This study aimed to investigate the structure characteristics Lonicera flos polysaccharides (LP) and the protective effects of LP on cyclophosphamide-induced immunosuppression in mice. The results showed the yield and purity of LP was 1.41% and 94.15%, the molecular weight was 53 kDa, and composed of arabinose, rhamnose, ribose, xylose, mannose, fructose, galactose and glucose; and LP had typical polysaccharide structural characteristics via ultraviolet and Fourier transform infrared (FTIR) spectroscopy, ¹H NMR and ¹³C NMR spectra, and scanning electron microscopy (SEM) analyses. Furthermore, LP obviously alleviated the injury of spleen and thymus; significantly promoted Interleukin-2 (IL-2), IL-6, tumor necrosis factor α (TNF-α), immunoglobulin (IgA, IgG and IgM) secretion; and improved the richness of gut microbiota and the contents of short-chain fatty acids (SCFAs) in immunosuppressive mice. Taken together, these results suggested that LP possessed strong protective effect on cyclophosphamide-induced immunosuppression in mice via modulating gut microbiota.

Ulcerative colitis (UC) is a modern, refractory disease, and studies have shown that UC is closely associated with the gut microbiota and intestinal immune barrier. This study evaluated the protective effects and regulatory mechanism of Chinese dwarf cherry [Cerasus humilis (Bge.) Sok.] fermentation juice (CFJ) on UC induced by dextran sulfate sodium (DSS). The results indicated that CFJ could significantly modulate the oxidative stress index in the serum and colon, observably reduce MPO and NO activity, and increase the SOD level. CFJ significantly downregulated the levels of TNF-α, IL-1β and IL-6 and reduced inflammation caused by DSS. SIgA and short-chain fatty acids (SCFAs) levels were effectively improved in the CFJ group, especially the acetic acid and butyric acid levels. Intestinal flora analysis showed that DSS could enrich harmful bacteria such as Alistipes and Oribacterium and that CFJ could increase the abundance of beneficial bacteria (Parasutterella, Bacteroides, Roseburia and Blautia). SIgA in the colon was positively correlated with Lachnoclostridium, Blautia, Lachnospiraceae_UCG-004, Prevotellaceae_NK3B31_group and other beneficial bacteria. The results showed that DSS group rats had immunity and signalling pathway disorders and that CFJ could regulate immune disorders, mainly by regulating the expression of IgA pathway components. Taken together, our results demonstrated that CFJ could regulate changes in the gut microbiota, improve the expression of immune protein-related genes, further regulate intestinal mucosal immune function and maintain intestinal mucosal barrier homeostasis.

Fermentation with Lactobacillus has been shown to improve the nutritional value of juice. In this study, Cerasus humilis juice was fermented using two commercial probiotics, namely, Lactobacillus acidophilus and Lactobacillus plantarum. The total antioxidant capacity (TAOC), viable count, chemical properties, antioxidant activity after in vitro digestion, and alterations in the gut microbiota composition of the fermented juice were investigated. After fermentation, the TAOC increased from 107.66 U mL⁻¹ to 126.72 U mL⁻¹; viable count increased from 5.85 lg (CFU mL⁻¹) to 8.17 lg (CFU mL⁻¹); and the contents of total phenols, total flavonoids, proanthocyanins, four organic acids, and 29 amino acids had changed. Overall, 47 compounds were identified in the juice, 20 of which were enriched after fermentation. Furthermore, Lactobacillus co-fermentation improved the antioxidant properties of the juice after in vitro digestion and increased the abundance of probiotics to regulate the gut microbiota. These findings illustrate the potential use of Lactobacillus acidophilus and Lactobacillus plantarum in the co-fermentation of C. humilis juice to enhance its nutritional and functional properties.