TOCOPHEROL (Vitamin E) Any of a group of related substances (alpha-, beta-, gamma-, and delta-tocopherol)  which constitute vitamin E.  The alpha-form (which occures naturally as the d-isomer) is the most potent.  Occurs naturally in plants, especially wheat germ.  All are derivatives of dihydrobenzo-gamma-pyran and differ of methyl groups.  Vitamin E is required by certain rodents for normal reproduction.  Muscular and central nervous system depletion along with generalized edema are deficiency symptoms in all animals. Properties:  Viscous oils; soluble in fats; insoluble in water; stable to heat in the absence of oxygen, to strong acids, and to visible light; unstable to UV light, alkalies, and oxidation. Use:  Medicine, nutrition, antioxidants for fats, animal feed additive