Ascorbic acid leads to glycation and interferes with neurite outgrowth

Ascorbic acid better known as vitamin C, is a reducing carbohydrate needed for a variety of functions in the human body. The most important characteristic of ascorbic acid is the ability to donate two electrons, predestining it as a major player in balancing the physiological redox state and as a necessary cofactor in multiple enzymatic hydroxylation processes. Ascorbic acid can be reversibly oxidized in two steps, leading to semi-dehydroascorbic acid and dehydroascorbic acid, respectively. Further degradation is irreversible and generates highly reactive carbonyl-intermediates. These intermediates are able to induce glycation of proteins, a nonenzymatic and unspecific reaction of carbonyls with amino groups involved to several age-related diseases. In this study, we investigated the effect of ascorbic acid- and dehydroascorbic acid-induced glycation on PC12 cells, which represent a model for neuronal plasticity. We found that both applications of ascorbic acid or dehydroascorbic acid leads to glycation of cellular proteins, but that ascorbic acid interferes more with viability and neurite outgrowth compared with dehydroascorbic acid.