Iridoids and polyphenols from chilean Gaultheria spp. berries decrease the glucose uptake in Caco-2 cells after simulated gastrointestinal digestion.

Berries are rich food sources of potentially health-beneficial (poly)phenols. However, they may undergo chemical modifications during gastrointestinal digestion. The effect of simulated gastrointestinal digestion on the content and composition of secondary metabolites from Gaultheria phillyreifolia and G. poeppigii berries was studied. The influence of the digested extracts on the in vitro metabolism and absorption of carbohydrates was evaluated. After simulated digestion, 31 compounds were detected by UHPLC-DAD-MS. The total content of anthocyanins decreased by 98-100%, flavonols by 44-56%, phenylpropanoids by 49-75% and iridoids by 33-45%, the latter showing the highest stability during digestion. Digested extracts inhibited α-glucosidase (IC50 2.8-24.9 µg/mL) and decreased the glucose uptake in Caco-2 cells by 17-28%. Moreover, a decrease in the mRNA expression of glucose transporters SGLT1 (38-92%), GLUT2 (45-96%), GLUT5 (28-89%) and the enzyme sucrase-isomaltase (82-97%) was observed. These results show the effect of simulated gastrointestinal digestion on the content and composition of Gaultheria berries.

Simultaneous extraction and separation of bioactive compounds from apple pomace using pressurized liquids coupled on-line with solid-phase extraction.

The objective of this work was the development of an on-line extraction/fractionation method based on the coupling of pressurized liquid extraction and solid-phase extraction for the separation of phenolic compounds from apple pomace. Several variables of the process were evaluated, including the amount of water of the first stage (0-120 mL), temperature (60-80 °C), solid-phase extraction adsorbent (Sepra, Isolute, Strata X and Oasis) and activation/elution solvent (methanol and ethanol). The best results were observed with the adsorbent Sepra. The temperature had a small effect on recovery, but significant differences were observed for phlorizin and a quercetin derivative. Results indicate that ethanol can be used to replace methanol as an activation, extraction/elution solvent. While using mostly green solvents (water, ethanol, and a small amount of methanol that could be reused), the developed method produced higher or similar yields of acids (2.85 ± 0.19 mg/g) and flavonoids (0.97 ± 0.11 mg/g) than conventional methods.