L-Arabinitol is a potential biomarker for the comsuption of the food products such as sweet potato deerberry moth bean and is also associated with Alzheimer's disease and ribose-5-phosphate isomerase deficiency.

N2,N2-Dimethylguanosine is an urinary nucleoside. The mean levels of urinary N2,N2-Dimethylguanosine in patients with colorectal cancer are significantly higher than those in patients with intestinal villous adenoma or healthy adults.

Pyrrole-2-carboxylic acid was first identified as a degradation product of sialic acids then as a derivative of the oxidation of the D-hydroxyproline isomers by mammalian D-amino acid oxidase.