Antioxidants are chemicals that counterbalance external and internal factors such as pollution, sun burn, metabolism problems and the like. Antioxidants help out in repairing the skin and are an effective anti aging skincare.

How does an antioxidant work as an anti aging skin care? Antioxidants slow down the oxidation process which results to the production of free radicals. Free radicals are substances that could damage the body cells, and the skin cells. Therefore free radicals, results in aging. Antioxidants fight aging through the regeneration of cells and inhibition of oxidation in the body. Since they will be the ones oxidized, the skin won’t be exposed to further damage by free radicals. In this way, aging is being slowed down making a person look as young as before.

Examples of antioxidants are reducing agents such as thiols and polyphenols. Foods rich in Vitamins A, C, and E are great source of antioxidant supplements for the body. Phytonutrient carotenoid is another major source of antioxidant supplements. Numerous antioxidants products have been released in the market to aid in anti aging skincare and there are more to come.

Antioxidants not only promote good skin but also a healthy life. The benefits of antioxidants includes the strengthening of the immune system, lowering the risks of cancer, preventing diseases like glaucoma, reducing the risks of heart attacks and strokes and of course, anti aging.

With the discovery of the benefits of antioxidants, has lead to a lot of products released today that offers great deal of antioxidants and anti aging in people. Since antioxidants are mainly found in fruits and vegetables, antioxidant products are mainly comprised of such. Some the examples of these products includes glutathione, ALA, Deva Nutrition, softgels.

Antioxidants are good for the body it helps you achieve fair skin and great health. You can still get your antioxidant supplements from eating plenty of fruits and foods rich in beta carotene and nutrients if you do not wish to spend money buying antioxidants products.

We hear a lot today about antioxidants, “free radicals” and what we can do about them. There is much confusion, so it may help to break down the key facts about these important, potentially life-saving and life-extending substances.

1. Oxygen is good and bad. In the human system, this basic element is both a help and a hindrance. Without it, no life. And yet, oxygen can work to break down other substances in the body as it is metabolized, creating what are called “free radicals” that displace electrons from other molecular structures. This is extremely damaging.

2. Oxidation is the name for this damage. An antioxidant, therefore, is anything that works to stop or retard this damaging breakdown by adding back an electron to the free radical and rendering it harmless.

3. We have natural antioxidants. Our bodies can fight this battle naturally, to an extent. Common nutrients such as beta-carotene, vitamin E, vitamin C and selenium have been found to have antioxidant properties.

4. There are serious repercussions. The body actually does need some free radicals to function effectively, but an excessive amount is correlated with such diseases as heart and liver disease, as well as cancer.

5. Environmental factors affect you. Oxidation is exacerbated by stress, tobacco, drinking alcohol, excess exposure to the sun, air and water pollution, and other environmental and behavioral factors. There are things you can do in your lifestyle beyond taken antioxidant supplements to combat this scourge.

6. Antioxidants can be preventive. They work by reducing the number and effect of free radicals may even work to inhibit the spread of cancerous cells. For one example, they are thought to help prevent the beginnings of heart disease due to oxidation. By limiting the number of unstable, electron-deprived molecules, antioxidants can prevent the free-radical “chain reaction” from starting in the first place, in various places and organs in the body.

7. Antioxidants can be curative. We already have evidence that antioxidants can help ameliorate both symptoms and side effects of many diseases that proliferate because of oxidation in our bodies. It is also clear that antioxidants are effective in the treatment of chronic inflammation, and other applications are being discovered all the time.

8. The body’s natural antioxidant mechanisms can be supported by supplementation.  Our bodies already circulate many nutrients precisely because of their antioxidant properties. They also create antioxidant enzymes expressly for the purpose of controlling free radicals and the damaging chain reactions. Our systems will utilize any other antioxidant substances in these same processes.

9. Mom was right: Take your vitamins. Vitamin E has been shown to suppress the “stickiness” of blood platelets and acts as an anticoagulant to decrease the formation of heart-attack-inducing blood clots. Vitamin C helps in this as well, by inhibiting a blood factor that is used to build clots.

10. Cancer is the next frontier. Antioxidants may have an important role in the fight against cancer through their ability to neutralize the DNA-damaging free radicals.  A huge amount of research is being done in this area right now, all around the world. The good news is that the therapies developed from natural substances will not be limited by the need for a physician’s prescription.

11. Antioxidants are good for the brain, too. Because they prevent injury to blood vessel membranes, antioxidants can help to stabilize and even increase blood flow to the brain and the heart. The additional defense they offer against the DNA damage that is at the root of many cancers also helps lower the risk of cardiovascular disease, dementia and even Alzheimer’s disease.

12. The science is evidence-based, not anecdotal. One of the most important things to remember is that reporting on antioxidants is done by some publications and websites that are also touting crystal power and other spurious cures. The fact is that antioxidant research is being done by real scientists in real labs, in both private enterprise and at leading universities and teaching hospitals.

Information on antioxidants and the ongoing research into their applications can fill a good-sized library, and more is being learned all the time. Your best bet is to stick with the news that is being reported by responsible, mainstream journalists, notwithstanding the occasional media bias against treatments that are portrayed as being “alternative” or “complementary.”

Read broadly, think clearly, ask questions of your doctor and always look for the original sources for any claims about the power of antioxidants. There are many reasons for hope, and the role of antioxidants in fighting both disease and the cell degradation that we call “again” is just starting to become clear. The next several years should see some amazing applications for antioxidant therapy, so stay tuned.

Antioxidants fight the free radicals that harm the cells, causing damage and premature aging. In other words, antioxidants skin care products help in preventing future damages and repairing past damages in the cells.

Antioxidants used to be found only in food, oral intake used to be the only way we get to use these. After people recognized the ability of antioxidants, they were combined with skin care products and they became part of how we take good care of our skin. Antioxidant skin care made it possible to counter the free radicals our skin may suffer from. Wrinkles and fine lines can be minimized with the use of antioxidants skin care products.

Skin care focuses in maintaining healthy, youthful dermis, preventing premature aging, reducing the appearance of lines and wrinkles, and keeping proper moisture. With the large number of products available, it is hard to know which ones have the ingredients that can harm the skin.

Vitamins E, A, and C, zinc and selenium are just some of the nutrients found in the properties of antioxidants. The use of antioxidant skin care products will help the body get the nutrients it needs, excluding the conventional way, which is to eat foods rich in antioxidants. All of these are important in keeping a healthy skin. Antioxidant skin care helps in achieving a youthful skin, and maintaining it.

While antioxidants are available in many foods, it is not like we get to obtain and use as much as we can and want. Using antioxidants skin care products make antioxidants available and within reach almost anytime.

Antioxidants also assist in the production of collagen and elastin. As one ages, the production of these two weakens. Collagen keeps the skin firm. Elastin adds and maintains elasticity. In other words, it helps prevent wrinkles and fine lines. It also adds resistance that helps prevent the skin from sagging.

A lot of products have indeed come out. It is best to know which ones are the most beneficial. Antioxidant skin care is approved and recommended because of the abilities antioxidants have. Being able to fight free radicals and being able to apply them topically was an advantage that was brought by this breakthrough.

While there are already antioxidants skin care products our in the market, companies are still trying to come up with the best blend of antioxidants. After all, the stronger the antioxidants are, better care and protection can be provided to the skin. These blends need to be proven as beneficial, that is why companies are taking their time in producing formulas. From the initial target of skin care, which is to help skin retain moisture and keep it firm, the goal has been moved up after realizing that antioxidants can minimize wrinkles and lines, and can even make you skin resistant to damages.

Its not like every other product is not safe, however, antioxidants skin care products are much safer and more beneficial in many ways. Nowadays, knowing what is good for you and your skin is a must. These products are proven effective, and at the same time less harmful. The only danger with these products is the possibility of incorrect usage. Check the instructions carefully, follow them, and if these are not enough, ask a professional for some assistance.

Wouldn’t we all like to age gracefully (if at all for that matter!) and ward off the wrinkly signs and ill symptoms for as long as possible. Keys to longevity may be more accessible than we think, and it appears our diets play a critical role. Antioxidants are the knights in shining armor that subjugate the attack of free radicals in the body, the hazardous molecules that damage cells and procure aging and disease. Though antioxidants are produced naturally in the body, these decline with age, hence an increasing need to acquire them from the foods in our diet.

Before examining antioxidants more closely, it is important to take a look at the free radicals they serve to neutralize.

Free Radicals

Free radicals are created as by-products in our use of oxygen during metabolism such as the burning of food for energy. They are essentially oxidant molecules that are missing an electron and seek to restore themselves by targeting nearby cells in an attempt to recover this electron, potentially harming enzymes, DNA, proteins and cell membranes in the process. This damage can mutate cells and alter cell function, increasing the risk of numerous diseases and chronic conditions including arthritis, diabetes, cataracts, cancer, heart disease and stroke. Free radical damage is implicated in the onset of aging and its degenerative symptoms and diseases.

As well as generated within the body, free radicals come from environmental sources such as pollution, radiation, unhealthy foods, bacteria, viruses, cigarette smoke and UV light.

Antioxidants

Antioxidants serve to mitigate the harmful effect of free radicals by giving up an electron and stabilizing them in the process. Although we produce many of our own antioxidants within the body, food provides an essential source for these key players of our defense system. Vitamins, minerals and phytonutrients all have antioxidant properties. The most common examples include vitamins A, C and E, selenium and zinc, carotenoids, flavonoids, co-enzyme Q10, alpha-lipoic acid and glutathione.

As there are many different types of free radicals in the body a variety of antioxidants are required to protect against them. Antioxidants function best as a team, with each other and other nutrients and phytochemicals, which is why incorporating a wide range of plant foods into your diet is recommended. Phytochemical groups such as flavonoids and carotenoids correspond to the colour, taste and smell attributes of plants, hence eating a rainbow array of vegetables and fruits can offer a diverse selection of these potent antioxidants.

Antioxidant Rich Foods

Foods especially high in antioxidants include berries, plums, pomegranates, oranges, spinach, green tea, avocado, kale, broccoli, peas, onions, grapes and pure chocolate.

Scientists at the USDA (United States Department of Agriculture) have developed a rating scale that measures the total antioxidant capacity of a given food. This is known as the ORAC score (Oxygen Radical Absorbance Capacity).

Of 40 common fruits and vegetables measured by the USDA, top ranking scores were those of prunes(5770), raisins (2830), blueberries (2400 – highest of all fresh foods with other berries close behind), kale (1770), spinach (1260), Brussels sprouts (980), plums (949), alfalfa sprouts (930), broccoli florets (890), beetroots (840), oranges (750 ), red peppers (710 ) and red grapes (739).

Pure cocoa surpasses all these foods with a whopping score of 26,00 units, more than 10 times the prestigious blueberry (though one is likely to eat far less in quantity). The extraordinary goji berry from Tibet also has outstanding antioxidant capacity with a score of 18,500 units; hardly surprising as they contain 500 times more vitamin C than oranges and even more beta-carotene than carrots!

According to studies on animals and human blood at the Human Nutrition Research Center on Aging at Tufts in Boston, high-ORAC foods may slow aging processes in the body and brain. Results found that high ORAC foods such as blueberries and spinach could increase the antioxidant power of human blood by 10-25%, prevent loss of long-term memory and learning ability in middle-aged rats, and protect rat blood vessels against oxygen damage.

Antioxidants and Aging

As we age, free radical levels rise and yet the body falls short in producing necessary amounts of antioxidants to meet this challenge. For example, cells generate more of the oxidants hydrogen peroxide and superoxide, yet levels of the necessary antioxidant glutathione required to neutralise these decline. The Free Radical Theory of Aging, first proposed by Harman in 1954, is supported by cross-species examination of animals with regard to life span, free radical damage and antioxidant defence. For example, the white-footed mouse lives about twice as long as the house mouse (8 versus 4 years), and is found to generate less oxidants and have higher levels of antioxidants. As Beckman and Ames write in The Free Radical Theory of Ageing Matures (1998), ‘Together, interspecies comparisons of oxidative damage, antioxidant defences, and oxidant generation provide some of the most compelling evidence that oxidants are one of the most significant determinants of life span.’

Very recent evidence comes from a study on dogs at the University of Toronto by Dr. Dwight Tapp and colleagues who found that ‘old dogs that were on an antioxidant diet performed better on a variety of cognitive tests than dogs that were not on the diet. In fact, the dogs eating antioxidant-fortified foods performed as well as young animals’.

Additional research by Dr. Rabinovitch and his team, studying aging at the University of Washington, Seattle, found that mice engineered to produce high levels of an antioxidant enzyme (catalase) lived 20 per cent longer and had less heart and other age-related diseases than controls.

In light of the role free radicals play in the onset of aging and disease, it is important to ensure our diets include a rich and diverse supply of antioxidants. These protective agents can be found abundantly in vegetables, fruits, nuts and seeds and are particularly high in superfoods.

We all know that natural antioxidants are essential for you health. They fight cancer, straighten your immune system, and have anti-aging properties. But what exactly do you need to eat, to get all antioxidants your body needs?

Common sense tells us that since most antioxidants are well known vitamins, the best source for them is fruits and vegetables. This is true, even though not all veggies are the same in this respect. So if you want to make sure that your antioxidant intake is enough, you should chose vegetables and fruits that are high in antioxidants.

Natural antioxidants best sources

Usually you can judge how much antioxidants a particular fruit or vegetable has by its color. Brighter the color, more useful vitamins you will get from eating it. Berries are the leaders when it comes to antioxidants – blackberry, raspberry, strawberry, cranberry and blueberry are all high in flavonoids. Flavonoids successfully neutralise the damage free radicals can do to your health including effect of peroxyl radicals, superoxide radicals, hydrogen peroxide, hydroxyl radicals, and singlet oxygen.

Healthy food doesn’t have to be dull; you can make delicious deserts from berries. Adding sugar doesn’t decrease berries antioxidant properties. However, adding milk, cream or any other milk product does. Apparently milk minimizes the effect of natural antioxidants. So keep this in mind when preparing berry deserts.

Oranges, grapefruits and other citruses are another popular source of antioxidant vitamins. If you prefer drinking fruit juice rather than eating oranges, chose freshly squeezed juices.

Where else to look for natural antioxidants

Not all antioxidants are in fruits and vegetables. Green tea is a great source of flavonoids. So if you are a tea lover, chose green varieties.

Another unusual source of antioxidants is coffee. Not only it helps you to wake up on a cold, slow morning, but it provides your body with antioxidants. According to a study by researchers at the University of Scranton, coffee is a leading source of antioxidants for Americans. Decaf coffee just as good antioxidant source as ordinary coffee, but you should remember – no milk.

Dark chocolate also contain antioxidants. So as you can see, sometimes foods we all love anyway, can bring great benefits to your health.

Including antioxidants in your diet

Teach yourself to eat fruits as snacks, instead of common junk snacks. Dry fruits are good natural source of antioxidants, dates and prunes being the leaders. But of course, if you are watching your weight you have to be careful, because all dry fruits are high on sugar as well.

Garnish like parsley, coriander and dill are excellent antioxidant sources. Add them to your meals. Most spices are also high in antioxidants, so not only they give your food rich flavor, but they also supply vitamins.

Stir fry is a preferred method of cooking, to preserve antioxidants in vegetables. Most vitamins are easily destroyed by heat, so less you cook your dish; the better it is for you.

Working antioxidant into you everyday life is not as difficult as you might think. One cup of black coffee in the morning, some fruit for a snack before lunch and a berry desert at dinner and you are all set. The key here is to do it regularly.

Antioxidants are the chemical substances that are capable of binding to the free oxygen radicals and averting the destruction of the healthy cells by these or antioxidants are the substances which inhibits oxidation. Antioxidants are predominantly important in perspective of biology and organic chemistry as all existing cells enclose intricate systems of the antioxidant chemicals or enzymes to avoid chemical harm to the cellular components through oxidation.

All Living organisms do have a composite scheme of chemicals and antioxidant enzymes some of which are conserved throughout the evolution and thus are necessary for life. Antioxidants have immense significance in the biological systems, including defending oxidative injure and contributing in major signaling passageways of the body cells.

The most important function of antioxidants in the body cells is to avert harm by action of the imprudent oxygen species like superoxide anion (O2), hydrogen peroxide (H2O2), and free radicals including hydroxyl radical (• OH). Such molecules are unsteady and extremely reactive, and capable of spoiling cells by chemical sequential reactions for example lipid peroxidation and DNA adducts formation that might lead to cancer-promoting alteration or death of the cell. All cells thus possess antioxidants serve to lessen or avoid its damage.

Antioxidants are further categorized as inert and pro- oxidant on the type of the product released at the end of the oxidation reaction in the cells. Antioxidants are principally imperative in the eukaryotic cells mitochondria as oxygen utilization during the process of generating energy generate imprudent oxygen species. The aerobic metabolism process requires oxygen as oxygen provides the final quiescent place for generated electrons by oxidation steps in citric acid cycle.

Antioxidants dietary supplements are essential to slow down, avoid, or even overturn certain illnesses that are due to certain cellular damage, and conceivably even dawdling down the normal aging process. Some of the important antioxidant dietary supplements are provitamin A (beta carotene) vitamin E, vitamin C and Selenium, or some special herbs known to have antioxidants values like those of jiaogulan and green tea.

Studies have recommended that antioxidants are significantly useful in several ways concerning the management of cancer. Antioxidants improve the efficiency of chemotherapy; reduce side effects of radiotherapy and chemotherapy and preventing some kinds of cancer. Adequate epidemiological revisions have revealed that ingesting antioxidants containing like vegetables and fruits, can reduce the jeopardy of numerous forms of cancer and it is observed in several studies that blood of cancer patients contain reduced level of antioxidants.

Antioxidant dietary supplement are those food supplements containing antioxidants obtainable from plants. Though antioxidants play a vital role in our bodily defense mechanism they are to be supplied from outside either as food or other ways. Investigations and studies on biological sciences reveal that consumption of antioxidant dietary supplements reduces harm to cells and biochemical in the free radicals.

Meet the “New-trients”
Today’s consumers are witnessing a new era in how foods are identified. New nutrients, not commonly understood for their health benefits, seem to be popping up on our grocer’s shelves every day. Omega fatty acids, newly defined sources of dietary fiber, and antioxidant phytochemicals are examples of healthful plant elements that are creeping into public media reports and water-cooler debates.

Laboratory and preliminary human clinical studies are revealing anti-disease properties of these “nutrients.” Extensive food and medical research underway presently will eventually translate the chemical properties into consumer understanding and terminology that we’ll grasp and use in everyday conversation.

With such potential significance to public health, the consumer education process should begin now in a way that people, from teenagers to grandparents, can readily understand antioxidants as easily as we now understand calories, carbohydrates, fat percentage, and vitamin C.

The scientific and regulatory bodies for food labeling have a great challenge ahead of them.
There are thousands of plant food sources with suspected health benefits with complicated chemical names that are unfamiliar and can be intimidating. The challenge at hand is to decipher this blizzard of names and to promote better nutrition for our families and for ourselves.

Why Antioxidants?

The beneficial antioxidant chemicals that we get from colorful plant foods represent our best defense against threatening oxidants. While oxidative stress is a normal part of cellular metabolism that occurs even in healthy people, left unchecked, it can lead to damage that accumulates with age.

Normally, oxidative species or “free radicals” are neutralized by antioxidant enzymes and food-derived antioxidants. However, the following circumstances can cause an imbalanced oxidant-antioxidant relationship that allows oxidative stress to go unopposed.
• Contamination by environmental conditions like pollution, radiation, cigarette smoke and herbicides
• Normal aging
• Poor diets that lack essential nutrients and phytochemicals
The result of this imbalance is cell and tissue damage that could lead to diseases like:
• Cancer
• Hypertension
• Diabetes
• Chronic inflammation
• Neuronal degeneration like Alzheimer’s disease

The Color Code for Antioxidants

Over the past five years, we have begun a valuable process for recognizing plant food antioxidant qualities by groupings of color—The Color Code, as written in two books entitled The Color Code and What Color is Your Diet? (publication information below).

The following is a summary of those color guides for antioxidants, and an example of how we can begin to classify and categorize the different antioxidants into the food color code.

Summary of the Color Code

This is a general scheme of example foods that can fit into each color class. Keep in mind that there are no firm lines between the classes, which allows for overlap.

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
Here’s a general breakdown of the color groups that have food chemicals with antioxidant qualities:

1.Enzymes (Brown/Gray)
A protein substance with a name ending in “ase”, enzymes stimulate biochemical reactions in living cells and help form new compounds that, in this case, would serve antioxidant functions.
Members of this enzyme class of antioxidants include:
• Superoxide dismutase
• Catalases
• Reductases
• Peroxidases
• Transferases

2.Vitamins (Brown/Gray)
Most consumers would already recognize the three main antioxidant vitamins—A, C and E—that are derived from food and supplements common to the public. Vitamins A and E are fat-soluble, providing antioxidant protection in cell structures like the outer membrane and inner nuclear organelles. Vitamin C dissolves readily in body water compartments, so it is well distributed in the body. Of particular note is the important role of vitamin C in protecting vitamins A and E from damaging oxidative free radicals.

3.Phenolics (BRPB)
With more than 8,000 individual chemicals that serve plants as pigments, the phenolics (also called phenols or polyphenols) are water-soluble acids that not only give plants colors, but also differentiate scents, tastes, and bitterness. The large class of phenolics (called flavonoids) is often mentioned in current public media. Quercetin, kaempferol and peonidin are examples of flavonoids that have been in the news recently.

4.Carotenoids (Orange/Yellow, Red)
A fat-soluble group of more than 600 individual chemicals, the carotenoids (e.g., beta-carotene, lycopene, lutein and zeaxanthin “zee-a-zan-thin”) are especially powerful antioxidants. Due to their chemical structure, they are an excellent source of electrons that are aggressively sought by oxidative free radicals. A carotenoid molecule donates electrons to a free radical, sacrificing itself in antioxidant defense. Terpenes and xanthophylls are included in this class.

5.Hormones (Brown/Gray)
A growing field of medical research is identifying normal hormones typically described with cell-to-cell messaging roles in the body as having antioxidant functions. Presently only a few hormones have this identified property such as melatonin, estradiol and insulin, but future research will likely unravel similar functions for the dozens of hormones known in human physiology.

6.Minerals (All colors)
Minerals have elements that enable enzyme activity. Selenium, zinc, manganese, magnesium and copper are minerals involved in hundreds of antioxidant roles in the body.

7.Glutathione (Brown/Gray)
Probably the human body’s single most important native antioxidant, glutathione is a water-soluble molecule synthesized from food-derived amino acids. It also depends on lipoic acid (below) for synthesis.

8.Lipid effectors (Orange/Yellow)
Lipoic acid is perhaps the “perfect” antioxidant because it is a small powerful molecule that dissolves readily both in fatty layers of cells and in water – the only antioxidant to do this. Other lipid oriented antioxidants include omega fatty acids, tocopherols (like vitamin E), phytosterols, perillyl alcohol and essential oils such as limonene.

9.Saponins, steroids and stilbenes (Green, BRPB)
Related in this discussion only by their common first letter “s”, this group has established antioxidant functions and includes some well-known chemicals such as resveratrol (a stilbene of red wine and dark grapes), brassinosteroid (the growth regulator of plants) and saponin (the waxy covering on plant leaves).

10.Sulfur-containing chemicals (Green, White)
Including organosulfides, tri and diallyl sulfides and sulforaphane, this group from plants like broccoli and cabbage has been shown to have properties affecting antioxidant enzyme activity, inflammatory mediators and tumor growth.

Proposing an Antioxidant Nomenclature

Just as vitamins have been given a nominal identity (Vitamin A, B, C…etc) so too should we refer to antioxidants. This is a new system not yet formally proposed to any regulatory authority or scientific body. Classification of antioxidants must undergo the scrutiny, revision and adoption by scientists, industry and government to be acceptable for food label use in the public.

Here is the proposed breakdown:

1. Antioxidant C – carotenoids
2. Antioxidant E – enzymes
3. Antioxidant G – glutathione
4. Antioxidant H – hormones
5. Antioxidant L – lipid-associated chemicals
6. Antioxidant M – minerals
7. Antioxidant P – phenolics
8. Antioxidant S – saponins, steroids, stilbenes, sulfurs
9. Antioxidant V – vitamins

Over time, the public must feel these proposed antioxidant classes are informative and practical for understanding antioxidants and choosing preferred foods. Time will tell, but this list gives us a simple working structure to get a handle on naming antioxidants.

Reading
* Heber D. What Color Is Your Diet? HarperCollins, New York, 2001.
* Joseph JA, Nadeau DA, Underwood A. The Color Code, Hyperion, New York, 2002.
* Lee J, Koo N, Min DB. Reactive oxygen species, aging, and antioxidative nutraceuticals. Compreh. Rev. Food Sci. Food Safety 3:21-33, 2004.
Copyright 2006 Berry Health Inc.

1. Introduction In the aerobic environment, the most dangerous by product are the species of reactive oxygen. The role of antioxidants is to detoxify reactive oxygen intermediates (ROI) in the body. Over the past several years, nutritional antioxidants have attracted considerable interest in the popular press as potential treatment for a wide variety of disease states, including cancer and other causes e.g. cancer, chronic inflammatory diseases and aging (Delany L. 1993).

Naturally occurring inhibitors of oxidation in food generally originate from plant-based materials. The active components, namely phenolics and polyphenolics, including tocopherols, are secondary plant metabolites and are first derived from phenylalanine and in certain cases and in some plants from tyrosine. The resultant phenylpropanoids may then undergo further transformation to yield benzoic acid derivatives as well as flavonoids, isoflavons, and other complex polyphenols. Thus, natural food phenolics are present as a complex mixture of compounds that provide a cocktail of many active components present in the free, esterified, glycosylated and bound forms (Shahidi and Naczk, 1995). The potency of preparations is therefore dictated by their chemical structures and governed by the hydrophilic-lipophilic balance (HLB) of the participating molecules in a concentration- and system-dependent manner. Thus, the mode of action of natural antioxidants may involve multiple mechanisms, depending on the source material and possible presence of synergists and antagonists.

*Correspondence to: wasim04101981@yahoo.co.in  

In order to use any antioxidant preparation in food, it must be safe, easy to incorporate, effective at low concentrations, with no undesirable odour, flavour or colour, heat stable, nonvolatile and with good carry through properties and cost-effective. In addition, presence and possible effects of antagonists must be carefully considered, as an antioxidant may become a prooxidant in the presence of certain other molecules. As an example, chlorophylls may overwhelm the antioxidant effect of phenolics due to photosensitized oxidation and transition metal ions such as those of iron and copper may render conditions that favour oxidation. Synergism among different phenolic antioxidants and between phenolics and non-phenolics should be considered in all application areas. Definition

Free radicals are atoms or groups of atoms with an odd (unpaired) number of electrons and can be formed when oxygen interacts with certain molecules. Once formed these highly reactive radicals can start a chain reaction. Their chief danger comes from the damage they can do when they react with important cellular components such as DNA, or the cell membrane. Cells may function poorly or die if this occurs. To prevent free radical the body has a defence system of antioxidants.  

An antioxidant is a substance that when present in low concentrations relative to the oxidizable substrate significantly delays or reduces oxidation of the substrate (Halliwell, 1995).

Antioxidants get their name because they combat oxidation. They are substances that protect other chemicals of the body from damaging oxidation reactions by reacting with free radicals and other reactive oxygen species within the body, hence hindering the process of oxidation. During this reaction the antioxidant sacrifices itself by becoming oxidized. However, antioxidant supply is not unlimited as one antioxidant molecule can only react with a single free radical. Therefore, there is a constant need to replenish antioxidant resources, whether endogenously or through supplementation.

2. Review of Literature

    Qin Yan Zhu et. al.(2001) studied antioxidant property of oolong tree. Inhibitory effect on FeCl2/ H2O2 – induced damage and the inhibitory effect on erythrocyte hemolysis of an oolonge tea extract (OTE) were evaluated. The OTE was found to have strong  antioxidant activity in all model system. When OTE was separated into fractions according to molecular weight it was found that fraction with higher amount of phenolic compound (with low molecular weight) have strong antioxidative activity.

   Yi Fang Chu and Xianzona Wu (2002) reported that increased consumption of fruits and vegetables containing high levels of phytochemicals have been recommended to prevent chronic diseases related to oxidative stress in human body. 10 common vegetables were selected. The study showed that Red peeper had highest total antioxidant activity followed by Broccoli, Carrot, Spinach, Cabbage, Onion, Potato etc.

   Jie Sun and Yi Fang (2002) reported that consumption of fruit & vegetable associated with reduced risk to Chronic disease due to present of antioxidant. According to them vitamin C is the major antioxidant in fruit.

   Jeong- Chae Lee (2002) assessed an ethanol extract of stem of opuntia to determine the mechanism of its antioxidant activities. The ethanol extract exhibited a concentration dependent inhibition of linoleic acid oxidation.

   Keni Chi Ya na Gimoto et. al. (2002) investigated the antioxidant activity of column chromatographic fractions obtained from brewed coffee to find antioxidant and to assess benefits of coffee drinking. Coffee contain many antioxidant and consumption of antioxidant  rich brewed coffee may inhibit disease caused by oxidative damage.

   Anaberta Cardadose et.al. (2003) showed that fraction extracted with ethyl acetate have antioxidant activity with potent free radical scavenging activity.

   Joon Hee Lee et. al. (2003) reported that Muscadine Grapes and its winary bi product have antioxidant capacity.

   Kizhiyedathu et. al. (2003) reported that extract obtained from sesame cake and oil have free radical scavenging capacity i.e. antioxidant property. 

   K.S. Shivashankara and Seiichiro Isobe (2004) reported that if greenhouse- grown tree ripe ( TR) and mature green ( MG) mangoes (cv. Irwin) were exposed to high electric field treatment before 20 and 30 days of storage at 5O C. MG fruits were allowed to ripen at room temperature after low- temperature storage and antioxidant capacity were estimated before and after the storage period. Antioxidant capacity of fruits remained unchanged up to 20 days of storage period and decreased thereafter.  Antioxidant capacity of fruits was significantly correlated only to ascorbic acids.    

   Joseph O. Kuti et.al. (2004) reported that total phenolics and antioxidant capacity were higher in raw that in cooked leaf extracts. Cooking reduced antioxidant activity. The results of their study indicate that tree spinach leaves are a rich source of natural antioxidants.

   Mahinda Wella singh and Kirk Parkin (2004) studied a broad range of antioxidant activities in crude extract of beet root tissues. Betalain pigment have been shown to posses various antioxidant function. 

3. Classification of  antioxidants Table 1. Classification of antioxidants based on their  roles

Enzymes

Antioxidant

Role

Remarks

Superoxide dismutase (SOD)

Mitochondrial

Cytoplasmic

Extracellular

Dismutates O2· to H2O2

Contains Manganese (Mn.SOD)

Contains Copper & Zinc (CuZnSOD)

Contains Copper (CuSOD)

Catalase

Dismutates H2O2 to H2O

Tetrameric hemoprotein present in peroxisomes

Glutathione peroxidase (GSH.Px)

Removes H2O2 and lipid peroxides

Selenoproteins (contains Se2+)

Primarily in the cytosol also mitochondria

Uses GSH

Vitamins

Alpha tocopherol

Breaks lipid peroxidation

Lipid peroxide and O2· and ·OH scavenger

Fat soluble vitamin

Beta carotene

Scavenges ·OH, O2·and peroxy radicals

Prevents oxidation of vitamin A

Binds to transition metals

Fat soluble vitamin

Ascorbic acid

Directly scavenges O2·, ·OH, and H2O2

Neutralizes oxidants from stimulated neutrophils

Contributes to regeneration of vitamin E

Water soluble vitamin

Table 2.Classification Of antioxidants based on their sources

Source Material

Example

Antioxidant

Vegetable Oils

Soybean oil

Tocopherols

Tropical Oils

Palm oil

Tocotrienols

Plant Oils

Palm oil

Carotenoids

Herbs and Spices

Rosemary and Sage

Complex phenolics

Cereals

Wheat and buckwheat

Flavenoids

Legumes

Soybean

Isoflavones

Oil Seeds

Canola and Mustard

Phenolic acids & Phenylpropanoids

Teas

Green Tea

Catechins and Polyphenols

Fruit skin and seeds

Grape seed and skin

Polyphenols and Tannins

  4. Antioxidant chemistry of some vitamins              4.1 Alpha tocopherol (vitamin E)                   Vitamin E -2D structure – C26H44O2 4.1.1  Nomenclature It is the major lipid soluble antioxidant found in cells. The name originated in the early 1920s when vegetable oil was discovered to restore fertility in rats. This unknown substance was designated vitamin E by Sure in 1924.The term tocopherol was first used by Evans. Because this compound permitted an animal to have offspring, he named it tocopherol from the Greek word tokos, meaning childbirth, and added the verb phero, meaning to bring forth. To indicate the alcohol nature of the molecule, ol was added to the ending.

Vitamin E is a generic term that includes all entities that exhibit the biological activity of natural vitamin E, d-alpha-tocopherol. In nature, eight substances have been found to have vitamin E activity: d-alpha-, d-beta-, d-gamma- and d-delta-tocopherol (which differ in methylation site and side-chain saturation (Kellof et al. 1996); and d-alpha-, d-beta-, d-gamma- and d-delta-tocotrienol. Also, the acetate and succinate derivatives of the natural tocopherols have vitamin E activity, as do synthetic tocopherols and their acetate and succinate derivatives.

Of all these, d-alpha-tocopherol has the highest biopotency, and its activity is the standard against which all the others must be compared. It is the predominant isomer in plasma.

4.1.2 Source and Nature

Vitamin E is an essential nutrient that functions as an antioxidant in the human body. It is essential, by definition, because the body cannot manufacture its own vitamin E and thus it must be provided by foods and supplements.

Tocopherols are present in oils, nuts, seeds, wheat germ and grains. Absorption is believed to be associated with intestinal fat absorption. Approximately 40% of the ingested tocopherol is absorbed. Most tocopherols enter the blood via lymph where they are associated with chylomicrons. Vitamin E was shown to be stored in adipose tissue. Phospholipids of the mitochondria & endoplasmic reticulum & plasma membranes possess affinities for alpha tocopherol & the vitamin tends to concentrate in these sites.

4.1.3 Mechanisms of Action

Vitamin E is more appropriately described as an antioxidant than a vitamin. This is because, unlike most vitamins, it does not act as a co-factor for enzymatic reactions.

Also, deficiency of vitamin E does not produce a disease with rapidly developing symptoms such as scurvy or beriberi. Overt symptoms due to vitamin E deficiency occur only in cases involving fat mal absorption syndromes, premature infants and patients on total parenteral nutrition. The effects of inadequate vitamin E intake usually develop over a long time, typically decades, and have been linked to chronic diseases such as cancer and atherosclerosis.

Hence, its main function is to prevent the peroxidation of membrane phospholipids, and avoids cell membrane damage through its antioxidant action. The lipophilic character of tocopherol enables it to locate in the interior of the cell membrane bilayers (Halliway and Getteridge, 1992; Borg, 1993). Tocopherol-OH can transfer a hydrogen atom with a single electron to a free radical, thus removing the radical before it can interact with cell membrane proteins or generate lipid peroxidation. When tocopherol-OH combines with the free radical, it becomes tocopherol-O·, itself a radical. When ascorbic acid is available, tocopherol-O· plus ascorbate (with its available hydrogen) yields semidehydroascorbate (a weak radical) plus tocopherol-OH (Halliway and Gutteridge, 1992). By this process, an aggressive ROI(Reactive Oxygen Intermediate) is eliminated and a weak ROI (dehydroascorbate) is formed, and tocopherol-OH is regenerated. Despite this complex defence system, there are no known endogenous enzymatic antioxidant systems for the hydroxyl radical.

Vitamin E also stimulates the immune response. Some studies have shown lower incidence of infections when vitamin E levels are high, and vitamin E may inhibit cancer initiation through enhanced immunocompetence.

Vitamin E also has a direct chemical function. It inhibits the conversion of nitrites in smoked, pickled and cured foods to nitrosamines in the stomach. Nitrosamines are strong tumour promoters.

Alpha-tocopherol has been shown to be capable of reducing ferric iron to ferrous iron (i.e. to act as a pro-oxidant). Moreover, the ability of alpha-tocopherol to act as a pro-oxidant (reducing agent) or antioxidant depends on whether all of the alpha-tocopherol becomes consumed in the conversion from ferric to ferrous iron or whether, following this interaction, residual alpha-tocopherol is available to scavenge the resultant ROI (Yamamoto and Nike, 1988).

4.1.4 Possible therapeutic effects

Ø Vitamin E decreases the incidence of ischaemic heart disease (Gey et al. 1991).

Ø Decreases the incidence of cataract (Packer, 1991; 1992).

Ø Decreases the incidence of osteoarthritis (Blankenhorn, 1986).

Ø Decreases the incidence of rheumatoid arthritis (Kheir El-dein et al. 1992).

4.2 Ascorbic acid (vitamin C)                      Vitamin C -2D structure C6H8O6 4.2.1 Source and Nature

Ascorbic acid (vitamin C) is a water-soluble, antioxidant present in citrus fruits, potatoes, tomatoes and green leafy vegetables.

Humans are unable to synthesize l-ascorbic acid from d-glucose due to absence of the enzyme L-gulacolactone oxidase (Ensimnger et al.1995). Hence, humans must therefore obtain ascorbic acid from dietary sources.

4.2.2 Mechanism of Action

The chemopreventive action of vitamin C is attributed to two of its functions. It is a water-soluble chain breaking antioxidant (Ishwarial et at 1991). As an antioxidant, it scavenges free radicals and reactive oxygen molecules, which are produced during metabolic pathways of detoxification. It also prevents formation of carcinogens from precursor compounds (Block and Menkes, 1988). The structure of ascorbic acid is reminiscent of glucose, from which it is derived in the majority of mammals.

One important property is its ability to act as a reducing agent (electron donor). Ascorbic acid is a reducing agent with a hydrogen potential of +O.08V, making it capable of reducing such compounds as a molecular oxygen, nitrate and cytochromes a and c. Donation of one electron by ascorbate gives the semi-dehydroascorbate radical (DHA). Ascorbate reacts rapidly with O2·?and even more rapidly with ·OH to give DHA. DHA, itself can act as a source of vitamin C.

Ascorbic acid     +     2O2· +     2H      ®             H2O2              +            DHA

It has also been shown that ascorbate is more potent than a-tocopherol in inhibiting the oxidation of LDL  (Low Density Lipoprotein)  in a cell free system (Jialal et at 1990). Co-incubation of LDL with ascorbate during similar oxidative condition inhibited LDL oxidation and resulted in preservation of the endogenous antioxidant in the LDL particle (Ishwarial et at, 1991). The concentration of ascorbate used to inhibit LDL oxidation (40-60 mm) is well within the normal plasma range (23-85 pm).

Vitamin C also contributes to the regeneration of membrane bound oxidized vitamin E. It will react with the a -tocopheroxyl radical, resulting in the generation of tocopherol in this process itself being oxidized to dehydroascorbic acid (Ward & Peters 1995). Vitamin C supplementation in animals leads to increased plasma and tissue levels of vitamin E.

In vitro studies suggest that the antioxidant properties of ascorbic acid may not increase linearly as ascorbic acid concentrations rise (Frei et al. 1989). Moreover, ascorbic acid alone can act as a “pro-oxidant” or reducing agent to react with copper or iron salts. Ferric iron (Fe3+) formed by the reaction, Fe2+ + H2O2 ® HO + ·OH + Fe3+, is converted by ascorbic acid to ferrous (Fe2+) ion. Ferrous iron is therefore recycled to promote the conversion of more H2O2 to ·OH (Halliway et al. 1992).

4.3 Beta Carotene

Me

2-D Structure of Beta Carotene 4.3.1 Source and Nature

Carotenoids are pigmented micronutrients present in fruits and vegetables.

Carotenoids are precursors of vitamin A and have antioxidant effects. While over 600 carotenoids have been found in the food supply, the most common forms are alpha-carotene, beta-carotene, lycopene, crocetin, canthaxanthin, and fucoxanthin. Beta-carotene is the most widely studied. It is composed of two molecules of vitamin A (retinol) joined together. Dietary beta-carotene is converted to retinol at the level of the intestinal mucosa.

4.3.2 Mechanisms of Action

The antioxidant function of beta-carotene is due to its ability to quench singlet oxygen, scavenge free radicals and protect the cell membrane lipids from the harmful effects of oxidative degradation (Krinsky and Deneke, 1982; Santamaria et al. 1991). The quenching involves a physical reaction in which the energy of the excited oxygen is transferred to the carotenoid, forming an excited state molecule (Krinsky, 1993). Quenching of singlet oxygen is the basis for beta-carotene’s well known therapeutic efficacy in erythropoietic protoporphyria (a photosensitivity disorder) (Matthews-Roth, 1993). The ability of beta-carotene and other carotenoids to quench excited oxygen, however, is limited, because the carotenoid itself can be oxidized during the process (autoxidation). Burton and Ingold (Burton and Ingold, 1984) and others have shown that beta-carotene autoxidation in vitro is dose-dependent and dependent upon oxygen concentrations. At higher concentrations, it may function as a pro-oxidant and can activate proteases.

In addition to singlet oxygen, carotenoids are also thought to quench other oxygen free radicals. It is also suggested that beta carotene might react directly with the peroxyl radical at low oxygen tensions; this may provide some synergism to vitamin E which reacts with peroxyl radicals at higher oxygen tensions (Cotgreave et al. 1988).

Carotenoids also have been reported to have a number of other biologic actions, including immuno-enhancement; inhibition of mutagenesis and transformation; and regression of premalignant lesions

          5. Antioxidant chemistry of some enzymes

This includes superoxide dismutase, catalase, and peroxidases.

 5.1 Superoxide dismutase (SOD) 5.1.1 Source and Nature

SOD is an endogenously produced intracellular enzyme present in essentially every cell in the body.Cellular SOD is actually represented by a group of metalloenzymes with various prosthetic groups.The prevalent enzyme is cupro-zinc (CuZn) SOD, which is a stable dimeric protein (32,000 D). SOD appears in three forms: (1) Cu-Zn SOD in the cytoplasm with two subunits, and (2) Mn-SOD in the mitochondrion (Mayes, 1993; Warner, 1994). A third extracellular SOD recently has been described contains Copper (CuSOD).

                             2O2·      +   2H  +   SOD    ®      H2O2     +      O2

5.1.2 Mechanism of action

SOD is considered fundamental in the process of 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 respective enzymes that interact with superoxide and H2O2 are tightly regulated through a feedback system. Excessive superoxide inhibits glutathione peroxidase and catalase to modulate the equation from H2O2 to H2O (see Fig.5). Likewise, increased H2O2 slowly inactivates CuZn-SOD. Meanwhile, catalases and glutathione peroxidase, by reducing H2O2, conserve SOD; and SOD, by reducing superoxide, conserves catalases and glutathione peroxidase. Through this feedback system, steady low levels of SOD, glutathione peroxidase, and catalase, as well as superoxide and H2O2 are maintained, which keeps the entire system in a fully functioning state (Fridovich, 1993).

SOD also exhibits antioxidant activity by reducing O2·? that would otherwise lead to the reduction of Fe3+ to Fe2+ and thereby promote ·OH formation. When the catalase activity is insufficient to metabolize the H2O2 produced SOD will increase the tissue oxidant activity. Hence, it was found that the antioxidant enzymes function as a tightly balanced system, any disruption of this system would lead to promotion of oxidation .

5.2 The catalase enzyme

This enzyme is a protein enzyme present in most aerobic cells in animal tissues. Catalase is present in all body organs being especially concentrated in the liver & erythrocytes.  The brain, heart, skeletal muscle contains only low amounts.

Catalase and glutathione peroxidase seek out hydrogen peroxide and convert it to water and diatomic oxygen. An increase in the production of SOD without a subsequent elevation of catalase or glutathione peroxidase leads to the accumulation of hydrogen peroxide, which gets converted into the hydroxyl radical. Indeed research in the pathogenesis of Down’s syndrome has revealed that the existence of trisomy 21 leads to the overproduction of SOD, the gene for which is located also on chromosome 21. This finding is intriguing in that it reveals the possibility of a genetic link to the increased activity of free radicals. (Krinsky, 1992)

                               2 H2O2 ® 2 H2O + O2          

5.3 Glutathione peroxidase enzyme

The glutathione redox cycle is a central mechanism for reduction of intracellular hydroperoxides.

5.3.1 Source and Nature

It is a tetrameric protein 85,000-D. it has 4 atoms of selenium (Se) bound as seleno-cysteine moieties that confers the catalytic activity. One of the essential requirements is glutathione as a cosubstrate.

Glutathione peroxidase reduces H2O2 to H2O by oxidizing glutathione (GSH) (Equation A). Rereduction of the oxidized form of glutathione (GSSG) is then catalysed by glutathione reductase (Equation B). These enzymes also require trace metal cofactors for maximal efficiency, including selenium for glutathione peroxidase; copper, zinc, or manganese for SOD; and iron for catalase (Halliwell, 1995).

H2O2 + 2 GSH ® GSSG + 2 H2O (equation A)

GSSG + NADPH + H+ ® 2 GSH + NADP+ (equation B)

6. Mode of action of antioxidants

There are four routes:

1.Chain breaking reactions, e.g. alpha-tocopherol which acts in lipid phase to trap “ROD” radical.

2.Reducing the concentration of reactive oxygen species e.g. glutathione.

3.Scavenging initiating radicals e.g. superoxide dismutase which acts in aqueous phase to trap superoxide free radicals.

4.Chelating the transition metal catalysts: A group of compounds serves an antioxidant function by sequestration of transition metals that are well-established pro-oxidants. In this way, transferrin, lactoferrin, and ferritin function to keep iron induced oxidant stress in check and ceruloplasmin and albumin as copper sequestrants.

7. Antioxidant System in our body

The body has developed several endogenous antioxidant systems to deal with the production of ROI. These systems can be divided into enzymatic and nonenzymatic groups.

The enzymatic antioxidants include superoxide dismutase (SOD), which catalyses the conversion of O2·? to H2O2 and H2O; catalase, which then converts H2O2 to H2O and O2; and glutathione peroxidase, which reduces H2O2 to H2O.

The nonenzymatic antioxidants include the lipid-soluble vitamins, vitamin E and vitamin A or provitamin A (beta-carotene), and the water-soluble vitamin C and GSH. Vitamin E has been described as the major chain-breaking antioxidant in humans (Packer, 1992). Because of its lipid solubility, vitamin E is located within cell membranes, where it interrupts lipid peroxidation and may play a role in modulating intracellular signalling pathways that rely on ROI (Kagan et al. 1990; Azzi et al. 1993). Vitamin E can also directly quench ROI, including O2·, ·OH, and (Algayer et al. 1992) O2.

8. Commercial Sources of Natural Antioxidants

The most common natural antioxidant preparations in the market are mixed tocopherols, which are by-products of vegetable oil refining. In addition, spices or their oleoresins and extracts, such as those of rosemary and sage, green tea extracts, other plant-based mixtures, such as those of mustard and certain unsaponifiables of edible oils, and, of course, carotenoids are also important (Table 2) ( Ho et al., 1994; Shahidi, 1997).

9. Efficacy of anti oxidants in different systems

The chemical composition and structures of active extract components are important factors governing the efficacy of natural antioxidants in different foods. Thus, phenolic compounds with ortho- and para- dihydroxylation or a hydroxy and a methoxy group are more effective than simple phenolics. In addition, phenylpropanoids with extended conjugation are more effective than benzoic acid derivatives. Furthermore, hydrophilicity and lipophilicity of the active components is dictated by the appropriateness of antioxidants in systems. In general, more hydrophilic antioxidants are better in stabilizing bulk oil than oil-in-water emulsions while the activity of lipophilic antioxidants follows the opposite trend. There are also many other factors that must be taken into account when considering and selecting antioxidants and extracts for food application. Specifically, attention should be paid to the photosensitizing effect of chlorophylls in natural extracts. In addition, the level of incorporation of antioxidants in foods should be optimized and the use of chelating agents considered, when and where appropriate. Many antioxidants behave prooxidatively at high concentrations or when present together with ions of transition metals; such effects are also important when considering the in-vivo activity of antioxidants ( Shahidi and Ho, 2000). Some chelators, such as polyphosphates, in addition to metal sequestration, may also exert other beneficial effects such as to improve the cooking yield and juiciness of meat and poultry products or keeping quality of fresh seafoods. The role of natural antioxidants in foods is expected to rise over the years to come.

10. Summary

Antioxidant are molecules that can safely interact with the free radicals and terminate the chain reactions before the vital molecules are damaged.Although there are several enzyme system and vitamins that scavenges free radicals the principle antioxidant in the body are Vitamin E, Vitamin C,beta carotene, catalase enzyme, super oxide dismutase enzyme,glutathion peroxidase enzyme etc.Vitamin E ,a lipid soluble antioxidant prevent peroxidation of phospholipid.Vitamin C is a water soluble chain breaking antioxidant. Beta carotene  protect cell membrane lipid from harmful effect of antioxidant damage.Catalase ,glutathion peroxidase ,super oxide dismutase  etc. enzyme systems also prevent our body oxidative damage by free radicals.

11. 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.Although  there is a little doubt that antioxidant are necessary component for good health , no one knows if supplements should be taken or not and if so how much is optimum.Though antioxidant supplement were thought to be harmless but as we are becoming more aware of this chemicals we come to know that antioxidant may be harmful for our body in some cases.In normal concentration vitamin C and beta carotene are antioxidant but at higher concentration they are pro oxidant and thus harmful .Also very little is known about the long term  consequences of megadoses of antioxidant .the body’s finely tuned mechanism are carefully balanced to withstand a variety of insults.Taking chemicals without understanding of all their effect may disrupt this balance. So we should follow the following recommendations. 

1.  It will be helpful for us to follow a balanced training program that emphasizes regular exercise and to eat 5 servings of fruit or vegetables per day. This will ensure that we are developing our inherent antioxidant systems and that our diet is providing the necessary components.

2.  Weekend warriors should strongly consider a more balanced approach to exercise. Failing that, consider supplementation.

3.  For extremely demanding races (such as an ultra distance event ), or when adapting to high altitude, it will be helpful to take a vitamin E supplement @ 100 to 200 IU per day for several weeks  up to and following the race.

4.  We should look for upcoming FDA recommendations, but we should be wary of advertising and media hype.

     5.  We should not over supplement. 

12. Future Scope of Research  

Antioxidant are necessary for our health but we do not know the exact dose and the way how to supplement it. So further research are required to know more about antioxidant. There are so many flora and fauna in our environment which may contain antioxidant  chemicals. So there is a huge scope to conduct research work in this interesting topic to know

1)    How much antioxidant supplementation is required.

2)    Natural sources of different antioxidant.

3)    To discover antioxidant property of different chemicals.

4)  To know whether they have any other pharmacological and toxicological effect.      

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