First-Row Transition Metal Complexes Incorporating the 2-(2′-pyridyl)quinoxaline Ligand (pqx), as Potent Inflammatory Mediators: Cytotoxic Properties and Biological Activities against the Platelet-Activating Factor (PAF) and Thrombin

Figures

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  Figure 1. (a) Organic antiplatelet agents (PAF-inhibitors); (b) Structures of known inflammatory mediators (metal-based analogs).

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  Figure 2. The molecular structure of the Platelet-Activating Factor (PAF).

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  Figure 3. Metal complexes bearing the pqx ligand, that have been evaluated as potent inhibitors of PAF and thrombin-induced aggregation, by our group (TM: transition metal). Colors showcase the different metal ions.

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  Figure 4. Molecular structures of complexes 1–7 described in this study.

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  Figure 5. Molecular structure of 3 in the solid state. Thermal ellipsoids are set at 50% probability. Hydrogen atoms are omitted for clarity.

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  Figure 6. (a) The UV-Vis spectrum of 2 in DMSO (7.6 × 10−4 M); (b) The UV-Vis spectrum of 3 in DMSO (1.7 × 10−4 M).

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  Figure 7. (a) The UV-Vis spectrum of 5 in DMSO (2.8 × 10−4 M); (b) The UV-Vis spectrum of 6 in DMSO (1.5 × 10−4 M).

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  Figure 8. The inhibition of the specific activity of dithiothreitol-insensitive PAF choline phosphotransferase (PAF-CPT) by the Fe(II) complex 6. The orange bullet represents the blank solution while the blue bullets display the reductive trend of the Fe(II) complex 6 against enzyme activity.

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  Figure 9. (a) The inhibition of the specific activity of lyso-PAF:acetyl-CoA acetyltransferase (lyso-PAF-AT), by the Ni(II)-pqx (7) complex. The green bullet represents the blank solution while the blue bullets display the reductive trend of the Ni(II)-pqx (7) complex against enzyme activity; (b) The inhibition of the specific activity of lyso-PAF:acetyl-CoA acetyltransferase (lyso-PAF-AT), by the Cr(III)-pqx (1) complex. The green bullet represents the blank solution while the blue bullets display the reductive trend of the Cr(III)-pqx (1) complex against enzyme activity.

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  Figure 10. The inhibition of the specific activity of Lipoprotein-associated phospholipase A2 (Lp-PLA2), by the Ni(II)-pqx (7) complex. The yellow bullet represents the blank solution while the blue bullets display the reductive trend of the Ni(II)-pqx (7) complex against enzyme activity.

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  Figure 11. Viability curves for HEK293T (a,c) and HeLa (b,d) cell lines for pqx metal complexes.