The Use of Ozone as an Oxidizing Agent to Evaluate Antioxidant Activities of Natural Substrates

Ergothioneine: a potential antioxidative and anti-melanosis agent for food quality preservation

The global population increase has increased the demand for food products. However, post-harvest deterioration due to oxidation and discoloration results in a drastic loss of food quality and supply. Thus, research has focused on developing strategies to minimize such losses. One of those strategies includes the application of ergothioneine (ET), a potent hydrophilic antioxidant, to several food products so as to overcome their short shelf-life. ET can be synthetic or derived from several species of edible mushrooms and their extracts, which are known sources of natural ET. Given the reported potential of ET in food quality preservation, this review compiles the recent applications of ET as a preservative for maintaining the quality of food commodities.

The biology of ergothioneine, an antioxidant nutraceutical

Ergothioneine (ERG) is an unusual thio-histidine betaine amino acid that has potent antioxidant activities. It is synthesised by a variety of microbes, especially fungi (including in mushroom fruiting bodies) and actinobacteria, but is not synthesised by plants and animals who acquire it via the soil and their diet, respectively. Animals have evolved a highly selective transporter for it, known as solute carrier family 22, member 4 (SLC22A4) in humans, signifying its importance, and ERG may even have the status of a vitamin. ERG accumulates differentially in various tissues, according to their expression of SLC22A4, favouring those such as erythrocytes that may be subject to oxidative stress. Mushroom or ERG consumption seems to provide significant prevention against oxidative stress in a large variety of systems. ERG seems to have strong cytoprotective status, and its concentration is lowered in a number of chronic inflammatory diseases. It has been passed as safe by regulatory agencies, and may have value as a nutraceutical and antioxidant more generally.

Pollution and Sun Exposure: A Deleterious Synergy. Mechanisms and Opportunities for Skin Protection

BACKGROUND

Pollutants are diverse chemical entities, including gases such as ozone and particulate matter PM. PM contains toxic chemicals such as polycyclic aromatic hydrocarbons (PAHs). Some PAHs can induce strong oxidative stress under UVA exposure. Pollution aggravates some skin diseases such as atopy or eczema, but epidemiological data also pointed to a correlation with early occurrence of (photo)-aging markers.

OBJECTIVE

This paper aims at reviewing current literature dealing with dermatological effects of pollution, either on in vitro models or using in vivo approaches (including humans). It particularly focuses on the probable deleterious synergy between pollutants and sunlight.

RESULTS

An exhaustive analysis of literature suggests that skin may be impacted by external stress through oxidation of some of its surface components. However, pollutants detected in plasma may also be provided to deep skin by the circulation of the blood. Oxidative stress, inflammation and metabolic impairments are among the most probable mechanisms of pollution- derived dermatological hazards. Moreover these stresses should be amplified by the deleterious synergy between pollution and sunlight. Some experiments from our lab identified few PAHs inducing a huge toxic stress, at nanomolar concentrations, when exposed to long UVA wavelengths. Prevention strategies should thus combine surface protection (long UVA sunscreens, antioxidants) and enhanced skin tissue resistance through stimulation of the natural antioxidation/detoxification pathway Nrf2.

CONCLUSION

In people exposed to highly polluted environments, pollutants and sunlight may synergistically damage skin, requiring a specific protection.

Smog induces oxidative stress and microbiota disruption

Smog is created through the interactions between pollutants in the air, fog, and sunlight. Air pollutants, such as carbon monoxide, heavy metals, nitrogen oxides, ozone, sulfur dioxide, volatile organic vapors, and particulate matters, can induce oxidative stress in human directly or indirectly through the formation of reactive oxygen species. The outermost boundary of human skin and mucous layers are covered by a complex network of human-associated microbes. The relation between these microbial communities and their human host are mostly mutualistic. These microbes not only provide nutrients, vitamins, and protection against other pathogens, they also influence human's physical, immunological, nutritional, and mental developments. Elements in smog can induce oxidative stress to these microbes, leading to community collapse. Disruption of these mutualistic microbiota may introduce unexpected health risks, especially among the newborns and young children. Besides reducing the burning of fossil fuels as the ultimate solution of smog formation, advanced methods by using various physical, chemical, and biological means to reduce sulfur and nitrogen contains in fossil fuels could lower smog formation. Additionally, information on microbiota disruption, based on functional genomics, culturomics, and general ecological principles, should be included in the risk assessment of prolonged smog exposure to the health of human populations.

Gold Nanoprobe-Enabled Three-Dimensional Ozone Imaging by Optical Coherence Tomography

Ozone (O₃) would be harmful to human skin for its strong oxidizing property, especially when stratum corneum or corneal epithelium is wounded. Imaging the penetration and distribution of ozone at depth is beneficial for studying the influence of ozone on skin or eyes. Here, we introduced a facile method for three-dimensional (3D) imaging of the penetration of O₃ into the anterior chamber of an isolated crucian carp eye by using optical coherence tomography (OCT) combined with gold triangular nanoprisms (GTNPs) as the contrast agent and molecular probe. We illustrated the specific response of GTNPs to ozone and demonstrated that GTNPs can function as an efficient nanoprobe for sensing O₃. The stabilities of GTNPs in different biologic solutions, as well as the signal intensity of GTNPs on an OCT imaging system, were investigated. Visualization of 3D penetration and distribution of O₃ in the biologic tissue was proved for the first time. The quantitative analysis of O₃ diffusion in the anterior chamber of the fish eye revealed a penetration depth of 311 μm within 172 min. Due to the strong scattering, near-infrared extinction band, and easy functionalization of GTNPs, they could further serve as nanoprobes for 3D OCT or multimodal imaging of other molecules or ions in the future.

Top 10 botanical ingredients in 2010 anti-aging creams

New developments in the realm of skin rejuvenation such as phytotherapy are at an astounding increasing pace in the cosmeceutical market. Yet, many of these products that are classified as cosmeceuticals are tested less vigorously and do not have to be approved by the Food and Drug Administration to establish efficacy and safety. Thus, as clinicians, we must ask the question, "Is there science-based evidence to validate the mechanism of these new treatments?" We assessed the top anti-aging creams currently on the market specifically evaluating their botanical ingredients. Some of the most common botanicals that are hot off the market are: Rosmarinus officinalis, Vitis vinifera (grape seed extract), Citronellol, Limonene, Oenothera biennis (evening primrose), Glycyrrhiza glabra (licorice extract), Aframomum angustifolium seed extract, Diosgenin (wild yam), N6 furfuryladenine (kinetin), and Ergothioneine. Through researching each of these botanical ingredients, we have concluded that randomized controlled trials are still needed in this area, but there is promise in some of these ingredients and science to validate them.

A comparison of the relative antioxidant potency of L-ergothioneine and idebenone

BACKGROUND

L-ergothioneine (EGT) is a stable antioxidant found in food plants as well as in animal tissue undergoing relatively high levels of oxidative stress. Idebenone is a stable analog of the antioxidant coenzyme Q(10). All are potent antioxidants found in skincare products, but their relative potencies are not well described.

AIMS

To establish the physiological relevance of EGT by examining transcription of the EGT transporter gene OCTN-1 and production of the receptor protein in skin fibroblasts. In addition, to compare the inhibition of lipid peroxide formation by coenzyme Q(10) and EGT. Furthermore, to compare the peroxide-scavenging abilities of EGT and idebenone in both simple solution and in cell cultures exposed to ultraviolet A (UVA).

METHODS

OCTN-1 expression and production in cultured fibroblasts were measured through real-time reverse transcription-PCR and Western blotting, respectively. Alloxan-induced lipid peroxidation in liposomes was used to evaluate the inhibition of lipid peroxide formation. The abilities of EGT and idebenone to directly scavenge hydroxyl radicals produced by H(2)O(2 )were determined. Finally, we irradiated fibroblasts with UVA340 radiation and compared antioxidant capabilities to scavenge free radicals.

RESULTS

We found that OCTN-1 is expressed and readily detectable in cultured human fibroblasts. EGT was more efficient in inhibiting lipid peroxide formation than coenzyme Q(10) or idebenone. Samples treated with EGT had significantly less peroxide than those treated with idebenone 120 min after adding the antioxidants to H(2)O(2). EGT acted significantly quicker and more efficiently in capturing reactive oxygen species (ROS) after UVA340 irradiation.

CONCLUSIONS

EGT is a natural skin antioxidant, as evidenced by the presence of the EGT transporter in fibroblasts. EGT is a more powerful antioxidant than either coenzyme Q(10) or idebenone due to its relatively greater efficiency in directly scavenging free radicals and in protecting cells from UV-induced ROS.

An on-line post-column detection system for the detection of reactive-oxygen-species-producing compounds and antioxidants in mixtures

Reactive oxygen species (ROS) can damage proteins, cause lipid peroxidation, and react with DNA, ultimately resulting in harmful effects. Antioxidants constitute one of the defense systems used to neutralize pro-oxidants. Since pro-oxidants and antioxidants are found ubiquitously in nature, pro-and antioxidant effects of individual compounds and of mixtures receive much attention in scientific research. A major bottleneck in these studies, however, is the identification of the individual pro-oxidants and antioxidants in mixtures. Here, we describe the development and validation of an on-line post-column biochemical detection system for ROS-producing compounds and antioxidants in mixtures. Inclusion of cytochrome P450s and cytochrome P450 reductase also permitted the screening of compounds that need bioactivation to exert their ROS-producing properties. This pro-oxidant and antioxidant detection system was integrated on-line with gradient HPLC. The resulting high-resolution screening technology was able to separate mixtures of ROS-producing compounds and antioxidants, allowing each species to be characterized rapidly and sensitively.

The dual action of ozone on the skin

The aim of this brief review is to summarize the recent literature on the effect of ozone (O3) on cutaneous tissues. Recently it has been reported that a chronic contact with O3 can be deleterious for the skin. Our group and others have shown a progressive depletion of antioxidant content in the stratum corneum and this can then lead to a cascade of effects resulting in an active cellular response in the deeper layers of the skin. Using an in vivo model we have shown an increase of proliferative, adaptive and proinflammatory cutaneous tissue responses. On the other hand the well known activity of O3 as a potent disinfectant and oxygen (O2) donor has been also studied for therapeutic use. Two approaches have been described. The first consists of a quasi-total body exposure in a thermostatically controlled cabin. This treatment has proved to be useful in patients with chronic limb ischaemia. The second approach is based on the topical application of ozonated olive oil in several kinds of skin infection (from soreness to diabetic ulcers, burns, traumatic and surgical wounds, abscesses and skin reactions after radiotherapy). We and other authors have observed a striking cleansing effect with improved oxygenation and enhanced healing of these conditions. It is now clear that, on the skin, O3, like other drugs, poisons and radiation, can display either a damaging effect from a long exposure or a beneficial effect after a brief exposure to O2 and O3 or to the application of ozonated oil to chronic wounds.