The yellow sphere is the redox | 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.

Thus, the function of antioxidant systems is not to remove oxidants entirely, but instead to keep them at an optimum level.

Selenium and zinc are commonly referred to as antioxidant nutrients, but these chemical elements have no antioxidant action themselves and are instead required for the activity of some antioxidant enzymes, as is discussed below.

Oregano is high in antioxidant activity, due to a high content of phenolic acids and flavonoids.

The most common non-ribosomal peptide is glutathione, which is a component of the antioxidant defenses of most aerobic organisms.

Dr Silvano Gallus, of the Mario Negri Institute for Pharmaceutical Research in Milan, attributed it to lycopene, an antioxidant chemical in tomatoes, which is thought to offer some protection against cancer.

Selenium is a component of the antioxidant enzymes glutathione peroxidase and thioredoxin reductase ( which indirectly reduce certain oxidized molecules in animals and some plants ).

Sulfur is an important part of many enzymes and in antioxidant molecules like glutathione and thioredoxin.

Consumption of tea ( especially green ) is beneficial to health and longevity given its antioxidant, flavanols, flavonoids, polyphenols, and catechins content.

However, C. botulinum tolerates traces of oxygen due to the enzyme superoxide dismutase ( SOD ) which is an important antioxidant defense in nearly all cells exposed to oxygen.

Orange juice is also a source of the antioxidant hesperidin.

However, there is no physiological evidence established to date that berry polyphenols have actual antioxidant value within the human body, and it remains invalid to claim polyphenols have antioxidant health value on product labels in the United States and Europe.

Smoke is an antimicrobial and antioxidant, but smoke alone is insufficient for preserving food in practice, unless combined with another preservation method.

For oily fish smoking is especially useful, as its antioxidant properties delay surface fat rancidification.

It is known for being extremely rich in vitamin C, almost as much as camu camu, although it also contains vitamins A, B1, B2 and B3 as well as carotenoids and bioflavonoids which provide important nutritive value and have antioxidant uses.

It is a fat-soluble antioxidant that stops the production of reactive oxygen species formed when fat undergoes oxidation.

It's also been suggested that the most important function of vitamin E is in cell signaling ( and, that it may not have a significant role in antioxidant metabolism ).

Vitamin E is widely used as an inexpensive antioxidant in cosmetics and foods.

It is often claimed that " Green " rooibos ( see above ) has a higher antioxidant capacity than fully oxidized rooibos.

The same sign is also seen in other diseases of lobsters and appears to be a nonspecific stress response, possibly relating to the antioxidant and immunostimulatory properties of the astaxanthin molecule.

Ascorbic acid, for example, can lose an electron to a free radical and remain stable itself by passing its unstable electron around the antioxidant molecule.

These can react with vital proteins in the eye that, if damaged, precipitate out, causing cataracts .< ref > This finding is contradicted by the results of another recent study, which found that St John's wort inhibits free radical production in both cell-free and human vascular tissue, revealing antioxidant properties of the compound.

A lack of melatonin could significantly contribute to gallbladder stones, as melatonin inhibits cholesterol secretion from the gallbladder, enhances the conversion of cholesterol to bile, and is an antioxidant, which is able to reduce oxidative stress to the gallbladder.

2 cups / day ) significantly reduced lipid oxidation and increased plasma antioxidant capacity in women with metabolic syndrome.

Preservative food additives can be antimicrobial ; which inhibit the growth of bacteria or fungi, including mold, or antioxidant ; such as oxygen absorbers, which inhibit the oxidation of food constituents.

Due both to its antioxidant activity and its common use to season lamb in Indian cuisine, it has been studied as an additive to radiation-processed lamb meat, and was found effective in delaying oxidation of fats and reducing formation of harmful substances, which can be detected using thiobarbituric acid as a reagent.

A 2010 Italian study that genotyped patients diagnosed with MCS, with suspected MCS, and healthy controls suggested inhibition of expression and activity of metabolizing and antioxidant enzymes in MCS, accelerated lipid oxidation, increased nitric oxide production and glutathione depletion and increased plasma inflammatory cytokines.

Thiyl intermediates also are produced by the oxidation of glutathione, an antioxidant in biology.

The antioxidant indicaxanthin, found in beets, in a spectrophotometric study showed that indicaxanthin can be reduce perferryl-Hb generated in solution from met-Hb and hydrogen peroxide, more effectively than either Trolox or Vitamin C. Collectively, results demonstrate that indicaxanthin can be incorporated into the redox machinery of β-thalassemic RBC and defend the cell from oxidation, possibly interfering with perferryl-Hb, a reactive intermediate in the hydroperoxide-dependent Hb degradation.

The action of one antioxidant may therefore depend on the proper function of other members of the antioxidant system.

All other carotenoids, including lycopene, have no beta-ring and thus no vitamin A activity ( although they may have antioxidant activity and thus biological activity in other ways ).

Most herbs and spices have substantial antioxidant activity, owing primarily to phenolic compounds, especially flavonoids, which influence nutrition through many pathways, including affecting the absorption of other nutrients.

Animal studies and in vitro research has identified possible anti-inflammatory and hepatoprotective activities which may be due to the antioxidant effects of flavonoids or other phenolic compounds and saponins the plant contains .< ref name = halr > Xiong et al.

In mango fruit pulp, the antioxidant vitamins A and C, Vitamin B < sub > 6 </ sub > ( pyridoxine ), folate, other B vitamins and essential nutrients, such as potassium, copper and amino acids, are present.

However, one study, using two different ways of measuring antioxidant activity, found conflicting data, with green rooibos showing more activity under one measure, and less activity using the other.

On the other hand, eating fresh fruits and vegetables that contain antioxidant vitamins ( such as A and C ) appears to lower the risk of stomach cancer.

Melatonin works with other antioxidants to improve the overall effectiveness from each antioxidant.

A range of mental and physical benefits are reported in these studies, including reduced levels of stress ( reduced cortisol — the " stress " hormone ), improved immune system, relief from anxiety & depression ( mild, moderate & severe ), increased antioxidant protection, and enhanced brain function ( increased mental focus, calmness and recovery from stressful stimuli ), among other findings.

Although it has many additional functions, thioredoxin reductase restores vitamin C and E as well as a number of other important antioxidant molecules back into their reduced forms, enabling them to counteract oxidative damage within body cells.

~ 2450 ),— a possible radical-scavenging antioxidant — on the other hand, with its 6 ellagic acid-type components and two additional monomeric phenolics, for a total of 14 gallic acid units ( and all of their substituent phenolic hydroxyl groups ), meets the criteria of both definitions.

There is, however, peer-reviewed research suggesting that S. regelii extracts have in vitro antioxidant properties, like many other herbs.

* Lecithin can also be used as a release agent for plastics, an antisludge additive in motor lubricants, an antigumming agent in gasoline, and an emulsifier, spreading agent, and antioxidant in textile, rubber and other industries.

However, the value of in vitro analysis of antioxidant strength is in question, as there is no current evidence that antioxidant phytochemicals present in XANGO or other fruit juices actually have functions inside the human body.

" Furthermore, there is increasing scientific understanding that xanthones or other polyphenols from plant foods do not serve antioxidant roles in the human body.

There was no statistically significant increase in brachial flow-mediated vasodilation or a significant change in other biomarkers of inflammation, lipid peroxidation, or antioxidant capacity.

Super Size Me also alleged inclusion of chemicals such as tertiary butylhydroquinone ( a phenolic antioxidant used as a chemical preservative ), polydimethylsiloxane ( an anti-foaming agent ), and other ingredients not used by a typical home cook.

Bausch & Lomb was a collaborator in the study and provides vitamins pre-packaged with this formulation, sold commercially as Ocuvite PreserVision antioxidant vitamin and mineral supplement, as do other suppliers, for example, Viteyes AREDS formula eye vitamins.

Along with other Annona species, Annona cherimola has been shown to possess antioxidant activity in its flesh and skin components

A recent randomized, double-blind, placebo-controlled crossover trial with 50 adults with coronary disease or ≥ 1 cardiac risk factors treated with muscadine grape seed supplementation concluded that: " Four weeks of muscadine grape seed supplementation in subjects with increased cardiovascular risk did not produce a statistically significant increase in brachial flow-mediated vasodilation or a significant change in other biomarkers of inflammation, lipid peroxidation, or antioxidant capacity.