Colonic fermentation of polyphenols from Chilean currants (Ribes spp.) and its effect on antioxidant capacity and metabolic syndrome-associated enzymes. (30th August 2018) - Burgos-Edwards, Alberto
Highlights: Polyphenols from Ribes fruits were submitted to in vitro colonic fermentation. Changes in phenolic profiles and bioactivity during fecal incubation were assessed. Metabolites derived from polyphenols were detected by HPLC-DAD-MS/MS. An increase in ORAC values was observed after 8 h fermentation in both species. The inhibitory activity against α-glucosidase is maintained after the fermentation. Abstract: The Chilean wild currants Ribes magellanicum and R. punctatum are a good source of polyphenols. Polyphenolic-enriched extracts (PEEs) from both species were submitted to in vitro colonic fermentation to assess the changes in phenolic composition, antioxidant capacity and inhibition of metabolic syndrome-associated enzymes. The phenolic profiles of the fermented samples showed significant changes after 24 h incubation. Nine metabolites, derived from the microbial fermentation, were tentatively identified, including dihydrocaffeic acid, dihydrocaffeoyl-, dihydroferuloylquinic acid, 1-(3, 4-dihydroxyphenyl)-3-(2, 4, 6-trihydroxyphenyl)propan-2-ol (3, 4-diHPP-2-ol), among others. The content of anthocyanins and hydroxycinnamic acids was most affected by simulated colonic conditions, with a loss of 71–92% and 90–100% after 24 h incubation, respectively. The highest antioxidant capacity values (ORAC) were reached after 8 h incubation. The inhibitory activity against the enzyme α-glucosidase was maintained after the fermentation process. Our results show that simulated colonic fermentation exerts significant changes on the polyphenolic composition of these berries, modifying their health-promoting properties.