OXIS - antioxidant, Ergothioneine,& l-ergothioneine

OXIS International

OXIS International, Inc. is engaged in the research, development and sale of products that counteract the harmful effects of “oxidative stress.”

Product Focus

Their products include therapeutic nutraceutical products, cosmeceutical products and proprietary formulations and clinical products that are developed internally and/or out-licensed to biotech and pharmaceutical companies as drug candidates.

They focus on naturally occurring protective substances since they are more likely to be both safe and efficacious. Our primary products incorporate and emphasize the multifaceted “super antioxidant” compound, L- Ergothioneine (“ERGO”), as a key component. We own several patents and pending applications related to ERGO that cover current and planned products relevant to our nutraceutical and cosmecuetical businesses. Our patents and patent applications address ERGO’s protective effects and activities and the ERGO manufacturing process.

An antioxidant is a molecule capable of inhibiting 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. In turn, these radicals can start chain reactions that damage cells. Antioxidants terminate these chain reactions by removing free radical intermediates, and inhibit other oxidation reactions. They do this by being oxidized themselves, so antioxidants are often reducing agents such as thiols, ascorbic acid 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. Low levels of antioxidants, or inhibition of the antioxidant enzymes, cause 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 widely used as ingredients in dietary supplements in the hope of maintaining health and preventing diseases such as cancer and coronary heart disease. Although initial studies suggested that antioxidant supplements might promote health, later large clinical trials did not detect any benefit and suggested instead that excess supplementation may be harmful. In addition to these uses of natural antioxidants in medicine, these compounds have many industrial uses, such as preservatives in food and cosmetics and preventing the degradation of rubber and gasoline.

Overview

Antioxidants are classified into two broad divisions, depending on whether they are soluble in water (hydrophilic) or in lipids (hydrophobic). In general, water-soluble antioxidants react with oxidants in the cell cytosol and the blood plasma, while lipid-soluble antioxidants protect cell membranes from lipid peroxidation. These compounds may be synthesized in the body or obtained from the diet. The different antioxidants are present at a wide range of concentrations in body fluids and tissues, with some such as glutathione or ubiquinone mostly present within cells, while others such as uric acid are more evenly distributed (see table below). Some antioxidants are only found in a few organisms and these compounds can be important in pathogens and can be virulence factors.

The relative importance and interactions between these different antioxidants is a very complex question, with the various metabolites and enzyme systems having synergistic and interdependent effects on one another. The action of one antioxidant may therefore depend on the proper function of other members of the antioxidant system. The amount of protection provided by any one antioxidant will also depend on its concentration, its reactivity towards the particular reactive oxygen species being considered, and the status of the antioxidants with which it interacts.

Some compounds contribute to antioxidant defense by chelating transition metals and preventing them from catalyzing the production of free radicals in the cell. Particularly important is the ability to sequester iron, which is the function of iron-binding proteins such as transferrin andferritin. 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.

Antioxidant metabolite	Solubility	Concentration in human serum (μM)	Concentration in liver tissue (μmol/kg)
Ascorbic acid (vitamin C)	Water	50 – 60	260 (human)
Glutathione	Water	4	6,400 (human)
Lipoic acid	Water	0.1 – 0.7	4 – 5 (rat)
Uric acid	Water	200 – 400	1,600 (human)
Carotenes	Lipid	β-carotene: 0.5 – 1 retinol (vitamin A): 1 – 3	5 (human, total carotenoids)
α-Tocopherol (vitamin E)	Lipid	10 – 40	50 (human)
Ubiquinol (coenzyme Q)	Lipid	5	200 (human)

[edit]Uric acid

The antioxidant in highest concentration in human blood is uric acid, which provides about half of the total antioxidant capacity of human serum. Uric acid is an oxypurine produced from xanthine by the enzyme xanthine oxidase, and is a waste product of purine metabolism in primates, birds, and reptiles. An overabundance of this chemical in the body causes gout. The effects of uric acid in conditions such asstroke and heart attacks are still not well understood, with some studies linking higher levels of uric acid with increased mortality. This apparent effect might either be due to uric acid being activated as a defense mechanism against oxidative stress, or uric acid acting as a pro-oxidant and contributing to the damage caused in these diseases.

[edit]Ascorbic acid

Ascorbic acid or "vitamin C" is a monosaccharide oxidation-reduction (redox) catalyst found in both animals and plants. As one of the enzymes needed to make ascorbic acid has been lost by mutation during primate evolution, humans must obtain it from the diet; it is therefore a vitamin. Most other animals are able to produce this compound in their bodies and do not require it in their diets. Ascorbic acid is required for the conversion of the procollagen to collagen by oxidizing proline residues to hydroxyproline. In other cells, it is maintained in its reduced form by reaction with glutathione, which can be catalysed by protein disulfide isomerase and glutaredoxins. Ascorbic acid is redox catalyst which can reduce, and thereby neutralize, reactive oxygen species such as hydrogen peroxide. In addition to its direct antioxidant effects, ascorbic acid is also a substrate for the redox enzyme ascorbate peroxidase, a function that is particularly important in stress resistance in plants. Ascorbic acid is present at high levels in all parts of plants and can reach concentrations of 20 millimolar in chloroplasts.

[edit]Glutathione

The free radical mechanism of lipid peroxidation.

Glutathione is a cysteine-containing peptide found in most forms of aerobic life. It is not required in the diet and is instead synthesized in cells from its constituent amino acids.Glutathione has antioxidant properties since the thiol group in its cysteine moiety is a reducing agent and can be reversibly oxidized and reduced. In cells, glutathione is maintained in the reduced form by the enzyme glutathione reductase and in turn reduces other metabolites and enzyme systems, such as ascorbate in the glutathione-ascorbate cycle, glutathione peroxidasesand glutaredoxins, as well as reacting directly with oxidants. Due to its high concentration and its central role in maintaining the cell's redox state, glutathione is one of the most important cellular antioxidants. In some organisms glutathione is replaced by other thiols, such as bymycothiol in the Actinomycetes, or by trypanothione in the Kinetoplastids.

[edit]Melatonin

Melatonin is a powerful antioxidant that can easily cross cell membranes and the blood-brain barrier. Unlike other antioxidants, melatonin does not undergo redox cycling, which is the ability of a molecule to undergo repeatedreduction and oxidation. Redox cycling may allow other antioxidants (such as vitamin C) to act as pro-oxidants and promote free radical formation. Melatonin, once oxidized, cannot be reduced to its former state because it forms several stable end-products upon reacting with free radicals. Therefore, it has been referred to as a terminal (or suicidal) antioxidant.

[edit]Tocopherols and tocotrienols (vitamin E)

Vitamin E is the collective name for a set of eight related tocopherols and tocotrienols, which are fat-soluble vitamins with antioxidant properties. Of these, α-tocopherol has been most studied as it has the highest bioavailability, with the body preferentially absorbing and metabolising this form.

It has been claimed that the α-tocopherol form is the most important lipid-soluble antioxidant, and that it protects membranes from oxidation by reacting with lipid radicals produced in the lipid peroxidation chain reaction. This removes the free radical intermediates and prevents the propagation reaction from continuing. This reaction produces oxidised α-tocopheroxyl radicals that can be recycled back to the active reduced form through reduction by other antioxidants, such as ascorbate, retinol or ubiquinol. This is in line with findings showing that α-tocopherol, but not water-soluble antioxidants, efficiently protects glutathione peroxidase 4 (GPX4)-deficient cells from cell death. GPx4 is the only known enzyme that efficiently reduces lipid-hydroperoxides within biological membranes.

However, the roles and importance of the various forms of vitamin E are presently unclear, and it has even been suggested that the most important function of α-tocopherol is as a signaling molecule, with this molecule having no significant role in antioxidant metabolism. The functions of the other forms of vitamin E are even less well-understood, although γ-tocopherol is a nucleophile that may react with electrophilic mutagens, and tocotrienols may be important in protecting neurons from damage.

Ergothioneine is a naturally-occurring amino acid and is a thiourea derivative of histidine, containing a sulfur atom in the imidazole ring. This compound is made in rather few organisms, notably Actinobacteria and filamentous fungi. Ergothioneine was discovered in 1909 and named after the ergot fungus from which it was first purified, with its structure being determined later, in 1911. This amino acid has antioxidant properties, but its chemistry differs from conventional sulfur-containing antioxidants such as glutathione or lipoic acid.

Although ergothioneine cannot be made in human cells, it is present in some tissues at high levels as it is absorbed from the diet. In humans ergothioneine is taken up from the gut and concentrated in some tissues by a specific transporter called ETT (gene symbol SLC22A4). However, even today, one hundred years after its discovery, precisely what ergothioneine does in the human body remains a mystery.

Metabolism and sources

Ergothioneine has been found in bacteria, plants and animals, sometimes at millimolar levels. Foods rich in ergothioneine include liver,kidney, black beans, red beans and oat bran, with the highest levels in bolete and oyster mushrooms. Levels can be variable, even within species and some tissues can contain much more than others. In the human body, the largest amounts of ergothioneine are found inerythrocytes, eye lens and semen, and it is also present in the skin.

Although many species contain ergothioneine, only a few can make it, the others absorb it from their diet or, in the case of plants, from their environment. Biosynthesis has been detected in Actinobacteria, such as Mycobacterium smegmatis and filamentous fungi, such asNeurospora crassa. Although the exact metabolic pathway is not clear, it is known that the imidazole ring is supplied by histidine, which is then methylated to produce histidine betaine, and then the sulfur atom incorporated from cysteine. Other species of bacteria, such asBacillus subtilis, Escherichia coli, Proteus vulgaris and Streptococcus, as well as fungi belonging to the groups Ascomycetes andDeuteromycetes, cannot make ergothioneine.

[edit]Possible functions

Despite its unusual chemistry, ergothioneine does still have antioxidant properties. It is a good scavenger of hydroxyl radicals andhypochlorous acid, and can inhibit the production of oxidants by metal ions. On the other hand, since these antioxidant properties were measured in simple cell-free systems, their relevance to the actual function of ergothioneine in the body has been questioned. Another possibility is that ergothioneine is important in protecting cells against the nitrosative stress produced by reactive nitrogen species such asnitric oxide. However, it might also be involved in metal ion transport and the regulation of metalloenzymes.

Ergothioneine is transported into human cells by a specific transporter called ETT (gene symbol SLC22A4). Mutants of this transporter are associated with the autoimmune disorders rheumatoid arthritis and Crohn's disease. Surprisingly, these mutant transporters are not impaired and instead can transport ergothioneine more efficiently than the normal forms of these proteins. This may also relate to the fact that higher blood ergothioneine levels have been associated with rheumatoid arthritis. Since the function of ergothioneine in humanmetabolism remains unknown, whether these findings point to a direct role for this amino acid in human disease is unclear.

ERGOTHIONEINE…THE SUPER ANTIOXIDANT FOR NUTRACEUTICAL, COSMECEUTICAL AND THERAPEUTICS

ERGO is naturally occurring, water soluble, amino acid multifaceted antioxidant produced by microbes in the soil and most commonly found in (but not produced by) various species of mushrooms and grapes, meats and dairy products. However, it is not commercially practical to extract ERGO from these natural sources and it essentially impossible to ingest a diet that provides enough ERGO to take full advantage of its potential health benefits. Humans and most animals typically have low levels of ERGO since the amount of ERGO in the diet is relatively small.

INTELLECTUAL PROPERTY AND SCIENCE BACKGROUND

Our intellectual property for ERGO includes three patents and two patent pending applications that cover the synthesis of highly-purified ERGO and the protective effect of ERGO on mitochondria and other pivotal body structures and functions. A number of peer reviewed scientific papers referenced in the Monograph[create link] on this website indicate that ERGO is one of the most potent, multifaceted biological compounds with both appreciable antioxidant, anti-inflammatory, neuroprotective and other protective properties. ERGO acts by itself, or in combination with other natural compounds to improve the body’s own intrinsic defenses against oxidative stress. Accordingly, Oxis is focusing its efforts on developing products that deliver the benefits of ERGO taken by itself and in combination with other elements that enhance various health protective systems.

BENEFITS OF ERGO

Some of the potential benefits of ERGO include its ability to:

• Conserve and maintain the levels of other antioxidants such as Vitamin E, Vitamin C and glutathione;
• Increase respiration and the oxidation of fat (possibly contributing to increased energy and exercise capacity);
• Protect mitochondria from damage (this is important because potentially damaging reactive oxygen species are generated when oxygen is normally metabolized in mitochondria,
• Reduce the damaging effects of environmental ultraviolet radiation (likely to be important in protecting the eyes against cataract producing oxidative injury);
• Neutralize increased oxidative stress by providing an ROS (reactive oxygen species) and RNS (reactive nitrogen species) scavenging capacity, a property that protects key molecules in the body.