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SummaryIn this study we investigated the influence of in vitro-simulated gastrointestinal digestion on the bioaccessibility and antioxidant activity of polyphenols from blueberries (Vaccinium spp.). Total phenolic, anthocyanin, and flavonoid content was determined, and extract and digesta compositions were analysed by HPLC-ESI-MS/MS. The phenolic compounds were relatively stable under a gastric environment, whereas polyphenols and anthocyanins were unstable under an intestinal environment. The bioaccessibility of polyphenol, anthocyanin, and flavonoid was greatly decreased after the intestinal digestion, and the recoveries were only 13.93%, 1.95%, and 15.68% (the IN sample), respectively. Polyphenolic profile alteration occurred during in vitro-simulated gastrointestinal digestion. Changes of phenolic compound antioxidant activity during digestion correlated with polyphenol, flavonoid, and caffeic acid concentrations. Digested extract cellular antioxidant activity was lower than non-digested extract activity (P < 0.05). Polyphenol dose-response correlations with cellular antioxidant activity were observed. These results indicated that in vitro-simulated gastrointestinal digestion significantly impact polyphenols and their antioxidant activity.

Anthocyanin, a natural antioxidant, is reported to have cytotoxicity against cancer cells; however, the mechanism remains unclear. The aim of the present study was to investigate the mechanism by which malvidin-3-galactoside (M3G), the prominent anthocyanin in blueberry, suppresses the development of hepatocellular carcinoma. In vitro, M3G suppressed the proliferation, polarization, migration, and invasion activities of HepG2 cells by regulating the protein expression of cyclin D1, cyclin B, cyclin E, caspase-3, cleaved caspase-3, Bax, p-JNK, and p-p38, activating phosphatase and tensin homologue deleted on chromosome 10 (PTEN), accompanied by a decrease in the p-AKT level, and lowering the protein expression levels of MMP-2 and MMP-9. In vivo, M3G promoted the apoptosis of liver tumor cells, as determined by immunohistochemistry (cleaved caspase-3, Ki-67, PTEN, and p-AKT), a terminal deoxynucleotidyl transferase dUTP nick end labeling assay, and hematoxylin− eosin staining. Overall, these results suggest that M3G, as an adjuvant ingredient or nutritional supplement, may be beneficial for liver cancer prevention and the modulatory mechanism seems to be associated with inhibition of proliferation, apoptosis, migration, and invasion-related pathways.

The aim of this study was the purification process of polyphenols from Aronia melanocarpa (chokeberry), and the purification parameters were optimised by adsorption and desorption tests. By comparing adsorption and desorption ability of polyphenols from chokeberry on six kinds of macroporous resin, XAD-7 resin was selected. Experiments prove that the best purification parameters of static adsorption and desorption were sample pH = 4.0 with 4 h of adsorption; and desorption solvent is 95% ethanol (pH = 7.0) with 2 h of desorption. The best dynamic parameters were 9.3 bed volume (BV) of sample loading amount at a feeding flow rate of 2 BV/h, and washing the column with 5.8 BV of water, followed by subsequent elution with an eluent volume of 5.0 mL at an elution flow rate of 2 BV/h. Next the antioxidant and antiproliferative activity of polyphenols from chokeberry, blueberries, haskap berries was studied on HepG2 human liver cancer cells. The results show that polyphenol from chokeberry has a strong antioxidant effect. Taking into account the content of polyphenols in fruit, polyphenols from chokeberry represent a very valuable natural antioxidant source with antiproliferative products.

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