Potentially Bio-Accessible Metabolites from an Extract of Cornus mas Fruit after Gastrointestinal Digestion In Vitro and Gut Microbiota Ex Vivo Treatment

Targeting pancreatic lipase and alpha-amylase by digestion-derived fractions of ethanolic-aqueous (60%, v/v) extract from Cornus mas fruit (CM) in relation to the control and prevention of metabolic disorders, including diabetes, was the first purpose of the present study. Taking into consideration the significance of bio-accessibility of compounds, we attempted to identify metabolites of CM after gastrointestinal digestion in vitro, as well as their kinetic changes upon gut microbiota treatment. The digestion of extract was simulated with digestive enzymes in vitro and human gut microbiota ex vivo (1 h, 3 h, 6 h, 24 h), followed by chromatographic analysis using the UHPLC-DAD-MSn method. The effect of fractions from gastrointestinal digestion in vitro on the activity of pancreatic lipase and alpha-amylase was studied with fluorescence-based assays. The gastric and intestinal fractions obtained after in vitro digestion of CM inhibited pancreatic lipase and alpha-amylase. Loganic acid as the main constituent of the extract was digested in the experimental conditions in contrast to cornuside. It was found in most analytes such as salivary, gastric, intestinal, and even colon (fecal slurry, FS) fractions. In all fractions, kaempferol hexoside and reduced forms of kaempferol, such as aromadendrin, and benzoic acid were assigned. The signals of tannins were detected in all fractions. Cornusiin A was tentatively assigned in the gastric fraction. The metabolites originating from kinetic analytes have been classified mainly as phenolic acids, hydrolyzable tannins, and flavonoids. Phenolic acids (protocatechuic acid, gallic acid), tannins (digalloylglucose, tri-O-galloyl-beta-D-glucose), and flavonoids (aromadendrin, dihydroquercetin) were detected in the late phases of digestion in fecal slurry suspension. Cornuside was found in FS analyte after 3 h incubation. It was not detected in the samples after 6 and 24 h incubation with FS. In conclusion, cornuside, aromadendrin, and phenolic acids may be potentially bio-accessible compounds of CM. The presence of plants' secondary metabolites in the intestinal fractions allows us to indicate them as responsible for decreasing glucose and lipid absorption.

Automated summary

The study aimed to investigate the targeting effect of Cornus mas fruit extract on pancreatic lipase and alpha-amylase, as well as the changes in metabolites and kinetics during gastrointestinal digestion. The results showed that the extract inhibited the activity of pancreatic lipase and alpha-amylase, and compounds such as loganic acid, kaempferol hexoside, and phenolic acids were found to be potentially bio-accessible.