engleski

The effect of ganglioside micelles on the iron-induced hydroxyl radical generation

Several mechanisms have been proposed to explain the antioxidant activity of gangliosides. In this study we investigated whether the antioxidant ability of ganglioside micelles is due to their scavenging of hydroxyl radical (OH• ) or their ability to bind iron. To assess the effect of GM1 and GT1b micelles on OH• generated by the Fenton reaction (75 㯀 M Fe2+, 500 㯀 M H2O2), the electron paramagnetic resonance with DMPO as a spin trap was applied. The mean hydrodynamic diameter and Zeta potential (comparable to the potential of micellar surface) were measured by Zetasizer Nano ZS. The addition of gangliosides to Fenton's reagent resulted in a significant decrease in the yield of OH• (51% and 83%, and 56% and 72% in the presence of 200 and 300 㯀 M GM1 and GT1b, respectively). The change in DMPO concentration by one order of magnitude showed that the spin trap did not compete with gangliosides in the elimination of free radicals, indicating that the mode of ganglioside action was via the inhibition of OH• formation. The addition of the Fe2+ to ganglioside solutions did not significantly affect the mean hydrodynamic diameter of GM1 and GT1b micelles. The changes of Zeta potential values indicate that the binding of Fe2+ to the oppositely charged ganglioside micelles could reduce the Fenton reaction (i.e.transfer of one electron to H2O2) and consequently decrease the OH• formation. The obtained data indicate important biological relevance of gangliosides in antioxidative processes.

ganglioside; free radicals

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