Gentian Violet

In aqueous solutions, gentian violet (GV) dissociates into positive (GV+) and negative (Cl−) ions that penetrate through the wall and membrane of both gram-positive and gram-negative bacterial cells. The GV+ ion interacts with negatively charged components of bacterial cells, including the lipopolysaccharide on the cell wall, the peptidoglycan, and DNA. A similar process of cell penetration and DNA binding is thought to occur in fungal cells as well. Because gentian violet is a mutagen and mitotic poison, it consequently inhibits cell growth. A photodynamic action of gentian violet, apparently mediated by a free-radical mechanism, has also been described in bacteria and in the protozoan T. cruzi. Evidence further suggests that gentian violet dissipates the bacterial (and mitochondrial) membrane potential by inducing permeability, which is then followed by respiratory inhibition. This anti-mitochondrial activity may explain why gentian violet is effective against both bacteria and yeast while having relatively mild effects on mammalian cells.