How to identify promising metal scavengers? d‐penicillamine with copper as a study case

Abstract

Therapeutic chelating agents are used to prevent the effects of the metal accumulation. These are molecules that form complexes with transition metals and they are referred here as metal scavengers. The main idea of this investigation is to recognize the most relevant chemical features to identify potential metal scavengers. D-penicillamine with copper (DPEN-Cu) is used for this purpose. The first requirement that must be fulfilled by a good metal scavenger is the exergonicity of the chelating reaction. In the DPEN-Cu case the most likely complexation pathway was found to have DG equal to 224.3 kcal/mol. It is desirable that the chelating molecule could also be a free radical scavenger. D-penicillamine is a good free radical scavenger following the hydrogen atom transfer reaction. An additional advantage is that the DPEN-Cu may act as ·OH-inactivating ligand.It is proposed that chelating agents fulfilling these requirements may be a promising candidate to be used in metal chelation therapies as metal scavengers. K E Y W O R D S antioxidant, antiradical, chelating therapy, scavenger Int J Quantum Chem. 2018;118:e25457.

Binding of multiple SO2 molecules to small gold cluster anions (AuN−, AuNOH−, N = 1‐8)

“…For neutral systems, the Gibbs free energy for the absorption of one SO 2 molecule followed an even‐odd pattern, with the odd‐N clusters showing stronger binding than the neighboring even‐N clusters. This even‐odd activity has previously been seen in the binding of O 2 to gas‐phase gold cluster anions . This behavior is observed for all the overall reactions involving Au N − but not in every case for Au N OH − clusters.…”

“…These results led to the conclusion that metal clusters could work as hunters of air pollutants. Furthermore, metal clusters and metal atoms could also serve as antioxidant systems capable of preventing oxidative stress …”

Antioxidant and UV-radiation absorption activity of aaptamine derivatives – potential application for natural organic sunscreens

“…The Cu(II) chelation of the studied aaptamines are better than the one of aminoguanidine (DG 0 , 13.8 kcal mol À1 ), 62 2-hydroxymelatonin and 4-hydroxymelatonin (DG 0 , À5.59 and 0.63 kcal mol À1 , respectively) 16 and D-penicillamine (DG 0 , 0.3 kcal mol À1 ). 66 Furthermore, it is noteworthy that the Cu(I) complexation is more favorable than the one of Cu(II) ion for all three compounds at the same chelation site. For example, the DH 0 and DG 0 values of the complexation process at the O14/N1 site of C1 are À9.4 and À15.4 kcal mol À1 , respectively.…”

Antioxidant and UV-radiation absorption activity of aaptamine derivatives – Potential application for natural organic sunscreens

“…The Cu(II) chelation of the studied aaptamines are better than the one of aminoguanidine (G 0 , 13.8 kcal mol -1 ), 62 2-hydroxymelatonin and 4-hydroxymelatonin (G 0 , -5.59 and 0.63 kcal mol -1 , respectively) 16 and D-penicillamine (G 0 , 0.3 kcal mol -1 ). 66 Furthermore, it is noteworthy that the Cu(I) complexation is more favorable than the one of Cu(II) ion for all three compounds at the same chelation site. For example, the H 0 and G 0 values of the complexation process at the O14/N1 site of C1 are -9.4 and -15.4 kcal mol -1 , respectively.…”

“…61 Regarding to Cu(II) ion, its complexation with the potential antioxidant compounds could sometime prevent the reduction process that forms Cu(I) ion and HO  radical. The fact was that, several potential antioxidants show good copper ions chelating abilities were reported with aminoguanidine, 62 pyridoxamine, 63 lipoic and dihydrolipoic acids, 64 purine, 18 citric acid, 65 D-penicillamine, 66 2-hydroxymelatonin and 4-hydroxymelatonin. 16 In this study, the Cu(II) complexes formed by the chelating process of the three aaptamines at different possible chelation sites in water phase are evaluated in Figure 6, while the similar complexes with Cu(I) ion are also presented in As can be seen in Figure 6, all the three aaptamine compounds show spontaneous and favorable Cu(II) ion chelating activities with negative H 0 and G 0 values.…”