New perspective of GABA as an inhibitor of formation of advanced lipoxidation end-products: it's interaction with malondiadehyde.

In this research, the obtained evidences support the hypothesis that gamma-aminobutyric acid (r-aminobutyric acid, GABA) can trap malondialdehyde (MDA) indirectly or directly. In vitro, reaction between GABA with fatty acid, which can be confirmed by detecting the formation and yield of MDA and the consumption of GABA, shows that GABA can trap the reactive intermediates during lipid peroxidation. Further study of the direct reaction between GABA and MDA indicated that GABA reacts readily with MDA under supraphysiological conditions to form different products. A nonfluorescent enamine (product 1) and a lipofuscin-like fluorescent 1,4-dihydropyridine (product 2) were obtained experimentally from reaction of equimolar of GABA+MDA and were detected by means of high performance liquid chromatography (HPLC) separation for the reaction mixtures at 48 h. We proposed a mechanism for the formation of these products from oxidation of polyunsaturated fatty acids (PUFA) to the reaction of GABA and MDA. The results suggest that the scavenging effects of GABA on reactive carbonyl compounds may play an important role in inhibiting the formation of advanced lipoxidation end-products (ALEs), and GABA, as a potent antioxidant or additive, is a novel functional factor for nutraceuticals.