Insights into Structure-Bioaccessibility Relationships of Polyphenols in Red Chicory by HPLC-MS/MS

Two varieties of red chicory from southern Po Delta area have been characterized in terms of polyphenols content. Attention has been mostly paid to phenolic acids and flavonoids1. Qualitative and quantitative determinations have been performed on sample extracts by HPLC-MS/MS. Both glycosylated and ester forms of phenolic acids as well as glycosylated flavonoids were mainly identified. Seven target bioactive compounds were selected and their bioaccessibility from red chicory vegetable matrix was investigated through simulated in-vitro static digestion process2,3. This gastro-intestinal model uses simulated fluids (i.e., salivary, gastric and duodenal) based on electrolytic solutions of different physiological enzymes miming the stages of digestion process. Fractions of polyphenols released from the vegetable matrix were quantitatively determined. Bioaccessibility results show well defined behaviors associated with both specific structures of aglycone or phenolic acid and position of O-glycosyl moiety. Dicaffeoyltartaric acid together with apigenin-7-O-glucoside and kaempferol-7-O-glucoside have similar bioaccessibility trend that is characterized by a higher value for duodenal phase than for gastric one. Quercetin-3-O-(6''-O-malonyl)-glucoside behave in reverse way and gastric bioaccessibility turns higher than duodenal. Lastly, the difference between gastric and duodenal bioaccessibility is ehnanced in the case of cyanidin-3-O-glucoside and two isomers of caffeoylquinic acid. Advanced investigations involved also living biological systems (i.e., cellular lines) and they were aimed at understanding effects of polyphenols on degenerative diseases. Particularly, investigation of the role of polyphenol metabolites and their positive synergic effects together with other nutraceutics was promising for uncovering hidden aspects of bioactives mode of action and their health effects.