Effects of polysaccharides from bee collected pollen of Chinese wolfberry on immune response and gut microbiota composition in cyclophosphamide-treated mice

•WBPPS reversed immune organ indexes and enhanced production of serum TNF-α, IL-10 and TGF-β1.•WBPPS effectively regulated the expression of immune-related genes in the colon.•WBPPS effectively prevented CTX-induced hepatotoxicity through anti-oxidant activity.•WBPPS promoted immune and regulated composition of gut microbiota in CTX-treated mice.•WBPPS could potentially serve as an effective immunomodulator.