Citrus flavanones enhance carotenoid uptake by intestinal Caco-2 cells

The health benefit of a diet rich in fruits and vegetables could be attributed to the presence of a large diversity of phytochemicals, including carotenoids. Bioactivities of carotenoids greatly depend on their bioavailability that could be modulated by the presence of other dietary constituents. Because citrus juices contain diverse antioxidant phytochemicals, the effects of flavonoids and ascorbic acid on intestinal carotenoid uptake were investigated. Experiments were conducted by using a Caco-2 cell monolayer exposed to micelles enriched in beta-cryptoxanthin (b-CX, 5 mu M) and beta-carotene (b-C, 5 mu M) in the presence of hesperetin (HES, 250 mu M), hesperidin (HES-G, 250 mu M), naringenin (NGN, 250 mu M), acid ascorbic (AA, 50 mu M) and iron. At 5 h or 24 h incubation, HES-G and HES significantly increased b-CX and b-C uptake by 1.7- and 1.6-fold, respectively (p < 0.05). Interestingly, AA was shown to eliminate the enhancing effect of HES-G by decreasing significantly the cellular uptake of carotenoids from 48.2 to 39.8% after 5 h incubation (p < 0.05). Iron decreased the carotenoid uptake, while HES-G in the presence of iron restored it, suggesting that the enhancing effect of HES-G on carotenoid uptake could be attributed to its iron-chelating activity.