Peroxyl Radicals Are Essential Reagents in the Oxidation Steps of the Maillard Reaction Leading to Generation of Advanced Glycation End Products

Abstract

Polyunsaturated fatty acids (PUFAs) are incorporated in all membranes of mammalian and plant cells and are extremely sensitive to oxygen. This property is used in nature to respond to any changes in cell membrane structure. In the first step of a response, lipid hydroperoxide molecules are generated. An increasing impact switches the enzymatic reaction to a nonenzymatic one by generation of lipid peroxyl radicals, which attack sugars by oxidation. In the course of these reactions, hydrogen peroxyl radicals are generated, resembling lipid peroxyl radicals in their reactivity. The reactions induced by these radicals are not under genetic control, they attack nearly all types of biological molecules (such as proteins, lipids, and sugars), and are responsible for the deleterious cell alterations in aging and age-related diseases (such as diabetes, Alzheimer's disease, or atherosclerosis) and probably also in autoimmune diseases, which involve sugars at the cell membranes. Lipid peroxidation processes are induced by heating fats, meat, and other nutritional products. The oxidation products generated by consumption of heated food cause damage of mammalian cells. The deleterious reactions can be partly reduced by consumption of plants and/or algae. These contain, among other well-known antioxidants, furan fatty acids, which are important scavengers of peroxyl radicals.