Hepatic uptake of grape anthocyanins and the role of bilitranslocase

Anthocyanins are water-soluble compounds that pigment berries, grapes and vegetables. Their flavonoid backbone endows them with oxygen radical scavenging activity. Thus, they could play a role in protecting the human organism from various degenerative and proliferative diseases, that are currently believed to result from an oxygen radical-mediated disruption of cellular components. Their great potential as functional food ingredients is, however, restricted by the incomplete knowledge of their bioavailability. In order to contribute to filling this gap, we looked for their presence in the liver, after administration of a solution of pure grape anthocyanins into the stomach of anaesthetised rats. We found that the liver contained both malvidin 3-glucoside and its p-coumarate ester, the main and the minor component of the mixture, respectively. Isolated, cultured liver cells were also found to be permeable to malvidin 3-glucoside and bilitranslocase was identified as the carrier protein involved, by using two different specific antibodies.