Melatonin Inhibits Peroxide Production in Plant Mitochondria.

The effect of melatonin on respiration and production (release) of hydrogen peroxide during succinate oxidation in mitochondria isolated from lupine cotyledons and epicotyls of pea seedlings was studied. It was shown for the first time that melatonin (10-7-10-3 M) had a significant inhibitory effect on the production of peroxide by plant mitochondria, which was characterized by concentration dependence and species specificity. At the same time, melatonin (at a concentration of up to 100 μM) had virtually no effect on mitochondrial respiration rate and respiratory control coefficient. The results confirm the antioxidant function of melatonin and indicate that it is involved in the regulation of ROS levels and maintenance of redox balance in plant mitochondria.