Differential modulation of cancer cell proliferation by fermented plant-based beverages: A comparative study of tiger nut, carob and rice beverages in colorectal adenocarcinoma cells

Fermentation represents a sustainable biotechnological approach for enhancing bioactive properties of plant-based foods, yet its anticancer effects remain underexplored. We evaluated the antiproliferative activity of fermented (with commercial probiotic lactic acid bacteria consortium) and unfermented plant-based beverages derived from tiger nut, carob, and rice using an in vitro model. Following INFOGEST 2.0 gastrointestinal digestion, bioaccessible fractions were applied to Caco-2 colorectal adenocarcinoma cells at 1:15 v/v dilution for 24 h. Analyses included cell viability, apoptosis detection, cell cycle distribution, reactive oxygen species production, glutathione content, mitochondrial membrane potential, and intracellular calcium levels. Fermented tiger nut achieved superior (p < 0.05) cytotoxicity compared to unfermented counterpart (39.6% vs. 77.4% cell viability) through dual mechanisms: depleting cellular antioxidant defenses (glutathione reduced to 55.9%) while inducing oxidative stress (180.3% ROS overproduction). This evoked irreversible apoptosis (76.9% early apoptosis) and extensive DNA fragmentation (84.8% SubG1 population) via calcium-independent pathways. Fermented carob operated through cytostatic mechanisms, inducing G0/G1 cell cycle arrest (74.7% vs. 44.2% in blank digestion cells) without oxidative stress. Fermentation reduced (p < 0.05) rice beverage antiproliferative activity (90.2% vs. 71.9% unfermented beverage cell viability). These findings establish lactic acid fermentation as effective for developing plant-based beverages with anticancer mechanisms, offering dietary strategies for colorectal cancer prevention.