Antioxidant effects of fructosyl arginine, a Maillard reaction product in aged garlic extract

The amino-carbonyl (Maillard) reaction of amino acids with sugars is a none nzymatic browning reaction that takes place during the processing, cooking, and storage of foods. Maillard reaction products (MRPs) have been shown to possess interesting chemical and biological properties including antimutag enic and antioxidant activity. In this study, we determined the antioxidant effects of fructosyl arginine (Fru-Arg), a MRP in aged garlic extract. Law density lipoprotein (LDL) was incubated with Cu2+ at 37 degrees C and 5% C O2 far 24 hours, which resulted in an increase of thiobarbituric acid react ive substances (TBARS) indicating lipid peroxidation. Coincubation of Cu2with Fru-Arg and LDL resulted in a significant inhibition of TEARS formatio n. Pulmonary artery endothelial cells (PAEC) were exposed to 0.1 mg/mL oxid ized LDL (Ox-LDL) at 37 degrees C and 5% CO2 for 24 hours. Lactate dehydrog enase (LDH) release, as an index of cell membrane damage, and TBARS were me asured Ox-LDL caused an increase of LDH release and TBARS formation. Pretre atment of PAEC with Fru-Arg inhibited these changes. Murine macrophages wer e incubated with Ox-LDL, and the release of peroxides was measured using a fluorometric assay Ox-LDL caused an increased release of peroxides. Coincub ation of macrophages with Fru-Arg and Ox-LDL inhibited the release of perox ides dose-dependently. In a cell free system, Fru-Arg was shown to scavenge hydrogen peroxide. These data suggest that Fru-Arg is a potent antioxidant , and thus may be useful for the prevention of atherosclerosis and other di sorders associated with oxidative stress. (J. Nutr. Biochem. 10:372-376, 19 99) (C) Elsevier Science Inc. 1999. All rights reserved.