Nitrosonium Cation as a Component of Nitroprusside Determining Its Cytotoxicity
摘要
It has been shown that the conversion of the nitrosonium (NO+) cation into the NO molecule in sodium nitroprusside under the action of a strong reducing agent, sodium dithionite, does not completely suppress the cytotoxic effect of sodium nitroprusside solution as a NO+ donor on MCF-7 tumor cell culture. The fact is that NO molecules and Fe2+ ions released from nitroprusside under these conditions form, together with thiol-containing ligands (thiosulfate as a degradation product of sodium dithionite and thiol groups of proteins), dinitrosyl iron complexes in which half of the nitrosyl ligands are represented in the form of cytotoxic nitrosonium cations. The amount of dinitrosyl iron complexes formed in this process is more than 3 times lower than the initial level of sodium nitroprusside and is the main reason for the weakening of the cytotoxic effect of sodium nitroprusside solution on cell culture.