Propolis as a Key Source of p-Coumaric Acid Permeating Honey and Sucrose Syrup Stores of Honey Bees

p-Coumaric acid is a natural phenolic compound supporting honey bee health by enhanc-27 ing detoxification, immunity and longevity. It also possesses antioxidant, anti-inflamma-28 tory and anticancer properties relevant to human health. While commonly detected in 29 honey and pollen, it is absent from nectar and sucrose-based supplements typically used 30 in beekeeping. Concerns have been raised whether supplemental saccharide feeding de-31 prives bees of this essential phytochemical. In this study, we quantified p-coumaric acid 32 in various bee-derived products and in supplementary sucrose syrup before and after 33 feeding to bees, using HPLC-HRMS analysis. Although fresh sucrose syrup contained 34 negligible amounts of p-coumaric acid, syrup stored in capped combs exhibited levels 35 comparable to or higher than those in honey. We identified propolis in combs as the pri-36 mary source of p-coumaric acid, diffusing into both honey and sucrose syrup during stor-37 age. Our findings demonstrate that supplemental feeding with sucrose syrup does not 38 diminish the bees' access to this key phytochemical and underscore the importance of 39 propolis-rich environment in bee health management.