Influence of Microwave Power on EPR Signal of Melanin Radical and Copper(II) Ions in DOPA-Melanin Complexes

Abstract

Electron paramagnetic resonance spectroscopy EPR was used for examination of microwave saturation in DOPAmelanin complexes with kanamycin and Cu(II) ions. The fast spinlattice relaxation processes take place in system of paramagnetic metal ions. EPR signal of melanin radical saturated with growing of microwave power used during measurements. After adding Cu(II) ions a shortening of relaxation time is observed for EPR signal of melanin radical.

Effect of UV irradiation on free radicals in synthetic melanin and melanin biopolymer from Sepia officinalis – EPR examination

“…These values are in the range obtained earlier for melanins with o-semiquinone free radicals [1,3,[11][12][13][17][18][19]. However g factor for broad EPR lines with unresolved hyperfi ne structure does not directly determine the type of free radicals in the samples.…”

“…3-6), according to the theoretical base [26,27]. Homogeneously broadened EPR lines for nonirradiated melanins were observed earlier [7,[11][12][13][17][18][19][20][21][22].…”

“…The linewidths changed after the UVA irradiation of DOPA-melanin-moxifl oxacin complexes [19]. Linewidths of melanin polymers changed after drug binding to melanin [16][17][18][19][20][21] and metal ions [11][12][13][14][15].…”

“…Electron paramagnetic resonance (EPR) investigations confi rmed the existence of free radicals in melanins [1][2][3][4][5][6][7][8][9][10], and melanin complexes with metal ions [1,7,[11][12][13][14][15] and drugs [7,12,[16][17][18][19][20][21]. Dia-and paramagnetic metal ions [11][12][13][14][15] and pharmacological substances [16][17][18][19][20][21] change the intensity of EPR lines of melanin.…”

“…Dia-and paramagnetic metal ions [11][12][13][14][15] and pharmacological substances [16][17][18][19][20][21] change the intensity of EPR lines of melanin. In this study, we concentrate on free radicals in melanins exposed to UV irradiation.…”