1-Methylhistamine dihydrochloride is a major metabolite of histamine by histamine N-methyltransferase in the pathway of histidine metabolism.?It has been used as a biomarker of histaminergic system activity in the brains of Alzheimer's disease patients as well as those with hypersomnia and other neurological conditions.

GDP-L-fucose is a nucleotide sugar widely found in fungi and plants, playing a role in both the slave and secondary remedial metabolic pathways.

5-Methylcytidine is a modified nucleoside derived from 5-methylcytosine and is a minor constituent of RNA as well as DNA for certain organisms.