Oxidative Chain Reactions Research Articles

Catalysis and autocatalysis of chemical synthesis and of hadronization

We compare the thermodynamics and catalysis of two important exothermic chemical reactions, the homogeneously catalyzed chain reaction of H2 oxidation and the heterogeneously catalyzed ammonia synthesis, with those of an important exothermic physical reaction, namely the proton or neutron synthesis from elementary particles, i.e. quarks or relativistic neutrinos, a process known as hadronization. We show that, surprisingly, hadronization has several similarities both with homogeneous autocatalytic chain reactions, as well as with heterogeneously catalyzed ammonia synthesis. In NH3 synthesis, the presence of electrical charge, namely alkali promoters or protons or electrons on transition metals, enhances the formation of catalytically active intermediate NH species, while in hadronization, free electrons or positrons lower the activation energy and facilitate the formation of catalytically active bosonic e±-neutrino intermediates. These entities liberate highly active neutrinos, creating, via their relativistic mass increase, a strong local gravitational field with all the mass-producing properties of the Higgs field. The main analogies and differences between the electric field effects in chemical catalysis and the electric and gravitational field effects in hadronization catalysis are identified and briefly discussed.

Chemical kinetic model of the chain reaction of atmospheric nitrogen oxidation initiated by electric discharge

To develop an adequate mathematical description of explosion in air observed under the specific conditions of electric discharge initiation, we considered a chemical kinetic model of interaction between two chain reactions: NO oxidation, which provides high concentration of О atoms required for obtaining nitrogen oxide in the processes O + N2(A3Σu+) → O(1S) and O(1S)–N2 + O → NO + NO(B2Π) and nitrogen oxidation, which leads to electronically excited NO2* molecules required for the formation of О atoms in the oxidation of NO. This positive feedback leads to an avalanche-like increase in the concentration of О atoms and the rate of both chain reactions, i.e., causes an explosion in air initiated by electric discharge.

Protective Effects of α-tocopherol on the Activity and Antioxidant Profile of Bovine Spermatozoa Subjected to Ferrous Ascorbate-Induced Oxidative Stress

As spermatozoa are highly vulnerable to oxidative stress development, in vitro antioxidants offer an additional line of defense to the male reproductive system against oxidative insults. α‑tocopherol (α-TOC) is the most abundant form of vitamin E identified in the seminal plasma and spermatozoa membranes, being able to terminate numerous oxidative chain reactions causing substantial damage to biomolecules vital for sperm survival. This study was designed to shed more light on the in vitro effects of α‑tocopherol with respect to the vitality and intracellular antioxidant profile of bovine spermatozoa subjected to ferrous ascorbate-induced oxidative stress. Spermatozoa were washed out from 50 bovine ejaculates, suspended in 2.9 % sodium citrate and subjected to α-TOC treatment (10, 50, 100 and 500 μmol/L) in the presence or absence of ferrous ascorbate (FeAA; 150 μmol/L FeSO4 and 750 μmol/L ascorbic acid) during a 6h in vitro culture. Spermatozoa motion parameters were assessed using the SpermVision™ computer-aided sperm analysis (CASA) system. Cell viability was examined with the metabolic activity (MTT) assay, and the nitroblue-tetrazolium (NBT) test was applied to quantify the intracellular superoxide formation. Cell lysates were prepared at the end of the experiments in order to assess the intracellular activity of superoxide dismutase (SOD), catalase (CAT), as well as glutathione (GSH) and malondialdehyde (MDA) concentrations. Treatment with FeAA reduced both spermatozoa motility parameters (P < 0.001) as well as viability (P < 0.05 with respect to Time 0 h; P < 0.01 in case of Time 2 h and P < 0.001 in relation to Time 6 h), decreased the antioxidant parameters of the samples (P < 0.001 in case of SOD; P < 0.01 with respect to CAT and GSH) but increased the superoxide production (P < 0.01 in case of Time 0h and P < 0.001 with respect to Times 2 h and 6 h) and lipid peroxidation (P < 0.001). α‑TOC administration resulted in a preservation of the spermatozoa motility characteristics (P < 0.001 with respect to 500 μmol/L α-TOC), viability (P < 0.001 in case of 500 μmol/L α-TOC and P < 0.05 with respect to 100 μmol/L α-TOC) and antioxidant profile (P < 0.01 related to the impact of 500 μmol/L α-TOC on the SOD activity; P < 0.05 in relation to CAT; P < 0.01 with respect GSH; 100-500 μmol/L α-TOC), with 500 μmol/L α-TOC being the most effective. Our results suggest that α‑tocopherol possesses significant antioxidant properties that may prevent the deleterious effects caused by free radicals to spermatozoa, and extend the fertilization potential of male reproductive cells.

ВИЗНАЧЕННЯ АНТИОКСИДАНТНОЇ АКТИВНОСТІ ЗАБАРВЛЕНИХ РОСЛИННИХ ЕКСТРАКТІВ IN VITRO

DETERMINATION OF ANTIOXIDANT ACTIVITY IN COLOR PLANT EXTRACTS IN VITRO G.R. Lamazian, I.M. Sytnik, P.A. Chernovol, I.S. Chekman, M.V. Khaitovych Bogomolets National Medical University, Kyiv Introduction. To date, the relationship between free radical oxidation and the development of most pathological processes - endocrinology and cardiovascular diseases is proved. Modern living conditions, the negative impact of environmental factors, emotional stresses, genetic factors - all these are a prerequisite for initiating redox balance disturbances in the body. A key role in this regard belongs to reactive oxygen species (ROS), which cause development of oxidative stress (OS). Recently, the antioxidant properties of medicinal plants (MP) in the prevention and correction of the OS are actively studied. It is commonly known that MP is a source of polyphenolic compounds - powerful natural antioxidants that inhibit free radical oxidation chain reaction through inhibition of oxidative enzymes, the formation of metal chelates or neutralization of radicals. The aim of this work was to study the antioxidant activity (AOA) of Hypericum perforatum (L.) and Citrullus colocynthis (L.) Shrad. extracts on the model of superoxide radical inhibition in vitro. Investigation methods. Determination of AOA was carried out spectrophotometrically according to the change in absorbance of studied extracts in a model test system of adrenaline autoxidation in an alkaline medium at a wavelength of 340 nm. Assessment of AOA was conducted by the degree of inhibition of superoxide radical, taking into account the impact of extracts’ color that absorbs certain wavelength in the visible spectrum. Results and discussion. Investigated extracts show high AOA in a range of all concentrations, preventing the formation of superoxide radical in vitro. It was somewhat higher in H. perforatum versus C. colocynthis. It should be noted that the AOA of extracts depends on their concentration. The highest value of AOA for H. perforatum (95,77%) is detected at a concentration of 0.5 mg/ml. C. colocynthis showed maximum AOA (88.62%) at a concentration of 0,5˟10-3 mg/ml. Values of absorbance after ten minutes exposure indicate that with time the AOA of extracts decreases due to their multi-component composition and interinfluence of biologically active substances, which can be both antagonists and synergists. It is known that the antioxidant effect of MP is achieved due to nonenzymatic molecules represented mainly by polyphenolic compounds – flavonoids, phenolcarbonic acids, catechins, stilbenes etc. Activation of cell protective mechanisms by plants polyphenols significantly reduces the manifestations of the OS. Thus, a number of epidemiological and experimental studies indicate that regular action of natural polyphenols improves the quality of patients’ lives with diabetes, Alzheimer's disease, hypertension, metabolic syndrome. Conclusions. 1. In was established that the plant extracts of H. perforatum (L.) and C. colocynthis (L.) Shrad. possess AOA in a range of all concentrations. 2. Extracts activity depends on the concentration. The highest value of AOA for H. perforatum (95,77%) is detected at a concentration of 0.5 mg/ml and for C. colocynthis (88.62%) - at a concentration of 0,5˟10-3 mg/ml. 3. The decrease in AOA with time (10 minutes exposure) was revealed, which may be due to the interinfluence of biologically active substances in extracts.

EFFECTS OF BIOLOGICAL ACTIVE SUBSTANCES TO THE SPERMATOZOA QUALITY

The aim of this short review is to investigate the effects of biological active substances namely vitamin C and E, Quercetin, Tannic acid, Lycopene, Resveratrol, and Curcumin to viability and cryopreservation of spermatozoa; as well as the sensitivity of spermatozoa to reactive oxygen species and the strategies how to avoid oxidative stress (OS) by using naturally occurring antioxidants mentioned above. The oxidative stress, which has been associated with male infertility and many degenerative diseases, can be reduced by antioxidants via breaking the oxidative chain reactions. Lycopene is one the most highly efficient antioxidant and free radical scavenger and has protective effect on spermatozoa. Trans-Resveratrol also has positive effects on the production of spermatozoa. Consequently, one of the most prominent compounds “curcumin” which has widely been studied for its anti-inflammatory, anti-angiogenic, antioxidant, wound healing and anti-cancer effects; as well as showed energy-promoting and protective effects on the testicular tissue and spermatogenesis.

Explosion in atmospheric air initiated by an electric discharge and associated with the growth of the concentrations of electronically excited species and free charges

Under certain conditions, the plasma of a discharge in atmospheric air exhibits an avalanche-like growth of the electric current and NO(B2Π) emission intensity. The kinetics of the radiation features two stages. In the first of them (preexplosion stage), the gas in the discharge gap emits violet and ultraviolet radiation, after which, 0.03–0.04 s later, the explosion occurs, during which most of the radiation comes from the blue-green region of the spectrum, with its brightness being much higher than in the previous stage. The mechanism of the development of the explosion involves the formation of N(2P) atoms in the chain reaction of oxidation of atmospheric nitrogen. These atoms lead to increase the conductivity of the plasma due to the occurrence of the associative ionization N(2P) + O → NO+ + e−. The growth of the concentration of electrons produces, in turn, an increase in the rate of the formation of metastable nitrogen N2(A3Σu+), which initiate a chain oxidation reaction.

The Chain Reaction of Atmospheric Nitrogen Oxidation, Initiated by an Electric Discharge in Air

The data, concerning to the nitrogen oxidation reaction, initiated by electrical discharge, are reviewed in this article. The reviewed data lead to conclusion that critical concentrations of NO molecules and NO3 radicals can be achieved in course of discharge in air at some special conditions, thereafter avalanche-like rise of reaction velocity is observed. At explosion conditions the oxidation of nitrogen proceeds until full exhaustion of atmospheric oxygen in the reaction zone. Explosion like kinetics of nitrogen oxidation results in high concentration of electronically excited molecules NO(B 2Π), it forms conditions for laser generation in the blue region of the spectrum. The generation of this kind was observed. The proposed mechanism of chain reaction explains all the experimental data.

Tribute to Professor Genady E. Zaikov on the Occasion of his 80thBirthday

“In the first part of his life any scientist is working for his reputation, in the second part his reputation is working for him”. This is a typical sentence one can say about Professor Genady Zaikov, Chief Scientist of the N. M. Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia. On January 7, 2014, Professor Zaikov's 79th birthday, a colleague reminded him that the numeric value 79 is the number of the element gold (Aurum) in the Mendeleev periodic table of elements. The number 80 refers to mercury (Hydrargium), also a very valuable metal, because of its active movement. This is what Professor Zaikov still does, in spite of his excellent reputation, gained over more than 50 years in science. On February 13, 1957, Genady started working at the Institute of Chemical Physics, Academy of Sciences of the USSR. He had the chance to begin his career in the laboratory of Professor Nikolai Markovich Emanuel, a well-known scientist in the field of chemical kinetics. During his first meeting, Emanuel asked him about his areas of expertise, and Genady answered: I know chemical kinetics, I am able to separate isotopes, and I also play the saxophone. Based on this, Emanuel invited him as a researcher to his laboratory, and also asked him to organize a jazz-band, which performed in the institute every weekend. On January 4, 1964, Genady defended his PhD thesis “The comparison of processes of butane oxidation in liquid and gas phases”. Based on these results, a plant was constructed to produce butane oxidation to acetic acid and metylethylketone, with a capacity of 10 thousand tons of acetic acid, at a Moscow oil-processing plant. His Doctor of Science thesis “Role of Media in the Radical Chain Reactions of Oxidation” was defended on April 16, 1968 and on May 20, 1968, he went to Canada (National Research Council of Canada, Ottawa) to work with Professor Keith Usherwood Ingold. After that he worked in the USA, the UK, Japan, and Germany for some time. In 1970, Genady became a Full Professor of Chemistry. Shortly after, his first book with the co-authors N. M. Emanuel and Z. K. Maizus was published in 1973 on the basis of the same research as his Doctor of Science thesis. This book was translated into English and published by Pergamon Press (Oxford, UK). To date, Professor Zaikov (with many co-authors) has published more than 400 monographs and volumes (about 300 in English and about 100 in Russian) and about 4,000 original articles in Russian and in English. All of them are devoted to chemical physics, chemical kinetics, biochemical kinetics, biochemical physics, polymer material science, composites and nanocomposites. One of his fields of expertise was the “degradation and stabilization of polymers”. Professor Zaikov also gained a good reputation in the area of flame retardancy of polymeric materials. During his career, he met many great scientists including Herman F. Mark, Austrian-US-American chemist, considered as one of the major founders of modern polymer physics. Professor Zaikov is still active as a professor at various Russian universities and as chief scientist at the Russian Academy of Sciences, gives many interesting lectures on international conferences, like the “Times of Polymers and Composites” (TOP) conference on the island of Ischia, Italy, 2014 (Figure 1), and will do this definitely also beyond his 80th birthday on January 7, 2015. For this I congratulate him very much and wish him good health for many more years in the field of polymer science.

Conjugated processes of the chemical transformation of sulfur dioxide under the effect of chain gas-phase reactions

The effect sulfur dioxide has on the dynamics of the spontaneous ignition of hydrogen-oxygen mixtures is studied. Additives of SO2 have no negative effect on spontaneous ignition and undergo chemical conversion to form elemental sulfur. The results are analyzed using the theory of branched chain reactions along with data on SO2 conversion under the action of chain reactions of hydrocarbon oxidation and slow hydrogen oxidation. The transformations classified as parallel reactions from the viewpoint of formal kinetics could actually be conjugated radical-chain processes.

Physicochemical, pasting, and functional properties of amaranth seed flours: effects of lipids removal.

The present work was carried out to evaluate physicochemical (composition, hunter color, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis [SDS-PAGE]), pasting, and functional properties (foaming, emulsification, water, and fat absorption capacity) of amaranth full-fat flours from 6 lines/cultivars (AFs), and to see the effects of lipid removal/defatting on these properties. Protein, ash, and lipid content of AFs ranged between 12.5% to 15.2%, 3.0% to 3.5%, and 7.1% to 8.0%, respectively. The flours showed a number of bands between 97 and 7 kDa, with main subunits of approximately 58, 37, 33, 31, 23, and 16 kDa in the SDS-PAGE profiles. The protein content and L* value increased, while b* values decreased following defatting for most of the lines/cultivars. The defatted flours (DAFs) had higher final viscosity and stability (lower breakdown viscosity) as compared to counterpart AFs. The protein profiling of the flours was not affected with the lipid removal/defatting. However, water absorption capacity and foam stability of the flours improved upon defatting. Principal component analysis revealed that pasting temperature was positively related to lipid content, while breakdown viscosity was negatively related to protein content. Foaming properties (capacity and stability) showed negative relationship with lipid content, and positive with protein content, ash content, water, and fat absorption capacity. Amaranth grains are known to have higher amount of proteins and lipids than cereals. Amaranth lipids are rich in unsaturated fatty acids, which are prone to oxidative rancidity. Removal of lipids or defatting of flours may be carried out to enhance product shelf life by preventing undesirable oxidative chain reactions. Therefore, this research was undertaken to see the effects of defatting on the functional properties of amaranth flours. The defatting was a value addition process as it improved the functional properties of the flours.

From Nutraceutics to Materials: Effect of Resveratrol on the Stability of Polylactide

Resveratrol is a naturally occurring polyphenol, well known as a nutritional supplement due to its strong antioxidant properties associated with anti-inflammatory activity and possible prevention of cardiovascular diseases. In this work, the effect of resveratrol on thermal, thermo-oxidative, and photo-oxidative degradation of polylactide is reported in the frame of developing fully biobased polymer formulations. Characterization of PLA films by thermal methods and photo-oxidative treatments demonstrated that resveratrol catalyzed high temperature transesterification reactions under inert atmosphere, whereas it efficiently inhibited the exothermal oxidative reactions of the polymer backbone. Low-temperature photochemical degradation experiments on PLA films allowed elucidating the stabilization mechanisms of the phenolic additive. Resveratrol is capable of slowing the oxidative chain reaction of PLA through a peroxyl radicals scavenging mechanism, while it has little effect on the direct photolytical cleavage of the ester bonds. Moreover, direct resveratrol oxidation as well as the reaction between the phenol and photo-oxidized polymer species yield secondary photoproducts, which are also able to protect PLA against photo-oxidation likely due to the UV screening effect of the formed chromophores. Resveratrol is thus proposed as an eco-friendly and biocompatible additive for a sustainable approach to the stabilization of PLA films in packaging and other applications.

Effect of SO2 on the chain reaction of hydrogen oxidation: Intermittent flames

The effect of SO2 on the chain reaction of hydrogen oxidation in the autoignition region (T = 470–510°C and p < 200 torr) is studied. In the absence of SO2 under flow conditions, the process occurs in a low-temperature flame mode with a characteristic pale blue glow. With the addition of sulfur dioxide, SO2 is transformed to elemental sulfur and a new phenomenon is observed. At a small contact time (less than 4–5 s), the process enters the mode of intermittent flames. Dependences of the rate and intensity of light flashes on pressure, temperature, and contact time are studied. An interpretation of the observed phenomenon is given.

Oxidative stress in carcinogenesis: new synthetic compounds with dual effects upon free radicals and cancer.

DNA mutation is a very important step in carcinogenesis and elevated levels of oxidative DNA damage have been monitored in a variety of tumors. The discovery of the role of free radicals in cancer has led to a new medical approach. Minimizing oxidative damage may be a significant advance in the prevention or treatment of these diseases, since antioxidants are able to stop the free-radical formation and prevent oxidizing chain reactions. These findings have generated great interest in therapeutic antioxidant-based cancer drug development. The design and development of synthetic compounds, able to scavenge free radicals, could present a significant therapeutic advance, in particular for treating pathological conditions such as cancer. This article will outline the state of the research on the relationship between antioxidant therapy and cancer, describing the new synthetic antioxidant molecules that have anticancer activities. Investigations and association between dietary antioxidants, oxidative stress, and cancer will be also discussed.

Release and in vitro skin permeation of polyphenols from cosmetic emulsions

Polyphenols are natural antioxidants, which can inhibit oxidative chain reactions in human skin and prevent therefore some skin diseases and premature ageing. A prerequisite of this behaviour is their permeation through the skin barrier, in particular the stratum corneum (SC). In this study, we investigated the skin permeation kinetic of polyphenols, incorporated to semisolid emulsions, and the release of polyphenols from the emulsions. Mixtures of model substances, consisting of catechin, epigallocatechin gallate (EGCG), resveratrol, quercetin, rutin and protocatechuic acid (PCA), were formulated into o/w emulsions with different oil phase content. The in vitro experiments were carried out in Franz-type diffusion cells by means of ex vivo pig skin and a cellulose membrane. The increased oil content in the emulsion led to a significant decrease in initial release coefficients (K(r)), diffusion coefficients within the formulation (D(v)) and skin permeation coefficients (K(p)), respectively. The study considered the dependence of K(r) on molecular weight and lipophilicity of polyphenolics. For both more hydrophilic and more lipophilic substance groups, the values for K(r) were inverse proportional to molecular weight. For catechin, quercetin, rutin, resveratrol and PCA, a good correlation between K(p) and K(r) parameters was obtained. The most permeable substance was PCA (K(p) = 1.2·10(-3) cm h(-1)), and the least permeable was quercetin (K(p) = 1.5·10(-5) cm h(-1)). All substances could pass the SC barrier and were found mostly in the epidermis and dermis, confirming the potential of polyphenols as anti-ageing active cosmetic ingredients.

Late preterm infants: lung and brain development

Vascular dysfunction in both conduit arteries and small vessels is a major contributor to the development of cardiovascular disease (CVD) in diabetes mellitus (DM). In diabetes there is a process of systemic chronic inflammation accompanied by high oxidative stress causing a subsequent decrease in vascular reactivity and negatively affect the metabolic processes responsible for functioning of the microvasculature. Vitamin E is classified as an antioxidant due to its ability to scavenge lipid radicals and terminate oxidative chain reactions. We conducted a double-blinded cross-over study with vitamin E versus placebo in individuals with type 2 DM and the Hp2-2 genotype and assessed different aspects of peripheral vascular function in these patients. Twenty patients completed the study with 10 individuals in each study cohort. We were able to show significant improvement of indirect indices of vascular function following 8 weeks of treatment with vitamin E. This improvement was consistent for weeks even after stopping the vitamin E treatment. We concluded that a pharmacogenomic rationale utilizing the Hp genotype might potentially provide cardiovascular benefit with vitamin E.

Intensified internal electrolysis for degradation of methylene blue as model compound induced by a novel hybrid material: Multi-walled carbon nanotubes immobilized on zero-valent iron plates (Fe0-CNTs)

This paper reported a novel iron–carbon hybrid material (Fe0-CNTs) as a technical improvement of internal electrolysis for water treatment. This material was fabricated by means of electrophoresis deposition (EPD) to immobilize carbon nanotubes on the surface of zero-valent iron plate and then stabilized by calcinations. The reactivity of Fe0-CNTs was examined by the degradation kinetics of methylene blue (MB) used as model compound. The presence of Fe0-CNTs material in water induced considerable enhancement in reaction rates, which was attributed to the numerous microscopic iron-carbon galvanic cells formed in situ. The oxidative pretreatment of carbon nano-tubes largely facilitated the electrochemical process due to the improvement in surface chemistry. The thickness of CNTs layer was optimized at about 10μm (EPD time of 3min) for a better performance of Fe0-CNTs. The Fenton-like oxidation chain reactions following Reactions (1)–(3) was verified to play the key role on the degradation of target organics. The direction of this pathway has been analyzed to depend on a complex stoichiometrical relation between hydrogen ion (H+) and dissolved oxygen (DO), since side reactions may also take place consuming both of them. This functionalized Fe0-CNTs material working through micro-electrolysis exhibited appreciable advantages in terms of reactivity, durability and operational simplicity. The knowledge gained from the effect of solution environments is of importance for process control.

Silver nanoparticle‐induced mutations and oxidative stress in mouse lymphoma cells

Silver nanoparticles (Ag-NPs) have increasingly been used for coatings on various textiles and certain implants, for the treatment of wounds and burns, as a water disinfectant, and in air-freshener sprays. The wide use of Ag-NPs may have potential human health impacts. In this study, the mutagenicity of 5-nm Ag-NPs was evaluated in the mouse lymphoma assay system, and modes of action were assessed using standard alkaline and enzyme-modified Comet assays and gene expression analysis. Treatments of L5178Y/Tk(+/-) mouse lymphoma cells with 5-nm uncoated Ag-NPs resulted in a significant yield of mutants at doses between 3 and 6 μg/mL; the upper range was limited by toxicity. Loss of heterozygosity analysis of the Tk mutants revealed that treatments with uncoated Ag-NPs induced mainly chromosomal alterations spanning less than 34 megabase pairs on chromosome 11. Although no significant induction of DNA damage in Ag-NP-treated mouse lymphoma cells was observed in the standard Comet assay, the Ag-NP treatments induced a dose-responsive increase in oxidative DNA damage in the enzyme-modified Comet assay in which oxidative lesion-specific endonucleases were added. Gene expression analysis using an oxidative stress and antioxidant defense polymerase chain reaction (PCR) array showed that the expressions of 17 of the 59 genes on the arrays were altered in the cells treated with Ag-NPs. These genes are involved in production of reactive oxygen species, oxidative stress response, antioxidants, oxygen transporters, and DNA repair. These results suggest that 5 nm Ag-NPs are mutagenic in mouse lymphoma cells due to induction of oxidative stress by the Ag-NPs.

ESSENTIAL OIL COMPOSITION ANDIN VITROANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES OFTHYMUS CAPPADOCICUSBOISS.

The present study was conducted to evaluate the phenolic contents, antioxidant and antimicrobial activities of methanol extract (ME), ethanol extract, water extract (WE) and essential oil of Thymus cappadocicus Boiss. The essential oil composition of a hydrodistilled essential oil of T. cappadocicus was analyzed by a gas chromatography/mass spectrometry system. Thymol (70.82%), p-cymene (9.52%), γ-terpinene (9.27%) and carvacrol (4.65%) were found to be the main constituents. Several potential antioxidant activities, including phosphomolybdenum, 2,2-diphenyl-1-picrylhydrazyl radical scavenging and β-carotene bleaching activity, were evaluated. ME was found to be the most active free radical scavenger. In the β-carotene-linoleic acid system, the extracts and essential oil exhibited strong inhibition against linoleic acid oxidation. The essential oil and extracts were also screened for their antimicrobial activity against 15 microorganisms. The results showed that the essential oil of T. cappadocicus had great antimicrobial activity potential against microorganisms tested. In contrast, the WE showed no antimicrobial activity. PRACTICAL APPLICATIONS Thymus species are widely consumed as a spice and tea in Turkish traditional medicine. Recently, there has been considerable interest in the extracts and essential oils of aromatic plants with antimicrobial activities for controlling pathogens and/or toxin producing microorganisms in foods. Antioxidants are compounds that, when added to food products, act as radical scavengers, prevent the radical chain reactions of oxidation, delay or inhibit the oxidation process and increase shelf life by retarding the process of lipid peroxidation. In addition, oxidized polyunsaturated fatty acids may induce the progression of a great number of pathological disturbances. Owing to the strong antimicrobial and excellent protective features that they exhibited in antioxidant activity tests, the extracts and essential oil of T. cappadocicus may be considered as a natural source suitable for use in the food and pharmaceutical industries, in addition to its use in alternative medicine and as a natural therapy.

Skin beautification with oral non-hydrolized versions of carnosine and carcinine: Effective therapeutic management and cosmetic skincare solutions against oxidative glycation and free-radical production as a causal mechanism of diabetic complications and skin aging

Advanced glycation Maillard reaction end products (AGEs) are causing the complications of diabetes and skin aging, primarily via adventitious and cross-linking of proteins. Long-lived proteins such as structural collagen are particularly implicated as pathogenic targets of AGE processes. The formation of α-dicarbonyl compounds represents an important step for cross-linking proteins in the glycation or Maillard reaction. The purpose of this study was to investigate the contribution of glycation coupled to the glycation free-radical oxidation reactions as markers of protein damage in the aging of skin tissue proteins and diabetes. To elucidate the mechanism for the cross-linking reaction, we studied the reaction between a three-carbon α-dicarbonyl compound, methylglyoxal, and amino acids using EPR spectroscopy, a spectrophotometric kinetic assay of superoxide anion production at the site of glycation and a chemiluminescence technique. The transglycating activity, inhibition of transition metal ions peroxidative catalysts, resistance to hydrolysis of carnosine mimetic peptide-based compounds with carnosinase and the protective effects of carnosine, carcinine and related compounds against the oxidative damage of proteins and lipid membranes were assessed in a number of biochemical and model systems. A 4-month randomized, double-blind, controlled study was undertaken including 42 subjects where the oral supplement of non-hydrolized carnosine (Can-C Plus® formulation) was tested against placebo for 3 months followed by a 1-month supplement-free period for both groups to assess lasting effects. Assessment of the age-related skin parameters and oral treatment efficacy measurements included objective skin surface evaluation with Visioscan® VC 98 and visual assessment of skin appearance parameters. The results together confirm that a direct one-electron transfer between a Schiff base methylglyoxal dialkylimine (or its protonated form) and methylglyoxal is responsible for the generation of the cross-linked radical cation and the radical counteranion of methylglyoxal. Under aerobic conditions, molecular oxygen can then accept an electron from the methylglyoxal anion to generate the superoxide radical anion causing the propagation of oxidative stress chain reactions in the presence of transition metal ions. Carnosine stabilized from enzymatic hydrolysis, carcinine and leucyl-histidylhydrazide in patented formulations thereof, demonstrate the Schiff bases' transglycating activities concomitant with glycation site specific antioxidant activities and protection of proprietary antioxidant enzymes in the skin during aging and with diabetes lesions. During oral supplementation with stabilized from enzymatic hydrolysis carnosine (Can-C Plus® formulation), the skin parameters investigated showed a continuous and significant improvement in the active group during the 3 months of supplementation as compared to placebo. Visual investigation showed improvement of the overall skin appearance and a reduction of fine lines. No treatment-related side effects were reported. The finding that already-formed AGE cross-links can be pharmacologically severed and attendant pathology thereby reversed by non-hydrolized carnosine or carcinine in patented oral formulations thereof has broad implications for the skin beautification and therapeutics of the complications of diabetes and skin diseases associated with aging.

MAXIMIZING ANTIOXIDANTS IN FRUITS

Fruits contain high levels of antioxidant compounds, such as carotenoids, flavonoids, vitamins and phenols. These antioxidants are capable of performing a number of functions including free radical scavengers, peroxide decomposers, singlet and triplet oxygen quenchers, enzyme inhibitors, and synergists. Antioxidants can also delay or prevent the oxidation of lipids or other molecules by inhibiting the initiation or propagation of oxidizing chain reactions. Preharvest conditions such as climate, temperature, light intensity, soil type, compost mulching, fertilization, increasing carbon dioxide concentration in the atmosphere, and application of naturally occurring compounds, all can affect the antioxidant content and antioxidant activity of the harvested fruits. Other factors affecting antioxidant activities including crop genotype variation and maturity, culture practices, postharvest handling and storage are also discussed. Methods to maximize antioxidants in fruits such as improving selection criteria among different horticultural cultivars, improving preharvest conditions and postharvest handling are presented.