Search results for "Active oxygen"

Creatine kinase is the main target of reactive oxygen species in cardiac myofibrils.

1996

Abstract Reactive oxygen species (ROS) have been reported to alter cardiac myofibrillar function as well as myofibrillar enzymes such as myosin ATPase and creatine kinase (CK). To understand their precise mode and site of action in myofibrils, the effects of the xanthine/xanthine oxidase (X/XO) system or of hydrogen peroxide (H 2 O 2 ) have been studied in the presence and in the absence of phosphocreatine (PCr) in Triton X-100–treated cardiac fibers. We found that xanthine oxidase (XO), with or without xanthine, induced a decrease in maximal Ca 2+ -activated tension. We attributed this effect to the high contaminating proteolytic activity in commercial XO preparations, since it could be p…

Improved co-oxidation of β-carotene to β-ionone using xanthine oxidase-generated reactive oxygen species in a multiphasic system

2007

beta-Ionone, an aroma compound exhibiting flower notes, can be obtained from beta-carotene in a cooxidation system utilizing xanthine oxidase-generated reactive oxygen species (ROS). ROS have to be controlled as, although they can give rise to beta-ionone, they may also degrade it. In this work, the biotransformation of beta-carotene into beta-ionone was investigated in systems containing variable proportions of decane to extract beta-ionone before degradation. The use of 50% or 90% decane resulted in increased production yields. Tween 80, which was added to further improve the production, slightly decreased the reactivity of the medium and the extraction of beta-carotene, but increased the…

Cytotoxicity of compounds from Xylopia aethiopica towards multi-factorial drug-resistant cancer cells.

2015

Abstract Introduction Multidrug resistance (MDR) in cancer represent a major hurdle in chemotherapy. Previously, the methanol extract of the medicinal spice Xylopia aethiopica displayed considerable cytotoxicity against multidrug resistant (MDR) cancer cell lines. Methods The present study was designed to assess the cytotoxicity of compounds, 16 α -hydroxy- ent -kauran-19-oic acid ( 2 ), 3,4′,5-trihydroxy-6″,6″-dimethylpyrano[2,3-g]flavone ( 3 ), isotetrandrine ( 5 ) and trans -tiliroside ( 6 ) derived from the methanol crude extract of Xylopia aethiopica against 9 drug-sensitive and -resistant cancer cell lines. The resazurin reduction assay was used to evaluate the cytotoxicity of these c…

Cytotoxicity of the crude extract and constituents of the bark of Fagara tessmannii towards multi-factorial drug resistant cancer cells.

2019

Abstract Ethnopharmacological relevance Fagara tessmannii Engl. is an African medicinal plant used in Cameroonian traditional medicine to treat various types of cancers. Aim of the study This work was designed to determine the cytotoxicity of the crude extract (FTB), fractions (FTBa-d) and compounds isolated from the bark of Fagara tessmannii, namely lupeol (1), fagaramide (2), zanthoxyline (3), hesperidin (4), nitidine chloride (5), fagaridine chloride (6), and β-sitosterol-3-O-β-D-glucopyranoside (7). The study was extended to the mode of induction of apoptosis by FTB, compounds 5 and 6. Materials and methods The resazurin reduction assay was used to evaluate the cytotoxicity of samples. …

Trehalose and trehalose-6-phosphate induce stomatal movements and interfere with ABA-induced stomatal closure in grapevine

2015

Aims: The effects of trehalose and trehalose-6-phosphate (T6P), among other sugars, were assessed on grapevine stomatal movements. Methods and results: Epidermal peels were used to assess the effects of sugars. Low concentrations of trehalose and T6P (1 μM) induced an osmotic-independent reduction of the stomatal aperture in light conditions. Furthermore, ABA-induced stomatal closure was reduced by sugar application in association with lower accumulation of reactive oxygen species in guard cells. Similar effects, although weaker, were observed in response to the disaccharides sucrose and maltose, but not in response to the monosaccharides fructose and glucose. Conclusion: This study clearly…

Détection hypothalamique de l’hyperglycémie : rôle de la dynamique mitochondriale dans la signalisation par les espèces actives de l’oxygène

2011

Characterization and role of nitric oxide production in Arabidopsis thaliana defense responses induced by oligogalacturonides

2011

Nitric oxide (NO) regulates a wide range of plant processes from development toenvironmental adaptation. In this study, NO production and its effects were investigated in aplant-pathogen context. The production of NO following Arabidopsis treatment witholigogalacturonides (OGs), an endogenous elicitor of plant defense, was assessed using the NOsensitive probe 4, 5-diamino fluorescein diacetate. Pharmacological and genetic approaches wereused to analyze NO enzymatic sources and its role in the Arabidopsis thaliana /Botrytis cinereainteraction. We showed that NO production involves both a L-arginine- and a nitrate reductase(NR)-pathways. OGs-induced NO production was Ca2+-dependent and modula…

The role of NtRBOHD in regulation of response to cryptogein in tobacco cells

2014

International audience

Alpha-lipoic acid: molecular mechanisms and therapeutic potential in diabetes.

2015

International audience; Diabetes is a chronic metabolic disease with a high prevalence worldwide. Diabetes and insulin resistance are associated with the development of cardiovascular and nervous diseases. The development of these disorders reflects complex pathological processes in which the oxidative stress caused by reactive oxygen species (ROS) and reactive nitrogen species (RNS) plays a pivotal role. It is widely accepted that diabetes impairs endothelial nitric oxide synthase (eNOS) activity and increases the production of ROS, thus resulting in diminished NO bioavailability and increased oxidative stress. Alpha-lipoic acid (LA) possesses beneficial effects both in the prevention and …

Heavy Metals and Metalloids as Autophagy Inducing Agents: Focus on Cadmium and Arsenic

2012

In recent years, research on the autophagic process has greatly increased, invading the fields of biology and medicine. Several markers of the autophagic process have been discovered and various strategies have been reported studying this molecular process in different biological systems in both physiological and stress conditions. Furthermore, mechanisms of metalloid- or heavy metal-induced toxicity continue to be of interest given the ubiquitous nature and distribution of these contaminants in the environment where they often play the role of pollutants of numerous organisms. The aim of this review is a critical analysis and correlation of knowledge of autophagic mechanisms studied under …