Dendrobium huoshanense Improves Lipid Metabolism Disorder by Restoring Gut Flora and Metabolites in Mice Fed a High-Fat Diet

Lipid metabolism disorders are widely acknowledged as crucial risk factors for a range of metabolic diseases, including hyperlipidemia, obesity, nonalcoholic fatty liver disease, and atherosclerosis. Dysbiosis of the gut microbiota is considered a potential mechanism of action in lipid metabolism disorders. Dendrobium huoshanense C.Z. Tang et S.J. Cheng (DH), an important edible and medicinal Chinese herb, has been shown to regulate the gut flora disorders and improve intestinal health. However, DH inhibits lipid metabolism disorders by regulating the gut flora remains unclear. Therefore, we aimed to explore the effect of the gut flora on improving blood lipid levels in mice that fed a high-fat diet supplemented with DH. Mice were randomly divided into normal control (CTR), high-fat diet (HFD), 2.25 mg/kg/day simvastatin (SIM), 300 mg/kg/day DH (LD-DH), and 600 mg/kg/day DH (HD-DH) groups for 14 weeks. Changes in serum and liver lipid levels and liver function were analyzed. Changes in intestinal microbiota and fecal metabolites were assessed using 16S rRNA gene sequencing and untargeted metabolomics. The relationships among lipids, intestinal microbiota, and fecal metabolites were analyzed using Pearson's correlation analysis to reveal the mechanism of action of DH against lipid metabolism disorders. The results indicated that DH effectively improved the lipid profiles in both the serum and liver of HFD mice. DH was also found to alter the structure of the gut flora, especially the relative abundances of Bifidobacterium pseudolongum and B. animalis, which dramatically increased with DH. Pearson's correlation analysis indicated that DH may mainly alter metabolites (amino acid metabolites, bile acid metabolites, lipid metabolites, etc.) to regulate lipid metabolism via the metabolic ability of the gut flora. B. pseudolongum and B. animalis may be the dominant bacterial species in the gut microbiota and play key roles in the alleviation of lipid metabolism disorders caused by HFD.