Oxidative stress and methods used for hydroxyl radical determination

Understanding the role of oxidative stress in brain as well as developing medical strategies to reduce its damaging potential in the aging process and pathogenesis of cancer, neurological diseases like Alzheimer’s diseases and Parkinson’s diseases and other incurable illnesses is an important direction in medicine and biochemistry over the world. This review outlines the processes by which hROS may be formed, their damaging potential and determinations methods. Also, the questions upon the nature of reactive hROS in a Fenton (like) system plays a crucial role will be addressed on this part and several lines of evidences will be presented in order to clarify this issue. Highly reactive hydroxyl radicals (hROS) have been implicated in the etiology of many diseases, therefore monitoring of hROS should be extremely helpful to further investigate and understand the role of hROS in the pathogenesis of neurological disorders and to develop medical strategies to reduce the damaging potential of hROS. The very short half-life of OH• requires the use of trapping agents such as salicylic acid or phenylalanine for detection, but their hydroxylated derivatives are either unstable, or implicated as reactant in biochemical processes. Based on already successfully in vitro and in vivo work done in our group in the past two decades, we decided to use sodium terephthalic acid as a trapping agent, the hydroxylation of which yields only one stable and highly fluorescent isomer, 2-hydroxyterephthalate (OH-TA)

Study of OH• Radicals in Human Serum Blood of Healthy Individuals and Those with Pathological Schizophrenia

The human body is constantly under attack from free radicals that occur as part of normal cell metabolism, and by exposure to environmental factors such as UV light, cigarette smoke, environmental pollutants and gamma radiation. The resulting “Reactive Oxygen Species” (ROS) circulate freely in the body with access to all organs and tissues, which can have serious repercussions throughout the body. The body possesses a number of mechanisms both to control the production of ROS and to cope with free radicals in order to limit or repair damage to tissues. Overproduction of ROS or insufficient defense mechanisms leads to a dangerous disbalance in the organism. Thereby several pathomechanisms implicated in over 100 human diseases, e.g., cardiovascular disease, cancer, diabetes mellitus, physiological disease, aging, etc., can be induced. Thus, a detailed investigation on the quantity of oxygen radicals, such as hydroxyl radicals (OH•) in human serum blood, and its possible correlation with antioxidant therapy effects, is highly topical. The subject of this study was the influence of schizophrenia on the amount of OH• in human serum blood. The radicals were detected by fluorimetry, using terephthalic acid as a chemical trap. For all experiments the serum blood of healthy people was used as a control group

Kinetics and mechanism of interaction of Pt(II) complex with bio-active ligands and <i>in vitro</i> Pt(II)-sulfur adduct formation in aqueous medium: bio-activity and computational study

<p>Kinetics of interaction between [Pt(pic)(H₂O)₂](ClO₄)₂, <b>2</b> (where pic = 2-aminomethylpyridine) with the selected ligands DL-methionine (DL-meth) and DL-penicillamine (DL-pen) have been studied spectrophotometrically in aqueous medium separately as a function of [<b>2</b>] as well as [ligand], pH and temperature at constant ionic strength. The association equilibrium constants (<i>K</i>_E) for the outer sphere complex formation have been evaluated together with the rate constants for the two subsequent steps. Activation parameters (enthalpy of activation ΔH^≠ and entropy of activation ΔS^≠) were calculated from the Eyring equation. An associative mechanism of substitution is proposed for both reactions on the basis of the kinetic observations, evaluated activation parameters, and spectroscopic data. Structural optimizations, HOMO-LUMO energy calculation, and Natural Bond Orbital (NBO) analysis of <b>2</b>–<b>4</b> were carried out with Density Functional Theory. Bonding mode of thiol and thio-ether is confirmed by spectroscopic analyses and NBO calculation. Cytotoxic properties of <b>2</b>–<b>4</b> were explored on A549 carcinoma cell lines; DNA-binding properties of the complexes were also investigated by gel electrophoresis.</p