Antioxidant characterization of native monofloral Cuban honeys

Five typical Cuban monofloral honeys were analyzed for their in vitro total antioxidant capacity (TAC), phenolic compounds, and ascorbic acid content. Identification and quantification of phenolics were carried out by HPLC-DAD-ESI/MS. Fourteen phenolic compounds could be identified (eight phenolic acids and six flavonoids), including three glycosylated derivatives. Similar contents of total phenolics were found in the different honeys, although they differed in their qualitative profiles. A significant (positive) correlation was found between the results of TAC obtained by parallel FIA-ABTS system and ORAC assay (r = 0.9565, p < 0.001). Similar correlations were also established between total phenolics and TAC, determined by either the ORAC (r = 0.9633; p ≤ 0.001) or the TEAC assay (r = 0.9582; p ≤ 0.001). Honeys were fractionated by solid-phase extraction into four fractions, and the relative contribution of each fraction to TAC was calculated. Phenolic compounds were significant contributors to the antioxidant capacity of the honeys, but they were not uniquely responsible for it. The antioxidant activity appeared to be a result of the combined activity of a range of compounds including phenolics and other minor components. Ascorbic acid was not detected.