Methylsuccinic acid is a normal metabolite found in human fluids. Increased urinary levels of Methylsuccinic acid (together with ethylmalonic acid) are the main biochemical measurable features in ethylmalonic encephalopathy a rare metabolic disorder with an autosomal recessive mode of inheritance that is clinically characterized by neuromotor delay hyperlactic acidemia recurrent petechiae orthostatic acrocyanosis and chronic diarrhea.

Indole is an aromatic heterocyclic organic compound. It has a bicyclic structure consisting of a six-membered benzene ring fused to a five-membered nitrogen-containing pyrrole ring.

PrP106-126 is a fragment of human prion protein that is present in biological samples. It has been shown to act as an agonist at the human FPR2/ALX GPCR.