Iron(III)-based contrast agents for magnetic resonance imaging

Reduction of paraquat-induced renal cytotoxicity by manganese and copper complexes of EGTA and EHPG

“…Some of these beneficial effects of EGTA have been credited to its ability to bind the excess Cu(II) ions which contribute to disease pathology; however, it is now also clear that complexing EGTA with Cu(II) or Mn(II) promotes significant SOD activity [25]. Recently, the related chelating agent EHPG, which is used as a contrast agent for magnetic resonance imaging and as a transferrin mimic in the study of manganese transport [28] and [29], has also been shown to exhibit significant SOD activity when complexed with Mn(II) or Cu(II) [25]. However, the ability of these complexes to reduce paraquat toxicity, in which superoxide generation plays a major part, is not known and formed the basis of this study.…”

“…Another chelator, ethylenebis(hydroxyphenylglycine) (EHPG), which is used as a contrast agent in imaging and as a transferrin mimic in the study of manganese transport [28] and [29], also exhibits SODm properties when complexed with manganese (Mn) (II) or copper (Cu) (II) [25]. A major advantage of the potential use of these agents for the treatment of disease is that EGTA and EHPG have already been used therapeutically [26], [27], [28] and [29]. Furthermore, Mn(II) and Cu(II) complexes of EGTA and EHPG are stable in solution and have a good safety profile in that they do not promote pro-oxidant activities [25].…”

Iron(III) Contrast Agent Candidates for MRI: a Survey of the Structure–Effect Relationship in the Last 15 ­Years of Studies

“…administration to mice [13] ), the free iron ions that are present in the intercellular space are believed to activate peroxidase (an iron metalloenzyme), leading to cell apoptosis. The potential drawback of CAs with endogenous micro-elemental metals has been raised by some scientists who mentioned the disruption of the natural iron equilibrium in the organism.…”

“…In addition, paramagnetic ions of lanthanides are under ongoing investigation with all of their benefits of high coordination numbers and high magnetic moments. [8,9] Ordinary manganese [10][11][12] and iron, [1,13] however, have also gained advocates because of their ubiquity and endogenous character with wellknown and highly predictable physiology.…”

“…The previous period of this research was covered thoroughly by the very good reviews of Richardson. [1,13] Richardson's elaborations were very important for the development of concepts and for designing models in order to satisfy both medical and technical requirements. Thus, this mini-review presents such a conceptual approach enriched with some introductory features of the structure-related properties and behavior of iron(III) complexes.…”