Electron spin resonance studies of chloroquine-melanin complexes.

Electron spin resonance (ESR) studies of chloroquine complexes with synthetic DOPA-melanin, synthetic catechol-melanin, melanin isolated from bananas and humic acid were performed. Two chloroquine concentrations (5 X 10(-5) M and 1 X 10(-3) M) were used for chloroquine-melanin complex formation. ESR studies showed differences in free radicals concentration depending on melanin origin. It was demonstrated that addition of chloroquine to melanin results in broadening of the melanin ESR signal and is accompanied by changes in the integrated intensity of the analyzed melanin samples.