Characterizing N-acetylcysteine (NAC) and N-acetylcysteine amide (NACA) binding for lead poisoning treatment

Abstract

Using antioxidants is an important means of treating lead poisoning. Prior in vivo studies showed marked differences between various chelator antioxidants in their ability to decrease both blood Pb(II) levels and oxidative stress resulting from lead poisoning. The comparative abilities of NAC and NACA to Pb(II) were studied in vitro, for the first time, to examine the role of the –OH/–NH2 functional group in antioxidant binding behavior. To assay the antioxidant-divalent metal interaction, the antioxidants were probed as solid surfaces, adsorbing Pb(II) onto them. Surface characterization was carried out using X-ray photoelectron spectroscopy (XPS) analysis to quantify Pb(II) in the resulting adducts. XPS of the Pb 4f orbitals showed that more Pb(II) was chemically bound to NACA than NAC. In addition, the antioxidant surfaces were probed via point-of-zero charge (PZC) measurements of NAC and NACA were obtained to gain further insight into the Pb-NAC and Pb-NACA binding, showing that Coulombic interactions played a partial role facilitating complex formation. The data correlated well with solution analysis of metal-ligand complexation. UV-vis spectroscopy was used to probe complexation behavior. NACA was found to have the higher binding affinity as shown by free Pb(II) available in solution after complexation from HPLC data. Electrospray ionization mass spectrometry (ESI-MS) was applied to delineate the structures of Pb-antioxidant complexes. Experimental results were further supported by density functional theory (DFT) calculations of supermolecular interaction energies (Einter) showing a greater interaction of Pb(II) with NACA than NAC.

N-Acetylcysteine Amide Exerts Possible Neuroprotective Effects in Newborn Pigs after Perinatal Asphyxia

“…Recently, it has been revealed that NAC amide (NACA), an NAC derivate with higher bioavailability and enhanced antioxidant properties [8,9], may significantly mitigate the detrimental consequences of various toxic substances in different organs, including the lungs and kidneys [10,11,12]. …”

N-Acetyl Cysteine Decreases Mice Brain Acetyl Cholinesterase Activity: An In Vitro Kinetic Study

“…N-acetylcysteine (NAC) is a thiol (SH) containing antioxidant, which has been investigated for many pathologies treatment, such as liver failure, inflammation, nephropathy and brain disorders [12]. It is a naturally occurring compound found in several vegetables, including garlic, onion [13], peppers and asparagus [14].…”

Organic matter induced mobilization of polymer-coated silver nanoparticles from water-saturated sand

“…The first two, modeled respectively with N-acetylcysteine (NAC) and sodium dodecylbenzenesulphonate (SDBS), both have organic sulfur but in different functional groups (-SH vs -SO 3 ). Moreover, NAC and SDBS have different functional groups and structures: NAC is hydrophilic with additional functional groups (-COOH and -NH 2 ) other than the thiol ligand while SDBS is a linear anionic surfactant with both hydrophilic and hydrophobic (dodecylbenzene) moieties (Chen et al, 2012;Zhai et al, 2004). Although organic sulfide has strong affinity with silver, the sulfur-silver interaction might differ and be specific to the organic molecule containing the sulfur (Levard et al, 2011;Gondikas et al, 2012).…”