L-Citrulline is an amino acid derived from ornithine in the catabolism of proline or glutamine and glutamate or from l-arginine via arginine-citrulline pathway.

N8-Acetylspermidine dihydrochloride is a polyamine that regulates ischemic cardiac apoptosis and resultant cardiac dysfunction.

5'-Deoxyadenosine is an oxidized nucleoside found in the urine of normal subjects. Oxidized nucleosides represent excellent biomarkers for determining the extent of damage in genetic material which has long been of interest in understanding the mechanism of aging neurodegenerative diseases and carcinogenesis.