Melatonin supplementation modifies experimental chronic colitis in mice

Melatonin (Mel) has been adopted by most living organisms as a circadian timing signal, but is also known to be a potent free radical scavenger and immunomodulatory agent (1) . Mel is not only synthesized in the pineal gland, but also in the gastrointestinal tract (GIT), where it does not depend on the light-dark cycle and may be induced by food intake or withdrawal. GIT-derived Mel may also have paracrine and autocrine functions, modifying the intestinal blood flow or mucosal regeneration (2) . The potent free radical scavenging activity of Mel may give rise to its protective and therapeutic application in chronic inflammation of the GIT (3) .