Antioxidant and anti-inflammatory activities, bioaccessibility, transmembrane transport of major phenolics from selected floral honeys using Caco-2 BBe1 cell model

In the present study, we assessed the antioxidant activity of the phenolic extracts and major phenolic compounds of alfalfa, buckwheat, clover and orange honeys collected in North America using chemical-based and cell-based antioxidant assays (CAA). Cell culture models using Caco-2 BBe1 were established to evaluate the effect of honey phenolics on antioxidant enzyme activities and secretion of interleukin 8 (IL-8). Moreover, bioaccessibility, transmembrane transport and cellular uptake of honey phenolics were also studied. Based on the same quantity of the honey studied, phenolic extract of buckwheat honey showed the highest FRAP, DPPH, ORAC and CAA values, and strongest activity in restoring activities of antioxidant enzymes (GR, SOD and CAT) and in reducing TNF-α-induced IL-8 secretion. Our results showed that compared to the major phenolic component of honey of plant origin, minor phenolics or combination of different phenolic compounds, particularly those derived from propolis, and their phase Ⅱ metabolites may play contribute more to the overall antioxidant and anti-inflammatory effects. Future research will focus on bioavailability of honey phenolics and their metabolites, and the molecular mechanism of the antioxidant, anti-inflammatory activities.