Effect of simulated gastrointestinal digestion on polyphenols and bioactivity of the native Chilean red strawberry (Fragaria chiloensis ssp. chiloensis f. patagonica)

Abstract

The native Chilean red strawberry (Fragaria chiloensis spp. chiloensis f. patagonica) is a wild strawberry with high polyphenol content and antioxidant activity originating in central-southern Chile. The aim of the present work was to compare the composition and bioactivity of polyphenol-concentrated extracts (PCE) of the fruit, before and after simulated gastrointestinal digestion (GID). Twenty nine compounds were tentatively identified in the non-digested PCE. After GID, 26 and 23 compounds were detected, in the gastric and intestinal steps, respectively. The compounds that were more affected by the simulated GID were cyanidin hexoside, bis hexahydroxydiphenic acid (HHDP) hexosides, bis HHDP galloyl hexosides, apigenin hexoside, and quercetin dihexoside. Results show a decrease in the total phenolic content by 3.4% and 43% at the end of the gastric and intestinal steps, respectively. In the same way, the total flavonoid content decreased by 60.4% and 90.9% at the end of the gastric and intestinal step, respectively. Overall, the antioxidant activity decreased during the gastrointestinal process; as well as the inhibitory activity against α-glucosidase and lipase was reduced by the simulated digestion. These results are a first approach to understand the effects induced by the gastrointestinal digestion on the bioactivity and polyphenolic profile of this native fruit.

Keywords: AGS cells; Antioxidant activity; Berries; HPLC-DAD-MS; Metabolic syndrome-associated enzymes; Phenolic compounds; Simulated digestion.