THE ANTIOXIDANT EFFECTS OF THYLAKOID VITAMIN-E(ALPHA-TOCOPHEROL)

Vitamin E (alpha-tocopherol) is essential for the prevention of photo-oxidative deterioration of biomembranes. The occurrence, relative biological activity and distribution of tocopherols in photosynthetic membranes is considered together with the possible biochemical and biophysical mechanisms by which tocopherols confer protection upon illuminated membranes. The common protective effects of Vitamin E in photosynthetic membranes and in medically important light-induced diseases and conditions of the skin and eye in animal cell membranes are discussed. The importance of the Vitamin E-Vitamin C thylakoid antioxidant system is also examined, in terms of susceptibility to photo-oxidative damage under stress conditions including chilling, ageing and senescence, drought, atmospheric pollutants, herbicides and photosensitizing fungal toxins.