 | DOI:10.1016/j.foodres.2026.118544