Effects of cassava polysaccharides on gut microbiome, intestinal barrier and macrophage activation

CPs possess considerable bioactive potential, yet their underlying immunomodulatory mechanisms remain incompletely elucidated. In the present work, CPCR were extracted from fresh cassava tubers and further separated into five purified polysaccharide fractions (CP1–CP5) with distinct monosaccharide profiles and molecular weights. Systematically investigated the immunomodulatory capacities of CPCR and its purified fractions via in vivo assays using Cy-induced immunosuppressed mice and in vitro tests on RAW264.7 murine macrophages. Multiple readouts were quantified, including gut microbial community structure, fecal SCFAs concentrations, intestinal tight junction protein expression, serum anti-inflammatory cytokine levels, as well as macrophage proliferation, phagocytic activity and inflammatory mediator release. In vivo data demonstrated that CPCR reshaped gut microbiota homeostasis by selectively enriching beneficial commensal genera and families linked to intestinal health, namely Muribaculaceae, Bacteroides, Alloprevotella , and Prevotellaceae . Enrichment of these probiotic taxa boosted intestinal SCFAs production; notably, fecal acetic acid concentration reached 141.0 mg/g following CPCR intervention, significantly exceeding levels measured in both normal control and Cy-induced immunosuppressed groups. Moreover, CPCR robustly upregulated the expression of intestinal barrier proteins ZO-1, occludin and Claudin-1, facilitating the repair and preservation of intestinal epithelial integrity. Serum cytokine profiling revealed prominent elevations in the anti-inflammatory mediators IL-2, IL-4 and IL-10 upon CPCR administration. Structural characterization of isolated subfractions revealed stark compositional disparities: CP1 predominantly consisted of 97% glucose with a molecular weight of 3 kDa, while CP2 contained 31.1% glucose, 20% galactose and 15.2% arabinose with a molecular weight of 62.4 kDa, this represents a preliminary structural characterization of the polysaccharide fractions. The results demonstrated that all CPs fractions could enhance immune cell activity, including phagocytic capacity and anti-inflammatory cytokine secretion. In summary, this study demonstrates that CPs exert immunostimulatory effects through dual pathways: direct activation of macrophage immune function and indirect regulation of gut microbiota-intestinal barrier homeostasis. Our results support the translational potential of CPs as bioactive functional food ingredients for immune regulation.