Evaluation of the immunomodulatory effects of a novel synbiotic made of combined use of probiotic-prebiotic-Chinese traditional herbs

Recent studies have discussed the preferred activity of synbiotics, which are a combination of probiotics and prebiotics. This study formulates a novel synbiotic that includes Chinese traditional herbs and evaluates its immunomodulatory function. This study aims to systematically investigate the effects of synbiotics on immune function using a cyclophosphamide-induced immunosuppressed mouse model. A literature-based approach was used to selectively identify medicinal herbs with immunomodulatory properties. Commercially available probiotics were used to investigate the immunomodulatory functions and potential mechanisms associated with the combination of Chinese medicinal herbs and prebiotics as carbon substrates. The immunomodulatory effect of the synbiotic will be assessed by measuring indicators such as body weight, organ index, immunoglobulins, cytokines, splenic lymphocyte proliferation status, NK cell cytotoxicity and gut microbiota. Our results demonstrated that the synbiotic significantly restored the decreased thymus index and the increased spleen index induced by immune deficiency in mice. Among them, the formula of the synbiotics significantly improves the thymus organ index of immune organs from 0.068 to 0.126, which is also significantly superior compared to other single components. Additionally, it significantly enhanced the proliferative capacity of splenic lymphocytes and the cytotoxic activity of natural killer (NK) cells in immune-deficient mice. Furthermore, the synbiotics enhanced the richness and diversity of the gut microbiota, rectifying the dysbiosis in gut microbial composition caused by immune deficiency. It decreased the relative abundance of Firmicutes from 67.41% to 44.06%, while increasing the relative abundance of Bacteroidota from 30.42% to 53.77%. It restored the disrupted gut microbial structure induced by cyclophosphamide damage, thereby ameliorating the disrupted intestinal microbial community associated with immune deficiency. The study demonstrated that the synbiotic was capable of modulating immune function, as evidenced by an increase in organ index, cellular immunity, and the ability to modulate intestinal flora disorders. Furthermore, the synbiotic demonstrated superior performance compared to other single components. • Developed a synergistic formulation combining TCM, probiotics and prebiotics. • Possible mechanisms of the immunomodulatory function of synbiotic formulations were explored. • Synergistic effects of synbiotic formulations were found from a number of perspectives.