Melatonin as a potential anti-fibrotic drug ?

Melatonin, N-(2-(5-methoxy-1H- indol-3-yl)ethyl)acetamide) is a hormone found in all living creatures. It is naturally synthesized from the amino acid tryptophan, via synthesis of serotonin, by the enzyme 5-hydroxyindole-O-methyl transferase.

Nobel Prize laureate Julius Axelrod performed many of the seminal experiments that elucidated the role of melatonin and the pineal gland in regulating sleep-wake cycles (circadian rhythms). In humans, melatonin is produced by the pineal gland, (a gland located in the center of the brain). Normally, the production of melatonin by the pineal gland is inhibited by light and permitted by darkness.

For this reason melatonin has been called "the hormone of darkness". The secretion of melatonin peaks in the middle of the night, and gradually falls during the second half of the night. Until recent history, humans in temperate climates were exposed to up to eighteen hours of darkness in the winter. In this modern world, artificial lighting typically reduces this to eight hours or less per day all year round.

And also we know that, in animal models, melatonin has been demonstrated to prevent the damage to DNA by some carcinogens. The antioxidant activity of melatonin may reduce damage caused by some types of Parkinson's disease, may play a role in preventing cardiac arrhythmia and may increase longevity; it has been shown to increase the average life span of mice by 20% in some studies. Melatonin appears to have some use against circadian rhythm sleep disorders, such as jet lag and delayed sleep phase syndrome. The primary motivation for the use of melatonin as a supplement is as a natural aid to better sleep, with other incidental benefits to health and well-being due to its role as an antioxidant and its stimulation of the immune system and several components of the endocrine system.

Now something interesting, melatonin has been tested as a potential anti-fibrotic drug. Congrats Professor. Jian-Ming Xu, (of Hospital of Anhui Medical University, China) and group.

The results suggested that treatment with melatonin (10 mg/kg) could decrease the scores of hepatic fibrosis grading, reduced the contents of hyaluronic acid (HA), laminin(LN) in serum and Hydroxyproline (HYP) in liver, treatment with melatonin (5,10 mg/kg ) could decrease serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and blocked the increase in malondialdehyde (MDA) in rats with hepatic injury caused by CCl4.

More over, the authors attribute this property of anti-fibrotic to the Antioxidant activity of melatonin..really interesting......