Crohn’s and ulcerative colitis are common inflammatory conditions associated with Inflammatory bowel disease. Owing to the importance of diet based approaches for the prevention of inflammatory gut conditions, the present study was aimed to screen the human isolates of Bifidobacterium strains based on their ability to reduce LPS-induced inflammation in murine macrophage (RAW 264.7) cells and to evaluate prioritized strains for their preventive efficacy against ulcerative colitis in mice. Twelve out of 25 isolated strains reduced the production of LPS-induced nitric oxide and inflammatory cytokines. Furthermore, three strains, B. longum Bif10, B. breve Bif11, and B. longum Bif16 conferred protection against dextran sodium sulfate induced colitis in mice. The three strains prevented shortening of colon, spleen weight, percentage body weight change and disease activity index relative to colitis mice. Lower levels of Lipocalin-2, TNF-α, IL-1β and IL-6 and improved SCFA levels were observed in Bifidobacterium supplemented mice relative to DSS counterparts. Bacterial composition of B. longum Bif10 and B. breve Bif11 fed mice was partly similar to the normal mice, while DSS and B. longum Bif16 supplemented mice showed deleterious alterations. At the genus level, Bifidobacterium supplementation inhibited the abundances of pathobionts such as Haemophilus, Klebsiella and Lachnospira there by conferring protection.

Probiotic lactic acid bacteria are known to modulate gut associated immune responses. Not many studies have reported on the role of Weissella species in preventing lipopolysaccharide (LPS) induced proinflammatory stress in murine macrophages as well as in human intestinal epithelial cells (Caco-2). Therefore, the present study was taken up to evaluate the probiotic attributes of four newly isolated Weissella strains (two each from fermented dosa batter and a human infant faecal sample); these attributes are cholesterol reduction, adhesion to Caco-2 cells and mucin and their ability to prevent LPS-induced nitric oxide and proinflammatory cytokine (IL-6, IL-1β and TNFα) production by the murine macrophages and IL-8 production by the human epithelial cells. Reduction in LPS induced pro-inflammatory stress was compared with a well-studied probiotic bacterium Lactobacillus rhamnosus GG. The results suggested that the strains were tolerant to gastric conditions (pH 3.0) and bile salts. In addition, the strains exhibited moderate cell surface hydrophobicity, cholesterol reduction and adhesion to Caco-2 cells and gastric mucin. All the strains could prevent LPS-induced nitric oxide and IL-6 production in murine macrophages, while strain 28 alone prevented IL-1β production. All the strains could prevent IL-8 production by the human epithelial cells. The present study led to the first line selection of W. cibaria 28 as a putative strain for future studies as it showed adhesion to Caco-2 cells and gastric mucin and cholesterol reduction besides preventing LPS-induced pro-inflammatory stress in macrophages and in human colonic epithelial cells.

Taxifolin (98%) and catechin (86.6%) are the major polyphenols in KM-PRE and FM-PRE. FM-PRE and KM-PRE prevent obesity, hepatic steatosis, and gut bacterial dysbiosis however, the effects of KM-PRE are more profound compared to FM-PRE.

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