Abstract
After being identified as the anti-scurvy factor vitamin C, ascorbic acid (AsA) became the subject of an astonishing amount of research. Many studies confirmed that AsA is essential to plants and animals, however, the molecular mechanisms by which AsA exerts its action are only in part understood. Much attention has been given to the so-called antioxidant function of AsA, but the concept of antioxidant is in itself rather vague and, at least in some studies, proper quantitative approaches to assess the actual relevance of AsA as an antioxidant are lacking. On the other hand, in the last few decades more and more research focused on the specific function of AsA as a regulatory co-factor of 2-oxoglutarate-dependent dioxygenases, a large class of enzymes catalyzing an array of different and apparently unrelated reactions, all sharing a complex mechanism based on the integration of relevant pieces of molecular information. The present contribution aims to critically discuss available evidence in support of current hypotheses on AsA function.