The oxidative modification of lipids in food and biological systems has been recognized to play a central role in food deterioration and in pathophysiology of human diseases. Although the association of lipid glycation with this process has been recently reported, the existence of lipid glycation products in food and biological materials has not been fully understood. In this study, we synthesized the Amadori products derived from the glycation of phosphatidylethanolamine (PE), i.e. Amadori-PEs. Dioleoyl-PE was incubated with glucose or lactose for 15 days, and the resultant Amadori-PEs were purified and isolated using a solid phase extraction followed by high performance liquid chromatography (HPLC). With this procedure, essentially pure Amadori-PEs glycated with glucose (Glc-PE) or with lactose (Lac-PE) were obtained and used as standards in the subsequent studies. In order to determine Amadori-PEs in food and biological samples, the carbonyl group of Amadori-PEs was UV-labeled with 3-methyl-2-benzothiazolinone hydrazone (MBTH), and the labeled Amadori-PEs were analyzed with normal phase HPLC-UV (318 nm). The detection limit was 4.5 ng for Glc-PE and 5.3 ng for Lac-PE. Amadori-PEs were detected in infant formula, mayonnaise, chocolate, cow milk, soybean milk and rat plasma.
- 3-Methyl-2-benzothiazolinone hydrazone
- Amadori product determination
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