Protective effects of phenylethanol glycosides from Cistanche tubulosa against ALD through modulating gut microbiota homeostasis

Ethnopharmacological relevance

Cistanche tubulosa (Schenk) Wight, a Chinese herbal medicine (Rou Cong Rong) with Xinjiang characteristics, was recorded in many medical books in ancient China and often used as a tonic medicine. Supported by the traditional Chinese medicine theory of “homology of liver and kidney,” C. tubulosa (Schenk) Wight has many clinical applications in tonifying the kidney and protecting the liver. Modern pharmacological studies have also found that the protective effects of phenylethanol glycosides from C. tubulosa (Schenk) Wight (CPhGs) play an important role in ameliorating alcoholic liver injury.

Aim of the study

We aimed to investigate whether CPhGs can enhance the therapeutic outcome of alcoholic liver disease (ALD) by targeting the “gut–liver axis,” thus contributing to the knowledge of how Chinese herbs alleviate disease by influencing the gut microbiota.

Materials and methods

An ALD mouse model was established using the Lieber–DeCarli alcohol liquid diet, and the effects of CPhGs on the intestinal barrier and gut microbiota of ALD mice were investigated in a pseudo-sterile mouse model and fecal microbiota transplantation (FMT) mouse model. We fed female C57BL/6N mice with Lieber-DeCarli ethanol liquid diet, according to the NIAAA model. Animal experiment of long-term, ethanol diet intervention for 6W, and short-term for 11d. The FMT experiments were also performed.

Results

CPhGs significantly improved ALD manifestations. ALD mice demonstrated significant gut microbiota dysbiosis and significantly abnormal proliferation of Allobaculum compared with the control diet group in long-term NIAAA mouse model (L-Pair). In mice that received the long-term intervention, the improvement in gut barrier function in the CPhGs-treated group was accompanied by a significant decrease in the abundance of Allobaculum and a significant increase in the abundance of Akkermansia. Furthermore, compared with the mouse were gavaged fecal microbiota from the long-term NIAAA mouse donors (FMT-EtOH), the number of goblet cells, abundance of Akkermansia, and the intestinal short-chain fatty acid concentrations were significantly increased in the mouse were gavaged fecal microbiota from high (700 mg/kg) doses of CPhGs orally in long-term NIAAA model donors (FMT-EtOH-H). Network analysis and species distribution results demonstrated that Akkermansia and Allobaculum were the genera with the highest abundances in the gut microbiota and that their interaction was related to propionic acid metabolism.

Conclusions

The results suggest that CPhGs exert a protective effect against ALD by modulating the abundance and composition of Akkermansia and Allobaculum in the intestine, maintaining the intestinal mucus balance, and safeguarding intestinal barrier integrity.