Guapian tea polysaccharides boost immunity and augment intestinal barrier integrity in cyclophosphamide-induced mice

Lu'an Guapian is a traditional Chinese green tea renowned for its special roasting process, while its functionalities rarely been revealed. This study aimed to explore the immunomodulatory effects of Guapian polysaccharides (LGP) on cyclophosphamide (CTX) -induced immunosuppressed mice. LGP with main molecular weight of 2.82 × 10⁶ Da significantly mitigated CTX-induced suppression of immune organs, enhanced the viability of macrophages and lymphocytes, and elevated serum levels of cytokines and immunoglobulins, thereby boosting immunity in mice. LGP could reverse CTX-induced morphological damage in the small intestine, including an increase in the number of goblet cells and the positive staining area of the intestinal lining. LGP facilitated the structural integrity of the small intestinal barrier by upregulating the expressions of mucin-2 and tight junction protein ZO-1. Besides, LGP modulated the intestinal flora composition in mice, restoring microbial balance disrupted by CTX. Collectively, as an efficacious immunomodulating agent, LGP's validation opens a new avenue for exploiting natural therapeutic products from tea resources.