Dendrobium huoshanense Polysaccharide Improves High-Fat Diet Induced Liver Injury by Regulating the Gut-Liver Axis.

Dendrobium huoshanense is an important Traditional Chinese medicine that thickens the stomach and intestines. Its active ingredient Dendrobium huoshanense polysaccharide (DHP), was revealed to relieve the symptoms of liver injury. However, its mechanism of action remains poorly understood. This study aimed to investigate the mechanism of DHP in protecting the liver. The effects of DHP on lipid levels, liver function, and intestinal barrier function were investigated in mice with high-fat diet-induced liver damage. Changes in the gut flora and their metabolites were analyzed using 16S rRNA sequencing and metabolomics. The results showed that DHP reduced lipid levels, liver injury, and intestinal permeability. DHP altered the intestinal flora structure and increased the relative abundance of Bifidobacterium animalis and Clostridium disporicum. Furthermore, fecal metabolomics revealed that DHP altered fecal metabolites and significantly increased levels of gut-derived metabolites, spermidine, and indole, which have been reported to inhibit liver injury and improve lipid metabolism and the intestinal barrier. Correlation analysis showed that spermidine and indole levels were significantly negatively correlated with liver injury-related parameters and positively correlated with the intestinal species B. animalis enriched by DHP. Overall, this study confirmed that DHP prevented liver injury by regulating intestinal microbiota dysbiosis and fecal metabolites.

Dendrobium huoshanense Polysaccharides Prevent Inflammatory Response of Ulcerative Colitis Rat through Inhibiting the NF-κB Signaling Pathway.

The polysaccharides of the Chinese herbal medicine Dendrobium huoshanense exhibit anti-inflammatory effects in multiple organs through regulating the immune responses. In the present study, we constructed ulcerative colitis (UC) model rats using dextran sulfate sodium to investigate the anti-inflammatory effects of D. huoshanense polysaccharides (DHP). After oral administration of DHP for two weeks, the indices of UC symptoms, including the ratio of colon weight to length, Disease Activity Index (DAI), and Colon Mucosal Damage Index (CMDI), all decreased significantly compared with the UC model group. The histological sections also revealed better cell orders in DHP treatments than in the UC model rats. Moreover, in treatment with high dose of DHP (200 mg/kg), the treatment efficacy arrived the similar levels to those in the treatment with 300 mg/kg sulfasalazine, which is a typical medicine to treat UC. These results indicated that DHP has a high efficacy to treat UC in model rats. Furthermore, serum levels of interleukin-1ß, tumor necrosis factor-α, interleukin-17, and transforming growth factor-ß were assessed using the enzyme linked immunosorbent assay (ELISA) method, and the levels of nuclear factor-κB in colon tissue sections were determined using the immunohistochemical method. The results showed that all these indices decreased significantly after administration of DHP in UC model rats, which might be the mechanisms underlying the DHP-suppressed UC inflammation. Overall, this study indicated that DHP might be directly used to treat UC and is a promising source to develop novel drugs against UC.