Probiotic fermentation of Polygonatum plant polysaccharides converting fructans to glucans with enhanced anti-obesity...

Probiotic fermentation represents a potential approach to increase the bioactivity of polysaccharides, although its mechanisms remain unclear. Polygonatum polysaccharides, an important health-promoting components of Polygonatum, may exhibit improved antiobesity effects following probiotic fermentation based on previous research findings. A bioactive polysaccharide from Polygonatum kingianum ("King Solomon's seal" (huangjing)) (PKP), consisting of →1)-β-D-Fruf-(2 → (35.6 %) with an average molecular weight (Mw) of 3469 Da, was fermented using a mixed bacterial powder of Bacillus sp. DU-106 and Lactobacillus plantarum nbk-MA2 (1:1 activity ratio) to yield FPKP. Structural modifications linked to enhanced antiobesity effects were identified, and the underlying mechanisms were explored. PKP0, an inulin-type fructan dominated by →1)-β-D-Fruf-(2 → residues, was transformed into FPKP0, a starch-type glucan primarily composed of →4)-β-D-Glcp-(1 → residues, with a reduced Mw of 2883 Da. This resulted in reduced lipid accumulation, decreased adiponectin secretion, and the regulation of lipid metabolism-related proteins (UCP1, CIDEA, CEBPα, PGC-1α, PPAR-γ, Adiponectin, and FAS) in 3T3-L1 cells, along with suppressed inflammation and enhanced M1-to-M2 macrophage polarization in RAW264.7 cells. FPKP0 had stronger effects than PKP0. Molecular docking suggested that the enhanced effects of FPKP0 were due to its lower CDOCKER (MD-based docking algorithm) energy, additional binding sites, and increased hydrogen bonds with PPARγ. These findings provide guidance for the use of probiotic fermentation to improve antiobesity polysaccharides.