Vitamin C (L-ascorbic acid, CAS # 50-81-7), a water-soluble vitamin naturally present in citrus and other fruits and vegetables, is an electron donor and a versatile free radical scavenger. It has been found to regenerate other antioxidants, including α-tocopherol (vitamin E) from the tocopheryl radical. It is a particularly efficient antioxidant because of its high electron-donation power and ready conversion back to the active reduced form. Vitamin C is necessary for the biosynthesis of collagen, Lcarnitine, and some neurotransmitters, it is also a participant in protein metabolism , and plays an significant role in immune function. 617