Inonotus obliquus Polysaccharides Prevent High-Fat Diet-Induced Obesity in Mice Related to Reshaping Gut Microbiota

Obesity development is linked to disturbances in the gut microbiota. Inonotus obliquus polysaccharides (IOPs) have potential therapeutic efficacy in alleviating metabolic disorders. However, the mechanism by which IOP prevents obesity via regulating gut microbiota remains elusive. IOP was extracted and structurally characterized by FT-IR and NMR spectroscopy, confirming typical polysaccharide structures. Structurally, IOP is a 5.4 kDa polysaccharide predominantly composed of glucose, galactose, xylose, mannose, galacturonic acid, glucuronic acid, as well as rhamnose, arabinose, and methyl-galactose. Administration of IOP to high-fat diet (HFD)-fed mice effectively curtailed weight gain and improved serum lipid parameters. Furthermore, it mitigated lipid deposition within hepatic and adipose tissues, while successfully countering HFD-triggered liver damage. Notably, IOP induced significant changes in microbial diversity and composition by selectively increasing the abundance of Streptococcaceae while suppressing Faecalibaculum rodentium at the family and species levels. These findings highlight that IOP is a promising functional food ingredient that regulates gut microbiota for obesity prevention.