Absorption of black currant anthocyanins by monolayers of human intestinal epithelial Caco-2 cells mounted in ussing type chambers.

Anthocyanins (ACNs) have been reported to have multiple biological properties imparting benefits to human health. Their role in human nutrition, however, needs to be related to biokinetic data, such as bioavailability. The purpose of the present study was to focus on the potential absorption of black currant ( Ribes nigrum L.) ACNs. Caco-2 monolayers were used as an in vitro model of the absorptive intestinal epithelium. For absorption studies, Caco-2 cells grown on permeable filters were mounted into Ussing type chambers. The monolayer integrity was monitored by measuring the transepithelial electrical resistance (TEER). Luminal to serosal transport of ACNs was examined by comparing ACN disappearance from the luminal solution of Ussing chambers not containing any inserts (control chambers) with that of Ussing chambers containing inserts. ACNs (C total ACN approximately 180 microM) were not detected in any serosal solution. However, it was shown that ACNs disappeared from the luminal side, not due to ACN degradation processes but rather--at least in part--due to physiological actions of the cells. The luminal net disappearance of ACNs was calculated (max(t20 min) approximately 11% for total ACNs) and labeled as "absorption efficiency". This apical transport might occur to a much larger extent than the further translocation across the basolateral membrane. Thus, cell metabolism and translocation across the basolateral membrane may be the key determinants of ACN absorption and bioavailability.