Water- and alkali-extracted wheat bran polysaccharides differentially affect antiproliferative and cell death responses in HCT116 and HT29 cells

Abstract

Wheat bran is a major by-product of cereal processing and a rich source of dietary polysaccharides with potential health-promoting properties. However, the biological activity of soluble polysaccharide fractions can be strongly influenced by extraction conditions and the resulting physicochemical characteristics. Soluble polysaccharide fractions were obtained from wheat bran using water (WSPF) and a new alkaline medium (ASPF) and characterized for their chemical composition, molecular features, and biological activity in cancer cells. Both extracts contained arabinoxylans, β-glucans, and associated polyphenols and showed similar monosaccharide compositions and overall chemical structures, but differed in molecular weight and purity, with ASPF exhibiting higher yield, purity, and molecular size. The antiproliferative effects of WSPF and ASPF were evaluated in human colorectal cancer cell lines. Both extracts significantly reduced cell viability, induced apoptosis, and caused cell cycle arrest, with an accumulation of cells in the G0/sub-G1 phase. Notably, WSPF showed greater efficacy in reducing cell viability without inducing detectable membrane damage, whereas ASPF promoted LDH release, indicating cytotoxic effects. These findings suggest that soluble wheat bran polysaccharides exert antiproliferative effects through mechanisms modulated by extraction conditions, influencing the balance between regulated cell death and nonspecific cytotoxicity. Overall, this study highlights the importance of the extraction strategy in defining both the physicochemical properties and biological responses of wheat bran polysaccharides, supporting their potential use as functional ingredients with anticancer-related bioactivity.