Bioavailable Citrus sinensis Extract: Polyphenolic Composition and Biological Activity.

Abstract: Citrus plants contain large amounts of flavonoids with beneficial effects on human health.In the present study, the antioxidant and anti-inflammatory potential of bioavailable polyphenols fromCitrus sinensis was evaluated in vitro and ex vivo, using the murine macrophages cell line J774A.1and primary peritoneal macrophages. Following simulated gastro-intestinal digestion, the in vitrobioavailability of Citrus sinensis polyphenolic extract was assessed using the human cell line Caco-2grown as monolayers on a transwell membrane. Data demonstrated a relative permeation of itscompounds (8.3%). Thus, the antioxidant and anti-inflammatory effect of polyphenolic Citrus sinensisfraction (Cs) was compared to the bioavailable one (CsB). Results revealed that Citrus extract wereable to reduce macrophages pro-inflammatory mediators, including nitric oxide, iNOS, COX-2 anddifferent cytokines. Moreover, the effect of Citrus sinensis polyphenols was associated with antioxidanteffects, such as a reduction of reactive oxygen species (ROS) and heme-oxygenase-1 (HO-1) increasedexpression. Our results provide evidence that the bioavailable polyphenolic constituents of theCitrus sinensis extract accumulate prevalently at intestinal level and could reach systemic circulationexerting their effect. The bioavailable fraction showed a higher anti-inflammatory and antioxidantpotential compared to the initial extract, thus highlighting its potential nutraceutical value.