**Abstract**

Brain tissue constitutes a small portion of the total body mass. With its high metabolic rate, brain tissue consumes approximately 20% of the total body oxygen. Brain and neural tissue contain higher levels of vitamin C (VC) than other tissues. It is reported that VC is a powerful and natural antioxidant that is not synthesized in any tissue including the brain. VC is abundant in fruits and vegetables. Its most wellknown function is by facilitating the hydroxylation of lysine and proline residues in collagen, allowing procollagen to fold intracellularly for export and accumulation as mature collagen. Firstly, it was reported that VC is transported very slowly across the blood brain barrier which distinguishes the central nervous system (CNS) from other systems in VC uptake. Second, the ability to maintain the VC concentration gradient from blood to neuronal cells is produced by cerebrospinal fluid (CSF) and brain cells. VC has neuroprotection and neuromodulation effects. In conclusion; since its distribution and concentration in different organs of the body depend on the requirements of VC the pharmacokinetic properties of ascorbate are closely related to the functions it performs in tissues.

**Keywords:** brain tissue, vitamin C, Alzheimer's disease, Parkinson's disease, Huntington's disease
