Resveratrol and 2-Ethyl-6-Methyl-3-Hydroxypiridine N-Acetyl Cysteinate as Protecting Agents upon the Stress Exposure.

The increased generation of reactive oxygen species (ROS) by mitochondria under stress conditions leads to lipid peroxidation (LPO) as a consequence of the ROS interactions with polyunsaturated fatty acids in the lipid bilayer of cell membranes, causing their damage. It was assumed that chemical preparations that reduce the excessive ROS generation by mitochondria should exhibit protecting properties under oxidative-stress conditions. In this context, the antioxidants resveratrol (RSV) and 2-ethyl-6-methyl-3-hydroxypyridine N-acetylcysteinate (NAC-3-HP) were examined as potential chemical protectors upon the exposure to stress, able to maintain the functional state of mitochondria.

Chemical, Biological and Biomedical Aspects of Bioantioxidants.

Bioantioxidants are biologically important antioxidants, a heterogeneous variety of molecules, which are difficult to classify using commonly shared structural features [...].

Kinetic Intricacies of the Light Emission and Antiradical Influence of Exogenous Bioantioxidants Transformation Products in the Chemiluminescence Bioantioxidant Assay.

The subject matter of the reported work refers to studying the interactions followed by the excited-state generation, which are chemical models of oxidative processes leading to a weak light emission emerging from living cells, and to explore the possibilities of using them as tools for evaluating the activity of oxygen-metabolism modulators, most prominently, natural bioantioxidants of biomedical value in particular. Methodologically, major attention is paid to analyzing the shapes of the time profiles of the light emission derived from a model sensory system in the presence of lipid samples of vegetable and animal (fish) origin rich in bioantioxidants. As a result, a modified reaction mechanism involving 12 elementary steps is proposed to rationalize the light-emission kinetics in the presence of natural bioantioxidants. We conclude that free radicals formed from bioantioxidants and their dimerization products contribute significantly to the general antiradical activity of lipid samples, which should be taken into account in developing efficient bioantioxidant assays for biomedical applications and while establishing the mechanisms of bioantioxidant effects on metabolic processes in vivo.

Influence of Nicotine from Diverse Delivery Tools on the Autonomic Nervous and Hormonal Systems.

BACKGROUND: Through measurements of the heart rate variability (HRV) accompanied by the pertinent biomarker assays, the effects of nicotine and byproducts derived from alternative nicotine delivery systems (ANDS) on the autonomic nervous system (ANS) and hormonal system have been investigated. METHODS: HRV was studied in a group of volunteers (17 people), involving non-smokers, i.e., who never smoked before (11), ex-smokers (4) and active smokers (2). ANDS and smoking simulators, including regular, nicotine-free and electronic cigarettes; tobacco heating systems; chewing gums and nicotine packs of oral fixation (nic-packs), were used. Blood pressure, levels of stress hormones in saliva and catecholamines in the blood were also monitored. RESULTS: HRV analysis showed relatively small changes in HRV and in the other studied parameters with the systemic use of nic-packs with low and moderate nicotine contents (up to 6 mg) compared to other ANDS. CONCLUSIONS: The HRV method is proven to be a promising technique for evaluation of the risks associated with smoking, dual use of various ANDS and studying the biomedical aspects of smoking cessation. Nic-packs are shown to be leaders in biological safety among the studied ANDS. A sharp surge in the activity of the sympathetic division of the ANS within the first minutes of the use of nicotine packs implies that nicotine begins to act already at very low doses (before entering the blood physically in any significant amount) through fast signal transmission to the brain from the nicotinic and taste buds located in the mouth area.

Effect of Humid Air Exposed to IR Radiation on Enzyme Activity.

Water vapor absorbs well in the infra-red region of the electromagnetic spectrum. Absorption of radiant energy by water or water droplets leads to formation of exclusion zone water that possesses peculiar physico-chemical properties. In the course of this study, normally functioning and damaged alkaline phosphatase, horseradish peroxidase and catalase were treated with humid air irradiated with infrared light with a wavelength in the range of 1270 nm and referred to as coherent humidity (CoHu). One-minute long treatment with CoHu helped to partially protect enzymes from heat inactivation, mixed function oxidation, and loss of activity due to partial unfolding. Authors suggest that a possible mechanism underlying the observed effects involves altering the physicochemical properties of aqueous media while treatment of the objects with CoHu where CoHu acts as an intermediary.

Natural Chain-Breaking Antioxidants and Their Synthetic Analogs as Modulators of Oxidative Stress.

Oxidative stress is associated with the increased production of reactive oxygen species or with a significant decrease in the effectiveness of antioxidant enzymes and nonenzymatic defense. The penetration of oxygen and free radicals in the hydrophobic interior of biological membranes initiates radical disintegration of the hydrocarbon "tails" of the lipids. This process is known as "lipid peroxidation", and the accumulation of the oxidation products as peroxides and the aldehydes and acids derived from them are often used as a measure of oxidative stress levels. In total, 40 phenolic antioxidants were selected for a comparative study and analysis of their chain-breaking antioxidant activity, and thus as modulators of oxidative stress. This included natural and natural-like ortho-methoxy and ortho-hydroxy phenols, nine of them newly synthesized. Applied experimental and theoretical methods (bulk lipid autoxidation, chemiluminescence, in silico methods such as density functional theory (DFT) and quantitative structure-activity relationship ((Q)SAR) modeling) were used to clarify their structure-activity relationship. Kinetics of non-inhibited and inhibited lipid oxidation in close connection with inhibitor transformation under oxidative stress is considered. Special attention has been paid to chemical reactions resulting in the initiation of free radicals, a key stage of oxidative stress. Effects of substituents in the side chains and in the phenolic ring of hydroxylated phenols and biphenols, and the concentration were discussed.

Updating the Chemiluminescence Oxygen-Aftereffect Method for Determining the Rate Constant of the Peroxy-Radical Self-Reaction: Oxidation of Cyclohexene.

Updating the facile chemiluminescence oxygen-aftereffect method, most suitable for determining the rate constant (kt ) of the peroxy-radical self-reaction (main chemiluminescence channel), pertained to considering the sensitivity of such a method toward a disturbing influence of the peroxy radicals of the initiator of the chain oxidation process. Such a disturbance may derive from the side chemiluminescent reaction, which involves peroxy radicals of both hydrocarbon and initiator. To examine the applicability and limitations of the chemiluminescence method under present scrutiny, cyclohexene was used as the model oxidizable hydrocarbon substrate. Computer simulations of the reaction and chemiluminescence kinetics have demonstrated the validity of the considered methodology at the value of the rate constant of the propagation of the overall chain process by peroxy radicals of the initiator higher than 1 m-1 s-1 . Despite that the chemiluminescence time profile and the stationary level of the total chemiluminescence intensity depend on the kinetics of the side chemiluminescence channel and on the ratio of the excited-state generation yields in the mentioned reaction channel and in the main chemiluminescence process, the value of kt assessed by the oxygen-aftereffect method has been found independent of variation of these characteristics.

Chemiluminescence of Cigarette Smoke: Salient Features of the Phenomenon.

The study disclosed herein provides for the first time a detailed experimental support for the general mechanism of the cigarette-smoke-derived chemiluminescence, as an example par excellence of the excited-state generation in a chemically complex aerosol medium. The mechanism involves chemiexcitation in a unimolecular transformation of the smoke-borne free radical species. However, the concentration of these radicals, [r∙], obeys a bimolecular (second-order) kinetics and depends on a particulate-phase content (total particulate matter, TPM) of the cigarette smoke. The decrease in [r∙] with increasing the TPM amount manifests radical-scavenging propensity of the smoke particulate phase. Astonishingly, no energy transfer takes place from the primary excited light-emitting species to luminophoric molecules abundant in the smoke. The reported results build up fundamentals of a facile chemiluminescence assay for free radical properties of the smoke. The experimental approaches developed for this study are of general scope and may be used for mechanistic elucidation of the excited-state generation in chemical systems and environments of an arbitrary complexity.

Stabilizing effects of hydrated fullerenes C60 in a wide range of concentrations on luciferase, alkaline phosphatase, and peroxidase in vitro.

Hydrated fullerene (HyFnC60) is a highly hydrophilic supra-molecular complex consisting of unmodified С60 fullerene molecule enclosed into a hydrated shell. It has been shown in numerous experiments that aqueous solutions of HyFnC60 manifest a wide range of biological activities both in vivo and in vitro even at very low concentrations of HyFnC60. We used a spectrophotometric method and a method of biochemoluminescence to demonstrate that HyFnC60 in concentrations below 10(-9) M down to 10(-23) M stabilizes peroxidase, alkaline phosphatase, and bacterial luciferase against inactivation due to long-term incubation of the enzymes at room temperature and also against heat inactivation. In addition, HyFnC60 was able to "revive" heat inactivated enzymes. These effects cannot be explained by the direct action of the fullerene molecules upon the enzymes. We suggest that the effects of HyFnC60 on the enzymes are related to the ability of hydrated fullerene C60 molecules to organize thick aqueous shells around them. One of the specific properties of water phase in these shells is its ability to optimize redox reactions, which can support enzyme stability against factors deteriorating their structure.

Changes in chemiluminescence of whole blood of COPD patients treated with Hypoxen and effects of C60 fullerenes on blood chemiluminescence.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is an inflammatory disease associated with reactive oxygen species (ROS) production. The aim of this study was to evaluate the effect of Hypoxen treatment and the effect of HyFnC60 on ROS production in patients' blood. MATERIAL/METHODS: ROS production in blood was estimated using chemiluminescence (CL) measurement with CL-amplifiers: luminol (LM), LM + zymosan (ZM) or lucigenin (LC) in the presence or absence of hydrated fullerenes (HyFnC60) added to blood in low concentrations. RESULTS: In all the patients with COPD in remission phase with Hypoxen prescription, the LM-dependent CL (LM-CL) with ZM and LC-enhanced CL (LC-CL) decreased after the treatment. Parameters of CL and effects of HyFnC60 upon them depended on blood state. Addition of HyFnC60 to blood decreased data scattering and helped to improve discrimination between different groups of patients. Using the discriminator analysis, we found the most important time-points in the kinetic curves of CL for classification of patients into groups (eg, COPD patients before and after treatment with Hypoxen; patients' blood with different sensitivity to HyFnC60 concentration). CONCLUSIONS: Monitoring of CL of non-diluted whole blood in COPD patients can be used for the estimation of the Hypoxen efficiency in complex therapy. Addition of HyFnC60 to blood increases sensitivity of the method.