Abstract by Jonas Pordel Vind
Introduction: Type 1 diabetes is a chronic autoimmune disease characterized by progressive dysfunction and destruction of insulin-producing pancreatic β-cells. Although immunotherapies can delay disease progression, additional strategies that safely modulate immune processes during early disease development are still needed. Propolis, a resinous honey bee product rich in bioactive compounds, is widely used for its curative properties and has been reported to exhibit both antioxidative and immunomodulatory effects. However, its pronounced chemical complexity and variability hinder standardization and reproducibility of its biological effects, thereby complicating its potential clinical integration. The aim of this thesis was to establish a framework linking propolis composition to its functional properties, and to determine whether dietary propolis can modulate immune processes relevant to type 1 diabetes development.
Methods: The chemical composition of propolis from different geographical origins and bee species, including cerumen from stingless bees, and its link with antioxidative activity were investigated using non-targeted spectroscopic techniques, including infrared, near-infrared, Raman, and proton nuclear magnetic resonance spectroscopy, combined with chemometric modeling. Immunomodulatory effects were evaluated in human immune cells, while liquid chromatography was used to identify compounds associated with these responses. Finally, the impact of dietary propolis supplementation on autoimmune diabetes development was investigated in the non-obese diabetic mouse model.
Results: Distinct geographical chemotypes were identified, with Scandinavian propolis enriched in aromatic compounds and exhibiting greater antioxidative and anti-inflammatory properties than Australian samples, while cerumen displayed a distinct terpenoid-rich profile. Spectroscopic and chemometric analyses enabled prediction of antioxidative capacity from chemical fingerprints, with near-infrared spectroscopy providing the most accurate predictions and demonstrating strong potential as a rapid standardization tool. Further analyses identified p-coumaric acid and ferulic acid as descriptors of antioxidative activity, and chrysin as an independent contributor to anti-inflammatory effects. In vivo, dietary supplementation delayed autoimmune diabetes onset, modulated T cell distribution and immune signaling, and altered gut microbiota composition. Together, these findings demonstrate that the biological activity of propolis is reflected by its chemical fingerprint and support its further evaluation as a dietary immunomodulatory strategy in autoimmune disease contexts.