Seabuckthorn polysaccharide ameliorates high-fat diet-induced obesity by gut microbiota-SCFAs-liver axis

Obesity has been reported to be associated with gut microbiome dysbiosis. seabuckthorn fruits have traditionally been used in Tibetan foods and medicines for thousands of years. Seabuckthorn polysaccharide (SP) is one of the main functional components in seabuckthorn fruits. However, the effects of SP on a high-fat diet (HFD)-induced obesity have not yet been elucidated. The purpose of this study is to explore the amelioration effect of SP on obesity induced by HFD and to reveal its mechanism of gut microbiota and its metabolites. Results showed that 12-week SP (0.1%, w/w) dietary supplementation could significantly reduce body weight gain, serum lipid level and liver triglycerides level in obese mice. Notably, the SP treatment elevated p-AMPKα and PPARα proteins expression stimulated the phosphorylation of ACC1 and inhibited the protein expression of FAS, PPARγ, and CD36 in the mice liver. Further, SP also reorganized the gut microbiome by up-regulating the proportion of Muribaculaceae_unclassified, Bifidobacterium, Rikenellaceae_RC9_gut_group, Alistipes, and Bacteroides, and down-regulating the abundance of Lactobacillus, Firmicutes_unclassified, Dubosiella Bilophila, and Streptococcus in HFD-induced obese mice. Moreover, the production of microbial metabolites short-chain fatty acids (SCFAs) in feces has also increased. In addition, correlation analysis results showed that obesity-ameliorating effects of SP were highly associated with levels of SCFAs in feces. Therefore, the regulation of SP on liver lipid metabolism may be due to the variation of the gut microbiome and raised production of SCFAs. These results indicate that SP could play the part of a potential nutraceutical for ameliorating obesity through regulation of the gut-liver axis.