Absorption, metabolism, and effects at transcriptome level of a standardized French oak wood extract, Robuvit, in healthy volunteers: pilot study.

The consumption of wine and spirits, traditionally aged in oak barrels, exposes humans to roburin ingestion. These molecules belong to a class of ellagitannins (ETs), and their only known source is oak wood. Very little is currently known about roburin bioavailability and biological activity. We reported for the first time human absorption of roburins from a French oak wood (Quercus robur) water extract (Robuvit) by measuring the increase of total phenols (from 0.63 ± 0.06 to 1.26 ± 0.18 μg GAE equiv/mL plasma) and the appearance of roburin metabolites (three different glucoronidate urolithins and ellagic acid), in plasma, after 5 days of supplementation. Robuvit supplementation induced also the increase of plasma antioxidant capacity from 1.8 ± 0.05 to 1.9 ± 0.01 nmol Trolox equiv/mL plasma. Moreover, utilizing a combined ex vivo cell culture approach, we assessed the effect of Q. robur metabolites (present in human serum after supplementation) on gene expression modulation, utilizing an Affymetrix array matrix, in endothelial, neuronal, and keratinocyte cell lines. The functional analysis reveals that Robuvit metabolites affect ribosome, cell cycle, and spliceosome pathways.