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The Araucaria araucana kernels are a traditional food in southern Chile and Argentina. The aim of this work was to determine the composition of the phenolic-enriched extracts (PEEs) of the boiled kernels as well as their antioxidant capacity, inhibitory activity on metabolic syndrome-associated enzymes and effect on postprandial oxidative stress in a simulated gastric digestion model. The PEEs composition was assessed by HPLC-DAD-MS/MS. The main PEEs constituents were catechin and epicatechin in the unbound form, while hydroxybenzoic acids occurred mainly in the bound form. The unbound phenolics from boiled kernels showed significant correlations with DPPH, FRAP, TEAC (Pearson’s r of 0.481, 0.331 and 0.417, respectively) and lipid peroxidation (r = 0.381) and were more active than the bound phenolics. The extracts were highly active against α-glucosidase (IC50: 0.33–3.15 µg/mL) and reduced lipoperoxidation. Traditional processing increases the flavan-3-ol content. Our results suggest that this traditional food has potential health promoting properties.

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.

The wild Chilean currants Ribes magellanicum and R. punctatum are a good source of polyphenolic compounds. The effect of simulated gastrointestinal digestion (GID) on phenolic content, composition and antioxidant capacity was determined. The inhibitory activity of the non-digested and digested samples towards metabolic syndrome-associated enzymes (α-amylase, α-glucosidase and lipase) was evaluated. The total phenolic (TP) and flavonoid contents (TF) decreased by about 50% at the end of the in vitro GID. Main anthocyanins and hydroxycinnamic acids were strongly affected by this process, with a loss of about 80%. A decrease in the antioxidant activity was observed throughout the digestion steps, which was correlated with the reduction in the TP and TF content. After the in vitro GID of the samples, only the inhibition of α-glucosidase was preserved. Our results show that the simulated GID modified the health-promoting properties of the studied currants.