Vitamin E: Antioxidant Properties

Vitamin E

• Tocopherol is a fat-soluble antioxidant that reduces the effects of aging and prevents membrane peroxidation in RBCs, muscles, nerves, and retina.
• The antioxidant effect of vitamin E is due to the presence of the phenolic - OH group on C6 of the ring.
• The recommended daily allowance (RDA) of vitamin E is 20 IU/day.
• Vitamin E can be found in vegetable oils, nuts, green leafy vegetables, dairy products, and fortified breakfast cereals.
• High doses of vitamin E can increase clotting time in subjects with low vitamin K status.

Vitamin A and Carotenoids

• Vitamin A is important for vision, bone growth, reproduction, and cell division, and regulates the immune system.
• Vitamin A can be found in animal sources (retinol) and plant sources (carotenoid).
• Foods rich in vitamin A include dairy products, liver, eggs, fruits, and vegetables (such as carrots, cantaloupes, and sweet potatoes).

Vitamin C

• Vitamin C is essential for the formation, growth, and repair of bone, skin, and connective tissue.
• It helps maintain healthy teeth and gums, aids in iron absorption, and promotes healing of burns and wounds.
• Vitamin C protects cells against damage by free radicals.
• Cooking can destroy some vitamin C in foods.
• Pregnancy, breastfeeding, fever, surgery, and smoking increase the body's requirements for vitamin C.
• High doses (2 gm/day) of vitamin C are not toxic to healthy adults.
• Scurvy is a disease caused by a severe vitamin C deficiency, which can lead to bleeding gums, loosened teeth, and bleeding under the skin.

Flavonoids

• Flavonoids are important in plant growth, development, and defense against infection and injury.
• They are responsible for the colors of flowers, fruits, and leaves.
• Flavonoids have antioxidant activity and may have protective effects against vascular diseases and certain types of cancers.
• Foods rich in flavonoids include flowers, berries, and fruits (such as grapes, hibiscus, and citrus fruits).

Phenolic Acids

• Phenolic acids are found in cereals and are readily absorbed through the intestinal tract walls.
• They have antioxidant effects and may prevent damage to cells resulting from free-radical oxidation reactions.
• Examples of phenolic acids include ferulic, caffeic, p-hydroxybenzoic, p-coumaric, and vanillic acids.

Resveratrol

• Resveratrol is found in grapes and has antioxidant effects.
• It has protective effects against cardiovascular and neurodegenerative diseases and cancer.
• It is also a cancer chemoprotective agent, anti-inflammatory, and anti-platelet.

Turmeric (Curcuma)

• Turmeric contains curcuminoids (curcumin, desmethoxycurcumin, and bis desmethoxycurcumin) and volatile oils.
• It has hepatoprotective, antioxidant, and anti-inflammatory effects.

Ginseng

• Ginseng contains saponins (ginsenosides), flavonoids, volatile oil, peptides, proteins, and polysaccharides.
• It has various effects, including:
  • General tonic (treats exhaustion and hypotension)
  • CNS stimulant (improves age-related depression and lack of concentration)
  • Enhances memory
  • Hepatoprotective
  • Protects neurons against ischemic damage
  • Antioxidant
  • Immunomodulatory
  • Improves carbohydrate tolerance in diabetics

Green and Black Tea

• Black tea is produced through the fermentation of tea leaves, which involves oxidation under controlled temperature and humidity for months to years.
• Green tea is produced through the drying of fresh tea leaves without fermentation.
• Tea constituents include:
  • Alkaloids (caffeine, theobromine, and theophylline)
  • Polyphenols (flavanols, flavonols, flavondiols, and phenolic acids)
  • Saponins
  • Tannins
  • Volatile oils
  • Bisflavanols and theaflavins (formed during the manufacture of black tea)
• Tea has various effects, including:
  • CNS stimulant (caffeine > theophylline > theobromine)
  • Mild diuretic (theobromine > theophylline > caffeine)