Antioxidant properties of geroprotective peptides of the pineal gland.

It was shown that peptide preparations from the pineal gland (epithalamin and epitalon) possess antioxidant properties exceeding in some cases the effects of the well-known scavenger of reactive oxygen species (ROS), the melatonin, which is also produced by the pineal gland. The methods used in our experiments in old rats included determination of total antioxidant and antiradical activities, as well as those of antioxidant enzymes (superoxide dismutase=SOD, glutathione peroxidase, glutathione-S-transferase, etc.) in blood serum, liver and brain. It has been revealed that epithalamin (polipeptide preparation from bovine brain) and its active fragment, epitalon (Ala-Glu-Asp-Gly) along with their ability to stimulate melatonin production, have an antioxidant mechanism that is quite different from the action of melatonin. Epithalamin can be more beneficial than melatonin because the former not only produces direct antioxidant effects, but also is able to stimulate the expression of SOD, ceruloplasmin and other antioxidant enzymes. The possibility of oxidation chains by their interaction with different ROS by means of binding of transition metals (Fe(2+)) cannot also be excluded. Thus, the results of our experiments testify that the pineal gland peptides enhance the antioxidant defense system, which can contribute to their geroprotective properties.