Flavonoids, phenolic acids, carotenoids and antioxidant activity of fresh eating citrus fruits, using the coupled in vitro digestion and human intestinal HepG2 cells model

With in-vitro digestion and human intestinal HepG2 cells, we analyzed the bioaccessibility and cell uptake of phytochemicals and determined the cellular antioxidant capacity (CAA) of fresh eating citrus fruits. The results showed that CAA of citrus fruits was higher in digesta than in extracts, and the CAA is strongly correlated with naringenin and beta-carotene uptake (p < 0.05). During in vitro digestion, vanillic acid and p-coumaric decreased, and ferulic acid increased in all citrus fruits significantly (p < 0.05); other phytochemicals varied among the fruits. During uptake, hydroxybenzoic acids, hesperidin, narirutin, naringenin and neohesperidin were detected in cells, Zeaxanthin, lutein, beta-cryptoxanthin and beta-carotene could be detected in the citrus varieties except for pummel, but hydroxycinnamic acids and hesperitin were not detected in cells. This work provides insights into the bioaccessibility and cell uptake of phytochemicals and cellular antioxidant activity of fresh eating citrus fruits.