Small but Mighty: Low Bio-Accessibility Preserves Polyphenols from Mini Purple Carrots for Direct Action Against Colon Cancer Cells

Carrots are exceptional sources of bioactive compounds with potential health benefits. This study investigated the relationship between the biodiversity of carrot cultivars (colour and size) and their potential chemopreventive properties. Four distinct carrot cultivars (orange, white, yellow, and purple) of normal and miniature sizes were comprehensively analysed for polyphenolic composition, bio-accessibility through in vitro simulated digestion, and in vitro antiproliferative activity against the HCT-116 colon cancer cell line. Our findings revealed that vegetable size influenced phytochemical composition more than vegetable colour, with mini purple carrots exhibiting exceptionally high polyphenolic concentrations and superior antiproliferative activity compared to orange, yellow, or white varieties. Notably, the bioaccessibility of bioactive compounds remained remarkably low across all samples, suggesting that these phytochemicals reach the colon in intact form, potentially enabling direct interaction with cancer cells. Interestingly, we found no direct correlation between total phenolic content and antiproliferative activity. In vitro cell cycle analysis revealed that mini purple carrot extracts induced S-phase arrest similar to the chemotherapeutic agent 5-FU, whereas other extracts caused G0/G1-phase arrest. The specific polyphenolic composition appears to be fundamentally important for bioactivity, with chlorogenic acid and diferulic acid-derivative isomer 2 potentially acting synergistically. These findings highlight the importance of carrot biodiversity in delivering functional foods with enhanced health-promoting properties, particularly for colorectal cancer prevention.