Antioxidants Presented by G. Anvesh Kumar(M Pharm Pharmacology) 10T21S0103. Under the guidance of Mrs. Geeta Reddy(Dept of Biotechnology)
An antioxidant is a molecule capable of inhibiting the oxidation of other molecules. Oxidation is a chemical reaction that transfers electrons or hydrogen from a substance to an oxidizing agent.Oxidation reactions can produce free radicals. In turn, these radicals can start chain reactions.
Types of Free Radicals 1. Hydroxyl radical (OH•)
2. Superoxide anion radical (O2–•)3. Singlet oxygen
Common antioxidants (scavengers) 1. Bilirubin 2. Carotenoids a. Beta-carotene b. Alpha-carotene c. Beta-cryptoxanthin d. Lutein e. Zeaxanthin f. Lycopene 3. Flavonoids a. Quercetin b. Rutin c. Catechin 4. Uric acids 5. Thiols (R-SH) 6. Coenzyme Q10 7. Vitamin A, C, E, D. Others antioxidants 1. Copper 2. glutathione (GSH) 3. Alpha lipoic acid 4.Manganise 5. Selenium6. Zinc
Mechanism of action of antioxidants Alpha tocopherol (vitamin E): Prevent the peroxidation of membrane phospholipids, and avoids cell membrane damage through its antioxidant action Ascorbic acid (vitamin C) Scavenges free radicals and reactive oxygen molecules, which are produced during metabolic pathways of detoxification Beta Carotene Ability to quench singlet oxygen, scavenge free radicals and protect the cell membrane lipids from the harmful effects of oxidative degradation .
Superoxide dismutase(SOD) Eliminating ROI by reducing (adding an electron to) superoxide to form H2O2. Catalase and the selenium-dependent glutathione peroxidase are responsible for reducing H2O2 to H2O. The catalase enzyme Catalase and glutathione peroxidase seek out hydrogen peroxide and convert it to water and diatomic oxygen. Glutathione peroxidase enzyme Glutathione peroxidase reduces H2O2 to H2O by oxidizing glutathione (GSH)
Antioxidant System in our body The enzymatic antioxidants Superoxide dismutase (SOD) Catalase Glutathione peroxidase The nonenzymatic antioxidants Vitamins E, C, A or Provitamin A(beta-carotene), GSH
Pro-oxidant activities Antioxidants that are reducing agents can also act as pro-oxidants. For example, vitamin C has antioxidant activity when it reduces oxidizing substances such as hydrogen peroxide, however, it will also reduce metal ions that generate free radicals through the Fenton reaction. 2 Fe3+ + Ascorbate -> 2 Fe2+ + Dehydroascorbate 2 Fe2+ + 2 H2O2 -> 2 Fe3+ + 2 OH· + 2 OH−
Oxidative stress in disease: Oxidative stress is thought to contribute to the development of a wide range of diseases including Alzheimer's disease, Parkinson's disease, the pathologies caused by diabetes, rheumatoid arthritis, and neurodegeneration in motor neuron diseases How to measure the oxidative stress d-ROMs T This test is used to determine the antioxidant capacity of plasma, mainly due to the level of hydroperoxides - a subclass of reactive oxygen metabolites (ROM) - amplifiers and considered markers of cell damage by free radicals. BAP Test This test is used to determine the efficiency of the plasma barrier opposes the attack of free radicals in terms of iron-reducing activity An increase in the values of d-ROMs Test (> 300 U CARR) and / or a reduction of the values of the BAP Test (<2200 micromol / L) are indicative of a condition of oxidative stress
Health effects: Disease treatment Disease prevention Physical exercise Adverse effects Benefits of antioxidants:
Destroy the free radicals that damage cells.
Promote the growth of healthy cells.
Protect cells against premature, abnormal aging.
Help fight age-related macular degeneration.
Provide excellent support for the body’s immune system, making it an effective disease preventative.
No Matter What Your Age…You Need Antioxidants!
Measurement and levels in food:
Measurement of antioxidants is not a straightforward process, as this is a diverse group of compounds with different reactivities to different reactive oxygen species. In food science, the oxygen radical absorbance capacity (ORAC) has become the current industry standard for assessing antioxidant strength of whole foods, juices and food additives
Antioxidants are found in varying amounts in foods such as vegetables, fruits, grain cereals, eggs, meat, legumes and nuts. Some antioxidants such as lycopene and ascorbic acid can be destroyed by long-term storage or prolonged cooking. Other antioxidant compounds are more stable, such as the polyphenolic antioxidants in foods such as whole-wheat cereals and tea.
The Color Code for Antioxidants: 1. Red – tomato, pink grapefruit, watermelon 2. Blue/Red/Purple/Black (BRPB) – blueberry, cherry, prune, blackberry 3. Orange/Yellow – carrot, pumpkin, orange, papaya 4. Green – broccoli, kale, spinach, pea 5. White – garlic, onion, cabbage, turnip 6. Brown/Gray – spices, nuts, seeds, endogenous sources How to Apply the Color Code 1.Enzymes (Brown/Gray) 2.Vitamins (Brown/Gray) 3.Phenolics (BRPB) 4.Carotenoids (Orange/Yellow, Red) 5.Hormones (Brown/Gray 6.Minerals (All colours) 7.Glutathione (Brown/Gray) 8.Lipid effectors (Orange/Yellow) 9.Saponins, steroids and stilbenes (Green, BRPB) 10.Sulfur-containing chemicals (Green, White)
Uses in technology: Food preservatives Industrial uses
Conclusion Antioxidant plays an important role to prevent cancer, and other disease. They also have role in slowing ageing process and preventing heart disease. So antioxidant are very much necessary for our body .But our body can’t manufacture these chemicals, so they must be supplied through diet.