Announcing a new article publication from Acta Pharmaceutica Sinica B. Morinda officinalis oligosaccharides(MOO) is an oral drug approved in China for the treatment of depression in China.

The authors of this article demonstrate that oral MOO acts ontryptophan→5-hydroxytryptophan (5-HTP)→serotonin (5-HT) metabolic pathway in the gut microbiota. MOO increases tryptophan hydroxylase levels in the gut microbiota which accelerates 5-HTP production from tryptophan; meanwhile, MOO inhibits 5-hydroxytryptophan decarboxylase activity, thus reducing 5-HT generation, and accumulated 5-HTP. The raised 5-HTP from the gut microbiota is absorbed to the blood, and then passed across the blood-brain barrier to improve 5-HT levels in the brain. Additionally, pentasaccharide, as one of the main components in MOO, exerts a significant anti-depressant effect through a mechanism identical to that of MOO.

This study reveals that MOO can alleviate depression via increasing 5-HTP in the gut microbiota.