Application of EPR Spectroscopy to Determine the Influence of Simvastatin Concentration on Free Radicals in G-361 Human Melanoma malignum Cells

Free radicals in G-361 human melanoma malignum control cells and the cells cultured with simvastatin were examined by EPR spectroscopy. The proliferation of the cells was determined. The aim of this work was to examine the influence of simvastatin used at different concentrations in the G-361 cell culture on its free radicals. The concentrations of simvastatin—0.1 μM, 1 μM, 3 μM, and 5 μM—were tested. EPR spectra of free radicals were measured by an X-band (9.3 GHz) spectrometer. Amplitudes, integral intensities, linewidths, and g factors were determined. Melanin biopolymers are the main source of o-semiquinone free radicals in G-361 human melanoma malignum cells, for which the EPR lines show characteristic g values of 2.0046–2.0059, but also, free radicals occurring in other cellular structures may contribute to these signals. The amount of free radicals decreases after interactions of simvastatin with the G-361 cells, and this effect depends on the concentration of simvastatin. The highest amounts of free radicals exist in G-361 cells cultured with simvastatin at concentrations of 3 μM and 5 μM. The relatively lower amounts of free radicals occur in G-361 cells cultured with simvastatin at concentrations of 0.1 μM and 1 μM. The fast spin–lattice relaxation processes exist in the control G-361 cells and in the cells cultured with simvastatin, regardless of simvastatin concentration.