Marine Hydroquinone Zonarol Prevents Inflammation and Apoptosis in Dextran Sulfate Sodium‐Induced Mice Ulcerative Colitis

We identified an anti‐inflammatory compound, zonarol, isolated from the brown algae as a marine natural product. To ascertain the in vivo functions of zonarol, we examined the pharmacological effects of zonarol administration on dextran sulfate sodium (DSS)‐induced inflammation in a mouse model of ulcerative colitis (UC). Our goal is to establish a safe and effective cure for inflammatory bowel disease (IBD) using zonarol. We subjected Slc:ICR mice to the administration of 2% DSS in drinking water for 14 days. At the same time, 5‐aminosalicylic acid (5‐ASA) at a dose of 50 mg/kg and zonarol at doses of 10 and 20 mg/kg, were given orally once a day. DSS‐treated animals developed symptoms similar to those of human UC, such as severe bloody diarrhea, which were evaluated by the disease activity index (DAI). Treatment with 20 mg/kg of zonarol, as well as 5‐ASA, significantly suppressed the DAI score, and also led to a reduced colonic ulcer length and/or mucosal inflammatory infiltration by various immune cells, especially macrophages. Zonarol treatment significantly reduced the expression of pro‐inflammatory signaling molecules, and prevented the apoptosis of intestinal epithelial cells. A marine bioproduct protects against experimental UC via the inhibition of both inflammation and apoptosis, very similar to the standard‐of‐care sulfasalazine, a well‐known prodrug that releases 5‐ASA.