Polysaccharides extracted from Phellinus linteus ameliorate high-fat high-fructose diet induced insulin resistance in mice.

Phellinus linteus polysaccharide (PLP) has hypoglycemic effects, but mechanisms remain unclear. Male C57BL/6 J mice were either fed a normal diet (CON) or a high-fat high-fructose diet (HFD) for 16 weeks, and starting from week 12, HFD-fed animals in PLP group were orally given PLP. PLP administration significantly reduced fasting blood glucose level and ameliorated glucose intolerance. Differentially expressed genes involved in FOXO signaling pathway and in vitamin B12 (VB12) transport were identified between HFD and PLP group. HFD decreased the phosphatidylcholine (PC) to phosphatidylethanolamine (PE) ratio and S-adenosyl methionine to S-adenosyl homocysteine ratio, which were recovered by PLP treatment. Plasma VB12 levels in HFD group was lower than CON or PLP group, and PLP stimulated the proliferation of gut bacteria in genus Porphyromonas with capability of VB12 synthesis. In conclusion, PLP administration improved insulin resistance via modifying hepatic phospholipids metabolism and rescuing insulin signaling transduction.