ascorbate

Ascorbate refers to the conjugate base or salt of ascorbic acid (vitamin C). In chemistry, ascorbate denotes the deprotonated form C6H7O6− that results when ascorbic acid loses a proton. It also appears in salt forms such as sodium ascorbate and calcium ascorbate, and in various esterified derivatives used in supplements and fortified foods.

In humans, ascorbate acts as a water-soluble antioxidant and as a reducing agent cofactor for several enzymes. It is essential for collagen synthesis, through its role in prolyl and lysyl hydroxylases, and it participates in the biosynthesis of catecholamines by dopamine beta-hydroxylase. Ascorbate also supports the activity of a family of dioxygenase enzymes involved in epigenetic regulation and hypoxia signaling. It helps regenerate vitamin E and scavenges reactive oxygen species.

In nutrition and medicine, adequate ascorbate intake prevents scurvy, a disease characterized by impaired collagen formation, gum disease, and poor wound healing. Ascorbate is widely used as a dietary supplement and as an antioxidant food additive; common forms include ascorbic acid, sodium ascorbate, and calcium ascorbate. In foods, these salts function as antioxidants and acidity regulators; in cosmetics they serve as stabilizers and antiaging agents.

Safety and metabolism: Ascorbate is generally well tolerated; excess amounts are excreted in urine, but very high intakes can cause gastrointestinal upset and may have interactions in individuals with kidney stones or iron overload. The dietary reference intake varies by age and sex, with a typical upper limit around 2000 mg per day for adults.