Lingonberries Retain Bioactivity Following Simulated Gastrointestinal Digestion and Colonic Fermentation

Background and objectives: Lingonberry (Vacciniumvitis- idaeaL) is a popular edible berry in Scandinavian countries and is increasing in popularity across Europe. Lingonberry possesses a complex polyphenolic profile consisting of a mix- ture of anthocyanins, phenolic acids, flavonols and proantho- cyanidins which is of interest due to their putative anticancer activity.After consumption, phenolic compounds are subject to digestive conditions within the gastrointestinal tract which alters their structures and potentially their bioactivity. Given limited bioavailability in the small intestine, a substantial portion of berry phenolic compounds are likely to pass into the colon where they are degraded by the colonic microbiota. Therefore, it is reasonable to infer that the colonic epithelium is exposed to both the parent phenolic compounds
and their degradation products

Aim: To evaluate the impact of digestion and colonic fermentation on
phenolic components and bioactivity of a lin- gonberry extract (LE).

Methods: LEs were produced by in vitro digestion and subsequent faecal fermentation and characterised by LC-MS and GC-MS. Bioactivity was tested using a physiologically relevant dose range (0-50 µg/ml phenols) with a 24 hour exposure in in vitro models representing key stages in
colon carcinogenesis namely initiation (comet assay, HT29, mutagenicity assayHT- 29G17neo) and invasion (Matrigel invasion assay, HT115).
Results: LC-MS and GC-MS analysis confirmed digestive and fermentation processes altered the polyphenol composition relative to the original LE with the levels of simple aromatic components increased in the fermented extract. Diges ted and fermented LE exhibited significant anti-genotoxic (p< 0.05), anti-mutagenic (p< 0.05) andanti-invasive (p< 0.05), effects compared
to the appropriate controls (ANOVA, Post Hoc Dunnett T test)in all in vitro models.

Conclusions: This study indicates that despite ex- tensive structural modification following digestion and fermentation,lingonberry extracts retain their ability to modulate cellular processes associated with colon cancer.