Binding efficacy of different polyphenolic phytochemicals with β- Lactoglobulin and Human Serum Albumin: Advancing prophylactics against neurodegenerative diseases

Nitrosative stress has recently been demonstrated as a crucial causal in the pathogenesis of Parkinson's (PD) and Alzheimer's (AD) diseases [1]. Specifically, increased levels of NO disrupt the redox activity of protein-disulfide isomerase, a key endoplasmic reticulum-resident chaperone by S-nitroso modification of its redox-active cysteines [1]. This leads to aggregation of misfolded proteins in AD and PD. We have recently demonstrated in vitro that polyphenolic phytochemicals, curcumin and masoprocol, can rescue Snitroso-PDI formation by scavenging NOx adducts [1]. By conducting extensive spectrofluorimetry experiments, we have determined the binding efficacy of curcumin to β-Lactoglobulin and curcumin to human serum albumin. Binding of this polyphenolic phytochemical to the milk protein and human transport protein ensures delivery to the microvilli of the intestine where it can be absorbed and transported directly into the systemic blood system. This is important because studies have proven that though curcumin is a well-known free radical scavenge, its bioavailability is very low [2]. Our study is designed to enhance the bioavailability of different polyphenolic phytochemicals as therapeutics. We also investigated the binding efficacy of a curcumin analog, 3, 5-bis (2-flurobenzylidene) piperidin-4-one (EF24), because it is a potent nitrosative stress scavenger. As mentioned previously, the same spectrofluorimeter experiments were carried out and we have determined that the binding efficacy of this polyphenolic phytochemical to β-Lactoglobulin and human serum albumin is exceptional. Additionally, we want to investigate the binding efficacy of other potent polyphenolic phytochemicals with human serum albumin or β-Lactoglobulin. Binding efficacy of these polyphenolic phytochemicals to βLactoglobulin and human serum albumin will be pre-screened by using existing protein-substrate binding simulation techniques. Based on empirical scorings and theoretical force fields, the publicly available automated docking program suite AutoDock finds low energy conformations using a genetic algorithm, a local search method, or a combination of both called Lamarckian genetic algorithm [3]. The commercially available software Glide narrows the search space by a first rough sampling of positions and scorings and then refines the results by minimizing torsional energies. Finally, Monte Carlo sampling of the best candidates finds accurate docked conformations [4]. Furthermore, we will explore the scavenging effects of these polyphenolic phytochemicals in vivo by exposing a dopaminergic cell line to MPTP (1-methyl4-phenyl-1,2,3,6-tetrahydropyridine), a pesticide which causes permanent symptoms of Parkinson's Disease by destroying dopaminergic neurons in the substantia nigra of the brain. References 1. Pal, R. , Miranda, M. , Narayan, M. Nitrosative stress-induced Parkinsonian Lewy-like aggregates prevented through polyphenolic phytochemical analog intervention. Biochemical and biophysical research communications. 2011 Jan 7;404(1): 324-9 2. Anand, P., Kunnumakkara, A. , Newman, R. , Aggarwal, B. , Bioavailability of Curcumin: Problems and Promises. Mol. Pharmaceutics, 2007, 4 (6), 807-818 3. Morris, G. M. , Goodsell, D. S. , Halliday, R. S. , Huey, R. , Hart, W. E. , Belew, R. K. , & Olson, A. J. (1998). Automated docking using a Lamarckian genetic algorithm and an empirical binding free energy function. Journal of Computational Chemistry, 19(14), 1639–1662. John Wiley & Sons, Inc. 4. Friesner, R. A. , Banks, J. L. , Murphy, R. B. , Halgren, T. A. , Klicic, J. J., Mainz, D. T. , Repasky, M. P., et al. (2012). Glide: A New Approach for Rapid, Accurate Docking and Scoring. 1. Method and Assessment of Docking Accuracy. J. Med. Chem., Journal of Medicinal Chemistry, 47(7), 1739–1749