Glutathione

Glutathione (GSH) is the most abundant intracellular antioxidant, acting as a direct scavenger of reactive oxygen species and as the electron donor for glutathione peroxidases that neutralise hydrogen peroxide and lipid peroxides. It participates in phase II hepatic detoxification by conjugating with reactive electrophiles via glutathione-S-transferases. In the immune system, GSH regulates lymphocyte proliferation and natural killer cell activity. The oxidised form GSSG is recycled to GSH by glutathione reductase using NADPH. GSH levels decline with age and under conditions of chronic oxidative stress.