Antioxidant Activity of Ruthenium(Ii) Complexes Containing Tridentate Triamines and Their Capability to Inhibit Xanthine Oxidase

Abstract

Biological activities of organoruthenium complexes [chloro [N,N′-[(2,6-pyridinediyl-κN) diethylidyne] bis-[benzenamine-κN]] [N-[(2-pyridinyl-κN) methylene] benzenesulfonamide-κN] ruthenium(II)] chloride (Cmplx 1), [chloro [2,2′-(2,6-pyridinediyl-κN) bis [1H-benzimidazole-κN3]][N-[(2-pyridinyl-κN) methylene] benzenesulfonamide-κN] ruthenium(II)] chloride (Cmplx 2), and [chloro[2,6-di(1H-pyrazol-3-yl-κN2) pyridine-κN] [N-[(2-pyridinyl-κN) methylene] [benzenesulfonamide-κN] ruthenium(II)] chloride (Cmplx 3) have been studies. The compounds were tested for in vitro biological activity on test models including 2,2-diphenyl-1-picryl-hydrazyl (DPPH) reducing power, superoxide anion radical-scavenging activity, and lipid peroxidation activity by ferric thiocyanate. It is established that Cmplx 2 with benzimidazole ligand displays significant xanthine oxidase inhibitory activity (IC50 = 53.80 ± 2.69 μM), DPPH free radical scavenging activity (79.49 ± 1.59), and superoxide anion radical scavenging activity (75.73 ± 2.85%). The coordination of benzenamine and benzenesulfanoamine ligands reduces lipid peroxidation as observed in the case of Cmplx 1 (87.17 ± 3.88%) and the higher reducing power of Cmplx 1 obtained at all concentrations. It was concluded from the test results that organoruthenium complexes showed much better antioxidant activity than expected.