Neopterin is a byproduct of the tetrahydrobiopterin (BH4) biosynthetic pathway, which requires Mg2+, Zn2+, and NADPH as cofactors. Tetrahydrobiopterin is an obligatory cofactor for phenylalanine, tyrosine, tryptophan hydroxylases and alkylglycerol monooxygenase, and for all isoforms of nitric oxide synthase (NOS). BH4 is synthesized by multiple metabolic routes, namely the de novo, salvage and recycling pathways. The de novo via generates BH4 from guanosine triphosphate (GTP) by the concert action of guanosine triphosphate Cyclohydrolase I (GTPCH), 6-pyruvoyl Tetrahydropterin synthase (PTPS) and sepiapterin reductase. GTPCH catalyzes the conversion of GTP to 7,8-dihydroneopterin triphosphate. Then, Alkaline Phosphatases removes the phosphates to generate, 8-dihydroneopterin, which is further converted to Neopterin by non-enzymatic oxidation. Neopterin is a recognized biomarker for immune system activation. IFN-g, which is released from activated Th1 cells during the initiation of the immunological cellular response, is one of the main stimuli for neopterin formation. The source of neopterin in the central nervous system (CNS) is not well understood. The evidence available in the literature has suggested that neopterin crosses the blood-brain barrier, therefore the CSF levels may reflect the serum or plasma neopterin concentrations. Cell culture studies strongly suggest that neopterin is not an inert compound, but a cytoprotective molecule synthesized and secreted by nerve cells as a response to damage or inflammation.

alpha-N-methyl-histamine is a metabolite of histamine that plays an important role in several (patho) physiological processes. alpha-N-methyl-histamine is being a potent agonist of histamine H3 receptor can be used as an effective therapeutic alternative in migraine patients.

Zinc dibutyldithiocarbamate (Zn DBDTC) is a vulcanization accelerator for natural rubber and latex and a stabilizer for rubber-based adhesive systems, isobutylene-isoprene copolymers and polypropylene. It is used in a number of rubber and rubber-based materials for food packaging and food handling, e.g. conveyor belts. Zinc dibutyldithiocarbamate (Zn DBDTC) is contact allergens that cross-react in some individuals. Zinc dibutyldithiocarbamate, like many low-molecular-weight contact allergens, can only trigger an immune response when bound to a protein in the form of an immunogenic protein–hapten complex. Haptenation of epidermally relevant skin proteins by Zinc dibutyldithiocarbamate has not been reported despite the numerous studies on the disposition and systemic toxicity of Zinc dibutyldithiocarbamate. The chelating properties of the dithiocarbamate ligand have been proposed to be responsible for the modification of some metalloproteins and metalloenzymes