Modulating Effects of Turmeric Polysaccharides on Immune Response and Gut Microbiota in Cyclophosphamide-Treated Mice

Turmeric, a traditional medicinal herb, is commonly used as a dietary and functional ingredient. This study aimed to investigate the effect of turmeric polysaccharides (TPs) on intestinal immunity and gut microbiota in cyclophosphamide (Cy)-induced immunosuppressed BALB/c mice. We verified that the oral administration of TPs-0 and TPs-3 (200 and 400 mg/kg, bw) improved thymus and spleen indexes, increased the whole blood immune cells (WBC) and lymph count index, and stimulated the secretion of serum immunoglobulin IgG. More importantly, TPs-0 and TPs-3 could repair intestinal immune damage and reduce intestinal inflammation. The specific mechanism is ameliorating the intestinal pathological damage, promoting CD4⁺ T cell secretion, regulating the expression of related cytokines, and reducing the level of critical proteins in the NF-κB/iNOS pathway. Interestingly, the intake of TPs-0 and TPs-3 significantly increased the content of short-chain fatty acids (SCFAs). Moreover, TPs-0 and TPs-3 relieved the intestinal microbiota disorder via the proliferation of the abundance of Lactobacillus and Bacteroides and the inhibition of Staphylococcus. Cumulatively, our study suggests that TPs-0 and TPs-3 can relieve intestinal immune damage by repairing the immune barrier and regulating intestinal flora disorders. TPs have potential applications for enhancing immunity as a functional food.