Evaluation of the total antioxidant capacity, polyphenol contents and starch hydrolase inhibitory activity of ten edible plants in an in vitro model of digestion.

The total phenolics contents, total antioxidant capacity (TAC) and starch hydrolase inhibitory activity of the aqueous extracts of 10 edible plants and the stability of these parameters after the gastric and duodenal digestion in an in vitro model was investigated. The TAC was evaluated using the oxygen radical absorbance capacity (ORAC) assay, ferric reducing antioxidant power (FRAP) and 2, 2-diphenyl-1-picrylhydrazyl (DPPH•) and 2, 2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+) radical scavenging assays. Characterization and quantification of five polyphenol compounds which were previously identified to be present in all the selected plants were carried out. None of the extracts showed a decrease in the total phenolics content or the ORAC and FRAP values following digestion. None of the quantified phenolic compounds had decreased during any of the digestion phases - an observation which was deemed as beneficial in terms of therapeutic properties. Overall, the parameters analyzed were relatively stable throughout the digestive process in all the extracts.