The identification and metabolic origin of 2-furoylglycine and 2,5-furandicarboxylic acid in human urine

1. Combined gas-liquid chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy have demonstrated the occurrence of 2-furoylglycine and 2,5-furandicarboxylic acid as normal constituents of human urine. 2. The amount of 2-furoylglycine in urine samples from 20 normal adults was 3–28 μg/mg of creatinine, and the excretion of 2,5-furandicarboxylic acid was 0.5–8.2 μg/mg of creatinine. 3. Dietary studies show that the furan derivatives or their precursors are of exogenous origin. Most probably they are derived from furan derivatives found in food prepared by strong heating. This may explain the absence of 2-furoylglycine and 2,5-furandicarboxylic acid in urine of breastfed children, and the absence of these acids in the urine of rat, pig, cow, ox, rabbit and monkey.