Both singlet oxygen and the hydroxyl radical are generated in mammalian ccHs by UVA (~3Z0---~3{50 rim) and possibly near-visible (~{50--420 nm) radiation. We have modulated the cellular levels of these two reactive oxygen species in order to compare their involvement in the induction of the human heme 0xygenase (I40) gene by broad spectrum UVA/nearvisible light 0LIVA/NVL). Irradiation in deuter...

The present work is carried out to study the antioxidant potential of ethanolic extract of Alstonia scholaris Linn. ( Apocynaceae ) using various in vitro tests including 1,1-diphenyl-2-picryl-hydrazil (DPPH . ) free radical scavenging, metal ion chelating, hydrogen peroxide scavenging, superoxide anion radical scavenging, and ferric thiocyanate reducing ability.   Ethanolic ex...

The methanolic extract of Sida retusa Linn.(Malvaceae),Urena lobata Linn.(Malvaceae)and Triumfetta rhomboidea Jacq.(Teliaceae) roots were found to inhibit lipid peroxidation, scavenge hydroxyl and superoxide radicals in vitro. The quantity of S.retusa root extract required for 50% inhibition of lipid peroxidation, scavenging hydroxyl radical and superoxide radical was 1130.24 ug/ml respectively...

This study was directed to the ability of oxygen free radicals to cause reversible vascular endothelial cell dysfunction. A well-characterized system for the production of the superoxide anion radical (O2(-).) and hydrogen peroxide (H2O2), employing xanthine and xanthine oxidase, was used to sublethally injure human umbilical vein endothelial (HUVE) cells in vitro. We examined the effects of a ...

Peroxynitrite is the product of the diffusion-controlled termination reaction between two radicals, nitric oxide and superoxide and is a strong oxidant and nitrating intermediate. Critical biomolecules like proteins, lipids and DNA react with peroxynitrite via direct or radical-mediated mechanisms, resulting in alterations in enzyme activities and signaling pathways. The biological consequences...

Glycolate oxidase that was partially purified from pea leaves was inactivated in vitro by blue light in the presence of FMN. Inactivation was greatly retarded in the absence of O2. Under aerobic conditions H2O2 was formed. The presence of catalase, GSH or dithiothreitol protected glycolate oxidase against photoinactivation. Less efficient protection was provided by ascorbate, histidine, tryptop...

The cytochrome P-450 in hepatic microsomes prepared from rats pretreated with hematoporphyrin derivative was shown to be rapidly destroyed in the presence of long-wave ultraviolet light. The photocatalytic destruction of the heme-protein was dependent on both the dose of ultraviolet light and of hematoporphyrin derivative administered to the animals. The destructive reaction was accompanied by ...

Xanthine oxidase (XO)-derived reactive oxygen species (ROS) formation contributes to experimental chronic hypoxic pulmonary hypertension in adults, but its role in neonatal pulmonary hypertension has received little attention. In rats chronically exposed to hypoxia (13% O(2)) for 14 days from birth, we examined the effects of ROS scavengers (U74389G 10 mg.kg(-1).day(-1) or Tempol 100 mg.kg(-1)....

The mechanism of the redox reaction of ebselen with superoxide was investigated using both ESR and electrochemical techniques. The reaction with superoxide in aprotic solvents was followed by means of cyclic voltammetry and ESR spin-trapping. A decrease in the oxidation current due to superoxide as a result of the addition of ebselen was clearly observed in the cyclic voltammograms. Ebselen red...

Previous reports have shown that safflower-seed extract and its major antioxidant constituents, serotonin hydroxycinnamic amides, attenuated atherosclerotic lesion formation in apoE-deficient mice, as well as inflammation and aortic stiffness in human subjects. In the present report, we examined a still unknown cell-based mechanism of serotonin derivatives against the development of atheroscler...