Ascorbic acid in the 21 st century - more than a simple antioxidant

Ascorbic acid (AA) is an essential micronutrient for man, with many biologi cal roles. It is a powerful antioxidant both directly via scavenging of rea ctive oxygen species and indirectly through regeneration of other antioxida nt systems. Paradoxically, under certain conditions (low concentration in v itro, presence of metal ions) it can exert a pro-oxidant effect, increasing oxidative damage to lipids, DNA and protein. Herein, the effects of vitami n C both in vitro and in vivo are addressed in terms of modulation of oxida tive DNA damage, gene expression and protein oxidation. The view of AA as a simple scavenger is outdated, where the arrival of new bioinformatic techn iques, heralds a new dawning in our understanding of ascorbate as a potenti al direct or indirect modulator of gene expression. (C) 2001 Elsevier Scien ce B.V. All rights reserved.