, 2004). However, there is a need for more efficient compounds with broader reactivation activity after exposure to different OPs and that are less toxic to humans. The crystal structure of AChE (Bourne et al., 1995, Ekström et al., 2006, Kryger et al., 1998 and Sussman et al., 1991) allows for detailed structural studies on ligand access to the enzyme’s active center gorge and the steric constraints within the active center gorge that govern selectivity during reactivation (Ashani et al., 1995, Grosfeld et al., 1996, Kovarik et al., 2004 and Wong et al., 2000). The orientation of the

compound within the narrow confines of the gorge when the active serine is phosphorylated is an important determinant of the

reactivation mechanism (Musilek et al., 2011). Selleck PD-332991 There are several in silico studies that illustrate the ability of this structural model to reliably predict molecular interactions. There is considerable interest in thiosemicarbazones due to their wide pharmacological utility (Beraldo and Gambino, 2004) and versatility as ligands. They have recently been investigated as radical scavengers (Wada et al., 1994) and our previous study (Barcelos et al., 2011) revealed that a thiosemicarbazone derivate, isatin-3-N4-benzilthiosemicarbazone this website (IBTC), is also effective as an antioxidant and antiatherogenic molecule. Although the use of thiosemicarbazone as an antiatherogenic molecule has been suggested previously (Barcelos et al., 2011), in vitro and in vivo toxicological screening is still needed. Therefore, the aim of this study was to test the toxicological effects of IBTC, a thiosemicarbazone derivate, and to identify the effective concentration of IBTC for protecting and reactivating

cholinesterases after exposure to MAP. In addition, any possible inhibitory effects of IBTC on the thiol-containing enzymes from the blood/liver and brain, namely delta-aminolevulinic acid dehydratase (ALA-D) and Na+/K+-ATPase, respectively, were also evaluated. Cytidine deaminase Docking studies were carried out in silico to evaluate the minimal energy IBTC conformations in the active site of human AChE when the active site serine is phosphorylated by MAP. The synthesis of isatin-3-N4-benzilthiosemicarbazone (IBTC) was performed as described previously (Fonseca et al., 2010) and the chemical structure of IBTC is depicted in Fig. 1. The reagents thiobarbituric acid (TBA), dicloroflouresceine diacetate (DCFH-DA), methyltetrazolium (MTT), ethylene glycol tetraacetic acid (EGTA), Ellman’s reagent (5,5′-dithiobis-(2-nitrobenzoic acid) or DTNB), N,N,N′,N′-tetramethylbenzidine and ouabaine were supplied by Sigma–Aldrich Chemical Co. (St. Louis, MO); acetylthiocholine iodide supplied by Merck. The other used reagents were obtained from local suppliers. Human red blood cells (RBC) were separated from heparinized blood that was drawn from a healthy donor.