Studies of interaction between iron (III) and intermediates of synthetic neuromelanin by means of cyclic voltammetry of Fe (CN)₆ ^{3 -} and dopamine

Neuromelanin is a complex polymer pigment found primarily in the dopaminergic neurons of the human substantia nigra, whose composition is complex including production of dopamine auto-oxidation, glutathione and a variety of amino acid. Neuromelanin forms stable complex with iron (III). We observed that 5,6-dihydroxyindole and its ramification possessed strong ability of chelating iron (III), and they are the production of dopamine auto-oxidation under physiological pH condition. In the present of l-cysteine, the relative yields of electrochemical oxidation of dopamine also had strong ability of chelating iron (III). The experimental results suggest that 5,6-dihydroxyindole and 5-S-cysteineldopamine play important roles in the process of synthetic neuromelanin chelating iron (III).