New study finds Japanese herbal medicine effective in treating colitis

Research has found that a common Japanese herbal remedy, Daikenchuto (DKT), reduced the severity of colitis in mice, preventing the loss of key bacteria in the gut and facilitating the activity of innate immune cells.

The study, published in the journal, Frontiers in Immunology, was conducted by researchers at the RIKEN Center for Integrative Medical Sciences (IMS) in Japan. As colitis is one of two conditions that make up inflammatory bowel disease (IBD), the investigators sought to explore whether DKT could serve as an anti-inflammatory agent to complement standard IBD therapies.

DKT is a formula containing ginger, pepper, ginseng, and maltose, and is one of the most frequently prescribed Kampo or Traditional Japanese herbal medicine preparations for digestive disorders, according to the study.

Colitis was induced in mice using dextran sodium sulfate, which is toxic to the cells that line the colon. When these mice were given DKT, their body weights remained normal, and they had lower clinical scores for colitis. Additional analysis revealed much less damage to the cells lining the colon. Having shown that DKT does help protect against colitis, the researchers proceeded to analyze the gut microbiome of the mice and expression levels of anti-inflammatory immune cells, according to the study.

Their analysis showed that a family of lactic acid bacteria were depleted in the colitic mice as was one of their metabolites, a short-chain fatty acid, propionate. Treating the model mice with DKT restored much of these missing bacteria—particularly those from the genus Lactobacillus—and levels of propionate were normal. In addition, when investigators looked at innate intestinal immune cells, they found that levels of a type called ILC3 were lower in the untreated colitic mice than in the DKT-treated colonic mice, and that mice engineered to lack ILC3 suffered more and could not benefit from DKT treatment.  According to the authors, this means that ILC3s are critical for protecting against colitis and that DKT works by interacting with them.

Overall, researchers found that DKP accelerated the recovery from experimental colitis in mice, along with improvements in several colitis-associated features of gut microbiota, their metabolites, and the colonic ILC3 population, according to the study.

The authors hope this work will open future therapeutic opportunity for IBD patients.