Hypoglycemic activity and gut microbiota regulation of a novel polysaccharide from Grifola frondosa in type 2 diabetic mice

GFP-N, a novel heteropolysaccharide with a molecular weight of 1.26 × 107 Da, was isolated from maitake mushroom and purified by anion-exchange chromatography on a DEAE cellulose-52 column and gel-filtration chromatography on a Sephadex G-100 column. Its structure was characterized by Fourier transform infrared spectroscopy and one-dimensional (1H- and 13C-) NMR spectra, 1H1H correlation spectroscopy, and 1H13C heteronuclear single-quantum coherence spectroscopy. The structure of GFP-N consisted of L-arabinose, D-mannose and D-glucose and mainly contained three kinds of linkage type units as →2,6)-α-D-Manp-(1 → 4, α-L-Araf-C1→, and →3,6)-β-D-Glcp-(1 → . GFP-N could activate insulin receptor substrate 1, phosphatidylinositol-3-kinase, and glucose transporter 4 and inhibit c-Jun N-terminal kinase 1/2 for hypoglycemic effects in diabetic mouse livers. This is also the first report…