Antioxidant protein signatures in honey: botanical influence and proteomic variability

Antioxidant capacity of honey derives from both polypHenols and proteins. We aimed to define putative antioxidant-protein signatures across honeys of differing botanical origin and relate them to pollen for authenticity assessment. Seven Lithuanian honeys were profiled by LC-MS proteomics, identifying 17 proteins with annotated antioxidant function (10 plant-, 6 bee-, 1 aphid-derived). Plant proteins, dominated by Brassica napus, were most abundant in monofloral B. napus honey. Bee proteins, glucose-methanol-choline oxidoreductases, were more variable and together comprised >75% of the summed antioxidant-protein signal. Correlations showed positive associations between B. napus pollen and most B. napus-derived proteins (r = 0.815-0.996) but not with bee-derived proteins; chalcone-flavonone isomerase correlated negatively. Fold-change analysis in comparison to monofloral B. napus honey confirmed up-regulation of B. napus proteins and down-regulation of several bee oxidoreductases. Altogether, plant proteins capture botanical origin, whereas bee proteins reflect apicultural factors, supporting a multi-indicator basis for honey authenticity and functional appraisal.