Cell antioxidant activity of phenolic compounds from amaranth flour after simulated gastrointestinal digestion

RODRÍGUEZ, MARIELA; FONTANA, ARIEL; TIRONI, VALERIA

Barcelona

Conferencia; 1st International Conference on Antioxidants: Sources, Methods, Health Benefits and Industrial Applications; 2023

MDPI

Amaranth flour (AF) is a source of different antioxidant components with potential health benefits for consumers, including polyphenols. This work aimed to study the antioxidant properties of polyphenols after simulated gastrointestinal digestion (SGID) of amaranth flour using in vitro acellular and cellular systems (Caco2-TC7 cultures).The whole A. mantegazzianus grain was milled (Udy mill), and a SGID was performed according to an internationally agreed protocol involving oral, gastric and intestinal stages. Polyphenolic compounds (PCs) obtained from 70/30 MeOH/water extraction were analyzed; the total polyphenols content (TPC) was determined using the Folin-Ciocalteu method and PC profiles andconcentration with LC-DAD-FLD. Antioxidant activity was evaluated: a) in acellular systems (ABTS, ORAC); b) in cellular systems: colon carcinoma cell cultures (Caco2-TC7) exposed to an oxidative-stress-inducing factor (H2O2). Cell viability was determined using lactate dehydrogenase (LDH) assay and intracellular ROS content through 2´,7´-dichlorofluorescein diacetate oxidation (DCFH-DA). Using commercial kits, reduced GSH content as well as SOD and GPx activities were measured in cell lysates sequentially exposed to phenolic extract (MeOH/water) evaporated and resuspended in phosphate buffer (35mM, pH 7,8) and then to H2O2 as an oxidative stress inducer.AF digestion (DAF) released/modified some phenols, reduced the diversity of PCs, and increased the total amount extracted given mainly by compounds of the flavanol family and stilbene trans piceatannol. The PTC of DAF was about 20 times greater than that determined for AF. Compounds extracted from DAF showed in vitro antioxidant activity in chemical assays (ORAC and ABTS+· scavenging), as well as the ability to inhibit intracellular ROS, increase SOD activity and GSH contents and raise GPx activity (to basal level) in H2O2 - induced cells. These results indicate activity against the cellular oxidative stress of bioaccessible AF-derived PCs, positioning the AF as a potential ingredient for the development of functional foods.