Reaotive oxygen generation by azomethine H: a new antimalarial drug

1995 ◽  
Vol 73 (8) ◽  
pp. 1189-1194 ◽  
Author(s):  
Ethel L. B. Novelli ◽  
Assunta M. M. Silva ◽  
Jose L.V.B. Novell F. ◽  
Paulo R. Curi

Superoxide radical [Formula: see text] is a free radical that may be involved in various toxic processes. Cu—Zn superoxide dismutase catalyzes the dismutation of the superoxide free radical and protects cells from oxidative damage. A rat bioassay validated for the identification of the toxic effects of azomethine H revealed increased serum activities of amylase, alanine transaminase, and alkaline phosphatase. The lipoperoxide and bilirubin concentrations were also increased in animals that received azomethine H (1 g/kg) from ascorbic or hydrochloric acid solutions. Azomethine H increased Cu–Zn superoxide dismutase activity. This elevation of Cu–Zn superoxide dismutase activity was highest on the 7th day and was at levels comparable with those of control rats from day 60 onwards. Superoxide is an important intermediate in the action and toxicity of azomethine H.Key words: azomethine H, superoxide radical, antimalarial, toxicity.

1992 ◽  
Vol 70 (5) ◽  
pp. 709-711 ◽  
Author(s):  
Ethel L. B. Novelli ◽  
Ney L. Rodrigues ◽  
Bartolomé O. Ribas ◽  
Paulo R. Curi

Superoxide radical [Formula: see text] is a free radical that may be involved in various toxic processes. Cu–Zn superoxide dismutase catalyses the dismutation of the superoxide free radical and protects cells from oxidative damage, and it has been used clinically. The concentration of Ni2+ and Cu–Zn superoxide dismutase activity were measured in lungs of rats at time intervals of 5, 12, 19, 26, 33, and 40 days following an intratracheal injection of 127 nmol of NiCl2. Nickel chloride increased nickel content and resulted in a significant increase of Cu–Zn superoxide dismutase activity in lungs. This elevation of Cu–Zn superoxide dismutase activity was highest on the 12th day (approximately threefold) and is at levels comparable to controls rats on day 40 onwards. Since Cu–Zn superoxide dismutase activity was increased in lung throughout our experimental period without corresponding increases of Cu2+ and Zn2+, we speculate that the elevation of Cu–Zn superoxide dismutase activity might be due to an increased half-life of the enzyme, induced by nickel.Key words: nickel chloride, intratracheal, Cu–Zn superoxide dismutase, lung.


1975 ◽  
Vol 30 (1-2) ◽  
pp. 58-63 ◽  
Author(s):  
Erich Elstner ◽  
Jörg Konze

Abstract Ethylene Biosynthesis, Chloroplasts, Superoxide Free Radical Isolated chloroplast lamellae from spinach produce ethylene in the dark from methylmercapto-propanal (MMP) or from 2-keto-4-methyl-mercaptobutyrate (KMB) only in the presence of both NADPH and ferredoxin. Anthraquinone-2-sulfonic acid can substitute for ferredoxin. Catalase, superoxide dismutase, ethanol and ascorbate are inhibitors of NADPH-dependent ethylene forma­ tion. Isolated NADP-ferredoxin reductase in the presence of NADPH, ferredoxin and an oxygen reducing factor (ORF, isolated by heat-treatment of chloroplast lamellae) catalyzes ethylene formation from the above substrates in the dark without chloroplast lamellae. From the results it is concluded that chloroplast lamellae in the dark can reduce oxygen monovalently at the expense of NADPH, with the production of the OH-radical as the reactive species responsible for ethylene formation from MMP of KMB.


1975 ◽  
Vol 30 (1-2) ◽  
pp. 53-57 ◽  
Author(s):  
Erich Elstner ◽  
Claus Stoffer ◽  
Adelheid Heupel

Abstract Formation of Nitrite from Hydroxylamine in the presence of illuminated chloroplast lamellae is inhibited by superoxide dismutase but not by catalase, indicating that the superoxide free radical ion and not H2O2 is responsible for the oxidation of hydroxylamine. Decarboxylation of α-keto acids on the other hand is strongly inhibited by catalase but only slightly by superoxide dismutase. Light-dependent hydroxylamine oxidation and decarboxylation of α-keto acids can be used, therefor, as specific and sensitive probes for the determination of either the superoxide free radical ion or hydrogen peroxide, respectively. Photosynthetic oxygen reduction in the presence of ferredoxin, (monitored by the above method) yields both H2O2 and O2·-. The addition of an oxygen reducing factor (ORF, solubilized by heat - treatment of washed chloroplast lamellae) instead of ferredoxin, however, stimulates only the production of H2O2 , while O2·- - formation is not observed. The cooperation of ferredoxin and ORF during photosynthetic oxygen reduction by chloroplast lamellae apparently produces H2O2 not only by dismutation of O2·-, but also by a separate mechanism involving ORF.


1986 ◽  
Vol 237 (2) ◽  
pp. 505-510 ◽  
Author(s):  
C F Kuo ◽  
I Fridovich

The superoxide radical O2.-, whether produced by the xanthine/xanthine oxidase reaction or infused as KO2, solubilized by a crown ether in dry dimethyl sulphoxide, initiated a free-radical chain oxidation of anionic 2-nitropropane. Superoxide dismutase, but not catalase, inhibited oxidation of the nitroalkane. Xanthine oxidase suffered a syncatalytic inactivation, during the co-oxidation of 2-nitropropane, which was reversed by dialysis. Cyanide exacerbated this syncatalytic inactivation and rendered it irreversible. The frequently observed oxidations of nitroalkanes by flavoenzymes now need to be re-examined to clarify the extent to which O2.--initiated free-radical chain oxidation contributed to the overall nitroalkane oxidation.


Author(s):  
İlker Durak ◽  
Orhan Canbolat ◽  
Murat Kaçmaz ◽  
Gülhan Özgen ◽  
Hasan Serdar Öztürk

2020 ◽  
Vol 22 (98) ◽  
pp. 46-50
Author(s):  
O. S. Kochevenko ◽  
I. O. Zhukova ◽  
O. M. Bobrytska ◽  
I. O. Kostiuk ◽  
L. A. Vodopyanova

In fact, Free radical oxidation is one of the required factors of homeostasis as far as the active forms of oxygen, which have unpaired electron, perform useful functions, they are necessary intermediaries of numerous processes of normal cells’ functioning such as biosynthesis of prostaglandins and leukotriene as well as other biologically active substances. Also, they take part in pathological processes such as: inflammation, fever and others. Free radical oxidation is the process of direct oxygen transferring to the substrate forming peroxide, ketones, aldehydes, etc. Some amino acids, proteins, water and carbohydrates prone to the processes of peroxidation, but crucial place is granted to lipids at the expanse of fatty acids which are included to their composition. The article highlights the information concerning the analysis of the state of antioxidant system of hens in the process of feeding them with subtoxic doses of fungicide of Derosal (BAYER, Germany) (0.1 LD50 for a fowl, 900 mg/kg of the body mass) which active ingredient is benzimidazole carbamate (carbendazim, BMC). It presents the changes of these indicators in the process of using pharmacological and natural antioxidants. The analysis has figured out that giving Derosal to the hens without corrections (II group) has been followed with the activation of the process of lipids’ peroxidation (POL) in the blood plasma, that is followed with the increase of concentration of primary and secondary lipoperoxidation products – diene conjugates (DC) and TBA-active products on the average up to 21.0–25.0 %, catalase activity – up to 38.5 % and decrease of superoxide dismutase activity (SOD) up to 21.8 % and АОА – up to 17.8 %, that shows the adverse effects of pesticides on the system of antioxidant protection of the organism. In the fowls’ groups III, IV and V the adding of antioxidant E-selenium, ascorbic acid and thermally untreated buckwheat seeds as the source of  quercetins and anthocyanins has led to the induction of antioxidant resources that is shown by the decrease in comparison with the control of content of diene conjugates, malonic dialdehyde and catalase (in average up to 13.6–33.6–18.0 % accordingly) and compensatory strengthening of superoxide dismutase activity and general activity of antioxidant (АОА) on the average up to 44.9–72.1–76.5 % and 15.3–13.4–21.7 % accordingly. In comparison with group II the activity of catalase has been lower as well as the activity of superoxide dismutase has been higher in all the groups almost in 1.5–2 times (Р ≤ 0.001).


Sign in / Sign up

Export Citation Format

Share Document