Digested galactoglucomannan mitigates oxidative stress in human cells, restores gut bacterial diversity, and provides chemopreventive protection against colon cancer in rats.

Galactoglucomannan (GGM) is the predominant hemicellulose in coniferous trees, such as Norway spruce, and has been used as a multipurpose emulsifier in the food industry. In vitro digestion with a cellular antioxidant activity assay was performed to determine the bioaccessibility and antioxidant activity of phenolic compounds, and the behaviour of GGM on in vivo experimental assay against induced colon cancer. The results showed that digestion decreased the bioaccessibility and antioxidant capacity of phenolic compounds. Cellular analysis did not support these findings once an antioxidant effect was observed in human cell lines. GGM attenuated the initiation and progression of colon cancer, by reducing the foci of aberrant crypts in rats, and modified the intestinal bacterial microbiota (disrupting the balance between Firmicutes and Bacteroidetes phyla). Thus, GGM provided chemopreventive protection against the development of colon cancer and acted as an intracellular antioxidant agent.

Blackcurrant press cake by-product: Increased chemical bioaccessibility and reduced antioxidant protection after in vitro simulation of gastrointestinal digestion.

This study describes the bioaccessibility in terms of total phenolic content (TPC) and antioxidant capacity before and after in vitro digestion from blackcurrant press cake extracts (BPC) and the bioactivity in cell culture, human erythrocytes as well as the in silico analysis. Chemical analysis of BPC presented an increase in TPC (270%) and anthocyanins (136%) after in vitro digestion, resulting in an improvement of antioxidant activity (DPPH 112%; FRAP: 153%). This behavior may be related to the highest activity of cyanidin-3-rutinoside, as confirmed by in silico analysis. The digested BPC did not exert cytotoxicity in cells and showed less antioxidant activity against the oxidative damage induced in endothelial cells and human erythrocytes compared to the non-digested extract. The results raise a question about the reliability we should place on results obtained only from crude samples, especially those that will be used to produce foods or nutraceuticals.

From waste to the gut: Can blackcurrant press cake be a new functional ingredient? Insights on in vivo microbiota modulation, oxidative stress, and inflammation.

Blackcurrant press cake (BPC) is a source of anthocyanins, and this study evaluated the bioactivity and gut microbiota modulation of blackcurrant diets with or without 1,2 dimethylhydrazine (DMH)-induced colon carcinogenesis in rats. In colon cancer-induced rats (CRC), BPC at the highest dosages increased pro-inflammatory parameters and the expression of anti-apoptotic cytokines, accentuating colon cancer initiation by aberrant crypts and morphological changes. Fecal microbiome analysis showed that BPC altered the composition and function of the gut microbiome. This evidence suggests that high doses of BPC act as a pro-oxidant, accentuating the inflammatory environment and CRC progression.