Chemical and Functional Characterization of Italian Propolis Obtained by Different Harvesting Methods

The composition and the antioxidant activity of Italian poplar propolis obtained using three harvesting methods and extracted with different solvents were evaluated. Waxes, balsams, resins contents were determined. Flavones and flavonols, flavanones and dihydroflavonols and total phenolics were also analyzed. To characterize the phenolic composition, the presence of 15 compounds was verified through HPLC-MS/MS. The antioxidant activity was evaluated through 1,1-diphenyl-2-picrylhydrazyl radical and reducing power assays. The ability of propolis to inhibit the lipids oxidation was monitored by analyzing the hydroperoxides and TBARS formation in lipids incorporated into an O/W emulsion. Acetone shows the highest extraction capacity. The wedges propolis have the highest concentration of active phenolic compounds (TP = 359.1 ± 16.3 GAEs/g; TFF = 5.83 ± 0.42%; TFD = 7.34 ± 1.8%) and seem to be the most promising for obtaining high-value propolis more suitable to prepare high quality dietary supplements. (TBARS = 0.012 ± 0.009 mmol std/g; RP = 0.77 ± 0.07 TEs/g).