Pigmented wheat whole breads: in vitro phenolic bioaccessibility and colorectal cancer-targeted effects

Abstract

Pigmented wheat varieties, naturally containing phenolic compounds and anthocyanins, have gained attention as potential functional foods. This study aimed to assess the in vitro bioaccessibility of individual phenolics and antioxidant capacities (ABTS, DPPH, and FRAP assays) in whole wheat breads prepared from red, purple, blue, and black wheats, and to compare their anticancer effects against HCT-15 colorectal cancer cells. Whole wheat breads were formulated using four distinct pigmented wheats. An in vitro gastrointestinal digestion model was applied to simulate human digestion, followed by fractionation into serum-accessible (IN) and colon-available (OUT) fractions. Total phenolic content (TPC) and antioxidant capacities were quantified, and the extracts' cytotoxic effects were assessed using HCT-15 cell viability assays. Digestion significantly altered phenolic profiles and antioxidant capacities, with bound phenolics demonstrating enhanced resistance to digestive conditions. After digestion, polyphenols and antioxidant capacity decreased, but they remained potentially bioaccessible. Notably, extracts from purple and blue wheat breads exhibited significantly greater cell viability-reducing activity against HCT-15 cells compared to red or black wheat extracts, suggesting a higher release and bioactivity of phenolics in these varieties. The superior inhibitory potency of purple and blue wheat breads highlights their potential as functional ingredients for the development of nutritionally enhanced wheat-based products, offering promising avenues for colorectal cancer prevention strategies.