Interaction of Pb2+, PbMe2+ 2 and PbPh2+ 2 with 3-(phenyl)-2-sulfanylpropenoic acid: A coordinative and toxicological approach

摘要

We investigated the reaction of Pb2+, PbMe2 2+ and PbPh2 2+ with 3-(phenyl)-2-sulfanylpropenoic acid (H2pspa) to give the complexes [Pb(pspa)], [PbMe2(pspa)], [PbPh2(pspa)], [HQ]2[Pb(pspa)2] and [HQ[2[PbPh2(pspa)2] (HQ = diisopropylammonium), which were characterized by IR and NMR (1H, 13C and 207Pb) spectroscopy and by fast atom bombardment (FAB) spectrometry. The structures of [PbMe2(pspa)], [PbPh2(pspa)], [PbPh2(pspa)(dmso)]dmso and [HQ[2[PbPh2(pspa)2] are interesting examples of unexplored Pb coordination kernels and supramolecular association. Pig renal proximal tubule LLC-PK1 culture cells were used to determine in vitro the effect of the pretreatment with H2pspa (alone or combined with vitamin B6) and [HQ]2[Zn(pspa)2] on the cytotoxicity of PbMe2+ 2 and PbPh2+ 2 by comparing the results with those of meso-2,3-dimercaptosuccinic acid (dmsa). The results show that the cell viability was scarcely affected by these agents. The ability of these reagents to decorporate lead was investigated in vivo by analysing the lead levels in the liver, kidney, brain and blood. In the case of the dimethyl derivative, and under certain protocols, undesirable effects such as an increase in brain and liver lead levels were detected. These increases were not detected when the diphenyl derivative was assayed but in this case a positive effect was not identified either. The blood lead levels also increased in the case of the dimethyl derivative and the activity of d-ALAD was significantly recovered upon treatment with vitamin B6 or H2pspa; neither the blood lead levels nor the d-ALAD activity was modified in the case of the diphenyl derivative.