Physicochemical properties of ternary oxovanadium(IV) complexes with oxydiacetate and 1,10-phenanthroline or 2,2′-bipyridine. Cytoprotective activity in hippocampal neuronal HT22 cells

Abstract

The aim of this work was to find a relationship between physicochemical properties of the oxovanadium(IV) complexes, namely [VO(ODA)(H2O)2], [VO(ODA)(phen)]·1.5H2O and [VO(ODA)(bipy)]·2H2O (ODA = oxydiacetate) as well as [VO(H2O)5](2+), and their biological activity. A potentiometric titration method has been used to characterize the stability of the complexes in aqueous solutions. Furthermore, the reactivity of the complexes towards superoxide free radicals was assessed by employing the NBT assay as well as a cyclic voltammetry (CV) technique. Additionally, the investigations of the antioxidant properties of the complexes were complemented by studying their reactivity towards organic radicals (the ABTS and DPPH tests). Finally, the biological properties of the complexes were investigated in relation to their cytoprotective activity against the oxidative damage generated exogenously by using hydrogen peroxide in the Hippocampal neuronal cell line HT22 (the MTT and LDH tests). The obtained results showed that all the compounds under study display antioxidant properties but a concentration-depended protective effect against the oxidative damage was found for [VO(ODA)(bipy)]·2H2O only.

Structural, physico-chemical and antioxidant characteristics of 2,2′-bipyridyl(iminodiacetato)oxidovanadium(IV) dihydrate

“…Comparing the stability of VO(ODA)bipy and VO(IDA)bipy complexes it can be concluded that the complex containing IDA ligand is more stable in aqueous solutions than the VO(ODA)bipy complex [27]. This behavior can be explained in terms of the basicity of the primary ligands that is slightly higher for IDA ligand.…”

“…All solutions used to measurements were degased with argon. The oxygen concentration in the measured solution was in the 1.5-2.2Á10 À3 mol/L range [12,[24][25][26][27].…”

“…The antioxidant activity against organic radicals was examined by the DPPH method described early in the literature [27,29]. The radical solution was prepared by dissolving 14.42 mg of DPPH Å in 250 mL of CH 3 OH.…”

“…The ABTS Å+ radical scavenging activity was determined according to the method described in the literature [27,30]. The radical solution was prepared by mixing 26.16 mg of ABTS and 14.10 mg of potassium persulfate (K 2 S 2 O 8 ) in water (500 mL).…”

“…The ability of VO(IDA)bipy to scavenge superoxide radicals were examined by the NBT test [2,27,38]. The best fitting for the curves based on the results of the NBT experiment was obtained for the equation y = y 0 + AÁe (x/t) .…”