Several studies have suggested that flavan-3-ols/procyanidins are associated with a reduced risk of developing obesity and metabolic syndrome. However, the role of highly polymeric procyanidins (PP), which are major non-absorbable flavonoids, in the biological effects, is not completely understood. Here, we show that 0.5% PP administration for 20 weeks alleviated obesity and regulate expression of genes related to lipid metabolism in C57BL/6J mice fed a high-fat/high-sucrose diet. PP-treatment attenuated weight gain and inflammatory effects including lipopolysaccharide and gut permeability. Additionally, metabolic urine profiling using high-performance liquid chromatography–quadrupole time-of-flight/mass spectrometry demonstrated that PP-treatment decreased the levels of endogenous metabolites associated with insulin resistance. Furthermore, microbial 16S rRNA gene sequencing of the cecum demonstrated that PP administration markedly decreased the Firmicutes/Bacteroidetes ratio and increased eight times the proportion of Akkermansia. These data suggest that PPs influence the gut microbiota and the intestinal metabolome to produce beneficial effects on metabolic homeostasis.

We previously described potential probiotic Lactobacillus rhamnosus strains, isolated from fermented mare milk produced in Sumbawa Island, Indonesia, which showed high adhesion to porcine colonic mucin (PCM) and extracellular matrix (ECM) proteins. Recently, mucus-binding factor (MBF) was found in the GG strain of L. rhamnosus as a mucin-binding protein. In this study, we assessed the ability of recombinant MBF protein from the FSMM22 strain, one of the isolates of L. rhamnosus from fermented Sumbawa mare milk, to adhere to PCM and ECM proteins by overlay dot blot and Biacore assays. MBF bound to PCM, laminin, collagen IV, and fibronectin with submicromolar dissociation constants. Adhesion of the FSMM22 mbf mutant strain to PCM and ECM proteins was significantly less than that of the wild-type strain. Collectively, these results suggested that MBF contribute to L. rhamnosus host colonization via mucin and ECM protein binding.