Colonic fermentation of polyphenols from Chilean currants (Ribes spp.) and its effect on antioxidant capacity and metabolic syndrome-associated enzymes

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.

Keywords: 1-(3,4-dihydroxyphenyl)-3-(2,4,6-trihydroxyphenyl)propan-2-ol (3,4-diHPP-2-ol, PubChem CID: 21722175); 3-Caffeoylquinic acid (PubChem CID: 1794427); Antioxidant capacity; Cyanidin-3-glucoside (PubChem CID: 92131208); Cyanidin-3-rutinoside (PubChem CID: 44256716); HPLC-DAD-MS/MS(n); In vitro colonic fermentation; Metabolic syndrome-associated enzymes; Polyphenolic profiles; Ribes spp..