What antioxidant's decrease is the first biochemical abnormality observed in Parkinson's disease?

The decrease of glutathione is the first biochemical abnormality observed in Parkinson's disease, making it the correct answer. Glutathione is a vital intracellular antioxidant that plays a crucial role in protecting cells from oxidative stress and maintaining cellular health. In Parkinson's disease, the reduction of glutathione levels contributes to the pathophysiology of the disease, as it leads to increased oxidative damage to neurons in the substantia nigra, the brain region primarily affected by the disease.

The loss of glutathione has been correlated with the degeneration of dopaminergic neurons and is significant in the progression of Parkinson's disease. This early decrease may impact the ability to detoxify harmful substances and combat oxidative stress, which are essential for neuronal survival. Understanding this relationship is vital for developing therapeutic strategies aimed at enhancing antioxidant defenses in affected individuals.

Other antioxidants mentioned, such as coenzyme Q10, vitamin E, and catalase, are important in the context of neuroprotection and oxidative stress but are not identified as the first biochemical change in the context of Parkinson's disease. Their roles, while significant, do not directly relate to the earliest detectable alterations in the disease's development, which is primarily linked to glutathione depletion.