Reflections on the Glycating Power of Simple Carbohydrates in the Maillard Reaction: The Conceptual DFT Viewpoint

Abstract

This study features an assessment of multiple density functionals in calculating the molecular structures and inherent properties in simple carbohydrates participating in nonenzymatic glycation involving amino acids and proteins in Maillard reactions. The occurrences of nucleophilic addition involving nonenzymatic glycation, initiate protein glycation reaction involving a carbonyl group derived from reeducating sugars and free amino group forming a reversible Schiff base. Calculations of chemical reactivity descriptors are attained in each molecular system using Conceptual DFT. A crosssectional comparison of results obtained through ?SCF procedure is attained to check for accuracy and validity of the density functional in Koopmans in DFT" (KID) procedure. The calculated HOMO and LUMO of each carbohydrate are presented through graphical sketches overlapped to their chemical structures. The Fukui function indices and condensed dual descriptor ?f(r) are used to examine the active sites where nucleophilic and electrophilic attacks occur. The assessment identifies several relationships involving glycating power and reactivity descriptors. The latter are found capable of predicting glycating behaviour in complex carbohydrates. The results obtained for this work shows the ability to predict the interaction sites of simple carbohydrates by applying DFT-based descriptors of chemical reactivity. Such include global electronegativity, global hardness, global electrophilicity, electrodonating powers, electroaccepting powers, net electrophilicity, Fukui function and condensed dual descriptor. Their use in characterising and describing preferred reactivity sites generated a firm explanation on the molecule reactivity.