Molecular mechanisms of polysaccharides from Ziziphus jujuba Mill var. spinosa seeds regulating the bioavailability of spinosin and preventing colitis.

In this study, the effect of Ziziphus jujuba Mill var. spinosa seeds (ZSS) polysaccharides on the bioavailability of spinosin in mice and its molecular mechanism were investigated. After continuously fed with ZSS polysaccharides 100 mg/kg·d for 28 consecutive days, the C57BL/6 mice absorbed spinosin at an obvious lower level compared with the control group. The expression levels of P-gp, MRP2 and Occludin in the colon were significantly increased. ZSS polysaccharides significantly regulated the composition of the gut microbiota, reducing the abundance of Bacteroidetes, and increasing the richness of Firmicutes and Verrucomicrobia. Moreover, ZSS polysaccharides can significantly regulate the expression levels of tight junction proteins and efflux transporters in Caco-2 cells. However, the gut microbiota culture supernatant showed no obvious biological activity in this regard. Furthermore, histopathological analysis revealed ZSS polysaccharides can alleviate TNBS-induced colitis, reduced inflammatory cell infiltration in mice. This immune regulation was related to the NF-κB and MAPK pathways in RAW264.7 cells.