THE IMPACTS OF ANTHOCYANINS ON GUT HEALTH: MICROBIOME DYNAMICS AND COLORECTAL CANCER CELL RESPONSES

Abstract

Anthocyanin (ACN)-rich foods are believed to suppress gut inflammation and may reduce the risk of colitis-associated colorectal cancer (CAC) through direct interactions with the gut epithelium or by modulating the gut microbiome. The overarching goal of this research was to investigate the dynamic changes in gut microbiome composition in response to ACN-rich foods within the context of a Western diet and to assess the direct effects of pure anthocyanins and their aglycones on colon cancer cell lines representing different disease stages. In the first study, male C57BL/6J mice were fed TWD supplemented with freeze- dried, ACN-rich whole food powders. The results demonstrated distinct shifts in gut microbiome composition as early as one day after exposure. However, these changes were not sustained after cessation of the diet, indicating that consistency is critical for persistent effects. Correlation analyses revealed that the unique ACN profiles of each food source were associated with specific microbial shifts, highlighting the differential microbiome-modulating potential of ACNs based on their structural composition. The second study evaluated the cytotoxic effects of purified anthocyanins and their aglycones on human colon cancer cell lines (HT29 and HCT116) at physiologically relevant concentrations. Contrary to expectations, these compounds did not significantly affect cell viability, apoptosis, or cell cycle progression. These findings suggest that the anticancer effects observed with ACN-rich whole foods are unlikely to result from pure anthocyanins alone but may instead depend on synergistic interactions among multiple bioactive compounds and gut microbiome-derived metabolites. Collectively, this research provides an integrative understanding of ACN-rich foods by combining dynamic microbiome analysis with physiologically relevant cancer models. It underscores the importance of whole food matrices and supports the need for further investigation into the role of gut microbial metabolism in mediating the anti-inflammatory and anti-carcinogenic potential of dietary anthocyanins.