Analysis of C-Glycosyl Flavones and 3-Hydroxy-3-methylglutaryl-glycosyl Derivatives in Blood Oranges (Citrus sinensis (L.) Osbeck) Juices and Their Influence on Biological Activity

Orange juices, especially from blood orange varieties, are one of the most worldwide consumed, due to the unquestionable health promoting properties, mainly attributed to flavonoids, and specifically anthocyanin compounds. Recently we have shown the presence of C-glycosyl flavones and 3-hydroxy-3-methylglutaryl-glycosyl flavonols (such as 3-hydroxy-3-methylglutaryl-glycosyl quercetin) by means of HPLC-DAD-MS-MS analyses, that can further increase the health promoting properties of this complex matrix. Hesperidin (106-545 mg/L) and narirutin (14-61mg/L) are, by far, the most abundant derivatives, followed by vicenin-2 (33-37 mg/L. Based on the scarce data on the impact of C-glycosyl flavone and 3-hydroxy-3-methylglutaryl-glycosyl flavonol derivatives on flavonoid biological benefits, we have started to evaluate also their health promoting potentiality, testing antioxidant and cytoprotective activity. Preparative RP-HPLC separation allowed us to gain further information on the contribution of these flavonoids to the total activity of crude blood orange juices.