SCOPE: Ulcerative colitis (UC) is a chronic inflammatory disease of the colon. 
α-Mangostin (α-MG), the most abundant xanthone in mangosteen fruit, exerts 
anti-inflammatory and antibacterial activities in vitro. We evaluated the impact 
of dietary α-MG on murine experimental colitis and on the gut microbiota of 
healthy mice.
METHODS AND RESULTS: Colitis was induced in C57BL/6J mice by administration of 
dextran sulfate sodium (DSS). Mice were fed control diet or diet with α-MG 
(0.1%). α-MG exacerbated the pathology of DSS-induced colitis. Mice fed diet 
with α-MG had greater colonic inflammation and injury, as well as greater 
infiltration of CD3(+) and F4/80(+) cells, and colonic myeloperoxidase, than 
controls. Serum levels of granulocyte colony-stimulating factor, IL-6, and serum 
amyloid A were also greater in α-MG-fed animals than in controls. The colonic 
and cecal microbiota of healthy mice fed α-MG but no DSS shifted to an increased 
abundance of Proteobacteria and decreased abundance of Firmicutes and 
Bacteroidetes, a profile similar to that found in human UC.
CONCLUSION: α-MG exacerbated colonic pathology during DSS-induced colitis. These 
effects may be associated with an induction of intestinal dysbiosis by α-MG. Our 
results suggest that the use of α-MG-containing supplements by patients with UC 
may have unintentional risk.