Antioxidant  
The prefix "anti" means against, in opposition to, or corrective in nature. In order to understand antioxidants, it helps to learn what exactly these agents oppose and correct.

Within the human body, millions of processes are occurring at all times. These processes require oxygen. Unfortunately, that same life giving oxygen can create harmful side effects, or oxidant substances, which cause cell damage and lead to chronic disease.

Oxidants, commonly known as "Free radicals," are also introduced through external sources such as exposure to the sun or pollution.

Other mediums include stress, as well as things that people put into their bodies, such as alcoholic beverages, unhealthy foods, and cigarette smoke.

In much the same way as oxidation creates rust, causing a breakdown on the surface of inanimate objects, oxidation inside the body causes a breakdown of cells. Free radicals produced by this breakdown attack healthy cells, usually DNA as well as proteins and fats. This chain of events weakens immunological functions as well as speeding up the aging process, and is also linked to several diseases such as cataracts, various forms of cancer, and heart disease. Some studies indicate possible links to arthritis and several other chronic conditions.

Antioxidants, or anti-oxidation agents, reduce the effect of dangerous oxidants by binding together with these harmful molecules, decreasing their destructive power. Antioxidants can also help repair damage already sustained by cells.

Certain antioxidant enzymes are produced within the body. The most commonly recognized of these naturally occurring antioxidants are Superoxide Dismutase, Catalase, and Glutathione. Superoxide Dismutase changes the structure of oxidants and breaks them down into hydrogen peroxide. Catalase in turn, breaks down hydrogen peroxide into water and tiny oxygen particles or gasses. Glutathione is a detoxifying agent, which binds with different toxins to change their form so that they are able to leave the body as waste.

Other antioxidant agents are found in foods, such as dark green leafy vegetables. Items high in vitamin A, vitamin C, vitamin E, and beta-carotene are believed to be the most beneficial. These nutrients are commonly found in fruits and vegetables, those with the strongest colors being healthiest. Orange and red peppers, tomatoes, spinach, and carrots are examples.

Choosing raw fruits and vegetables rather than cooked, provides the highest concentration and best absorption of antioxidants. Dietary supplements are also available for those that do not consume enough antioxidant-producing foods.
   
An antioxidant is a molecule capable of slowing or preventing the oxidation of other molecules. Oxidation is a chemical reaction that transfers electrons from a substance to an oxidizing agent. Oxidation reactions can produce free radicals, which start chain reactions that damage cells. Antioxidants terminate these chain reactions by removing free radical intermediates, and inhibit other oxidation reactions by being oxidized themselves. As a result, antioxidants are often reducing agents such as thiols or polyphenols.

Although oxidation reactions are crucial for life, they can also be damaging; hence, plants and animals maintain complex systems of multiple types of antioxidants, such as glutathione, vitamin C, and vitamin E as well as enzymes such as catalase, superoxide dismutase and various peroxidases.

 

 
Space-filling model of the antioxidant metabolite glutathione. The yellow sphere is the redox-active sulfur atom that provides antioxidant activity, while the red, blue, white, and dark grey spheres represent oxygen, nitrogen, hydrogen, and carbon atoms, respectively.
 
 
 Low levels of antioxidants, or inhibition of the antioxidant enzymes, causes oxidative stress and may damage or kill cells.
As oxidative stress might be an important part of many human diseases, the use of antioxidants in pharmacology is intensively studied, particularly as treatments for stroke and neurodegenerative diseases. However, it is unknown whether oxidative stress is the cause or the consequence of disease. Antioxidants are also widely used as ingredients in dietary supplements in the hope of maintaining health and preventing diseases such as cancer and coronary heart disease. Although some studies have suggested antioxidant supplements have health benefits, other large clinical trials did not detect any benefit for the formulations tested, and excess supplementation may occasionally be harmful. In addition to these uses in medicine, antioxidants have many industrial uses, such as preservatives in food and cosmetics and preventing the degradation of rubber and gasoline.
   

Free radicals

Free radicals are organic molecules responsible for aging, tissue damage, and possibly some diseases. These molecules are very unstable, therefore they look to bond with other molecules, destroying their vigor and perpetuating the detrimental process. Antioxidants, present in many foods, are molecules that prevent free radicals from harming healthy tissue.    Back

Enzymes

In biology, one of the factors that defines a living thing from an inanimate object is the organism's ability to carry out chemical reactions that are crucial for its survival. Even one-celled organisms are capable of hundreds of chemical reactions within their cell walls. Imagine the infinite amount of reactions that a large organism such as a human carries out. None of these reactions are possible without enzymes.

Enzymes are biological catalysts or assistants. Enzymes consist of various types of proteins that work to drive the chemical reaction required for a specific action or nutrient. Enzymes can either launch a reaction or speed it up. The chemicals that are transformed with the help of enzymes are called substrates. In the absence of enzymes, these chemicals are called reactants.    Back