Use of in vitro models to identify biologically relevant phenolic forms from olive mill wastewater extracts

The objective of the present study was to use an in vitro digestion/Caco-2 human intestinal cell model to assess the bioaccessibility and intestinal absorption/metabolism of verbascosides from a partially purified OMWW extract. In vitro digestive recoveries (bioaccessibility) of verbascoside and isoverbascoside following simulated gastro/intestinal digestion, were found to be 35.5 ± 0.55% and 9.2 ± 0.94% respectively. Accumulation of verbascoside and isoverbascoside from OMWW extract by Caco-2 monolayers was found to be linear between 10 and 100?M and rapid with peak accumulation occurring by 30min. Verbascoside was found to be metabolized by Caco-2 primarily by O-methylation generating two distinct metabolite forms with m/z of 634.5 and 353. Combined, these data support the notion that verbascosides from OMWW extract are bioaccessible and should be considered biologically relevant phenolic forms from OMWW.