Superoxide Scavenging Activity of Spin-Labeled Nitrosourea and Triazene Derivatives

Abstract

Superoxide scavenging activities (SSA) of newly synthesized spin-labeled nitrosourea and triazene derivatives, and their precursor nitroxides were investigated by the ESR/spin-trapping method using the spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and hypoxanthine/xanthine oxidase as the superoxide-generating system. The spin-labeled nitrosoureas, triazenes and their precursor nitroxides exhibited excellent SSA, whereas clinically used nitrosourea and triazene, which do not contain the nitroxide moiety, did not show any SSA. Furthermore, it was deduced that these nitroxides scavenge superoxide by redox cycling between nitroxide and corresponding hydroxylamine.

Nitroxides Increase the Detectable Amount of Nitric Oxide Released from Endothelial Cells

“…Additionally, tetrahydrobiopterin, a cofactor of NOS, was found to rapidly oxidize ⅐ NO through the generation of O 2 . (44), respectively). The rank order of efficacy for the four compounds tested was the same in the cell culture and SIN-1 experiments: SOD Ͼ TEMPOL Ͼ CP Ͼ ECP (Table I).…”

Comparative Real Time EPR Investigation of Natural and Synthetic Antioxidants: As Potential Anticancer Agents and Radio-protectors

“…4(b)) bringing to controls showed that in a great extent synthetic antioxidants were able to neutralize ongoing oxidative processes. This finding may be explained by their well expressed scavenging activity against superoxide radicals 40,10 . The lowest ROS levels were observed after P. corylifolia treatment in liver and blood of mice.…”

“…Our study confirms once again in vivo protective abilities of SLENU against oxidative toxicity of clinically used antitumor antibiotics and radiation 38,39 . Gadjeva and co-workers, 1994 40 using in vitro spintrapping EPR method demonstrated that SLENU possessed high superoxide radical scavenging activity (SSA) even higher than antioxidant Trolox. Later on well expressed in vitro SSA for SLCNUgly was also found 10 .…”

Comparative Investigation on Radical Scavenging Activity and Protective Properties of Natural Isolated and Synthetic Antioxidants

“…EPR spectroscopy is a highly sensitive technique utilized for investigation of free radical scavenging capacity and radical structures in synthetic and naturally isolated antioxidants (9,10,11,12,13). Formerly, by in vitro EPR spin trapping technique we reported a well expressed superoxide anion scavenging activity for SLENU due to the presence of the nitroxyl radical moiety in its structure (4).As is seen on (Fig. 3A) in the solution of SLENU the typical triplet EPR signal of the nitroxyl free radical was registered, while in the aqueous solution of SQGD an EPR signal with a single line was recorded (Fig.…”

“…In recent years, increasing studies are performed on the effects of the treatment of many diseases with combinations of synthetic medicines and other radical scavengers. Use of appropriate natural and synthetic antioxidant substances reduces the level of lipid peroxidation and increases the activity of antioxidant enzyme defense system and ultimately reduces radiotherapy-and chemotherapy-induced oxidative stress and negative consequences (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15). The purpose of this study was to evaluate and compare the free radical scavenging activity and protective properties of the natural product SQGD isolated from a radioresistant bacterium Bacillus sp.…”