Quinolinic acid is an organic compound derived from the metabolism of the amino acid tryptophan. It is a neurotoxin and an endogenous metabolite, primarily produced by the kynurenine pathway in the brain. Quinolinic acid plays a role in modulating various neurotransmitter systems, particularly glutamate, and has been studied for its involvement in several neurological disorders, including Alzheimer’s disease, Huntington’s disease, and depression. Its overproduction can lead to excitotoxicity, contributing to neuronal damage.