Antioxidant Capacity of Honeys from Various Floral Sources Based on the Determination of Oxygen Radical Absorbance Capacity and Inhibition of in Vitro Lipoprotein Oxidation in Human Serum Samples

Honeys from seven different floral sources were analyzed for in vitro antioxidant capacity and total phenolic content. Antioxidant capacity was measured by the oxygen radical absorbance capacity (ORAC) assay and by monitoring the formation of conjugated dienes as an index of the inhibition of copper-catalyzed serum lipoprotein oxidation. ORAC values ranged from 3.1 to 16.3 micromol Trolox equivalent/g honey. The darkest colored honeys, such as buckwheat honey, had the highest ORAC values. A linear correlation was observed between phenolic content and ORAC activity of the investigated honeys (p < 0.0001, R (2) = 0.9497). The relationship between the ORAC activity and inhibition of lipoprotein oxidation by the honeys yielded a correlation coefficient of 0.6653 (p = 0.0136). This work shows that honey may be used as a healthy alternative to sugar in many products and thereby serve as a source of dietary antioxidants.